January, 2008 2-1 Section 2 Geometric Design Policy for Bridges 2.1 Purpose This policy provides the minimum requirements for bridge roadway and facility widths, vertical under-clearances and design live loads for NYSDOT projects. These standards have been developed to provide minimum safe geometrics for each application; primarily based on providing a level of geometric consistency between the bridge and the approach roadway and recognizing the highway functional classification and traffic that the bridge serves. This policy serves as the Department's standard for bridge widths on both Federal- and non-Federal aid- funded-projects and recognizes certain Federal approval requirements for bridges on the National Highway System. 1 2.2 Geometric Design Policy Glossary The following terms are specific to the Geometric Design Policy. For a more complete glossary, see the end of this manual. Approach Roadway Width The uniform width of the roadway on either end of the bridge. When determining the existing approach roadway width, measurements should be taken no closer than 30 m from the ends of the bridge. Bicycle Facility Provision of space on a structure for the use of bicyclists, generally in the form of a usable shoulder, wide curb lane or striped bike lane. See Chapter 17 of the Highway Design Manual. Bridge A structure, including supports, erected over a depression or an obstruction such as water, highway, or railway and having a track or passageway for carrying traffic or other moving loads, and having an opening measured along the center of the roadway of more than 20 ft. (6.08 m) between undercopings of abutments or spring lines of arches, or extreme ends of openings for multiple boxes. Multiple pipe configurations will qualify as bridges where the clear distance between openings is less than half of the smaller adjacent opening, and the total length along the center of the roadway is greater than 20 ft. (6.08 m). 1 Refer to the NYSDOT Project Development Manual Exhibit 4-2 for the Approval Matrix for projects on the NHS.
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January, 2008 2-1
Section 2 Geometric Design Policy for Bridges
2.1 Purpose
This policy provides the minimum requirements for bridge roadway and facility widths, vertical under-clearances and design live loads for NYSDOT projects. These standards have been developed to provide minimum safe geometrics for each application; primarily based on providing a level of geometric consistency between the bridge and the approach roadway and recognizing the highway functional classification and traffic that the bridge serves. This policy serves as the Department's standard for bridge widths on both Federal- and non-Federal aid-funded-projects and recognizes certain Federal approval requirements for bridges on the National Highway System.1
2.2 Geometric Design Policy Glossary
The following terms are specific to the Geometric Design Policy. For a more complete glossary, see the end of this manual.
Approach Roadway Width
The uniform width of the roadway on either end of the bridge. When determining the existing approach roadway width, measurements should be taken no closer than 30 m from the ends of the bridge.
Bicycle Facility Provision of space on a structure for the use of bicyclists, generally in the form of a usable shoulder, wide curb lane or striped bike lane. See Chapter 17 of the Highway Design Manual.
Bridge A structure, including supports, erected over a depression or an obstruction such as water, highway, or railway and having a track or passageway for carrying traffic or other moving loads, and having an opening measured along the center of the roadway of more than 20 ft. (6.08 m) between undercopings of abutments or spring lines of arches, or extreme ends of openings for multiple boxes. Multiple pipe configurations will qualify as bridges where the clear distance between openings is less than half of the smaller adjacent opening, and the total length along the center of the roadway is greater than 20 ft. (6.08 m).
1 Refer to the NYSDOT Project Development Manual Exhibit 4-2 for the Approval Matrix for projects on the NHS.
NYSDOT Bridge Manual
2-2 April, 2006
Bridge Rehabilitation
That type of work that is intended to enhance or restore the structural capacity, operational efficiency and/or serviceable life of an existing bridge. Rehabilitation will usually be accomplished by contract, although occasionally the same result will be achieved by the intensive efforts of maintenance forces. A bridge rehabilitation may include a varying degree of structural repair and/or restoration, including a complete deck replacement, or replacement of the entire bridge superstructure and portions of the substructure.
Bridge Project A construction project whose primary objective is to construct a new bridge or to replace, rehabilitate, or remove an existing bridge, or to repair the deck of an existing bridge. Some incidental highway work may be included on the approaches to the bridges, as a necessary transition between the bridge and the untouched existing highway.
Bridge Reconstruction
A vague term that should be avoided, but if that is impossible, it should be interpreted as that type of rejuvenation of an existing bridge that would include either replacement or rehabilitation.
Bridge Replacement
That type of work where an existing bridge is removed and is fully replaced at the same site, or at an adjacent location, by a substitute bridge, as part of the same project.
Bridge Widening A type of rehabilitation where the primary purpose is to provide additional traffic lanes on a bridge. Under this policy, bridge widening projects shall be subject to the same clear roadway width provisions as a new bridge.
Bridge Removal That type of work where an existing bridge, whether open to traffic, or closed, or collapsed, is fully or substantially removed from the site, without a substitute bridge being constructed as part of the same project. A bridge removed and replaced by a culvert or fill should be classified as bridge removal, as would the removal of a bridge and its substitution by the restoration or introduction of a grade crossing.
Geometric Design Policy for Bridges
April, 2006 2-3
Bridge Deck Repair
That type of work that is intended to return the structural deck of an existing bridge to a condition of suitable ride quality and/or safe wheel load capacity. The deck may be composed of concrete, steel or other material, and the type of construction may include monolithic decks as well as separate wearing surfaces over a slab. The restorative work may include overlay or separate wearing surfaces (with or without a waterproof membrane) over the whole deck area of the bridge or over substantial areas. For purposes of this policy, a complete bridge deck replacement should be classified as a bridge rehabilitation. Under this policy, bridge deck repair done in conjunction with other superstructure or substructure restoration work also should be classified as a bridge rehabilitation. A bridge deck repair project may include some incidental structure repair work that is related to the deck repair work (e.g., header or backwall repair).
Clear Roadway Width of Bridge
The clear distance between inside faces of bridge railing, or the clear distance between faces of curbs, whichever is less. The typical Department 125-mm brush curb (introduced at the bridge only) shall not be considered to reduce the rail-to-rail dimension.
Design Speed A speed determined for design and correlation of the physical features of a highway that influence vehicle operation. It is the maximum safe speed that can be maintained over the bridge and its immediate approaches, when conditions are so favorable that the design features of the highway govern. It is that speed which is appropriate for the particular circumstances, which may or may not be equal to the statewide limit or to the posted speed limit at the bridge site. The design speed is determined according to Chapter 2 of the Highway Design Manual.
Federal-Aid Project
A bridge or highway project that is to be funded, either entirely or partially, with Federal-aid funds.
Highway Project A construction project whose primary objective is to construct a new highway, or to reconstruct, or to restore and preserve, an existing highway. The project may include bridge work of any type that is incidental to the primary objective.
Narrow Bridge A bridge carrying two-way traffic, but less than 5.4 m in clear width between railing or curbs, or a one-way ramp less than 3.6 m wide.
National Highway System (NHS)
A network of major roads that were designated by the Federal Highway Administration in consultation with the individual states and signed into law in November 1995.2
2 A list of designated NHS Highways is contained in the “National Highway System Route Listing” and is maintained by the Highway Data Services Bureau of the Office of Technical Services.
NYSDOT Bridge Manual
2-4 April, 2006
New Bridge A bridge constructed to serve a new or relocated highway that is not intended to serve as a substitute for an existing bridge being removed as part of the same project. It shall be considered a new bridge when a bridge is constructed to ultimately become a substitute for an existing bridge which will be removed in a subsequent project.
One Lane Bridge A particular type of narrow bridge, carrying two-way traffic but less than 4.9 m in clear width between railing or curbs.
Pedestrian/Bicycle Bridge
A structure provided specifically for the travel of bicyclists and pedestrians, frequently as part of a shared use path facility.
Planned Improvements
Improvements to the roadway width projected within a 20-year planning horizon. They do not necessarily need to be programmed. These are, however, documented plans the Department or local municipality hopes to accomplish when funding becomes available and when it fits into the Region's or local agency's capital program. Whether or not there are planned improvements shall be addressed in the scoping documentation used to establish the project design criteria. Refer to the Project Development Manual for requirements on addressing planned improvements in project scoping and development.
Roadway That portion of a highway, including all through traffic lanes, auxiliary lanes, and shoulders, suitable for vehicular use. Also referred to as "surfacing" or "pavement."
Shoulder That portion of the roadway, graded but not necessarily paved or surfaced, for accommodation of stopped vehicles, for emergency use and for lateral support of subcourses and surface courses. For purposes of this policy, the shoulder shall refer to the usable shoulder (see Appendix 2A for illustrations of shoulders). For applying this policy, the existing approach shoulders should be measured no closer than 30 m from the ends of existing bridges. If the approach shoulder width varies, a determination must be made of what the most typical shoulder width is for that section of highway. Be aware that providing the typical width may cause the project limits to be extended slightly to widen the varying shoulder.
Sidewalks Space provided on a structure exclusively for the use of pedestrian travel, generally separated from the roadway by a raised curb. See Chapter 18 of the Highway Design Manual.
Surfaced Shoulder A roadway shoulder that is paved, or stabilized and maintained with a bituminous or other similar surface treatment.
Traveled Way That portion of the roadway exclusive of shoulders, designed for the movement of vehicles.
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January, 2008 2-5
2.3 Clear Roadway Width Standards for Bridges
2.3.1 General
Unless specifically noted in the provisions, the geometric design standards provided in this section shall apply to all projects, whether or not the project is a Federal-Aid Project. For purposes of this policy the "AASHTO Policy" shall refer to the AASHTO A Policy for Geometric Design of Highways and Streets, 2004.
Bridge Approach Widths: Bridge widths shall be established consistent with Table 2-1, Clear Bridge Roadway Width Standards. For bridge replacements or rehabilitations that are not part of a highway project, the bridge widths determined from this policy shall also be used for the widths of any highway reconstruction work necessary on the bridge approaches. Approach widths for bridges that are part of a highway project shall be determined according to Chapter 2 of the Highway Design Manual.
