Session 62 Henry Bollmann - Florida Department of ... · PDF fileSession 62 FL. Dept. of ... Over lapping joints at splice locations ... impact, seawater corrodes steel reinforcing

New Plastic Fenders System : Philosophy / Design Approach

Topic Description

New standard sheets for fender systems are introduced. The design philosophy, based on energy concepts, is discussed. Use of the standards and limitations are described.

Speaker Biography

Henry Bollmann is a Senior Structures Design Engineer working in the FDOT Central Office, Tallahasse Fl. Henry received his MSCE degree from the University of Florida in 1974 and has spent his entire professional career working in many facets of bridge engineering while focusing on design.

Henry Bollmann

Session 62

FL. Dept. of Transportation CO

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Structures Design Office FDOT Design Conference 2006 Structures Design Office

Fender SystemsFender Systems

Henry Henry BollmannBollmann & Jerry Hocking & Jerry Hocking -- Structures Design OfficeStructures Design Office

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Barge ImpactBarge Impact

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TopicsTopics

Fender PurposeFender PurposeDesign Guidance & SpecificationsDesign Guidance & SpecificationsStandard Index DrawingsStandard Index Drawings

Heavy Duty Fender SystemHeavy Duty Fender SystemMedium Duty Fender SystemMedium Duty Fender SystemLight Duty Fender SystemLight Duty Fender System

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TopicsTopics

Guidance for Selection of FenderGuidance for Selection of FenderDesignDesign Method and ExampleMethod and ExampleCost ConsiderationsCost ConsiderationsPlastic Pile Bending TestPlastic Pile Bending TestPile and Wale Capacity ComparisonPile and Wale Capacity Comparison

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SeabreezeSeabreeze

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SeabreezeSeabreeze

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Concrete and TimberConcrete and Timber

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Clearwater InletClearwater Inlet

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Boynton BeachBoynton Beach

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St. George IslandSt. George Island

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Evans CraryEvans Crary

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SR 312SR 312

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Purpose of Fender SystemPurpose of Fender System

In general, a bridge over a navigable waterway that is under the jurisdiction of the U.S. Coast Guard will have a bridge fender system.Primary function is to delineate channels and redirect aberrant vessels.

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Purpose of Fender SystemPurpose of Fender System

It is considered as a sacrificial structure.The channel pier is designed for full ship impact. i.e. Neglecting effect of fender system.

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Design Guidance and SpecificationsDesign Guidance and Specifications

FDOT Standard SpecificationsFDOT Standard SpecificationsNew Section 973 New Section 973 –– Material Material Requirements of Plastic Piles and Requirements of Plastic Piles and WalesWalesNew Section 471 New Section 471 –– Construction & Construction & Installation of Fender SystemInstallation of Fender SystemModify Section 455Modify Section 455--44 44 –– Installation Installation Requirements of Plastic PilesRequirements of Plastic Piles

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Design Guidance and SpecificationsDesign Guidance and Specifications

SDG Section 3.14 SDG Section 3.14 –– Fender SystemsFender SystemsSDM Chapter 12 SDM Chapter 12 –– Fender SystemsFender SystemsAASHTO AASHTO –– Guide Specification and Guide Specification and Commentary For Vessel Collision Commentary For Vessel Collision Design of Highway BridgesDesign of Highway Bridges

C3.8 Vessel Collision EnergyC3.8 Vessel Collision EnergyC7.3.1 Fender SystemsC7.3.1 Fender Systems

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New Standard Index DrawingsNew Standard Index Drawings

Index 21900 Index 21900 –– General Notes & LayoutGeneral Notes & LayoutIndex 21910 Index 21910 –– Heavy Duty Fender SystemHeavy Duty Fender SystemIndex 21920 Index 21920 –– Medium Duty Fender Medium Duty Fender SystemSystemIndex 21930 Index 21930 –– Light Duty Fender SystemLight Duty Fender SystemCADD Cells for Quantities and List of CADD Cells for Quantities and List of VariablesVariables

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Plan and ElevationPlan and Elevation

