UIC 772-1

Std. 625.1 L 57855

UtC Code 772 -1 R

1 st edition, 1-7-1987

Standard principles for the use

of bearings made from various materials

for railway bridges

o 1 FEB 2007 st ~e

[C?~'" A L - Ii A t.J fLt\ SA H l ~~!,:,::::t:~ lternational Union of Railways

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Leaflet to be classified in Volume :

VII - Way and works

Amendments •

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J

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Contents

L - General

2. - Bearing design

3. - Dimensioning of the bearings

• 4. - Choice of bearing

•

5. - Provisions for superstructures and substructures

6. - Installation of the bearings

7. - Corrosion protection

8. - Maintenance and replacement of the bearings

Appendix: Illustrations of bearing types (Figs. 1-19)

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1- General

1.1- Scope

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This leaflet is intended as a recommendation for the use of bearings for railway bridges.

It is to be applied to the bearing construction itself as well as to their positioning with respect to the supports (abutment bed-plates, abut-ment bed-stones, blocks) and superstructures. •

Furthermore, it applies to the installation and maintenance of the bea-rings as well as to provisions for piers, columns, and abutments requi-red for the installation or maintenance of the bearings.

Piers and walls, whose elasticity permits movement, as well as long rocker piers and walls are not covered by this leaflet.

1.2 . Oassification of bearings

1.2.1 - Oassification according to function

Transmission of forces Flexibility

Bearing type (horizontally or vertically) Deflection Rotation

Fixed bearing Vertically and horizontally in None all directions

Bearing flexible to Vertically and horizontally in Horizontally one side one direction one-sided

Bearing flexible in Vertically Horizontally in One all directions all directions axis or

multiple

Horizontal force Horizontally in all directions Vertically axes

bearing

Guide bearing Horizontally in one direction Vertically and horizontally in one direction

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1.2.2 - Oassification according to construction

(1) Steel bearing.

(2) Elastomeric bearing.

(3) Pot bearing.

(4) Spherical knuckle bearing.

(5) Concrete hinges.

(6) Simplified bearing.

(7) Special constructio.ns .

1.3 - Principles of bearing design

1.3.1 - General

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1.3.1.1 - The superstructures of railway bridges must generally be sup­ported by suitable bearings or hinges on abutments and columns or piers, unless they are connected to the substructures in a flexurally stiff manner.

1.3.1.2 - The type of construction of the bearing to be used and its site of installation must be determined with a view to ensuring the sta­ble and constraint-free support of the superstructure.

1.3.1.3 - In deviation from the principles of 1.3.1.2 single-field beams in solid construction may be provided with fixed bearings on the two abutments, when the support span of such superstructures does not exceed approximately 15 m.

• In the case of very high, slim piers the use of fixed bearings is permit­ted on both sides even with longer spans. In this connection the fixing strength of the abutment or pier in the ground must be taken into account.

For highly skew superstructures this type of support is not recommen­ded.

1.3.1.4 - A simplified support without special bearing constructions can be used in the case of solid superstructures with a short span. The conditions set out in sections 2.6, 4.6 and 6.6 must be observed.

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1.3.2 .. Force transmission

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1.3.2.1 - The bearings must be dimensioned so that they can transmit the vertical and horizontal bearing forces arising during the construc­tion and use of the bridge.

The magnitude of the bearing forces must be determined in accor­dance with UIC Leaflet no. 776-1/R.

1.3.2.2 .. Horizontal bearing forces must be supported, on principle, • by fixed bearings or special horizontal force bearings. The admissibi-lity of elastomeric bearings in place of fixed bearings is governed by section 4.2.

1.3.2.3 - For the transmission of horizontal bearing forces in the direc­tion lateral to the longitudinal axis of the superstructure (e.g. arising from wind, lateral impact or centrifugal force) the bridge must be secured in each bearing axis against lateral deflection by suitable construction of the bearing.

1.3.3 .. Bearing movement

1.3.3.1- The bearings must be so designed that all movements (rota­tion and deflection), which may arise during the construction and during the use of the bridge, can be supported. For the purpose of dimensioning the bearings a safety margin must be added to these movements.

