Bearing and girder movement was monitored on both bridges. Pdhonline course c485 2 pdh fhwa bridge inspection manual section 9 bridge bearings 2012 instructor. As all the loads from the superstructure are transferred through the bearing and the movement is also controlled, albeit being a small item in the overall bridge. Steel bridge bearings may be divided into three general types. Kansas department of transportation bridge construction manual version 107 kdot bridge section 11. The elastomeric bearing pad and its role in bridge design.
This is typically made of a strong and pliable material such as neoprenea type of heavyduty industrial rubber. Pot ptfe bearings are capable of bearing vertical load, horizontal forces and allows movement as well as rotation alongany horizontal axis. Fhwa bridge inspection manual section 9 bridge bearings. Stage 4 completed structure once the deck has hardened, the steel bridge girders are composite with the deck and stability of the top flange is provided. User guide to bridge standard detail sheets, section 9. Bridge bearings introduction aashto defines a bearing as a structural device that transmits loads while facilitating translation andor rotation. Different bridge bearings have different appearances, but all of them are in small size, which means they are smaller than bridge deck sometimes even the piers they sit on. Bridge bearings, which are applied to support the upper structure of the railway bridge, should be designed to accommodate a high rotation angle that may be induced by wheel load since unlike.
Bridge decks supported by piers are susceptible to damage due to movement of the vehicle and heat expansion. The purpose of a bearing is to allow controlled movement and thereby reduce the stresses involved. These horizontal forces require that bearing stability be investigated. Bridge bearing fuse systems home northeastern university. To model a different bearing layout, delete the links automatically created, then, outside. Memo to designer s 71 june 1994 bridge bearings introduction aashto defines a bearing as a structural device that transmits loads while facilitating translation andor rotation. D, pe retired pdh online pdh center 5272 meadow estates drive. Whether bearings are proprietary or fabricated, their design and manufacture must conform to en 37 ref 3. Bridge design bridge abutment design example to british. To insure stability, total bearing thickness should not exceed the smaller of l3, b3 or. Bearings can be fixed in both the longitudinal and transverse directions, fixed in one directi on and expansion in the other, or expansion in both directions. Spherical bearing, also called spherical bridge bearing, is one type of bridge bearings with large rotation capacity. Bearing pads are either plain or reinforced with respect to the loads defined. Introduction elastomeric bearings introduced nearly 60 years ago, laminated steelelastomer bearing pads are now in.
Articulation is the term for the configuration of bridge supports and choice of structural bearings that provides the necessary restraints to the superstructure whilst at the same time providing freedom to some displacements and rotations in order to avoid unnecessary forces on both the superstructure and substructure due to constraint. Van lund, washington state department of transportation the washington state department of transportation wsdot has removed and replaced nonfunctioning bridge bearings to extend the service lives of existing bridges. Kinedyne incorporated, established in 1982, has been a leader in the bridge industry for over 30 years. It is noted that stability is a part of bridge bearing design, and that bearings must be designed and detailed to meet required vertical and horizotal load capacities. Bridge bearings california department of transportation. Ccl advanced solutions help create innovative bearings that anticipate. Elastomeric bridge bearings have generally performed satisfactorily under current aashto and state dot materialstest methods and requirements. The san franciscooakland bay bridge elastomeric bearing pad role of the elastomeric bearing pad. The bearings broke due to excessive lateral load at the inclined. Movement could be thermal expansion or contraction, or movement from other sources such as seismic activity. This website and documents are provided for use by persons outside of the kansas department of transportation as information only. This chapter also addresses corrosion protection measures. The architects of extensions must assure themselves that bridge bearings can transmit the highlevel heaps of current outlines.
The bridge deck is fixed in one corner and horizontal movements are controlled by the use of guided unidirectional bearings. We pride ourselves on designing and fabricating the best solution for each project. The effect of resetting the original natural rubber bearings at the slaughter creek bridge was compared with the effect of replacing the rubber bearing with a neoprene bearing. Bridge rehabilitation world scientific publishing company. Many of our products are available either sealed or unsealed and are suitable for. During the earthquake, all bearings under the superstructure of this bridge have been damaged figures 195 and 196. Reinforced elastomeric bearings are an often used type of bridge bearings and already been installed in many kinds of structures all over the world. The extent of flat to vertical load is expanding because of the present pattern toward constant.
And the purpose of bridge bearing is to transfer forces from the superstructure to the substructure or reduce the ground vibration to the superstructure. Inoperable roller nests and seismically vulnerable. The required passage may be for a road, a railway, pedestrians, a canal or a pipeline. Department of transportation federal highway administration by the. Bridge bearings, structural bearing, ptfe sliding bearing. While covering the subject of bridge bearings during various courses at iricen the absence of a document covering all aspects of different types of bridge bearings was acutely felt.