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SS Bolts

Spacer Blocks

16” dia. Piles

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SS Splice Plate

SS Bolts

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PilesPiles

Pile SpacingPile SpacingHeavy Duty Fender Heavy Duty Fender –– Spacing = 5Spacing = 5’’-- 44””Medium Duty Fender Medium Duty Fender –– Spacing = 8Spacing = 8’’-- 00””Light Duty Fender Light Duty Fender –– Spacing = 5Spacing = 5’’-- 44””

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PilesPiles

Pile LengthPile Length8 feet above MHW8 feet above MHWMHW MHW -- MLW (approx. 4 feet )MLW (approx. 4 feet )Channel depth 12 feet Channel depth 12 feet Approximate soil embedment 24 feet Approximate soil embedment 24 feet 48 feet total48 feet total

All Piles Driven Plumb All Piles Driven Plumb

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WalesWales

Wale lengths and sizeWale lengths and size16 & 32 feet in length16 & 32 feet in length

Over lapping joints at splice locations Over lapping joints at splice locations for greater continuity strength at pile for greater continuity strength at pile locations.locations.

1010”” x 10x 10”” squaresquareStainless steel connection bolts and Stainless steel connection bolts and splice plates.splice plates.

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CatwalkCatwalk

Two deck options availableTwo deck options availablePlastic marine lumber (nonPlastic marine lumber (non--reinforced)reinforced)Fiberglass open gratingFiberglass open grating

Width 2Width 2’’--66””

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General Layout Sheet and General Layout Sheet and Table of VariablesTable of Variables

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Table of VariablesTable of Variables

Control Point “C”

Station

Offset

Dimension “L”

Cle

ar

Cha

nnel

Skew Angle

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Guidance For Selection of Guidance For Selection of Fender SystemFender System

From SDG 3.14.3B and 3.14.4CFrom SDG 3.14.3B and 3.14.4CHeavy Duty Fender SystemHeavy Duty Fender System

Channel pier strength requirement Channel pier strength requirement from risk analysis exceeds 2500 kipsfrom risk analysis exceeds 2500 kipsi.e. Two loaded jumbo hopper barges i.e. Two loaded jumbo hopper barges + push boat at 4.0 knots+ push boat at 4.0 knots

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Guidance For Selection of Guidance For Selection of Fender SystemFender System

Medium Duty Fender SystemMedium Duty Fender SystemChannel pier strength requirement Channel pier strength requirement from risk analysis 1000 to 2500 kipsfrom risk analysis 1000 to 2500 kipsi.e. One loaded jumbo hopper barge + i.e. One loaded jumbo hopper barge + push boat at 3.6 knotspush boat at 3.6 knots

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Guidance For Selection of Guidance For Selection of Fender SystemFender System

Light Duty Fender SystemLight Duty Fender SystemMinor commercial traffic, pier strength Minor commercial traffic, pier strength requirement less than 1000 kipsrequirement less than 1000 kipsi.e. One unloaded jumbo hopper i.e. One unloaded jumbo hopper barge + push boat at 4.2 knotsbarge + push boat at 4.2 knots

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Design MethodologyDesign Methodology

The loss of kinetic energy of the vessel is transformed into an equal amount of energy absorbed by the protective structure. The kinetic impact energy is dissipated by the work done by the displacement of the protective system.

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Design MethodologyDesign Methodology

Develop a force versus deflection diagram via analysis or physical testing. The area under the diagram is the energy capacity of the protective system. The forces and energy capacity of the protective system is then compared with the design vessel impact force and energy to determine if the vessel loads have been safely resisted.

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Design AssumptionsDesign Assumptions

Channel Depth at MHW 12 ft.Channel Depth at MHW 12 ft.8 ft. from MHW to top of pile8 ft. from MHW to top of pileWeak cohesionless soilWeak cohesionless soil

Phi = 30 deg.Phi = 30 deg.Subgrade modulus = 20 pciSubgrade modulus = 20 pci

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Design AssumptionsDesign Assumptions

Coefficient of friction (mu) between Coefficient of friction (mu) between barge and plastic wale = 0.15barge and plastic wale = 0.15Impact angle = 15 deg.Impact angle = 15 deg.