1.3.3.2 .. The angular variation at points of support arising from the deformation of the superstructure must be taken into account. For this reason it must be made possible for all fixed and expansion bearings to rotate in the longitudinal direction of the bridge (e.g. with linear rocker bearings).

1.3.3.3 .. When more substantial lateral deformation or rotation may occur (e.g. with very wide or skew bridges), the possibility of mul­tiaxial rotation must be made possible (e.g. with point rocker bea­rings).

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1.4 • Testing and approval

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The design loads, on which the bearing calculations are based, as well as the dimensioning of the bearing constructions and their connections with the superstructures and substructures should be checked by the railway.

An approval of the bearings with reference to the installation situation by the railway can be recommended .

2 - Bearing design

2.1 • Steel bearings

2.1.1 - Types of steel bearings

A distinction is made between the following fixed and expansion bridge bearings:

Fixed bearings:

- Linear rocker bearing.

- Point rocker bearing.

- Spherical knuckle bearing.

- Horizontal force bearing· .

Etpansion bearings :

- Sliding bearing.

- Roller bearing.

- Knuckle leaf bearing.

- Linear rocker - sliding bearing·.

- Point rocker - sliding bearing·.

- Guide bearing*.

Bearings marked * are treated in section 2.7 as special constructions.

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2.1.2 - FIxed bearings

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FIxed bearings shou1d have a minimum of play in order to attain direct force transmission. The effective bearing play shaH not exceed 2mm. (linear rocker bearing Fig. 1, point rocker bearing Fig. 2).

2.1.3 - Expansion bearings

2.1.3.1 • Sliding bearings

Steel sliding bearings without the use of special slip layers (poly tetra­fluorethylene = PTFE) must be built with rounded bed-plates similar to the linear rocker bearings, on which steel girders can slide.

However, they must be used only in justifiable exceptional cases and for superstructures with a short span.

2.1.3.2· Roller bearings

(1) Roller bearings have freedom of movement in one direction, which is normal to the roller axis. To ensure immovability in the direction of the roUer axis guide bars must be provided.

(2) To prevent skew movement of the rollers the bearing forces must be applied as centrally as possible. The provision of suitable guide arrangements serves the same purpose and can be recom­mended.

(3) Single roller bearings or two-roller bearings must be used. (Fig. 3 and Fig. 4).

(4) The use of rollers made from surface hardened material is not recommended.

(5) The use of pile bearings (bearings with cut rollers) should be res­tricted to exceptional applications and requires certain precau­tions. If reasons of space make the use of pile bearings unavoida­ble, a greater safety margin must be added in the calculation of the maximum horizontal deflection and, when installing the bea­rings, this situation must be considered with special care.

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2.2 - Elastomer bearings

2.2.1 - General

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In the case of the elastomer bearings the high elastic deformability and the excellent incompressibility of certain elastomers is utilised. This makes it possible to transmit forces in a direction normal to the bea­ring surfaces with little change of form, while only little resistance is offered to constrained movements parallel to the bearing surfaces .

On principle, only reinforced elastomer bearings must be installed. Their characteristic feature is that steel plates are interposed between elastomer layers.

2.2.2 - Anchoring

Reinforced elastomer bearings may be installed, as required, with or without anchoring (see Fig. 5). Anchoring may be provided either with pegs, bolts, stud plates or profiled cover and base plates. The anchoring design should make allowance for bearing replacement.

If sideward flexibility of the reinforced elastomer bearings is to be pre­vented, this can be obtained by providing appropriate steel retaining fixtures (see Fig. 6), installing round steel anchors or setting into concrete (see Fig. 7).

2.3 - Pot bearings

2.3.1 - Pot bearings consist of a round elastomer plate, which is enca­sed on all sides by an upper and lower steel plate as well as a steel ring.

Under high pressure the elastomer plate behaves like a liquid and, therefore, permits angular variations in all directions (Fig. 8).

Pot bearings can transmit high loads and have a low construction height. Horizontal forces are transmitted through the contact pressure between the steel ring and the bearing plates.

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2.3.2 - The use of a PTFE slip disc pennits horiwntal movement of the bearing. With the installation of a guide fixture this deflection pos­sibility can be limited to one direction.

2.3.3 - Special attention is drawn to the limited life of the elastomer plate. As a rule, pot bearings should not be used in areas where pro­longed periods of temperatures below - 30 °C may occur.