Examples of this sort of direction are axial ball and roller bearings. These include rockers, rollers, pins, pots, steel girder hangers, ptfeelastomeric, and elastomeric pads. Bridge bearings are small integral parts of the entire bridge structure serving several purposes, such as connection, transfer of forces, allowing movements, force damping etc. Bridge bearings trelleborg marine and infrastructure. Furthermore, if the horizontal shear force is greater than onefifth of the minimum permanent dead load, the bearing. Sliding multidirectional ptfe spherical bearings allow polytetrafluoroethylene horizontal movements in any direction. Kinedyne manufactures a wide variety of expansion joints and high load bearing components for highway bridges including, but not limited to, the following. Latest developments and applications for bridge bearings summary. A bridge bearing is a superstructure element that provides an interface between the. Bearing design spread sheet based on aashto 16th edition 1197 interim method a aashto lrfd by arp visit. In addition, they are easily installed and maintenancefree. Test methods for elastomeric bearings on bridges by y. That standard comprises numerous separate parts, relating to general rules, and rules for individual types of bearings or components of bearings.
Nevertheless, there has been concern that bearings are being unnecessarily rejected because of noncom. Bridge bearings, structural bearings, ptfe sliding bearings, rocker bearings, pot bearings, pin bearings, level sensors, detectors, indicators, point level switches. Depending on the area of application and country requirements maurer elastomeric bearings can be supplied in accordance with various standards, e. Although many different types of bridge bearings have been used by the nysdot, elastomeric and multirotational bearings are the. Fhwa bridge inspection manual section 9 bridge bearings 2012 instructor. A uniaxial displaceable pot bearing guided pot bearing releases the lateral movements of bridge in any one direction utilizing a guide on the lid and a guiding groove in the gliding plate.
A bridge bearing is a component of a bridge transmitting the loads received from the deck on to the substructure and to allow controlled movement due to temperature variation or seismic activity and thereby reduce the stresses involved. Bridge flexibility is primarily achieved by a component called bridge elastomeric bearing pad. The selection of the target reliability assumes a significant amount of redundancy in the foundation system is present, which is typical for pile groups containing at least five piles in the. Anulab pot cum ptfe bridge bearing 260 mt rotation test as per irc 83 part iii. For stability, the total effective height of the rubber should not be higher than a quarter of. Rocker and pin bearing should be considered when the bridge movement is adequately known and described, since such bearings can make rooms for both translational and. Laminated elastomeric bearings with known rated loads bearings to australian standard 5100. Bearings are designed and manufactured to transmit vertical and horizontal loads from the superstructure to the substructure, while allowing specific movements and rotations of the superstructure caused by wind or seismic effects, temperature variations, deck deflections, elastic shortening due to creep, shrinkage or posttensioning, etc.
Simple bridge bearing layout single span on pot bearings the arrangement above shows the layout for a simple single span structure with skew. Steel bridge design handbook bearing design volume 15. Joint failure can lead to increased damage to bridge substructures including rust formation on metal bearings as well as increased spalling on precast beam ends, concrete abutments, and concrete piers. Pdf bearing is very small part of bridge compared to all other components. The loadmeasuring pot bearing with builtin load cell proposed in this study has been conceived as shown in.
Rotation may occur on any axis and is accommodated by deformation of the elastomeric pad. Dearen r ansrain federal high way administration july 2016. Situated in the heart of the west midlands, bridge bearings is the largest manufacturer of semiprecision bearings, for the materials handling industry, in the uk today. Information on bridge articulation is given in gn 1. Furthermore, if the horizontal shear force is greater than onefifth of the. Bridge bearings support structures at a constant elevation, carrying forces from the superstructure into the substructure and allowing necessary superstructure motions to take place. Users may specify different girderbearing properties at each bent and abutment.
Trelleborg designs and manufactures elastomeric bridge bearings in accordance with this standard. Information on bridge bearings is available in various technical literatures but it is scattered. Our bearing range includes steel and plastic housed bearings for all types of conveyor rollers as well as bearings for overhead conveyors which include crowded race, sintered iron caged and ribbon caged construction. To prevent further bridge damage, joints are often repaired or replaced. The material in this report will be of immediate interest to bridge designers and materials engineers. Loadmeasuring pot bearing with builtin load cell part i. Since 2005 the european standard en 373 has applied to elastomeric bearings for architectural and civilengineering applications. Besides the functional requirements, the standard describes the design rules, the material properties, the production tolerances and the acceptance tests. Bridge bearing, as connection component, can provide a resting surface between bridge and bridge piers. Uplift forces are also seen on some curved girder bridges and in flood prone regions where high water can result in the bridge becoming buoyant. Design step 6 design of bearings prestressed concrete bridge design example task order dtfh6102t63032 63 elastomer grade is selected based on the temperature zone of the bridge location and by table s14. The task of the bridge designer is to define a schedule of forces and. Bearing design spread sheet based on aashto 16th edition. Jan 26, 2020 bridge bearings 2 types of bearings for a girder bridge published by bimlesh on january 26, 2020 january 26, 2020 the devices fixed on abutments and piers to allow for free expansion, contraction, and deflection of the bridge superstructure are known as bridge bearings.