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Design MethodologyDesign Methodology

η KEbarge⋅ Workfender≤

Governing EquationGoverning Equation

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Design MethodologyDesign Methodology

Work done by Fender System Work done by Fender System (Absorbed Energy)(Absorbed Energy)

Increment load until Pile Nominal Increment load until Pile Nominal Moment Capacity is reachedMoment Capacity is reachedFind DeflectionFind Deflection

∑Work fender

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P i∑⋅ Δ i⋅

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FBFB--Pier Model Pier Model Medium Duty FenderMedium Duty Fender

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Fender EnergyFender Energy

Area = 132 k-f

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KE12

M⋅ V2⋅

2 g⋅tonne

kip

29.18ft

sec2=KE

12

CH⋅Wg

⋅ V2⋅

KECH W⋅ V2

⋅

29.2

Barge EnergyBarge Energy

Kinetic Energy of Barge (Vessel Energy)Kinetic Energy of Barge (Vessel Energy)

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Design Example Design Example Medium Duty FenderMedium Duty Fender

1 loaded jumbo hopper barge => 1900 tons1 loaded jumbo hopper barge => 1900 tons

Push boat => 260 tonsPush boat => 260 tons

Total Weight W = 1900 + 260 = 2160 tons, 1956 tonnesTotal Weight W = 1900 + 260 = 2160 tons, 1956 tonnes

nn*KE*KEbargebarge = = nn*Ch*W*V*Ch*W*V22 /29.2= Energy/29.2= Energyfenderfender

nn = 0.05 (for= 0.05 (for mu = 0.15 & angle of impact = 15 deg.)mu = 0.15 & angle of impact = 15 deg.)fig. C3.8fig. C3.8--1 1 AASHTO AASHTO –– Guide Specification andGuide Specification andCommentary For Vessel Collision Design of Highway Commentary For Vessel Collision Design of Highway BridgesBridges

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Determination of EtaDetermination of Eta

0.05

For:

Mu = 0.15

Alpha = 15 deg.

Graph shows:

Eta = 0.05

15 deg.

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Design Example Design Example Medium Duty FenderMedium Duty Fender

1 loaded jumbo hopper barge => 1900 tons1 loaded jumbo hopper barge => 1900 tons

Push boat => 260 tonsPush boat => 260 tons

Total Weight W = 1900 + 260 = 2160 tons, 1956 tonnesTotal Weight W = 1900 + 260 = 2160 tons, 1956 tonnes

nn*KE*KEbargebarge = = nn*Ch*W*V*Ch*W*V22 / 29.2 = Energy/ 29.2 = Energyfenderfender

nn = 0.05 (for= 0.05 (for mu = 0.15 & angle of impact = 15 deg.)mu = 0.15 & angle of impact = 15 deg.)fig. C3.8fig. C3.8--1 1 AASHTO AASHTO –– Guide Specification andGuide Specification andCommentary For Vessel Collision Design of Highway Commentary For Vessel Collision Design of Highway BridgesBridges

Ch = 1.05 for under keel clearanceCh = 1.05 for under keel clearance

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Design Example Design Example Medium Duty FenderMedium Duty Fender

nn*KE*KEbargebarge = = nn*Ch*W*V*Ch*W*V22 /29.2/29.2 = Energy= Energyfenderfender

nn*KE*KEbargebarge = 0.05*1.05*1956*V= 0.05*1.05*1956*V22 /29.2= 132k/29.2= 132k--ff

Solving for velocity: V= 6.12 f/s = 3.62 knotsSolving for velocity: V= 6.12 f/s = 3.62 knots

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Initial Cost ConsiderationsInitial Cost Considerations

There are multiple sources of supply of the There are multiple sources of supply of the Structural Plastic piles and timbers. Structural Plastic piles and timbers. Therefore, there will be competitive bids.Therefore, there will be competitive bids.In terms of cost per lineal foot, Structural In terms of cost per lineal foot, Structural Plastic piles are twice the cost of 14Plastic piles are twice the cost of 14””square prestressed concrete piles. square prestressed concrete piles. Total cost of Plastic Fender System is Total cost of Plastic Fender System is approximately twice that of the 14approximately twice that of the 14”” square square concrete pile system.concrete pile system.