2.3.4 - Pot bearings must be anchored. In the case of concrete support • structures anchoring should generally consist of dowelled setbolts, in the case of steel support structures, of customary steel construction joints (bolts or welds).

2.4 - Spherical knuckle bearings

2.4.1 - Spherical knuckle bearings are used, when angular variations between under- and substructure in any direction are to be made pos­sible.

2.4.2 - In the case of spherical knuckle bearings angular variation is achieved by the sliding of a cup-shaped element in a spherical bearing bowl with the same radius.

To reduce friction one friction surface is covered with a thin PTFE slip layer, which slides over the other friction surface consisting of • polished rust-free, hard chromium plated or austenitic steel (see Fig. 9).

If additionally a further PTFE slip disc and steel plate are installed in the bearing (see Fig. 10), horizontal movement in one or any direction can be provided (spherical knuckle - sliding bearing).

2.4.3 - In the case of a low vertical force and high horizontal forces spherical knuckle bearings should not be used or only with special care.

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2.5 - Concrete hinges

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Concrete hinges must be used only in special cases. Normally, they are designed in the form of linear bearings with freedom of movement about one axis (see Fig. 11).

The hinge neck is reduced in strength as much as possible in both directions and circularly rounded in the area of height t to prevent concrete from splitting off. The arrangement of reinforcement steels through the hinge neck is not absolutely necessary. They must be arranged to lie only in the direction of the normal force.

2.6 - Simplified bearing

In the case of solid superstructures with a short span the following simplified bearings may be used:

- direct bed-plate on a separating layer of bituminous board, rubber or cork in accordance with Fig. 12,

- direct bed-plate in accordance with Fig. 13. Force transmission is through vertical or vertical and cross-wise slanting steel bars,

- 20 to 50 mm thick mortar ledges combined with round steel bar anchors to contain the horizontal forces,

- rails or steel sections set in concrete, horizontal movement being prevented by suitable stops on an upper bearing plate.

• 2.7 - Special constructions

2.7.1 - General

2.7.1.1 - Special constructions are defined to be bearings designed to perform functions, which cannot, or only partly, be fulfilled by the bearings of conventional design described in the other sections of this leaflet (steel bearings, elastomeric bearings, etc.).

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2.7.1.2 - So as to comply with the conditions imposed on special bea­ring constructions the construction elements of conventional bearings - e.g. rocker ledges, slip layers, rollers, etc. - are often used in the design of such bearings in a suitable manner.

2.7.1.3· Since special bearing constructions are generally much more expensive than bearings of the conventional types, they should only be installed in situations where the desired effect cannot be obtained with conventional constructions.

2.7.2 - Types of special constructions

In accordance with the current state of technical development the main special bearing constructions are the following:

(1) Horizontal force bearings (Fig. 14).

(2) Guide bearings (Fig. 15).

(3) Rocker hinges (Fig. 16).

(4) Sliding bearings (PTFE).

These are used in combination with the bearings mentioned in the other sections (linear rocker bearings, point rocker bearings, spherical knuckle bearings, pot bearings, elastomeric bearings) with the provi­sion of a special sliding plane formed from PTFE. There are :

- Linear rocker - sliding bearings (Fig. 17).

- Point rocker - sliding bearings (Fig. 18).

- Spherical knuckle - sliding bearings (Fig. 10).

- Deformation - sliding bearings (Fig. 19).

(5) Compound bearings.

(6) Bearings for containing negative bearing forces (hold-down constructions).

(7) Adjustable bearings.

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3 - Dimensioning of the bearings

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The bearing dimensions required are determined in accordance with the construction to be used, based on the bearings reactions and taking into account the rotations and deflections to be expected. This can be accomplished by :

- the use of approvals,

- calculation in accordance with the usual methods of strength theory,

- tests .

3.1 - Steel bearings

Dimensioning of steel bridge bearings must generally be carried out with the usual methods of strength theory, respecting the material characteristics of the steel used.

3.2 - Elastomeric bearings

Dimensioning of elastomeric bearings must be carried out in accor­dance with the provisions of UlC Leaflet No. 772-2 R.

