- Bridge articulation and bearing specification
- Bridge ABUTMENT DESIGN EXAMPLE
Bridge abutment bearings
General design rules. A common solution to this problem is to use tapped holes in the taper plate, which is then welded to the underside of the girder; when using this detail, the horizontal forces on the bearing need to be minimised. The bridge designer should specify the expansion joints in a similar manner to bearingsgiving details of characteristic and design values of displacements to the joint designer. Restraint against longitudinal forces should be provided at one support, with guided restraints aligned to allow movement at the other supports. The proposed deck consists of 11No. When this load is applied on the deck it will act at bearing shelf level. Spans should be arranged so as to avoid uplift at bearing positions it is a very complex and costly matter to provide restraint against uplift in a bearingparticularly when dealing with skewed structures. About Projects Contact Welcome.
Simple bridge bearing layout (single span on pot bearings) accommodated by an expansion joint, which isolates the abutments from the displacements and. Many types of abutments can be satisfactorily utilized for a particular bridge site.
If both abutments are connected by fixed bearings to the superstructure (as in. Let us assume that this maximum shade air temperature of 16oC for fixing the bearings is specified in the Contract and design the abutments.
If the deck is guided radially, then the accuracy of the geometry becomes critical for the bearings furthest from the fixed point.
In some cases, there is also a rotation about a vertical axis associated with plan bending of the structure but this is usually small in magnitude. Menu Home About. Attachment of bearing by bolting through girder flange.
The following is an attempt to guide the designer through the relevant parts of the Eurocodes relating specifically to bearings and expansion joints as the onus is on the designer to specify the range of displacement at the ultimate limit state.
The abutments also support the bearing devices and the.
Read chapter 10 Bridge Bearings: TRB's second Strategic Highway Research Program (SHRP 2) Report S2-R19A-RW Design Guide for Bridges for Service. During conventional bridge construction, bridge bearings are set during the In bridge engineering, the abutment, piers, and other support structures are called.
Initial Sizing for Base Dimensions There are a number of publications that will give guidance on base sizes for free standing cantilever walls, Reynolds's Reinforced Concrete Designer's Handbook being one such book.
For a Group 4 type structure see fig.
Examples of bearing layouts for a 2-span bridge on pot bearings. Sc, C. Analysing the fixed abutment with Load Cases 1 to 6 and the free abutment with Load Cases 1 to 5 using a simple spreadsheet the following results were obtained: Fixed Abutment Base:.
Serviceability and Ultimate load effects need to be calculated for the load cases 1 to 6 shown above.
Bridge abutment bearings
|Further examples of bridge articulation arrangement are given in Guidance Note 1.
Clause A. Guide bearing.
Video: Bridge abutment bearings Jacking and Bearing Removal Video
Most bridges will require some form of mechanical restraint to resist the horizontal forces and ensure that thermal expansion and contraction occurs in the right direction.
Generally, the structure will rotate about longitudinal and transverse axes at its supports and these rotations must either be accommodated in the bearings or the bearings must be designed to resist them in which case the effects on the structure must also be considered.
Abstract: Integral abutment bridges provide an excellent alternative to conventional bridges built with bearings and expansion joints.
Integral abutment bridges. expansion joints and bearings at supports, simplified construction, and reduced. Notes: 1. All abutment and wingwall concrete shall be Class D (Bridge). 2.
This puts the elastomer under high pressure, making it behave like a liquid, permitting rotation in any direction with very little resistance. Eurocode 1: Actions on structures: General actions.
Different load factors are used for serviceability and ultimate limit states so the calculations need to be carried out for each limit state using 'at rest pressures' Using the Fixed Abutment Load Case 1 again as an example of the calculations:.
The advantage of these bearings is that torsional restraint is provided about the axis orthogonal to the line of contact and therefore can be useful in U frame bridges. All horizontal forces and movements are then accommodated by shear deformation of the bearings.
Elastomeric bearing. At road level, these movements are accommodated by an expansion joint, which isolates the abutments from the displacements and maintains the integrity of the surfacing at the end of the bridge.