Policy Exceptions: Unless there is a clear safety issue involved, bridge widths greater than the minimums described below should not be used, except where extenuating circumstances exist. The final decision for such policy exceptions will be made by the Regional Director responsible for design approval and documented accordingly. Bridges with adjacent prestressed box beams may have a greater width because of economic considerations as discussed in Section 9.2.1. The use of bridge widths for a particular project that do not meet the minimum requirements of this policy shall be documented as a nonstandard feature; approval must be requested from the Regional Director and/or FHWA and/or the Deputy Chief Engineer where required. Refer to the Highway Design Manual for requirements for justification of nonstandard features.
2.3.2 Railroad Bridges
Each individual railroad will be responsible for providing a trackage section showing horizontal offsets and clearance diagrams for the bridge. The distance between the centers of multiple tracks shall also be set by the railroad. The Rail Agreements Section in the Design Quality Assurance Bureau should be contacted to assist in obtaining these design parameters. Also, see Section 2.5.3 for more details.
2-6 April, 2006
Facility Carried by the Bridge
Type of Bridge Work No Planned Improvement Planned Improvement
Interstate All Full approach roadway width, but not less than the AASHTO’s Interstate Standards, 2005, unless approved by FHWA. See Approval Matrix in the Project Development Manual.
Non Interstate Freeways All Generally match the approach roadway width, but no less than Chapter 8 of AASHTO’s A
Policy on Geometric Design of Highways and Streets, 2004.
New Full approach roadway width. If on the NHS, HDM Chapter 2 roadway widths shall be met.
Replace Wider of full approach width or approach plus 1.2 m clearance on each side.
Rural Arterial
Rehab If NHS, wider of full approach width or approach plus 1.2 m clearance on each side.
Full width of planned roadway. If on the NHS, HDM Chapter 2 roadway widths shall be met with the exception of long bridges. A minimum 1.2 m shoulder applies to long bridges (over 60 m in length).
New Full approach roadway width.
Replace
Match approach traveled way with shoulders not exceeding Table N of Appendix 2A nor less than 1.2 m on each side.
Minor Arterial (Non-NHS)
Rehab
Match approach traveled way with shoulders not less than 0.6 m on each side. Where cost-effective, match approach roadway section.
Full width of planned roadway. Nonstandard if does not comply with HDM Chapter 2 roadway widths with the exception of long bridges. A minimum 1.2 m shoulder applies to long bridges (over 60 m in length).
New Replace Urban Arterial
Rehab
Full approach roadway width. If on the NHS, HDM Chapter 2 roadway widths shall be met.
Full width of planned roadway. If on the NHS, HDM Chapter 2 roadway widths shall be met.
New
Replace
Full approach roadway width, but never less than Table R of Appendix 2A or greater than Table N of Appendix 2A.
Full approach roadway width, but never less than Table R of Appendix 2A or greater than Table N of Appendix 2A. Rural Local and
Collector Road and Street
Rehab
Desirable is to match full approach roadway width, but never less than Table X of Appendix 2A or greater than Table N of Appendix 2A. Regional Director may approve existing width.
Desirable is to match full approach roadway width, but never less than Table X of Appendix 2A or greater than Table N of Appendix 2A.
New
Replace
Full approach roadway width, but never less than Table R of Appendix 2A or greater than Table N of Appendix 2A.
Full approach roadway width, but never less than Table R of Appendix 2A or greater than Table N of Appendix 2A. Urban Local and
Collector Road and Street
Rehab
Desirable is to match full approach roadway width, but never less than Table X of Appendix 2A or greater than Table N of Appendix 2A. Regional Director may approve existing width.
Desirable is to match full approach roadway width, but never less than Table X of Appendix 2A or greater than Table N of Appendix 2A.
Pedestrian Minimum clear width should be 2.4 m. Recommended clear width of 3.7 m for structures with multiple usage such as bicycle and pedestrian traffic.
Notes: 1. Clear bridge roadway width measured between curb faces or when uncurbed, the bridge rails. 2. Approach roadway includes travel lanes and surfaced shoulders. Parking lanes on the approaches are not included in the
approach roadway width. However, they may be considered on bridges less than 15 m in length. 3. Approach sidewalks should be carried across the bridge if they are proposed on both sides of the bridge. The minimum
width of sidewalk is 1.7 m measured from the face of curb to the inside of the bridge rail. 4. When determining the appropriate width for a bridge on a local road or collector that has a different approach cross section
at each end of the bridge, consider neither the larger or smaller section as the control. Rather, determine the bridge width using both sections and select the one that provides the most economy, consistency, and safety.
5. See Appendix 2B for the One-Lane bridge replacement policy. 6. The accident experience and other operational conditions must be analyzed before determining that there are no planned
improvements or that the existing width can be retained.
TABLE 2-1 Clear Bridge Roadway Width Standards
Geometric Design Policy for Bridges
April, 2006 2-7
2.3.3 Miscellaneous Bridge Width Considerations
Curbs: For curbed highways and streets, the full curb-to-curb width and the curbing should generally be carried across the bridge. The full shoulder dimension or curb offset dimension will be measured to the face of curb. If a concrete barrier is used, a separate stone curb is not used on the bridge and the offset dimension is taken to the inside edge of the barrier.
On structures that introduce a curb where one is not present on the highway approach, a minor curb encroachment is allowed into the shoulder for structures with steel railing systems. Railing systems will be allowed a 125 mm encroachment, with the full shoulder dimension being measured to the face of railing.
On structures with sidewalks, the minimum sidewalk width does not include the width of the curb. The minimum dimension from face of rail or barrier to face of curb is 1.7 m. This dimension is arrived at by taking the minimum 1.525 m sidewalk width and adding 0.175 m for the width of the curb on the highway approach. The face of curb on the bridge and the highway approach should line up.
It is no longer recommended that encroachments be allowed on concrete barriers in determining the curb to curb width of the bridge.
Stage Construction: In order to maintain minimum traffic lane widths during construction, it is sometimes necessary to build a wider structure than required for the permanent condition. Depending upon the magnitude of the widening, wider permanent shoulder or sidewalk widths may result. The railing/barrier line should normally be placed at the fascia with a transition to the highway section taking place on the approach.
For projects that must accommodate truck traffic during staging, the minimum recommended temporary travel lane width is 3.3 m. Where low volumes of passenger vehicles traveling at low speeds are anticipated, temporary travel lanes as narrow as 2.75 m may be considered. The use of temporary structures for the maintenance of pedestrian traffic should be considered prior to making a new structure much wider than necessary.
Twin Structures: Many major highways have medians that vary in width from some minimal dimension to distances in excess of 30 m. When building new, widening existing, or rehabilitating existing structures, the joining of the structures between these opposing alignments should be considered. Two factors are used as evaluation criteria:
1. If the distance between the median edges of the two opposing travel lanes is less than 7.3 m, the median should be closed. However, once the total bridge width exceeds 30 m, the use of a longitudinal open joint at the center line of the median is recommended.
2. If the maintenance and protection of traffic scheme is best addressed by the closure of a median larger than the previous identified 7.3 m dimension, then the median should be closed and the use of a longitudinal joint considered.
NYSDOT Bridge Manual
2-8 April, 2006
Curved Alignments: There are four possible configurations to consider when a curved highway alignment is to be carried on a bridge (See Figure 2.1). The relationship of the beam, fascia line and railing or parapet would fall into one of the following cases:
Case I Straight beams Straight fascia line Straight railing/fascia line Case II Straight beams Straight fascia line Curved railing/parapet line Case III Straight beams - variable overhang Curved fascia line Curved railing/parapet line Case IV Curved beams Curved concentric fascia line Curved concentric railing/parapet line
Steel girders will usually follow Case III or Case IV depending on the radius of curvature.
Prestressed concrete slab and box unit structures will normally be built in accordance with Case I or II. Case I will allow the anchorage for the railing/barrier to be located at a fixed location. Case II will require varying the anchorage location.
Prestressed concrete I-beams or Bulb-tee units would be fabricated straight and could follow Case I, II, or III, with Case III the preferred option. When Case III is selected, consideration must be given to the width of the top flange and the width of the concrete deck slab overhang.
For bridges with sidewalks, the curb should follow the curved alignment and the railing/barrier should follow the fascia line. Provisions must be made on the approach to properly transition the railing/barrier line on the structure to the typical highway railing system.
In circumstances where a sharply curved roadway is carried by a straight bridge the railing/barrier should follow the curve of the roadway to avoid confusion to the motorist.
When using a straight fascia and a curved railing/barrier, consideration should be given to the deck area that would be exposed behind the back of the railing/barrier. If this area gets too large it can become a safety concern.
Geometric Design Policy for Bridges
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Figure 2.1 Curved Alignment Layout
NYSDOT Bridge Manual
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Miscellaneous: A reduction in shoulder widths may be considered for long viaduct type structures. For these structures consideration may be given to reducing the 3 m or 2.4 m right shoulder to a minimum of 1.8 m. The possibility of vehicle breakdowns should be accommodated with minimum shoulder widths of 1.2 m left and 1.8 m right.
In urban areas, parking lanes are not normally carried across bridges and shall only be considered for bridges less than 15 m.
In urban areas, sidewalk widths greater than the minimum may be carried across the structure.
2.4 Vertical Clearances
2.4.1 Over Highways for Highway, Pedestrian, and Overhead Sign Structures
Minimum vertical clearance requirements over highways help accommodate the movement of large vehicles for maintenance operations, utility work, and the transport of people, products, construction equipment, military equipment for national defense, etc. To facilitate the movement of large vehicles, the Federal government established a 4.9 m vertical clearance network that consists of the National Highway System (NHS), with a few exceptions. The NHS includes:
C All routes on the Interstate System. C The Strategic Highway Corridor Network (STRAHNET) and its highway connectors to major
military installations. The STRAHNET includes highways important to the United States strategic defense policy and which provide defense access, continuity, and emergency capabilities for the movement of personnel, materials, and equipment in both peace time and war time.
C Other major routes, as established by the 1995 NHS Act. The following portions of the NHS are exempted from the 4.9 m vertical clearance route:
C Parkways. C Portions of the New York State Thruway, I-90, and I-190 (See Appendix 2C.) C All NHS routes within an urban area which has a federally approved 4.9 m vertical clearance
routing (The approved 4.9 m vertical clearance routes were distributed by G. Cohen’s 12/11/97 memo to the Regional Program and Project Managers.) Note that portions of the STRAHNET within the urban area must still have a 4.9 m vertical clearance.