3.3 - Pot bearings

3.3.1 - As a rule, dimensioning is governed by the manufacturer's spe­cifications. He must be able to prove that the suitability of the bea­rings has been demonstrated by tests and that all calculable elements were dimensioned in accordance with accepted state-of-the-art stress

• theory.

3.3.2 - In particular, the following proof must be provided :

- The required bearing size is determined from the vertical bearing reaction, taking into account the permissible average elastomeric pressure and the permissible concrete pressure in the bearing joint.

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- The horizontal force is transmitted from the upper bearing plate to the lower bed-plate through the pot ring, which must be appropria­tely dimensioned.

3.4 - Spherical knuckle bearing

Dimensioning is governed corresponding with the information given in 3.3.1.

3.5 - Concrete hinges

Concrete hinges are regarded as imperfect hinges, because a rotation is only possible by mostly plastic deformation. Their use, therefore, is only permitted with the following restrictions:

(1) The maximum lateral force acting on the hinge must not exceed 115 th of the associated normal force.

(2) The ratio between the residual normal force and the maximum normal force must be greater than 0.5.

(3) The width of the neck a must not be smaller than 10 em and not greater than 30 em or 0.3 d (see Fig. 11).

The following stress calculations must be carried out :

- Calculation of the permissible normal force.

- Calculation of out-of-centre due to lateral moments.

- Calculation of the angle of the hinge reaction.

Calculation of the split-resisting tensile reinforcement in the hinge area.

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3.6 - Simplified bearings

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In the case of the simplified bearing construction the transmission of the vertical and horizontal forces must be calculated, normally, by assigning:

- the vertical loads to the concrete and

- the horizontal loads to the steel reinforcements (vertical pins or crossed oblique steel bars).

The transmission of the vertical loads may also be assigned to the ver­tical steel reinforcements alone. The concrete is then regarded as pro­viding corrosion protection only.

3.7 - Special bearings

As regards bearings consisting of a combination of several construc­tion elements the specifications and calculations applicable to the spe­cific elements apply.

4 - Choice of bearing

The following important aspects govern the choice of bearing:

(1) Static loading

Vertical loads. Horizontal loads. Deflection values . Rotational angles.

(2) Constructive restraints Superstructure. Abutment bed. Piers.

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(3) Climatic conditions and environmental influences Temperature. Moisture. Chemicals.

(4) Technical maintenance and preservation requirements Accessibility . Exchangeability.

(5) Economics

Repair liability. Durability.

(6) Aesthetic requirements Object design. Landscaping.

4.1 - Steel bearings

4.1.1- Unless pot bearings or special constructions are preferred - steel bearings may be used very successfully with steel support structures as well as with steel reinforced concrete and prestressed concrete support structures.

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4.1.2 - Linear rocker bearings may only be used in applications, where a principal rotation of the point of support is expected to occur in only one direction. When constructing the bearing, care must be taken that the pivotal axis of the bearing is situated to correspond with the • rotational direction of the support structure. This must be especially observed for skew support structures, in particular in the case of slabs.

4.1.3 - Point rocker bearings must be used wherever the point of sup­port has freedom of rotation in all directions.

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4.1.4 - Ro11er bearings must be used when horizontal deflections can occur in one direction only. Care must be taken that the direction of movement of the point of support of the structure and of the bearing rollers are coincident.

4.1.5 - When multi-axial deflections or rotations cannot be supported with conventional steel bearing constructions, special constructions must be used (e.g. spherical knuckle - sliding bearing, rocker - sli­ding bearing) .

4.1.6 - Steel bearings have the following advantages:

-long service ]ife,

- ease of inspection and maintenance,

- favourable temperature behaviour.

4.1.7 - The following disadvantages of steel bearings need to be men­tioned:

- extreme force concentrations in the bearing roHers and bearing lines,

- great construction height, especially in the case of bearings with two-directional flexibility,

danger of roller blockage, e.g. by corrosion.

4.2 - Elastomeric bearings

Reinforced elastomeric bearings can be used to support solid supers­tructures as well as steel substructures.

When selecting the elastomeric material, the sensitivity of the material to oil products, UV radiation, ozone and low temperatures must be considered.

