Plain and reinforced elastomeric bearings have become the most common type of bearing in recent years because of their desirable performance characteristics. A pin bearing is a type of fixed bearings that accommodates rotations through the use of a steel. Bearings gives the supporting conditions to super structure. Although many different types of bridge bearings have been used by the nysdot, elastomeric and multirotational bearings are the. Effective isolation in all seismic zones and soil types no corrosion, stickslip, wear or aging effects. Bearings used at that time were metal plates sliding one on the other or, of rollers or, of a combination of both. Bearing used in the construction of bridge structure is divided into two major categories namely. Rail bridge that connects piermont, ny hudson river to dunkirk. These bearing types provide limited horizontal movement.
In all instances, the use of intermediate expansion joints should be avoided wherever possible. Translational and rotational movement of bridge superstructure may be due to shrinkage of concrete elastic shortening of concrete due to prestressing. There are several different similar types of bridge bearings that include neoprene bearing pads, neoprene bridge bearings, laminated elastomeric bearings and seismic isolators, which are all generally referred to as bridge bearing pads in the construction industry they are designed and manufactured based on standards and. Pot bearings for bridges and structures plain bearing products. Types of elastomeric bearing pads plain and laminated elastomeric bearings pads. A support with a f will have a bearing device that will resist longitudinal movements. The bridge designer will prohibit movement in some bearings and allow movement in others. Pot bearing, made of elastomeric pad embedded into the steel plate is divided into fixed bearing, guided bearing and free pot bearing.
There are bridge lengthskew limitations when considering this abutment type. Load load aa b ad ae g h kn kn mm mm mm mm mm mm kg. A bearing is a machine element which supports another moving machine element known as journal. Although many different types of bridge bearings have been used by the. Steel bridge bearings may be divided into three general types. Bearings are important elements in large infrastructures such as bridges, heavy buildings and high rise buildings, ensuring load transfer, movement, rotation, vertical or horizontal restraints as required by the design at critical locations in a structure. The required passage may be for a road, a railway, pedestrians, a canal or a pipeline. Steel bridge bearing selection and design guide steel building.
A more detailed analysis in bridge bearing design considers the following. Evaluate both the initial rotation and its short duration. Substructure guidelines bridge substructure types are determined during the preliminary design phase of the bridge design. Bridge bearings types of bearings for bridge structures and details. There are many factors to consider when deciding on the most appropriate substructure. At intermediate stages of construction, add deflections and rotations due to the progressive girders to distribute the load uniformlyweight of the bridge elements and construction equipment to the. In addition to above application of bearings, the modern bearing system combines. Bridge bearing types and functional properties the most important detail of the pot bearings is the seal, preventing the leakage of the elastomer through the gap between pot and piston and governing the. We have been focusing on research and development in recent years and we have made great achievement in this industry. There are several different similar types of bridge bearings that include neoprene bearing pads, neoprene bridge bearings, laminated elastomeric bearings and seismic isolators, which are all generally referred to as bridge bearing pads in the construction industry. For this an anchor plate will be vulcanised onto the bearing upper and lower surface. In a tapered roller bearing, the center lines do not converge at a common point. Ail machines necessarily employ them and all engineers must possess some knowledge of their design, construction, lubrication, adjustment. Bridge bearings introduction aashto defines a bearing as a structural device that transmits loads while facilitating translation andor rotation.
These early concrete piles were the castinplace type. Tp sq hole ctrs hole ctrs hole dia height mass reference no. Bearing is the component of bridge on which the girder in case of girder bridge, or solid slabin case of slab bridge rests. A large variety of bearings have evolved using various combinations of these mechanisms. Collectively, these bearings are known as high load multi.
Plain bearing, consisting of a shaft rotating in a hole. Types of bearings geometer discusses the various types of bearing in common use and gives examples of their use b earings are the means by which shafts are located, enabled to carry loads and transmit power. In the years immediately preceding the turn of the twentieth century, several types of concrete piles were devised. Another type of bridge bearing is the mechanical bridge bearing. Linear bearing types range from ball bearing cagesessentially bare cages holding balls that are often used as diepost bushingsto recirculating ball designs where the balls roll linearly along the shaft and then return to their starting points through channels on the nonshaft sides of the bearings. 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. Spherical bearing spherical bearing, with fixed, guided and free sliding type is suitable for more complex bridges in low temperature regions.
A bridge bearing is a component of a bridge which typically provides a resting surface between bridge piers and the bridge deck. There are many types of bridge bearings, and the followings types are widely used in projects. The arch squeezes together and this squeezing force is carried along the curve to support at each end. Laminated rubber bearings provide the simplest method of isolation and are most suitable for high frequency ground motions. Wisdot bridge manual chapter 27 bearings july 2019 273 27. Bridge bearings are devices for transferring loads and movements from the deck to the substructure and foundations. A valuable tool for selecting bearing types is presented in lrfd table 14. Pin bearing a pin bearing is a type of fixed bearings that accommodates rotations through the use of a steel. Seismic isolation bearing systems bridge the world with leading infrastructure solutions bridges 300 east cherry street north baltimore, oh 45872 telephone.
Information on bridge bearings is available in various technical literatures but it is scattered. A bridge is a structure providing passage over an obstacle without closing the way beneath. A bearing is the boundary between the superstructure and the substructure. This iricen publication is a result of the desire to fill the gap. Rocker and pin bearings for bridge structures rocker is an expansion bearing composed of curved surface at the bottom, which accommodate translational movement and a pin at the top makes room for rotation. In general, there are two types of supports shown on plans, fixed f or expansion e. Steel bridge design handbook bearing design volume 15. 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. All bearings do, however, have at least the bearing or bearing surface.