The Regional Planning and Program Management Group should be contacted to determine if the route is part of the 4.9 m vertical clearance network.
Vertical clearances shall be established consistent with Table 2-2 Vertical Clearance Over Highways (Travel Lane and Paved Shoulder). If the minimum vertical clearance cannot be met, a nonstandard feature justification, prepared in accordance with the Highway Design Manual, Chapter 2, Section 2.8, is required. Appendix 2C of the Bridge Manual describes the substitute 4.9 m network for which no exception to the 4.9 m vertical clearance can be entertained. Appendix 2D contains the special procedures for nonstandard vertical clearances over the Interstate System.
January, 2008 2-11
Highway System Crossed
Type of Work on Bridge
Over Highway
Functional Classification / Designation3 of Highway
Notes: 1. The minimum vertical clearance for all pedestrian bridges is 300 mm over the minimum vertical clearance determined using
this table. An additional 150 mm is desirable for future resurfacing. 2. The minimum vertical clearance for overhead sign structures is 300 mm over the minimum vertical clearance determined
using this table. An additional 150 mm is desirable for future resurfacing. Note that bridge mounted signs shall have a minimum vertical clearance equal to the bridge.
3. The federally approved 4.9 m vertical clearance routes through urban areas were distributed by G. Cohen’s 12/11/97 memo to the Regional Program and Project Managers.
4. Refer to Appendix 2C for bridges over the Thruway, I-90, I-190, I-290 and I-81 that are exempt from the 4.9 m vertical clearance network. A minimum vertical clearance of 4.3 m shall be used for these bridges. Additionally, a nonstandard feature justification for using less than 4.9 m vertical clearance shall be prepared. The justification is to be based on the exempt list and approved in accordance with the TEA-21 matrix to satisfy FHWA administrative requirements. Note that per FHWA, a vertical clearance of less than 4.3 m cannot be justified.
TABLE 2-2
Vertical Clearance Over Highways (Travel Lane and Paved Shoulders) 1,2
NYSDOT Bridge Manual
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2.4.2 Railroad Grade Separations
The standard minimum vertical clearance above operating mainline railroad tracks shall be 6.71 m. On occasion, a higher clearance may be justified for certain corridors where existing clearances are higher. See Chapter 23, Section 23.10.1 of the Highway Design Manual for additional discussion. For track other than mainline and where clearance is restricted by other bridges, a minimum less than 6.71 m may be allowed. Additional information is contained in the NYSDOT’s “Branchline Vertical Clearance Policy” issued June 10, 1993. The Office of Structures will provide guidance, with the cooperation of the Office of Design.
Vertical clearances over superelevated railroad tracks may need to be increased because of the effect of the superelevation. Because of superelevation, the clearance diagram is rotated so that its base is on a plane passing through both rails. The necessary increase in vertical clearance is small but needs to be accounted for. The typical railroad clearance diagram is shown in Figure 2.5. Specific requirements of a railroad shall be determined prior to final design.
2.4.3 Waterways
A thorough hydraulic design is required for all new and replacement stream bridges, to assure that an adequate hydraulic opening is provided for a 50 year design flood and for the passage of ice and debris.
Any stream structure that provides a minimum freeboard of 600 mm for the 50-year flood shall be considered as satisfying normal hydraulic clearance requirements. However, where that 600-mm minimum freeboard is difficult or costly to provide, an analysis and evaluation should be accomplished to determine whether a minimum allowable freeboard of less than 600 mm may be appropriate. Items to be investigated should include: history of debris, changes in water surface elevations, consequence of debris clogging, potential damage, and the degree of difficulty or the amount of extra cost necessary to provide the full 600-mm freeboard. In an extreme case, negative freeboard could be accepted for a replacement of an existing bridge that is already inundated by the 50-year design flood, but in no case shall the proposed negative freeboard exceed the existing negative freeboard.
It is important to understand that there is no absolute minimum freeboard requirement or standard which must be met to satisfy a specification or regulation. Whatever minimum allowable freeboard is finally chosen, in accordance with accepted practice and application of these guidelines, should be considered as meeting all State requirements and standards.
2.4.4 Navigable Waterways
The only waterway in New York State that has prescribed requirements for vertical clearances is the New York State Barge Canal System. The minimum requirements are as follows:
Geometric Design Policy for Bridges
April, 2006 2-13
C Champlain Canal, Cayuga-Seneca Canal, and Erie Canal (west of Three Rivers) have a minimum vertical clearance of 4.72 m above maximum navigable pool elevation. The channel depth shall be no less than 3.7 m from normal pool elevation.
C Oswego Canal and Erie Canal (from Waterford west to Three Rivers) have a
minimum vertical clearance of 6.1 m above maximum navigable pool elevation. The channel depth shall be no less than 4.3 m from normal pool elevation.
NOTE: Variances for reductions will not be granted for channel depth or vertical clearance standards.
Bridges undergoing replacement or major rehabilitation that do not currently provide these minimum requirements shall be designed to comply with the prescribed vertical clearances. In some instances, the existing bridge exceeds the minimum clearances. This does not always mean that a replacement or rehabilitation project may reduce the existing vertical clearance. Coordination with the N.Y.S. Canal Corporation in early project development is required to determine the acceptable vertical clearance.
Other navigable waterways such as the Hudson River (south of Albany), St. Lawrence River/Seaway, etc., may fall under the jurisdiction of other local, state and federal agencies, commissions, and /or authorities. These agencies may have their own requirements for vertical clearance to be provided or may desire to increase or decrease the existing vertical clearance. In instances that involve a state owned bridge, coordination between all the interested parties is necessary to achieve the most appropriate vertical clearance.
Vertical clearance for other navigable waterways may be determined in many ways; i.e. existing, upstream and downstream clearances, type and size of vessels utilizing the waterway, etc. This information is also valuable in considering the need to provide pier protection (refer to Section 2.5 - Horizontal Clearances: Under-Bridge Features). Ordinary High-Water elevation for nontidal or Mean High Water for tidal areas will be used when determining minimum vertical clearance. Water depth will be determined from Normal Pool Elevation in nontidal waters or Mean Sea Level in tidal areas.
2.4.5 Miscellaneous Vertical Clearance Criteria
Thru-Truss - The end portals of all newly designed highway trusses shall allow for 4.9 m of vertical clearance plus an additional 150 mm to accommodate oversize vehicles and future overlays.
Flood Control Project - Where a bridge project crosses an established or proposed flood control project, the responsible agency (e.g., U.S. Army Corps of Engineers) will establish the desired vertical clearance over the Floodway Project Design Elevation. The Hydraulics Unit of the Office of Structures will provide assistance in obtaining the criteria.
Trails/Bikeways/Bridle Paths - Structures crossing over existing or proposed recreational trails shall provide a minimum of 2.5 m vertical clearance with 3.0 m preferred. The minimum vertical clearance over a bridle path is 3.0 m with 3.65 m preferred.
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Canal Trails - Along all sections of the canal system, access corridors are being established. This system of trails on the banks parallel to the canal should also provide, when possible, 3.0 m of vertical clearance. At locations with a trail on each side, a vertical clearance of at least 4.0 m should be provided, if possible, on at least one side. This will allow access for maintenance equipment such as small cranes and dump trucks. Early coordination with the Canal Corporation is recommended.
Extended Berm (Bench) - In places where an abutment has a larger than standard berm in front of the bridge seat a minimum clearance of 1.0 m is desired between the bottom of the low beam elevation and the top of the bench. This provides access for inspection of the underside of the superstructure.
Parkways - Table 2-1 shall be followed for vertical clearance requirements. However, many structures crossing parkways are required to be of certain configuration, i.e., arches, frames, etc. These configurations can significantly affect horizontal and vertical clearances. If there are considerable constraints on profile adjustments and if the required minimum vertical clearance is 4.3 m, it shall be provided over at least one lane. The remaining lanes may provide a lower minimum of 3.8 m.
Up to an additional 150 mm should be added to the vertical clearance for future resurfacing. Where the under roadway has previously been overlaid, some relief in the amount of vertical profile adjustment can be obtained by considering a reduction in the future overlay allowance. Existing pavement elevations near the bridge should be compared to the record plans and an existing thickness of overlay should be determined. This value should be compared to the normal 150 mm overlay allowance, and appropriate reduction in the future allowance be considered. Pavement overlay projects will require milling or removal of the existing overlay once the thickness approaches 150 mm.
If the existing vertical clearance is nonstandard, the need for improvement in the vertical clearances should be investigated during major rehabilitation (as defined in Section 19.1) or replacement projects involving the existing highways and structures.
2.5 Horizontal Clearances: Under-Bridge Features
2.5.1 Highway
Whenever possible, a substructure unit should be located to minimize the potential of vehicle impact as well as to lessen the effects of a hostile environment such as salt laden road spray and snow. The desired roadside horizontal clearances to fixed objects and recommended roadside clear areas shall be provided in accordance with the current AASHTO Roadside Design Guide and Chapter 10 of the Highway Design Manual. Piers located in narrow medians should be made parallel to the roadway whenever possible to allow for the possible future widening of the under roadway. In wider medians, a graded earth berm treatment should be used in the pier area. (See Figure 2.2 for details.)
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Figure 2.2
Schematic of a Median Berm
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In urban areas, a minimum setback of 3.0 m from the face of curb to the face of any substructure unit should be provided. This corridor allows for sidewalk and utility placement independent of the roadway. Design speeds and class of highway may require greater setback distances. Refer to the Highway Design Manual for the recommended clear zone.
Horizontal stopping sight distance is also a critical design element. See Chapter 2 and Chapter 5 of the Highway Design Manual for more information.
2.5.2 Navigable Waterways
Waterways in New York State vary in type from intermittent streams to large lakes and rivers which can support navigation involved in interstate or foreign commerce. Actual navigation on these waterways may be nonexistent, strictly recreational (rafts/canoes) or mixed recreational and commercial. Jurisdiction for approval of work in these waterways may rest with the New York State Department of Environmental Conservation, the U. S. Coast Guard, U. S. Army Corps of Engineers, New York State Department of State, Adirondack Park Agency, Office of Parks and Recreation and Historic Preservation, United States Fish and Wildlife Service, National Marine Fisheries, National Park Service, or New York City Department of Environmental Protection.