For reasons connected with the track a floating support cannot be recommended. It is only permissible with a thickness t ~ 25 mm of the elastomeric material and a superstructure span up to approximately 15 m. The track should be of the continuous welded type or rail joints should be at least 40 m distant from the ends of the support structure. The latter should be secured crosswise mechanically.

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Elastomeric bearings are suitable for supporting greater horizontal forces only when special fixing-down constructions are provided.

4.3 - Pot bearings

Pot bearings can be used to support concrete as well as steel supers­tructures. Depending on whether it must be possible to transmit hori­zontal forces in one or several directions, pot bearings are constructed in the form of :

- fixed pot bearings, •

- pot bearings flexible in one direction,

- pot bearings flexible in all directions.

With an appropriate constructive design of fixed and one-directionally flexible pot bearings large horizontal forces can be supported.

4.4 • Spherical knuckle bearings

Spherical knuckle bearings must be selected when the point of support cannot deflect into any direction, but greater rotations in all directions are to be permitted.

Section 3.3 also applies correspondingly to spherical knuckle bearings.

4.5 ... Concrete hinges

The scope of application is restricted to structures built of in-situ cast concrete and is then mainly used as a special solution for selected pro­jects.

4.6 - Simplified bearings

The scope of application covers superstructures built of in-situ cast concrete and pre-cast components, including piers.

When used as fixed, conditionally rotatable bearings for the support of vertical and horizontal forces, it is permissible to use mortar ledges in combination with pins as well as a support on rails set in concrete for a superstructure span up to ~ 10 m.

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4.7 .. Special bearings

4.7.1- Horizontal force bearings and guide bearings

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Horizontal force or guide bearings must be installed, when the vertical loads of a support structure are taken up exclusively by bearings flexi­ble in all directions.

All horizontal forces must then be supported by horizontal force bea­rings (if horizontal forces act in all directions) or guide bearings (if horizontal forces act in one direction only).

4.7.2 - Roller hinges

Clad roller hinges are used when linear movement of the point of sup­port is impossible and rotation in one direction is required.

4.7.3 .. Rocker-sliding bearings

Rocker-sliding bearings (i.e. bearings with a rocker ledge and a sliding layer) must be used when rotation of the bed-point in one or several directions is to be expected and capabiJity of deflection in all direc­tions is desirable.

A distinction is made between point rocker-sliding beating and linear rocker-sliding bearing.

4.7.4 - Deformable-sliding bearing

Deformable-sliding bearings consist of a deformable bearing (elasto­meric bearing) in combination with a slip layer (PTFE).

To be used when the possibility of deflection in all directions is requi­red, but the deformability of an elastomeric layer is sufficient.

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5 - Provisions for superstructures and substructures

5.1- Provisions for superstructures

When bearings have to be replaced or adjusted, it must be possible to raise the superstructure. This can be achieved by the application of jacks to appropriately dimensioned lifting girders (lifting cross-beams) or to the main girders. As a rule, the aim should be to make provision for lifting in the abutment axis.

5.2 - Provisions for substructures (Abutment bed)

5.2.1- Continuous reinforced abutment beds nlust be provided prima­rily. Provisions must be made for the possibility of lifting the support structure by means of jacks - normally from the abutment bed - for bearing replacement.

5.2.2 - For this reason the abutment bed must be designed so that during lifting the jacking forces can be supported and safely transmit­ted. The application points for the jacks must be entered on the design drawing as well as unmistakably marked on the abutment bed by suitable methods.

5 .. 2.3 .. A bearing joint consisting of cement mortar or plastics mortar must be provided between bearing and abutment bed (except for dry laid elastomeric bearings). When using cement mortar, the joint thickness should not be less than 2 cm and not be more than 5 em.

5.2.4 - The bearing members should be easily accessible at all times.

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For inspections, replaeement or adjustment of the bearings a clear • space of at least 60 cm must be provided between the bottom edge of the support structure and the top edge of the abutment bed.

Bearings with a low construction height must be set on steel reinfor­ced concrete abutment blocks which must be connected to the abut­ment bed in a flexural and shear resistant manner and suitably dimen­sioned for the forces encountered.