Bridge bearings 2 types of bearings for a girder bridge. General in the majority of steel bridges it is convenient to. Bridge bearing replacement transportation research board. Disktron bearings can be easily modified for uplift restraint which is common in seismic zones. This specification covers bearings, which consist of all elastomer or of alternate laminates of elastomer and steel, when the function of the bearings is to transfer loads or accommodate relative movement between a bridge superstructure and its supporting structure, or both. It is noted that stability is a part of bridge bearing design, and that bearings must be designed and detailed to meet required vertical and horizotal load capacities, rotation limits, and anchor bolt clearances. Elastomeric bridge bearing design design spreadsheet based on aashto 16th edition 1197 interim method a aashto lrfd.
Information on the attachment of bearings is given in gn 2. Pdf effect of change in radius of curvature in plan on bridge. Therefore, bridge rehabilitation has also become a very essential factor sometimes. Taking advantages of the small size, all forces converge on a small point and to be transferred to the foundation through a very compact line.
However, bridge bearings could create more problems for the bridge structure than it solves if not properly understood, especially. Overwrite options are located under brim bridge object abutments and bents. A bridge bearing is a component of a bridge which typically provides a resting surface between bridge piers and the bridge deck. Bridge bearings are used to transfer forces from the superstructure to the substructure, allowing the following types of movements of the superstructure. Bridge bearings types of bearings for bridge structures. Bridge bearings types of bearings for bridge structures and. A bridge is a manmade structure built to avoid physical obstacles without closing the way underneath such as a body of water, valley, or road. The purpose selected sealing systems of the elastomeric pad, are designed to resist extrusion of the elastomeric pad when under load.
Due to liquefaction and ground movement, some piers moved and associated spans shifted on bearing supports. Steel bridge bearing design and detailing guidelines section 1 elastomeric bearings 1. Plain and laminated elastomeric bridge bearings are designated by hardness durometer, size, and configuration and, in the case of laminated bearings, by the thickness of the individual layers of elastomer and the size and position of any steel top plates. Design guidelines for bridge widenings, steelreinforced elastomeric bearings fo r pretensioned concrete beams, stru tandtie method, and culverts. For circular bearings, stability may be investigated. Policy for archiving bridge design notes in txdots bridge inspection database management system. Both rocker and pin bearings are mainly employed in steel bridge structure. The same principles apply to all types of structure where forces are exerted. W, stability shall be investigated by interchanging l and w in eqs. Posted on june, 2018 august 21, 2018 author sundari comment0 abstract. Pot bearings are often regarded as suitable for use when bridge bearing rotations are too large. This iricen publication is a result of the desire to fill the gap. Plain and reinforced elastomeric bearings have become the most common type of bearing in recent years because of their desirable performance characteristics, durability, low maintenance requirements, and relative economy.
Trbs second strategic highway research program shrp 2 report s2r19arw2. With extensive experience in bridge engineering, freyssinet is able to provide a onestopshop for the design, manufacture and installation of bridge bearings, from assessment and temporary works design through to supply and installation. Granor pot type structural bearings feature a circular elastomeric pad encapsulated inside a metal pot having a close fitting lid, which acts as a piston. Standard specifications for bridge construction section 1, excavation march 20 1 1 1. Notes on bridge abutment design and the loads that need to be considered. Not applied to free abutment if sliding bearings are provided case 1 fixed abutment. Drew e gilstad, bridge bearings and stability in asce, new.
Astm d4014 032018 standard specification for plain and. Bridge bearings and stability journal of structural. Bridge bearings technical knowledge base computers and. Pot bearings are special types of bearing pads for taking larger loads, translation and rotation in confined areas. In the last two decades, the rapid deterioration of bridge structures has become a serious technical and economical problem in many countries, including highly developed ones. Wisdot bridge manual chapter 27 bearings july 2019 273 27. Bridge bearings are elements transmitting the loads from. Our internal team of engineers and fabricators will work with you to design the right solution for your bridge project. Design step 6 design of bearings prestressed concrete. The information included is intended to permit efficient fabrication, installation, and maintenance of these bearings. Bridge bearings are the largest materials handling bearing manufacturer and supplier in the uk. The bridge modeler locates bearing links directly below the girder web. Possible causes of movement are thermal expansion and contraction, creep, shrinkage, or fatigue due to the properties of the material used for the bearing.
Rocker and pin bearing should be considered when the bridge movement is adequately known and described, since such bearings can make rooms for both translational and rotational movements in one direction only. Bridge engineers today usually do not design bearings. Dec 18, 2019 user guide to bridge standard detail sheets section 9 bridge bearings ptfespherical sliding bearing details. The addition of a lowfriction sliding surface allows a standard laminated elastomeric bearing device to accommodate unlimited horizontal displacement without increasing the height of the bearing assembly. Two levels of stability criteria, for normal conditions and for extraordinary temporary conditions, are. Similar with pot bearing, spherical bearing also can be divided into three types.
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