In the early phases of project development, all projects involving a waterway should be evaluated by the NYS Department of Transportation’s Regional Environmental Coordinator. Procedures to be followed for locally administered projects can be found in Chapter 8 of the Procedures for Locally Administered Federal Aid Projects Manual (LAFAP). Table BTA-1, Appendix 8-2 of the LAFAP manual indicates the need to include a Coast Guard Jurisdiction Checklist. A copy of the Coast Guard Jurisdiction Checklist can be found in Appendix 2E of this manual.
Bridge projects that require fill and/or excavation in or adjacent to surface waters, including wetlands and special aquatic sites, or that impact state and federal rare, threatened or endangered species require early coordination with the Regional Environmental Contact. Regulatory permit conditions may influence the type of work performed. For example, replacing an existing single span with a precast reinforced concrete box requires prior approval from the Department of Environmental Conservation and the Corps of Engineers. For further information on permitting issues relating directly to the disturbances of surface waters and associated riparian areas, please refer to Chapter 4 of the Environmental Procedures Manual and Chapter 8 of the Highway Design Manual.
Waterways that support commercial navigational traffic typically require a formal Coast Guard Permit. The Coast Guard Compliance Unit of the Office of Structures will help determine the need, and normally prepare the paperwork, for a Coast Guard permit for state administered projects. For locally administered projects, it shall be the responsibility of the project sponsor or his designee to assemble the necessary permit documents and submit them to the appropriate Coast Guard District for their action. Access to the Coast Guard Bridge permit Application Guide is provided on the Internet through the Bridge Administration Web Page (http://www.uscg.mil/hq/g-o/g-opt/g-opt.htm)
Geometric Design Policy for Bridges
April, 2006 2-17
Rivers that are designated for inclusion in the State or Federal Wild, Scenic and Recreational Rivers systems may have restrictions on the placement of piers within the banks of the river. Contact should be made with the appropriate Regional Environmental Coordinator prior to establishing span lengths.
The location of piers and pier protection systems for structures in the New York City/Long Island Region, the Lower Hudson River area, the Great Lakes Region, and the St. Lawrence River/Seaway should be handled on a case by case basis. Coordination with the appropriate Coast Guard District is required.
Early attention should be paid in determining the various types of permits needed and required supporting documentation. If identified too late, the permit process can become the critical path for a project.
The only waterway in New York State that has prescribed requirements for horizontal clearances is the New York State Barge Canal System. The following guidelines should be considered binding in designing new or replacement bridges over the canal system. Minor variances to the stated criteria may be granted on a case by case basis. Final decisions on variance requests will rest with the N.Y.S. Canal Corporation and N.Y.S. Dept. of Transportation.
1. Horizontal Clearance: Consideration should be given to hydraulic/hydrologic factors, canal curvature and local navigation conditions. Adverse site conditions which may merit an increase in horizontal clearance standards should be identified early in project development and all subsequent design reports. Adequate documentation must be provided (accident records, groundings, etc.) for considerations that will increase project cost due to required increases in the minimum stated criteria.
2. Access Trails: The lands adjacent to the Barge Canal System are being developed for recreational use by the public. Where appropriate, the placement of a new substructure shall accommodate an access trail beneath the structure. The elevation of this trail should be kept above ordinary high water whenever possible. Adequate vertical clearances shall also be provided (See Miscellaneous Vertical Clearance Criteria, Canal Trails). Minimum trail widths can be found in AASHTO’s Guide for the Development of Bicycle Facilities.
3. Defined Channel: The edge of channel is defined as the outside edge of the theoretical bottom angle. Therefore, in a typical earth section of 22.9 m, the channel is 22.9 m wide. Figures 2.3 and 2.4 show typical channel sections and minimum requirements for the location of a pier and pier protection system. All substructures, including cofferdams and fender systems, shall be placed a minimum of 1.5 m outside of channel limits. Encroachment upon earth or rock section channel limits will not be allowed. Please note that typical sections are subject to transition areas which will vary from the stated widths.
NYSDOT Bridge Manual
2-18 April, 2006
4. Pier Protection: Where barge traffic exists, all new or replacement substructures located in water depths exceeding 600 mm shall have an impact attenuator system around the pier(s). A typical system shall consist of a permanent steel sheeting cofferdam with a tremie seal and filled with screened gravel (a heavy-duty galvanized gabion cover in river sections is required). The minimum gravel fill requirement is 1.5 m from face of pier to inside edge of sheeting. Steel sheeting will extend to 900 mm above maximum navigable pool elevation. A rubber dock-fender system will be installed on the channel sides of sheeting and wrap around the face of the pier so that it extends at least one meter beyond the point at which the sheeting is parallel with the pier. The centerline of the rubber dock fender shall be located 450 mm above normal pool elevation. Should normal pool elevation and maximum navigable elevation differ by more than 600 mm, a second fender shall be placed at an elevation of 450 mm above maximum navigation elevation. In all cases the minimum horizontal clearance from centerline of pier to edge of channel shall be 4.9 m.
5. Where the potential for barge traffic exists, and construction of a pier does not require the use of a sheet piling cofferdam (i.e., areas that can be dewatered), any proposed bridge project shall consider using the same guidelines as above. This approach would allow the option of constructing an impact attenuator system at a future date and not encroach on channel limits. The minimum horizontal clearance of 4.9 m from centerline of pier to the edge of channel should be used.
6. Column pier configurations are not typically recommended for use on canal bridge projects. If column piers are chosen their use shall be limited to areas outside of the designated channel and shall be placed on a solid pier plinth that extends no less than one meter above maximum navigable pool elevation. In instances where an impact attenuator system is not required at this time, a rubber dock fender system is necessary to protect both vessel and structure from damage. Therefore, all substructures located in water depths exceeding 600 mm of depth (from normal pool) will have a rubber dock fender system installed. Installation requirements are the same here as they are for the impact attenuator system.
7. Rehabilitation Projects: Rubber dock fenders and/or an impact attenuator system for substructures located in the navigable portion of the canal should be considered on an individual basis and practicality of such an installation. It is also important to note that any rehabilitation work which will change the width of the superstructure, skew angle or alter existing horizontal and/or vertical clearances over the canal will require a U. S. Coast Guard bridge permit before construction may commence. When this occurs, navigation lights not previously required may become mandatory. Questions should be directed to the Office of Structures, Coast Guard Compliance Unit.
8. Permits: All bridges (permanent or temporary) constructed over the canal require a Section 9 bridge permit before construction may commence. The Office of Structures, Coast Guard Compliance Unit or the bridge owner or his designee is responsible for obtaining the bridge permit and coordinating with the U.S. Coast Guard.
Geometric Design Policy for Bridges
April, 2006 2-19
2.5.2.1 Navigation Lights
The U.S. Coast Guard is the sole authority in determining the requirements for navigation lights. The Office of Structures, bridge owner, or the bridge owner’s designee is responsible for securing Coast Guard approval. Once approval of the lighting system is obtained, modifications cannot be made without additional Coast Guard review.
For fixed bridges required to have navigation lighting, each fascia of the superstructure shall indicate channel limits of passage through the structure for nighttime traffic. The edge of channel will be marked by a red channel margin light which shall show through a horizontal arc of 180 degrees. The center of channel will be marked by a green navigation light showing through a horizontal arc of 360 degrees. The focal plane (center of lens) of all navigational lights shall never be less than 150 mm below “Low Steel”. Navigation lights are not considered an encroachment on vertical clearances and should be placed over actual channel limits whenever possible.
Due to the variety of structure types and navigable conditions, some bridge locations may be exempted from displaying navigation lighting. The Office of Structures or the bridge owner or his designee will coordinate with the U. S. Coast Guard for proper lighting requirements.
2.5.2.2 Additional Navigation Aids
The U.S. Coast Guard is the sole authority in determining the requirements for numerous other aids to navigation. Ordinarily, they do not mandate such items but the possibility does exist. The Office of Structures, bridge owner, or the bridge owner’s designee is responsible for coordination with the Coast Guard. Possible items that may be required to be installed to aid navigation are retroreflective panels, pier lights, daymarks, radar reflectors, racons, painting of the bridge piers, and vertical clearance indicators.
NYSDOT Bridge Manual
2-20 April, 2006
Figure 2.3 – Typical Canal Channel Sections
Geometric Design Policy for Bridges
April, 2006 2-21
Figure 2.4 Canal Pier Details
NYSDOT Bridge Manual
2-22 January, 2008
2.5.3 Railroads
For projects crossing railroads, it is desirable to carry the railroad's existing section or planned standard section under the bridge without alteration. However, FHWA has specified participation limits which determine the length of bridge they will fund. The Department concurs with these limits which are shown in Table 2-3. The distance from the centerline of the outside track to the 1 on 2 embankment shall be measured along a horizontal line at the top of rails at right angles to the track. In the case of superelevated tracks, the horizontal line is at the top of the high rail. This distance shall not exceed that shown in Table 2-3. For single track layouts, an off track maintenance roadway is provided on one side only. The railroad will specify the side. In multiple track situations, off track maintenance roadways may be required on both sides. The railroad shall specify a need for two roadways and identify their locations.
In the event that the railroad has, or plans to have, a wider cross section, Table 2-3 will govern at the bridge, and the railroad drainage ditch shall be piped through the embankment (See Figure 2.6). Greater dimensions may be justified on the basis of effective span arrangements and extraordinary drainage conditions, such as defined streams. In the event the railroad's actual existing or proposed section is less than that given in Table 2-3, the railroad's actual section shall be used.
For railroad sections that are in an earth cut, see Figure 2.7. When the railroad is in a rock cut, the distance to the toe of the highway embankment will be determined by the actual section and the characteristics of the rock (see Figure 2.8).
Geometric Design Policy for Bridges
April, 2006 2-23
Figure 2.5 Railroad Clearance Diagram
*Check individual RR for acceptance of the clipped corners
NYSDOT Bridge Manual
2-24 January, 2008
Notes:
1. This detail applies for multiple track installations on a tangent. 2. This detail also applies to new track installation constructed simultaneously with new
structure construction. 3. W.P.1 is a working point used to establish the shoulder break length as shown in
Figure 3.1. 4. The 6.1 m-offset to the face of pier accommodates an off track maintenance
roadway. If multiple tracks exist, this offset may be required for both sides as well as between various sets of tracks.