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6 - Installation of the bearings

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Care must be taken to ensure that the bearing forces and calculations agree. This applies especially in the case of statically indeterminate and skew or torsionally stiff support structures. In such cases it is defi­nitely to be recommended that bearings be installed in conformance with force conditions and not according to geometrical considerations, as small height variations may entail great variations in the bearing reactions. Self-levelling mortars may be used .

When support structures have to be pushed or lifted into position during brief traffic breaks or brief track closures, the infill mortar used must be a material, which attains a high strength in the shortest possi­ble time so that on resumption of railway traffic the full traffic load can be transmitted from the bearings to the abutment bed.

6.1- Steel bearings

In the installation of steel bearings the following points, among others, must be observed:

- Unrestricted and unconstrained flexibility and rotatability by appro­priate arrangement of the pivotal or roller axis.

- Anchoring of the bearings by suitable methods (pins, thrust pieces, etc.), which ensure proper transmission of the horizontal forces into the abutment bed.

- Suitable provisions for bearing replacement.

- Displacement of the bearings, while ensuring the parallel arrange-ment of top and bottom bearing plates.

- Correct choice of bearing adjustment in the case of roller bearings (installation temperature).

6.2 - Elastomeric bearings

The following principles must be observed, when installing elastomeric bearings:

- in the case of bearings with rectangular cross-sectional dimensions the shorter side must always be arranged to be normal to the main axis of rotation,

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- in exceptional cases the bearings may be installed dry without a mortar layer,

- the horizontal forces in the lateral direction of the superstructure must by design be transmitted in such a manner that no lateral deflection can occur,

- anchored bearings also must be designed to be replaceable,

- to compensate for inaccuracies inherent in the construction, espe-cially in the case of deviations from parallel between the bearing surfaces, a margin must be added to the calculated angle of rota- • tion.

6.3 - Pot bearings

The following must be observed during installation :

- in the bearing area the superstructure must have flat, horizontal sur­faces,

- it must be ensured that under-filling extends over the full surface,

- exchangeability must be ensured.

6.4 - Spherical knuckle bearings

The conditions stated for the steel and pot bearings apply correspon­dingly.

6.5 - Concrete hinges

In the construction of concrete hinges the quality of the concrete is of • special importance.

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6.6 • Simplified bearings

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In the case of in-situ cast concrete constructions attention must be paid to the flawless encasement of the reinforcement steel with well compacted cement mortar to achieve corrosion protection. When constructing bearings with precast elements, it is important to ensure parallel alignment of the superstructure and bearing surfaces.

6.7 • Special constructions

When installing special bearings, the manufacturer's instructions must be observed; in all other respects the fundamental instal1ation condi­tions stated for the other bearings apply correspondingly.

7 - Corrosion protection

Corrosion protection of steel bearing components is normally provi­ded using the same procedures as those applied to steel superstruc­tures.

The small dimensions of the bearing construction permit the use of hot galvanisation (provided the material is suitable·) or spray zinc pla­ting. This can provide increased durability compared with applying paint alone.

8 - Maintenance and replacement of the bearings

• 8.1 - Maintenance

The proper functioning of the bearings should be checked regularly. In particular, the following must be checked:

- the alignment of the bearing components depending on tempera­ture,

- firm seating of the top and bottom plates.

(*) In the case of high strength steels attention is drawn to the danger of brittle frac­ture due to hydrogen absorption.

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- condition of the bearing infill,

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- effectiveness of the elastomer layers,

- twist and deflection of the elastomer layers,

- gap thickness in the case of pot bearings,

- interaction of the various elements of pot bearings.

In addition, maintenance comprises cleaning, possibly lubrication, as well as repair or renewal of the corrosion protection and bearing infill.

Treatment of the bearings with oil and grease should be limited to • exceptional cases and is generally not recommended, because this would promote dirt accumulation.

In the case of larger support structures built of pre-stressed concrete checking of the bearing reactions by measurement is recommended.

8.2 - RepJacement

Generally, bearings have a shorter life than other elements of a rail­way bridge. Bearing replacement, therefore, must be regarded as a nonnal process.

Provision for lifting the superstructure, as required for replacement purposes and certain maintenance activities, should be made in the original construction (see section 5).

Nonnally, jacks are used for lifting.

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In exceptional cases space conditions may require the use of especially flat jacks (box jacks).

During replacement it must be remembered that all forces normally transmitted through the bearing must be supported by other means.