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Initial Cost ConsiderationsInitial Cost Considerations

However, when comparing cost you must However, when comparing cost you must consider the entire system. For example, consider the entire system. For example, the typical mediumthe typical medium--duty structural plastic duty structural plastic system uses approximately 100 system uses approximately 100 -- 1616”” OD OD structural plastic piles versus the structural plastic piles versus the traditional prestressed concrete pile traditional prestressed concrete pile system that uses over 200.system that uses over 200.

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Initial Cost ConsiderationsInitial Cost Considerations

The higher, per lineal foot cost of the The higher, per lineal foot cost of the structural plastic piles is offset by 2 structural plastic piles is offset by 2 factors:factors:

Fewer piles means the material cost is Fewer piles means the material cost is reducedreducedFewer piles reduces labor cost (less pile Fewer piles reduces labor cost (less pile driving)driving)

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LifeLife--Cycle Cost ConsiderationsCycle Cost Considerations

Expect structural plastic members to last Expect structural plastic members to last the life of the bridge (75+ years). the life of the bridge (75+ years). Stainless hardware will fail before the Stainless hardware will fail before the structural plastic piles & timbers.structural plastic piles & timbers.

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LifeLife--Cycle Cost Considerations Cycle Cost Considerations

In contrast, timber and concrete have a far In contrast, timber and concrete have a far shorter service life:shorter service life:

Timber Timber waleswales offer a maximum service life of offer a maximum service life of 1010--15 years15 yearsPrestressed concrete piles begin failing at the Prestressed concrete piles begin failing at the time of the first significant impact to the fender time of the first significant impact to the fender system. The prestressed pile cracks on system. The prestressed pile cracks on impact, seawater corrodes steel reinforcing impact, seawater corrodes steel reinforcing strands & the concrete begins to spall.strands & the concrete begins to spall.

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LifeLife--Cycle Cost ConsiderationsCycle Cost Considerations

In contrast, structural plastic fender In contrast, structural plastic fender systems absorb the energy of these systems absorb the energy of these impacts without requiring any impacts without requiring any maintenance. As a result, the structural maintenance. As a result, the structural plastic fender systems offer a substantially plastic fender systems offer a substantially lower life cycle cost for the State of lower life cycle cost for the State of Florida. Florida.

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Wale Bending TestWale Bending Test

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1010”” sq. Plastic Wale sq. Plastic Wale LoadLoad--Displacement CurveDisplacement Curve

1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 162

0

2

4

6

8

10

12

14

16

18

20

22

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new waleold wale 2old wale 1 initial testold wale 1 final test

displacement (inches)

load

(kip

s)

P = 22.4 k Mn = 78.4 k-f

Load

(k)

Displacement (in)

P = 18.5 k My = 58 k-f

My = S*Fy (Fy = 4.5 ksi)

35 %

4 – 1.25”dia. bars

4 – 1” dia. bars

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FullFull--Scale TestingScale Testing

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EnergyEnergy--Absorption ComparisonAbsorption Comparison

190 kN

42.7 k

267

mm

10.5

in

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Plastic Pile DesignPlastic Pile Design

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Fender Pile CapacitiesFender Pile Capacities

19216516” dia. FRPw/16 - 1” dia. bars

12811014” sq. PS Concrete Pilew/8 - ½” dia. strand

1008612” dia. Timber Pile

35330416” dia. FRPw/16 – 1 1/2” dia. bars

% of Timber

Pile

Mn (k-f)Element

Moment Capacities

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1074510” sq. Plastic Walew/4 - 1” dia. bars

1004210” sq. Timber Wale

1817610” sq. Plastic Walew/4 - 1 1/2” dia. bars

% of Timber Wale

Mn (k-f)Element

Moment Capacities

Fender Wale CapacitiesFender Wale Capacities

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Questions / CommentsQuestions / Comments

Henry Bollmann, P.E. Henry Bollmann, P.E. Structures Design OfficeStructures Design Office

Florida Department of TransportationFlorida Department of Transportation605 Suwannee St., MS 33605 Suwannee St., MS 33

Tallahassee, Fl. 32399Tallahassee, Fl. [email protected]@dot.state.fl.us