5. Whenever possible, the pier and the highway embankment should be located to avoid established drainage ditches. When unavoidable, drainage pipes may be used to carry surface drainage through the embankment, The bottom of footing for a pier should be placed below the bottom of ditch elevation.
6. Any pier located within 7.62 m of the centerline of a set of tracks shall be protected by crash walls designed in accordance with current American Railway Engineering and Maintenance of Way Association (AREMA) specifications, or the requirements of the affected railroad.
Figure 2.6 Track on Embankment
(Section Perpendicular to Centerline of Track)
Geometric Design Policy for Bridges
April, 2006 2-25
Notes:
1. This detail also applies to multiple track installations on a tangent. 2. W.P.2 is a working point used to establish the shoulder break length as shown in
Figure 3.1. 3. The 6.1-m offset accommodates an off track maintenance roadway. If multiple
tracks exist this offset may be required for both sides as well as between various sets of tracks.
4. Any pier located within 7.62 m of the centerline of a track shall be protected by crash walls designed in accordance with current American Railway Engineering and Maintenance of Way Association (AREMA) specifications or the requirement of the affected railroad.
5. When possible, piers should be kept out of ditch areas. The bottom of footing elevation for a pier should be placed below the bottom of ditch elevation.
Figure 2.7 Track in Cut
(Section Perpendicular to Centerline of Track)
NYSDOT Bridge Manual
2-26 April, 2006
Notes:
1. This detail also applies to multiple track installations on a tangent. 2. The 6.1 m offset accommodates an off track maintenance roadway. If multiple
tracks exist, this offset may be required for both sides as well as between various sets of tracks.
3. Ditching through the structure area shall meet and match adjoining existing drainage ditches for both alignment and profile.
4. Any pier located within 7.62 m of the centerline of a track shall be protected by crash walls designed in accordance with current American Railway Engineering and Maintenance of Way Association (AREMA) specifications or the requirement of the affected railroad.
5. When possible, piers should be kept out of ditch areas. The bottom of footing elevation for a pier should be placed below the bottom of ditch elevation.
Figure 2.8 Typical Railroad Rock Cut Section
(Section Perpendicular to Centerline of Track)
Geometric Design Policy for Bridges
January, 2008 2-27
Lateral Distance from Centerline of Outside Track to 1 on 2 Embankment*
Railroad Section With Off-Track Maintenance Roadway
Without Off-Track Maintenance Roadway
Fill 8.55 m 6.10 m
Cut 9.15 m 6.70 m
Cut−Heavy Snow Area** 10.05 m 7.60 m * When the outer track is on a horizontal curve, increase these dimensions 25 mm for every degree
of curvature to a maximum of 450 mm. ** Heavy Snow Area - All portions of state except NYC area and Long Island.
TABLE 2-3
Piers located within 7.62 m of the centerline of a track shall be of heavy construction or be protected by a concrete crash wall in accordance with current American Railway Engineering and Maintenance of Way Association (AREMA) specifications.
Railroad Bridges−A typical single track, thru-girder bridge is shown in Figure 2.9. Presently, all railroads still require English units for all dimensions that are of interest to the railroad. This requires the use of double dimensions. The dimensions shown in Figure 2.9 are only for reference. Prior to final design, the railroad involved must provide an approved section. A general clearance diagram for railroad bridges is shown in Figure 2.5.
2.5.4 Miscellaneous Corridors
At times, besides being required to cross a major feature such as a roadway or river, the new bridge must accommodate secondary corridors. These corridors can range from a defined paved bikeway/walkway to a level area of natural ground which would allow passage under the bridge of such things as cattle and wildlife. This requirement should be identified in the design report as well as on the Bridge Data Sheet - Part 1.
A minimum corridor width and a desired headroom should be indicated if it becomes a control feature. Unpaved access roadways for fire, emergency or maintenance equipment also fall into this category.
NYSDOT Bridge Manual
2-28 January, 2008
Figure 2.9 Typical Thru-Girder Railroad Bridge
2.6 Live Loading Requirements
2.6.1 New and Replacement Bridges
When performing designs using the NYSDOT LRFD Bridge Design Specifications, new and replacement bridges shall be designed to carry not less than the AASHTO HL-93 live load and the NYSDOT Design Permit Vehicle.
When performing designs using the NYSDOT Standard Specifications (Blue Book), new and replacement highway bridges shall be designed to carry not less than the AASHTO MS23 (HS 25) live load.
Geometric Design Policy for Bridges
January, 2008 2-29
2.6.2 Bridge Rehabilitation
Existing highway bridges should be rehabilitated to carry the AASHTO MS18 (HS 20) live load, unless economically unjustified.
Bridges whose superstructures are completely replaced while retaining all or part of the substructure will also be designed to carry the MS23 live load. Existing substructures to remain shall not be upgraded solely to accommodate the MS23 live load.
Where the MS18 (HS 20) loading cannot be economically justified, bridges should be rehabilitated to support an M18 (H 20) live load. In some cases, locally owned bridges or State-owned bridges carrying local roads may be rehabilitated to a lesser loading provided that heavy loads are anticipated to be rare. The minimum acceptable loading for a rehabilitated structure is M13.5 (H 15). Rehabilitation of any structure to a live loading less than MS18 must be expressly approved by the Regional Director.
2.6.3 Temporary Bridges
Temporary structures carrying vehicular traffic shall generally be designed for an MS18 live load. While an MS18 design live load is sufficient for all current legal loads, it is recognized that in a few situations, the design live load for temporary structures should be increased to the full MS23 design live load now used for permanent structures. This should be considered for only the following types of projects:
C Interstate or equivalent highways with very high Average Daily Truck Traffic (ADTT). Very high ADTT can generally be taken to be over 10,000.
C Interstate or equivalent highways where it is anticipated that the temporary structures will be in service longer than one year.
C Other locations that may have unique situations in regard to very heavy industrial truck traffic, anticipated very heavy permit vehicles or access to railroad yards and port facilities.
It is also recognized that some locations may not require a MS18 design live load for temporary structures. This would most often be the case for structures on parkways or in rural areas. However, locations in rural areas should be treated with caution since many low volume roads frequently carry heavy vehicles such as logging trucks, milk tankers and heavy farm machinery. Structures on parkways that will be in use over a winter season should also be treated with caution because snow removal equipment may approximate MS18 loading.
All uses of temporary structures with design live load less than MS18 need to receive approval from the Regional Structures Engineer. In certain circumstances, temporary structures designed for a live load less than MS18 will require posting. In no case will approval be granted for a design live load less than M13.5. In no case shall a temporary bridge on an NHS designated route be designed for less than MS18.
Place Standard Note #9 from Section 17.3 on the plans for all projects containing temporary structures.
NYSDOT Bridge Manual
2-30 January, 2008
2.6.4 Pedestrian Bridges
All pedestrian bridges will be designed in accordance with AASHTO prescribed loadings. Pedestrian bridges 1.83 m in width or greater that could have vehicle access should also be designed to accommodate an occasional vehicular load of 45 kN (M 4.5) distributed over a two axle arrangement; 9 kN front axle and 36 kN total for the rear axle. For pedestrian bridges with widths greater than 3.0 m, a 90 kN (M 9) vehicle load should be used; 18 kN front axle and 72 kN total for the rear axles. The provisions of the AASHTO Guide Specification for the Design of Pedestrian Bridges should be used.
2.6.5 Railroad Bridges
All structures carrying railroads will be designed for Cooper E-80 loading (U.S. Units), unless noted otherwise.
2.7 Alignment, Profile and Superelevation
2.7.1 Horizontal Alignment
The alignment of a bridge can be controlled by a highway realignment project or be set by the standards that are to be used for a bridge only replacement project. Three factors normally dictate the chosen alignment: class of highway, design speed and traffic volume. The requirements of each individual project should be reviewed prior to establishing the necessary horizontal and vertical control standards. If possible, the highway designer should avoid placing spiral alignments and compound curve alignments on structures. Conventional highway treatments such as spiral alignments, reverse curves and superelevation banking transitions, when used on a bridge, can complicate the design, increase cost and make construction difficult.
Severely skewed alignments can cause uplift, seismic design and maintenance problems, and may result in a structure that is considerably longer than the existing structure.
2.7.2 Profile
When selecting project standards, such as maximum grades and stopping sight distances, the highway designer should avoid placing a sag curve at the bridge location. If this is not possible, the bridge designer should avoid placing the beam itself on a sag and fabricating it with negative camber. The placement of a level (0%) grade on the bridge should be avoided. If possible, steel beams shall use haunches for sag correction with the top and bottom flanges remaining parallel on a vertical tangent. (See Section 8.9.1 for further discussion on sag cambers for steel bridges.)
Prestressed units shall not be subjected to negative camber. The only corrective measure which can be used for adjacent units is to vary the thickness of the wearing surface. If this procedure cannot accommodate the geometry of the curve in a reasonable manner, the use of the adjacent slab or box units is not recommended. Prestressed I-beam or spread box/slab units can use varying haunches to accommodate some sag vertical curvature.
Geometric Design Policy for Bridges
January, 2008 2-31
2.7.3 Superelevation
Transitions in the cross slope of a bridge deck should be avoided whenever possible. When it has been determined that transition on the bridge is unavoidable, the following procedure is to be used:
The length of the transition shall be determined from the appropriate "Superelevation Table" found in the current edition of AASHTO's A Policy on Geometric Design of Highways and Streets. Maximum superelevation rates are 4% for urban conditions and 8% for rural conditions
Simple Circular Curve Alignments
Between 90% and 60% of the runoff shall be applied in the tangent and between 40% and 10% will be carried into the curve. The typical split is 70% - 30%. The runout will be applied to the tangent prior/after the runoff. See Figure 2.10 for sample banking diagram, and Figure 2.12 for banking details of a bridge deck.