This is especially important, if railway traffic is not to be interrupted.

When replacement of the bearing is impossible - a situation, which should be permitted only in exceptional cases - the bearing must have a simple, robust and particularly durable construction.

(final version)

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LINEAR ROCKER BEARING

• Upper bearing plate

H L :=:.-:~ ! " { { "I Rocker ledge

Lower bearing plate

• SECTION B-B

FIGURE 1

27

SECTION A-A

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H . Q

POINT ROCKER BEARING

• Rotatable Rotatable

Upper bearing plate

HL

Spherical rocker

Lower bearing plate

• A.J SECTION B-B

FIGURE 2

/ ( \ ~

SECTION A·A

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He

• Rotatable

•

SINGLE ROLLER BEARING

Upper bearing

Guide stri

Roller • I . J Indicator

A.J SECTION B-B

Guide stri

Lower bearing

plate

p

~

plate

FIGURE 3

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BI i I r

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B~ SECTION A-A

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• Rotatable

•

TWO-ROLLER BEARING

I (

\ Iv

Moveable -c:::)-- -- -- -- ~I

Rocker plate

t-E2L _. 7]1 ----'-1 j-t----- Rocker ledge

Upper bean

Guide

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Rolle Indicati

Guide

Lower bean

A~ SECTION B·B

~ plate

ip

ip

g plate

FIGURE 4

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BI

B~ SECTION A·A

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H limited

Limited movement ...c::t--- - - - -c:-

• • REINFORCED ELASTOMERIC BEARING

(Rubber laminated bearing)

Elastomer layer

Steel plate \ "OlE t=e= : CIr/::::::.: Non-anchored

.:I===== .. --..... ------~ elastomeric

~ Rotatable within limits

J ~ abO bearing

J..~r~2 5 2 ·

abO

-=tr~~ ~~l ~~

abO

FIGURE 5

Anchored elastomeric bearing with freedom of movement to all sides, anchored by pins or bolts

Anchored elastomeric bearing with freedom of movement to all sides, anchored by round dowel plates

Anchored elastomeric bearing with freedom of movement to all sides, anchored by profiled plates

• • ELASTOMERIC BEARING, FIXING-DOWN ARRANGEMENT

Longitudinally fixed Dowelled set-bolts

-t IP. QI

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Laterally fixed

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p / Dowelled set-bolts

/ u

_D:~~ ___ ,' __ u~ 10 c _ _ c..fr-15

_---=b=----_-' 10

o o ...-

8 ... -

I ~ I

.....:J FIGURE 6 .....:J

N

~ t-l

• ELASTOMERIC BEARING

I

• Pre-fabricated superstructure element

Clearance for pins

Round steel 8 mm dia. appro 500 rom long, weld-jointed

Steel tube

Pins t/J == d

Reinforced elastomeric bearing

Elastic rubber pad

Abutment bed

Cement mortar, fast setting

Profiled clearance

I Reinforced elastomeric bearing -- ---t--------'--'-- 1

I I I

----to--J -=:J--- - - - ---c:>-

Moveable Elastic rubber pad

Detail Z ________

r-------+----_-... Steel tube

I~ .. ,--l ___________

.. ~ rr.z::_ .:z:::z:::z::z:. ;;::;1:;::7.(. :::z:z:z::. ::f:tf_ .)!~~.. \\\ ~ - Round steel anchor '\ cil' Y--e ------\,,--- // ~

:::--' -ti

FIGURE 7

I w 'C

I

•

Elastic pot bearing

Rotatable within limits

Fixed pot bearing

! (

\

Rotatable within limits

H

I (

\

POT BEARING

Moveable

FIGURE8a

FIXED POT BEARING

FIGURE 8b

•

"-------

Austenitic steel plate

PTFE layer

Sliding plate

Pot

Seal

Elastomer

Piston ~

Pot I-"

Seal

Elastomer

.......