Types of beam bridges are girder bridge, box girder bridge, plate girder bridge etc. The submerged timber piles of this bridge, which were driven in 900 ad, were found in good condition and were reused. The construction layout sheet in the plans will show the designers intent. As the name suggests, arch bridge consists of curveshaped abutment at each end. A roving bridge, changeline bridge or turnover bridge is a bridg e over a canal constructed to allow a horse towing a boat to cross the canal wh en the towpath changes sides. However, the span restriction for sliding bearing utilization can be disregarded when it is used in combination with other bearing types. 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. Elastomeric bearings for construction industry in neoprene and natural rubber compound laminated rubber bearings provide the simplest method of isolation and are most suitable for high frequency ground motions. Types of elastomeric bearing pads construction rubber. The design of the bearing may, for example, provide for free linear movement of the moving part or for free rotation around a fixed axis. Ccl advanced solutions help create innovative bearings that anticipate.
Trbs second strategic highway research program shrp 2 report s2r19arw2. Bridge bearing bearing is a mechanical device placed between superstructure and substructure to transmit vertical and horizontal load allowing some translational and rotational movement. These include rockers, rollers, pins, pots, steel girder hangers, ptfeelastomeric, and elastomeric pads. Bridge articulation and bearing specification from 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. They were gradually improved by incorporation of swivel arrangements to provide rotational movements 9. The designer must determine which bearing type is best suited to cost effectively accommodate the design requirements. Over 30,000 references with bridge bearings in 65 countries. 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 a range of different bearing types is available.
Bridge bearings types of bearings for bridge structures and. Spherical bearing made from maurer sliding alloy msa. Flat land bearings will carry only 1020 % of the load of other thru st bearing types, because flat parallel surfaces. Expansion joints and bearings september 2017 where practical and where additional protection for bearing assemblies and hinges is warranted, provide a secondary sealing system below the expansion joint assembly. It permits a relative motion between the contact surfaces of the members, while carrying the load. The same principles apply to all types of structure where forces are exerted. A common form of modern bridge bearing is the elastomeric bridge bearing. Pot bearings are special types of bearing pads for taking larger loads, translation and rotation in confined areas. A bridge is structure which allows passage over an obstruction. Ball bearings, as shown below, are probably the most common type of bearing.
Bridge bearings types of bearings for bridge structures. Bearings transfers loads from super structure to sub struc. The rolling elements distinguish the two basic bearing types ball bearings and roller bearings. The purpose of a bearing is to allow controlled movement and thereby reduce the stresses involved. Bridge bearings until the middle of this century, the bearings used consisted of following types. The bearing can be secured against horizontal sliding by means of shear dowels for example. Bridge bearings support structures at a constant elevation, carrying forces from the superstructure into the substructure and allowing necessary superstructure motions to take place. The obstacle to be crossed may be a river, a road, railway or a valley. Bearing systems bridge the world with leading infrastructure solutions bridges. Apr 23, 2015 bridge bearings until the middle of this century, the bearings used consisted of following types.
In general, it is best to use a fixed or semi expansion bearing utilizing an unreinforced. Fuller descrip tions of some bearing types, with illustrations, are given in lee. The separator, which retains the balls or rollers, is also called the cage. Pin bearing a pin bearing is a type of fixed bearings that accommodates rotations through the use of a steel translational movements are not allowed. There are several types of mechanical bridge bearing, such as the pinned bearing, which in turn includes specific types. Different types of bridges with pdf file engineering. This module provides practical information for efficient bearing design and. The oldest form of bridge bearing is simply two plates resting on top of each other. The average bearing pressure on the concrete is 20 mpa. Section 2 special design requirements for different bearing types.
The designer must determine which bearing type is best suited to cost effectively accommodate the design. Bridge design bridge design and assessment bridge bearings. Rollingelement bearing, in which rolling elements placed between the turning and stationary races prevent sliding friction. Bridge bearings are used to transfer forces from the superstructure to the substructure, allowing the following types of movements of the superstructure. There are various types of bridges classified based on span, materials, types of bridge structures, functions, utility and position etc. 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. Bearing pads are either plain or reinforced with respect to the loads defined. The obstructions may be river, valley, rail route or road way etc. Elastomeric bearings for construction industry in neoprene and natural rubber compound. There are at least 6 common types of bearing, each of which operates on different principles. A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts. There are many types of bearings, each used for different purposes.
These include ball bearings, roller bearings, ball thrust bearings, roller thrust bearings and tapered roller thrust bearings. Bridges are classified into so many types based on different criterias. Bridge bearings indian association of structural engineers. In situations where the bridge skew exceeds 30 degrees, consult the bearing and expansion joint specialist and the bridge design engineer for recommendations and approval. The three new bearing types most widely used today in the united states are pot, spherical and disk. Possible causes of movement are thermal expansion and contraction, creep, shrinkage, or fatigue due to the properties of the material used for the bearing. Pot bearings are often regarded as suitable for use when bridge bearing rotations are too large. Generally, the roadway of bridge lies on the arch structure. The maximum horizontal load can only be applied if it is less than 33% of the simultaneous vertical load. They are found in everything from inline skates to hard drives. An elastomeric bridge bearing is a commonly used modern bridge bearing. Types of bridges based on span, materials, structures. In highway bridge bearings movements are accommodated by the basic mechanisms of internal deformation elastomeric, sliding ptfe, or rolling.
1265 1037 84 1405 789 704 3 327 101 1233 1617 1510 62 1286 290 426 1162 820 1278 287 1201 1267 252 302 191 1078 723 115 755 118 842 803