Spiral/Circular Curve Alignments
The full required superelevation shall be obtained by the time the SC (Spiral to Curve) point is reached. Full superelevation will be carried through the circular curve until the CS (Curve to Spiral) point is met. The superelevation transition length (LT ) will consist of two parts; the length of spiral equal to the LS value in the appropriate "Superelevation Table" and an additional length of transition known as the Tangent Runout (TR).
LT = LS + TR
TR = L x (N.C.) eNreqd
See Figures 2.10 and 2.11
The Point of Rotation (POR) and the superelevation rates for the lanes and shoulders will be identified for each individual project. On a structure, the low-side shoulder will maintain the same cross slope as the adjacent travel lane. If the high side shoulder is broken back it should maintain a constant downward slope of 2%. For recommended rollover combinations see Highway Design Manual Figure 3-5.
When the slope exceeds 6% a breakback will not be allowed for adjacent concrete beams. The designer should consider other options for the structural system if a break-back is required. When the cross slope exceeds 4% Bulb Tee beams should not be used due to excessive haunch depths. AASHTO I-beams should be considered.
For bridges with reinforced concrete approach slabs, the shoulder transition from the 6% highway cross slope norm to the 2% cross slope on the bridge will be applied prior to the approach slab. The approach slab will be treated the same as the bridge deck. The difference of the grades for the high-side shoulder and the adjacent travel lane should never exceed 10%. The high shoulder will almost always be set at a 2% down slope.
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2-32 April, 2006
The number and location of the breaks in the cross slope should be kept to a minimum, due to the limitations of deck finishing machines. If the travel lane and adjacent shoulder on the low side of the bridge are in transition, that is decreasing the cross slope, a break will be introduced when the transitioning cross slope reaches 2%. At that point the shoulder will retain the 2% down slope, and the travel lane will continue to transition until it reaches the required cross slope.
For buried structures such as box culverts, the standard highway section will be carried across the structure, if possible. The shoulders will be the same as on the highway sections. If necessary to provide minimum pavement thickness, the shoulder banking may be treated like a bridge deck shoulder.
Further information on superelevation and transitions can be found in Chapters 2 and 5 of the Highway Design Manual.
Geometric Design Policy for Bridges
January, 2008 2-33
LT = Length of Transition = Runoff + Runout N.C. = Value of Normal Crown Banking P.O.R. = Point of Rotation e = Superelevation required for a specific horizontal curve Outside Edge = Larger radius of horizontal alignment P.C. = Point of Curvature
See Chapter 5 of the Highway Design Manual for Runoff and Runout Formulae.
Figure 2.10 Banking Simple Curve
NYSDOT Bridge Manual
2-34 April, 2006
Lt = Length of Transition L= Length of Spiral TR = Tangent Runout N.C. = Value of Normal Crown Banking P.O.R.= Point of Rotation e = Superelevation required for a specific horizontal curve Outside Edge = Larger Radius of horizontal alignment S.C. = Spiral to Curve Point T.S. = Tangent to Spiral Point
Figure 2.11 Banking Spiral Curve
Geometric Design Policy for Bridges
April, 2006 2-35
Figure 2.12 Banking Details for Bridge Decks
(Break-Back Option Shown – See HDM Figure 3-5 for Full Bank Option)
January 2008 2A-1
Appendix 2A Bridge Roadway Width Tables
The tables included in the following two pages have been derived from Chapters V and VI of AASHTO’s A Policy on Geometric Design of Highways and Streets, 2004.
Tables N and R apply to new and replacement bridges on local and collector roads and streets. Table R provides minimum permissible widths, while Table N provides maximum widths regardless of the approach roadway geometry for non-NHS roadways. Table N also provides the maximum shoulder width for non-NHS minor arterial bridges where no improvements are planned.
See Section 2.3 and Table 2-1 for additional discussion on bridge roadway widths.
Table X applies to certain bridge rehabilitations on local and collector roads, see Table 2-1.
Additional clarifications:
1. All traffic is two-way.
2. The average daily traffic (ADT) in vehicles per day is always the design year traffic.
3. Refer to Project Development Manual (PDM) Appendix 5 for the design year for bridge work.
4. "Traveled way" is the portion of the roadway for the movement of vehicles, exclusive of shoulders.
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2A-2 January, 2008
Table R Minimum Roadway Widths For New and Replacement Bridges (Non-NHS)
(Local and Collector Roads)
Design Volume (veh/day) Minimum Roadway Width of Bridge a
Under 400 Width of traveled way plus 0.6 m each side
400 - 1500 Width of traveled way plus 1 m each side
1500 – 2000 Width of traveled way plus 1.2 m each side b
Over 2000 Approach roadway width b
(Ref. AASHTO’s A Policy on Geometric Design of Highways and Streets, 2004, Exhibit 6-6)
Notes:
a Where the approach roadway width (traveled way plus shoulders) is surfaced, that surface width should be carried across the structures.
b For bridges in excess of 30 m in length the minimum width of traveled way plus 1 m on each side is acceptable.
Bridge Roadway Width Tables
January, 2008 2A-3
Table N
Maximum Width of Traveled Way and Shoulder (Non-NHS) (Local and Collector Roads)
Design Volume (veh/day)
Under 400
400 to 1500
1500 to 2000
Over 2000
Design Speed (km/h)
Width of Traveled Way (m)
30 6.0 6.0 6.6 7.2
40 6.0 6.0 6.6 7.2
50 6.0 6.0 6.6 7.2
60 6.0 6.6 6.6 7.2
70 6.0 6.6 6.6 7.2
80 6.0 6.6 6.6 7.2
90 6.6 6.6 7.2 7.2
100 6.6 6.6 7.2 7.2
- Width of Shoulder on Each Side of Road (m) a
All Speeds 1.2 b 1.5 1.8 2.4
(Ref. AASHTO’s A Policy on Geometric Design of Highways and Streets, 2004, Exhibit 6-5)
Notes:
a The shoulder widths noted in this table also serve as maximum values for the shoulders on non-NHS minor arterials where no planned improvements are anticipated.
b Per HDM Chapter 2, Table 2-5, a 1.2 m shoulder is required where barrier is utilized.
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2A-4 April, 2006
Table X Minimum Roadway Widths For Bridge Rehabilitations b
(Local and Collector Roads – Two Lanes)
Design Traffic (veh/day) Minimum Clear Roadway Width (m) a
Under 400 6.6
400 to 1500 6.6
1500 to 2000 7.2
Over 2000 8.4
(Ref. AASHTO’s A Policy on Geometric Design of Highways and Streets, 2004, Exhibit 6-7)
Notes: a Clear width between curbs or railings, whichever is less, shall be equal to or greater than
the approach traveled way width.
b Table X does not apply to structures with a total length greater than 30 m. These structures should be analyzed individually by taking into consideration the clear width provided, safety, traffic volumes, remaining life of structure, design speed and other pertinent factors.
Bridge Roadway Width Tables
April 2006 2A-5
Figure 2A.1 Usable Shoulder Details
Appendix 2B One-Lane Bridge Policy
A. Objective: This policy sets forth criteria used to determine where it would be acceptable to replace an existing one-lane bridge by another one-lane bridge.
When an existing one-lane bridge has deteriorated beyond a point where rehabilitation is appropriate, an evaluation shall be made to determine whether closure of the road or removal of the bridge is an acceptable solution. If that evaluation indicates that the bridge is deserving of replacement, then a determination must be made of the number of traffic lanes to be carried by the proposed bridge. The objective of this policy is to govern that decision.
B. Definitions: Existing One-lane Bridge: One upon which two vehicles, traveling in the same or opposite direction, will not normally attempt to pass one another. The bridge may or may not be signed as a "One-lane Bridge". In the absence of recorded or observed experience, any bridge less than 4.9 m wide, curb to curb or rail to rail, shall be considered as a one-lane bridge. A ramp bridge, carrying traffic in only one direction, is not a one-lane bridge for the purpose of this definition.
Existing One-lane Road: One upon which two vehicles, traveling in the same or opposite direction, will pass one another only with care, usually by the slowing or stopping of one or both vehicles, and perhaps by the movement of one or both vehicles partially off the pavement surface, often accomplished at intermittent widenings which may occur naturally or which may be developed deliberately to facilitate such passing. In the absence of recorded or observed experience, any road measuring less than 4.9 m wide, edge to edge of roadway (including pavement plus graded shoulders), shall be considered as a one-lane road, unless it carries traffic in only one direction.
C. Requirements: An existing one-lane bridge may be replaced by another one-lane bridge if each of the following requirements are met:
1. The project must be controlled by Chapter V of the AASHTO Policy on Geometric Design of Highways and Streets - 2004.
2. The current two-way ADT must be less than 350, and the predicted ADT for the 30th year after completion of the project must be less than 500.
3. The current and anticipated future operating speeds must be not greater than 60 km/h.
4. An analysis of the three-year accident experience must reveal no more than one reported accident, with no accident being reported during that same period as being directly attributable to the narrowness of the existing one-lane bridge.
April, 2006 2B-1
NYSDOT Bridge Manual
2B-2 April, 2006
5. The replacement bridge and its approaches must be signed as a "One-lane Bridge" in accordance with the MUTCD.
6. Horizontal and vertical sight distances must be provided to allow approaching motorists to safely observe an opposing vehicle on the bridge or its far approaches.
D. Desirable Conditions: In addition to the above requirements, other relevant factors should be evaluated and considered before a final decision is made in favor of a bridge replacement to carry one-lane of traffic. Several of these factors are subjective in nature, and others may be very difficult to measure or identify with exactness. All should be treated as desirable conditions which should be met, but which are not absolute requirements. A list of such preferable conditions would include, but not be limited to, the following:
1. The local authorities should have no substantive objection to a one-lane bridge.
2. The existing two-way approach roadway should be one-lane wide and operating as a one-lane road (although this may be difficult to determine with confidence).
3. There should be no plans for the future improvement of the highway which would be expected to substantially alter existing operating conditions.
E. Supporting Documentation: Sufficient information should be supplied in the Scoping Phase so that the requirements and desirable conditions can be evaluated and a decision reached prior to the preparation of the Design Approval Document. If portions of that information are lacking, the final decision on the number of lanes may be made at a later time, but must, in any event, be resolved at or prior to Design Approval.