....... N

= ~

• Rotatable

Hl

•

SPHERICAL KNUCKLE BEARING

Rotatable

I I \

-43-

~ "\,,,,~ Sphe~~ surface VI ~. '< " , • , . Austemtlc steel plate

A~ PTFElayer B~ SECTION B-B SECTION A-A

FIGURE 9

772-1

R

HO

• ( t

Rotatable l \ Ai

• A~ SECTION B·B

SPHERICAL KNUCKLE . SLIDING BEARING

Rotatable

Austenitic steel plate

! ( l

\

!v

BI

-45-

---........, =:2 Moveable ---c-

=T'~:/-7(/ ~//Z7;777/j Sliding plate

Spherical surface ~)~ . M-I

PrFE slip layer "' . J_/ .

Austenitic steel plate B:J SECTION A·A

FIGURE 10

772-1

R

• •

CONCRETE HINGE

d

~MZ ____ '0}~ ___ . -'~CI:----b-- --·IJ>~·

-~-----"""'1 f.L Q ____

Geometrical conditions

a ~ 0.3 d

a~0.4 b

~ ,-c:.~-- 1-----"'=-,

br~0.7 a~4cm

b = arbitrary

t~0.2a~4cm

tanp-~

FIGURE 11

I ~ -..I

I

! Rotatable ( within limits

\ Elastic decay-resistant, H L intenne diate layer

(

Rotatable i within limits \

I

~

o In C" ...

• • DESIGN OF IN-SITU CAST CONCRETE CONSTRUCTIONS

-

FIGURE 12a

o ltl I

o N

- Separating layer, e.g. bituminous board

DESIGN OF CONSTRUCTION USING PRE·FABRICATED COMPONENTS

Jv

Ce~ent mortar, fast setting

FIGURE 12b

Simplified bearing

I to I

SIMPLIFIED BEARING

•

• FIGURE 13

-51-

772-1

R

• Hl c-v#g~

A~ • SECTION B-B

HORIZONTAL FORCE BEARING

Top plate

Support block

Bottom plate

FIGURE 14

-53-

1/ /// Lt··c;::, ,\" <]/ / / / /1

B~ SECTION A-A

772-1

R

HQ

• H

A~ • SECTION B-B

GUIDE BEARING 772-1

R

Top plate

Support block

Bottom plate

FIGURE IS

55-

8......e 1 Moveable

-=:::J-- - -.- --c::-

=:f7 /1Z42???{~ ---ICd~;;;~~,~,~ ~-~'4---I-J ------;wW&d»?P/~

B - J SECTION A-A

ROLLER HINGE

• ! { Rotatable

\

• SECTION B·B

FIGURE 16

-57-

r BI n n II II _ ......... _

I I

II

~.J SECTION A-A

II U

772-1

R

! Jv

• Rotatable l Ai \

Moveable -=:J--- - - ---c:-

• A -SECTION B-B

LINEAR ROCKER - SLIDING BEARING

-59-

IV

Bj Austenitic steel plate,

Moveable / " -0--- - -- ---c:-

Sliding plate

PfFE layer Top bearing plate

Rocker ledge

Bottom bearing plate

"" " '" '" '" "

B~ SECTION A-A

FIGURE 17

772-1

R

•

•

POINT ROCKER - SLIDING PLATE -61-

Rotatable ( r Iv

Ai !

Rotatable r

\ ____ r~~~~~~~¥~~.~~~~/~~~=~A-~~- \B~ V2Vff0~~:; ~5¥; ~ Sliding plate ,",- -co-- Moveable ~. ~# '" ~ .- .' ,i' " .~ ~ ~ ) • i

Moveabl~ .",.. ~

A~ SECTION B-B

PTFE layer Top bearing plate

Rocker ledge

Bottom bearing plate

FIGURE 18

SECTION A-A

772-1

R

•

•

Rotatable within limits

! {

\

Iv

AI

A~ SECTION B-B

DEFORMABLE SLIDING BEARING

Sliding plate

Austenitic steel plate PrFE layer

PTFE holding plate Elastomeric bearing

FIGURE 19

Rotatable within limits

B~ SECTION A·A

-63-

772-1

R

•

•

-65 -

Application

As from 1 July 1987. All railways in the Union.

Record references

Heading under which the question has been examined:

772-1

R

- Question 7/ J /17 - Establishment of common principles for the use of various types of bearings for railway bridges. (Sub-Committee for Bridges: Paris, January 1987) .

~t~~ " 6 2.. 6~ . ,1 <s ?- '1 ,5 /J-

•

•