F. Justification: In order to achieve economics, one-lane bridge replacements shall be permitted when certain safety requirements have been met and certain conditions evaluated. Compared against the cost of a complete two-lane bridge, a minimum savings of 10 to 15 percent can be routinely expected, with appreciable greater savings when existing substructures can be retained.
G. Conclusion: When all requirements have been met, and when a final decision has been made to replace an existing one-lane bridge by another one-lane bridge, and when Design Approval, specifying that decision, has been obtained, the structural design normally shall produce plans for a bridge 4.3 m wide between railings, except that the replacement shall not be narrower than the existing one-lane bridge. Minor variations are permissible to account for the intricacies of particular structural components.
Appendix 2C Vertical Clearance over the New York State Thruway,
I-90 and Revised 4.9 m (16') Clearance Network
The current statewide 4.9 m (16') vertical clearance network in the west to east direction is described below:
State Route 17/I-86 from the Pennsylvania state line east to I-81, I-81 from Route 17/I-86 north to I-88, I-88 east to I-90 (Thruway exit 25A) and I-90 east to I-87 (Northway) in Albany (Thruway Exit 24); and State Route 17/I-86 from the Pennsylvania state line east to I-81, I-81 south to the Pennsylvania line, and I-84 east to the Connecticut state line.
As part of a December 12, 1991 agreement with FHWA, the Department made a commitment to provide 4.9 m (16') clearance on this network. Accordingly, regardless of funding sources, no exceptions will be entertained to the 4.9 m clearance requirement for bridges over the routes described above if the project involves:
C Bridge replacement or
C Bridge rehabilitation including deck replacement
Justification for retention of nonstandard clearance is required for bridges along the identified additional routes listed below:
1. I-90 from the Pennsylvania State line east to I-88 (Thruway Exit 25A) in the Capital District;
2. I-90 from I-87 Northway (Thruway Exit 24) east to the Massachusetts State line;
3. I-87 from Route 300 (Thruway Exit 17; I-84), north to I-87, Northway (Thruway Exit 24);
4. I-190 in the Buffalo-Niagara Falls area.
At the end of this appendix is a listing of the bridges along these particular routes. When a project involves one of the listed bridges whose clearance is 4.3 m (14') or greater but less than 4.9 m (16') and the existing clearance is not being diminished, the Region will request approval to retain the existing clearance in accordance with the TEA-21 Matrix.
The request should include the following nonstandard feature justification:
The structure carrying...over..., BIN...provides a minimum vertical clearance of .... This structure is one of those on the listing of structures in Appendix 2C of the NYSDOT Bridge Manual whose existing clearance can be retained as agreed by FHWA on December 12, 1991.
When a project results in reducing existing vertical clearance of bridge(s) listed, a full nonstandard feature justification will be required. FHWA has stated that the Department cannot approve any vertical clearance less than 4.3 m (14').
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Coordination with SDDC: Based on a January 27, 1998 letter from the Department of the Army, the Military Traffic Management Command, Transportation Engineering Agency (now Surface Deployment and Distribution Command (SDCC)) has concurred with a batch design exemption for the bridges along the above six routes as long as the existing clearances are not being diminished. All exceptions to the 4.9 m vertical clearance standard along the routes described in the first paragraph of this appendix are to be coordinated with the SDDC (see Appendix 2D). On other urban Interstate routes, where the 4.3 m vertical clearance standard applies, there is no requirement to coordinate with nor notify the SDDC.
This Appendix applies only to listed bridges and to those on the 4.9 m vertical clearance network described in this Appendix. Existing rules relative to vertical clearance continue to apply to all other bridges.
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Vertical Clearance
List of bridges over the Thruway, I-190, and I-90 with vertical clearance less than 4.9 m (16') that NYSDOT and FHWA have agreed to exempt from the 4.9 m (16') requirement by use of this Appendix.
RC BIN Feature Carried Feature Crossed Vertical Clearance Thruway
Milepoint
Metric Feet/Inches
11 1015970 Rte. 20 87IX 4.4 m 14'-6" 0014685
11 1022440 Old Rte. 32 87IX 4.4 m 14'-6" 0013954
11 1025320 443 443 11022005 87IX 4.5 m 14'-8" 0014247
11 1033101 87I 87I11081000 90I 4.3 m 14'-0" None
11 1033102 87I 87I11081000 90I 4.3 m 14'-0" None
11 1047510 396 396 11011064 87IX 4.4 m 14'-4" 0813461
11 5513349 912MX 87IX 4.5 m 14'-8" 0080000
11 5513500 Beaver Dam Road 87IX 4.3 m 14'-2" 0013542
11 5513520 Clapper Road 87IX 4.3 m 14'-3" 0013670
11 5513530 Wemple Road 87IX 4.3 m 14'-2" 0013804
11 5513580 New Scotland Ave. 87IX 4.3 m 14'-2" 0014431
11 5513600 Russell Rd. Co. 204 87IX 4.3 m 14'-1" 0014538
11 5513610 Schoolhouse Rd. 87IX 4.5 m 14'-8" 0014642
13 1018030 23A 23A13011324 87IX 4.7 m 15'-4" 0011001
13 1031060 81 81 13021199 87IX 4.3 m 14'-2" 0012221
13 1038060 144 144 13011008 87IX 4.3 m 14'-2" 0012756
13 1053550 9W 9W 13041188 87IX 4.6 m 15'-1" 0012369
13 5513180 Brick Schoolhouse 87IX 4.3 m 14'-1" 0010862
13 5513200 Old Kings Highway 87IX 4.6 m 15'-3" 0011257
13 5513220 CR 23B 87IX 4.4 m 14'-7" 0011364
13 5513230 NYSTA INT 21 87IX 4.3 m 14'-3" 0011389
13 5513290 New Balt Ser Rd 87IX 4.3 m 14'-1" 0012728
86 5515540 L Katrine Rd CR90 87IX 4.3 m 14'-3" 0009527
86 5515550 Ruby Road 87IX 4.3 m 14'-3" 0009656
86 5515570 Mt Marion Rd CR34 87IX 4.3 m 14'-3" 0009807
86 5515580 Peoples Road 87IX 4.3 m 14'-2" 0010232
86 5515590 Malden Rd CR89 87IX 4.3 m 14'-2" 0010316
86 5515600 Katsbaan Road 87IX 4.3 m 14'-3" 0010404
86 5515610 Asbury Road 87IX 4.4 m 14'-4" 0010534
Appendix 2D Required Coordination with the Department of Defense
on Nonstandard Vertical Clearances over Interstate Routes
Introduction In 1998, the Federal Highway Administration (FHWA) informed the Department that the FHWA and Department of Defense (DOD) updated the interagency coordination when a project on an Interstate System roadway is to be advanced with a design exception to standard vertical clearances. This Appendix describes the NYSDOT procedures to provide this coordination. The procedures are based on the guidance in the included August 15, 1997, memo, “Vertical Clearance, Interstate System Coordination of Design Exceptions” from FHWA’s Associate Administrator for Program Development of the FHWA Regional Administrators and the Federal Lands Highway Program Administrator.
Requirements For projects on the Interstate System to be advanced with a design exception to the standard 4.9 m (16') vertical clearance, the NYSDOT or the New York State Thruway Authority will coordinate with the Surface Deployment and Distribution Command-Transportation Engineering Agency (SDDCTEA)1 during preliminary design, prior to requesting FHWA’s concurrence with the design exception. This coordination applies for all Interstate routes except:
1. Interstates in urban areas where another route provides the single 4.9 m (16') routing for the urban area. (These single 4.9 m (16') routings are identified for the New York City, Kingston, Albany-Schenectady, Utica, Syracuse, Rochester and Buffalo urban areas in the package from FHWA that the Planning and Program Development Group’s December 11, 1997, memo forwarded to the Regional Planning and Program Managers.)
2. Sections of I-90, I-87 and I-190, which were exempted from the 4.9 m (16') vertical
clearance as described in Appendix 2C. (NYSDOT will still have to prepare nonstandard feature justifications per the TEA-21 Matrix on these bridges as described in Appendix 2C.)
For projects to be advanced with a design exception to the standard vertical clearance over an Interstate route, except those routes noted in (1) and (2) above, the NYSDOT Region or Thruway Authority will coordinate with the SDDCTEA. This will be done late in Design
1 In previous editions of the Bridge Manual, the Department of Defense coordinating agency was the Military Traffic Management Command–Transportation Engineering Agency. In 2004, the name was changed to the Surface Deployment and Distribution Command–Transportation Engineering Agency. Because of on-going changes in the structure of the Department of Defense, the designer should verify the name and address of the Transportation Engineering Agency.
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Phase I by forwarding a copy (or applicable sections) of the draft Design Report, Design Report/Environmental Assessment or Design Report/Draft Environmental Impact Statement to the SDDCTEA for their review of the proposed nonstandard vertical clearance. This SDDCTEA coordination step is listed in the Design Phase I steps in the 1999 version of the Design Procedure Manual (DPM). FHWA and the Design Quality Assurance Bureau should be copied on this letter.
The SDDCTEA is to reply by letter or e-mail within 15 calendar days. If no reply is received within 15 calendar days, it is assumed they have no comment. The text of Chapter III.C.2.a of the “Full” Design Report should then be modified to state that coordination with the Department of Defense has occurred and whether or not the SDDCTEA replied. If they do reply, a copy of their response is to be included in the attached appendices of the design report as important correspondence received on the project. Appropriate consideration should be given to any SDDCTEA comments and the treatment of the nonstandard feature and/or the justification of the nonstandard feature modified accordingly. FHWA will consider any SDDCTEA comments in their evaluation of the retention of the non-standard vertical clearance.
The request for coordination should be addressed to:
Director Surface Deployment and Distribution Command Transportation Engineering Agency (SDDCTEA) Attention: MTTE-SA 720 Thimble Shoals Boulevard, Suite 130 Newport News, VA 23606-2574 (Telephone - 757-599-1117) (Fax - 757-5991560) A sample letter for this coordination with the SDDCTEA is included in this Appendix.
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SAMPLE LETTER
State of New York
Department of Transportation Albany, N.Y. 12232
http://www.dot.state.ny.us Thomas Madison, Jr. George E. Pataki Commissioner Governor
William S. Brown, P.E. Regional Design Engineer NY State Dept. of Transportation State Office Building 1 Washington Drive Sample, New York 12201 October 12, 2005 Director Surface Deployment and Distribution Command Transportation Engineering Agency (SDDCTEA) ATTN: MTTE-SA 720 Thimble Shoals Boulevard, Suite 130 Newport News, VA 23606-2574 RE: PIN 9999.99 Route 33/I777 Interchange Town of Washington, Lincoln Co. Dear Sir/Madam This letter is to provide coordination in accordance with the Federal Highway Administration/Department of Defense interagency coordination procedures when a project on an interstate system roadway is to be advanced with a design exception to standard vertical clearance. The subject project, to reconstruct the Route 33/I777 interchange, includes retention of a nonstandard vertical clearance at the Francis Palmer Road Bridge over I-777. this nonstandard feature and the justification for its retention are described in Section III.C.2.a on page 19 of the attached draft of the Design Report/Environmental Assessment, dated October 2005.
SAMPLE LETTER Page 2 of 2 October 12, 2005 Please inform us of your comments on the retention of this nonstandard vertical clearance by responding by letter or e-mail. If we do not receive a response within 15 calendar days from the date of this memo, we will assume you have no comments. If you have any questions, please contact John Smith at (555)555-5555. A response by e-mail should be sent to [email protected]. Sincerely WILLIAM S. BROWN Regional Design Engineer WSB:bb bcc: Robert Arnold, Division Administrator Director, Design Quality Assurance Bureau, 50 Wolf Road, POD 23
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MEMORANDUM
U.S. Department of Transportation Federal Highway Administration
Subject: ACTION: Vertical Clearance, Interstate
System Coordination of Design Exceptions
Date: August 15, 1997
From: Associate Administrator for Program Development
Reply toAttn of:
HNG-14
To: Regional Administrators Federal Lands Highway Program Administrator
For almost 30 years, the Federal Highway Administration (FHWA) and the Military Traffic Management Command Transportation Engineering Agency (MTMCTEA) of the Department of Defense (DOD) have cooperated to meet the demands of military traffic on the Interstate System, particularly in the area of vertical clearances. This need has been met with the adoption of standards by FHWA for vertical clearance on the Interstate that require a clear height of structures over the entire roadway width, including the useable width of shoulder, of 4.9 meters for the rural Interstate. In urban areas, the 4.9-meter clearance is applied to a single route, with other Interstate routings in the urban area having at least a 4.3-meter vertical clearance.
In 1960, at the request of the DOD, and with the cooperation of the States, the above standards were established to accommodate military traffic on the Interstate. At that time, a large number of structures on the Interstate, constructed under previous criteria, existed which did not conform to the new minimum standard. The correction of all these deficiencies could not be economically justified. Consequently, in 1969, the MTMCTEA, the American Association of State Highway and Transportation Officials (AASHTO) (then AASHO) and the FHWA agreed to concentrate on a subset of the Interstate judged to be priority routes. The subset contained a significantly smaller number of deficient structures on 41 842 kilometers of the Interstate. The 41 842 kilometer priority network served about 95 percent of the major military installations.
Since then, the MTMCTEA has developed and continues to refine the Strategic Highway Network (STRAHNET). The STRAHNET report dated January 1991 was distributed to Regional Federal Highway Administrators by memorandum from the Director, Office of Environment and Planning dated March 22, 1991. Since 1991, there have been a few changes made to STRAHNET. These changes have been coordinated with the States and the field offices. Maps delineating the changes were distributed to the affected regional offices by HEP-l0. The STRAHNET is a system of highways that provides defense access, continuity and emergency capabilities for movements
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of personnel and equipment in both peacetime and wartime. The STRAHNET was based on quantifiable DOD requirements, addressing their peacetime, wartime, strategic, and oversize/overweight highway demands. The network consists of approximately 96 000 kilometers of highway. The STRAHNET has been incorporated into the National Highway System (NHS). Almost 75 percent of the system in the continental United States (about 70 000 kilometers) consists of roadways on the Dwight D. Eisenhower National System of Interstate and Defense Highways.
The currently established procedures require the FHWA to coordinate with the MTMCTEA when a clear height of structures of less than 4.9 meters is created as the result of a construction project or the project does not provide for the correction of existing substandard vertical clearance on the 41 842-kilometer priority network prior to approving the exception. For routes not on the priority network, coordination is not required although the FHWA policy provides that the MTMCTEA be notified of all exceptions to vertical clearance on the remainder of the Interstate System. The approval action for exceptions to vertical clearance has been delegated to the field offices, which can contact the MTMCTEA directly. When the State highway agency (SHA) has approval authority for design exceptions under one of the 23 U.S.C. 106(b) exemption provisions, coordination with the MTMCTEA is still required and may be accomplished through the FHWA or directly with the MTMCTEA.
The development of the STRAHNET, the establishment of Power Projection Platforms, base realignments, and the evolving role of the military have created a need to revise coordination procedures between the MTMCTEA and the FHWA, concerning exceptions to the vertical clearance requirements on the Interstate System. Therefore, the FHWA and the MTMCTEA have agreed that all exceptions to the 4.9-meter vertical clearance standard for the rural Interstate and the single routing in urban areas, whether it is a new construction project, a project that does not provide for correction of an existing substandard condition, or a project which creates a substandard condition at an existing structure, will be coordinated with the MTMCTEA beginning upon receipt of this memorandum. This agreement extends to the full roadway width including shoulders for the through lanes, as well as ramps and collector-distributor roadways in Interstate-to-Interstate interchanges. This change in effect eliminates the 41 842-kilometer priority network as a separate subset of the Interstate System. The revised coordination procedures do not change the standards adopted for the Interstate enumerated in "A Policy on Design Standards - Interstate System," AASHTO, July 1991, or the delegations of authority in FHWA Order M1100.1A.
A number of toll roads are part of STRAHNET by virtue of being incorporated into the Interstate System under the former provisions of Section 129(b) of Title 23, United States Code. While the FHWA does not have any particular "leverage" on the toll authorities to comply with Federal standards on non-federally funded projects, it is expected that the SHA's have established appropriate procedures to assure that proposed changes or alterations of the toll road will meet applicable policies established for the Interstate System. The working relationship should ensure the needs of the military are considered and that necessary coordination occurs.
A request for coordination may be forwarded to the MTMCTEA at any time during project development prior to taking any action on the design exception. It should include a time period of 10 working days (after receipt) for action on the request. The office initiating a request for coordination to the MTMCTEA should verify receipt of the request by telephone or fax. If the MTMCTEA does not respond within the time frame, the FHWA should conclude that the
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MTMCTEA does not have any concerns with the proposed exception. If comments are forthcoming, the FHWA and the SHA will consider mitigation to the extent feasible.
A request for coordination should be addressed to:
Director Military Traffic Management Command Transportation Engineering Agency (MTMCTEA) ATTN: MTTE-SA 720 Thimble Shoals Boulevard, Suite 130 Newport News, VA 23606-2574 (Telephone: 757-599-1117, Fax: 757-599-1560)
The Federal Aid Policy Guide Non-regulatory Supplement, 23 CFR 625, Paragraph 7 of Transmittal 13 dated July 21, 1995, will be revised as appropriate at the earliest opportunity. Questions regarding this memorandum should be directed to William A. Prosser at 202-366-1332, or Robert C. Schlicht at 202-366-1317.
/s/ Thomas J. Ptak
Appendix 2E Coast Guard Jurisdiction Checklist
PIN _____________ Route______________________________ BIN______________ Waterway ______________________________________ County________________ This checklist is designed to help determine the need for a Section 9 Permit from the US Coast Guard for bridge construction projects. Final determination for such a need shall be verified by the N.Y.S. D.O.T. Main Office, Structures Division, Coast Guard Compliance Unit. (1) Is the noted waterway presently used (or susceptible to use in its natural condition or
by reasonable improvement) as a means to transport interstate or foreign commerce?
Yes ☐ No ☐
A "yes" answer for question 1 indicates a clear need for the noted permit. (2) Is the noted waterway subject to the ebb and flow of tide?
Yes ☐ No ☐
A “no” answer to question 1 but a “yes” answer to question 2 indicates a need for further discussion with the Coast Guard, or FHWA if federal funds are utilized.
Answers to the following questions will be used for information during discussions
with the U.S.C.G. This information will be used to request a determination and when necessary to supplement the data necessary for a public notice and formal permit process.
(3) Marine craft utilizing this waterway at or in the vicinity of the project site include: (CHECK ALL THAT APPLY) None ☐
Canoes/Rowboats ☐
Small Motorboats (15' max.) ☐
Medium Motorboats (20' max.) ☐
Large Vessels (over 21') ☐
Recreational ☐
Commercial ☐ (4) Give normal pool or ordinary water depths in vicinity of bridge: 0' to 2' ☐ 3' to 5' ☐ over 5' ☐
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(5) Is there likely to be navigation passing under the existing bridge during periods of
poor visibility (i.e., nighttime, fog, bad weather, etc.)?
Yes ☐ No ☐
(6) Does the existing bridge have navigation lights?
Yes ☐ No ☐
(7) Does secondary lighting in the area provide a clear definition of the navigable channel and bridge opening?
Yes ☐ No ☐
(8) Does the waterway exhibit characteristics which may pose risk to navigation such as constricted navigation channel, piers in waterway, dams, rapids, etc.?
Yes ☐ No ☐
(9) Give minimum vertical clearance at mean high water (or maximum navigable pool elevation) for: A) Existing Bridge ____________________________ B) Downstream Bridge_________________________ C) Upstream Bridge ___________________________ (10) Give expected minimum vertical clearance at mean high water (or maximum
navigable pool elevation) for the Proposed Bridge_______________________. (11) Will this project utilize Federal funds?
Yes ☐ No ☐
This checklist was completed by: Title/Organization: Date: / / If the need for a permit has not been determined, forward a copy of this checklist to M.O. Structures Division, Coast Guard Compliance Unit. Determination: Permit ☐ No Permit ☐ Determination Date: / / Name: Organization: (D.O.T.-Regional Office, D.O.T.-Main Office, Coast Guard District, FHWA) Include a copy of this form in the Design Approval Document for the project after a final determination has been made.