A bearing is the boundary between the superstructure and the substructure. Bridge bearings types of bearings for bridge structures and. In addition to above application of bearings, the modern bearing system combines. The obstacle to be crossed may be a river, a road, railway or a valley. The maximum horizontal load can only be applied if it is less than 33% of the simultaneous vertical load. 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. There are many types of bridge bearings, and the followings types are widely used in projects. The purpose of a bearing is to allow controlled movement and thereby reduce the stresses involved.
Flat land bearings will carry only 1020 % of the load of other thru st bearing types, because flat parallel surfaces. Spherical bearing made from maurer sliding alloy msa. The bridge designer will prohibit movement in some bearings and allow movement in others. 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. There are several types of mechanical bridge bearing, such as the pinned bearing, which in turn includes specific types. 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. A bridge bearing is a component of a bridge which typically provides a resting surface between bridge piers and the bridge deck. 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. Different types of bridges with pdf file engineering. Tp sq hole ctrs hole ctrs hole dia height mass reference no. Rollingelement bearing, in which rolling elements placed between the turning and stationary races prevent sliding friction.
These include rockers, rollers, pins, pots, steel girder hangers, ptfeelastomeric, and elastomeric pads. Bridge bearings types of bearings for bridge structures. Bearing used in the construction of bridge structure is divided into two major categories namely. Bridge bearings until the middle of this century, the bearings used consisted of following types. Pot bearings are special types of bearing pads for taking larger loads, translation and rotation in confined areas. For this an anchor plate will be vulcanised onto the bearing upper and lower surface. Information on bridge bearings is available in various technical literatures but it is scattered. Laminated rubber bearings provide the simplest method of isolation and are most suitable for high frequency ground motions. They were gradually improved by incorporation of swivel arrangements to provide rotational movements 9. Evaluate both the initial rotation and its short duration. Ail machines necessarily employ them and all engineers must possess some knowledge of their design, construction, lubrication, adjustment.
There are at least 6 common types of bearing, each of which operates on different principles. Bearings transfers loads from super structure to sub struc. Spherical bearing spherical bearing, with fixed, guided and free sliding type is suitable for more complex bridges in low temperature regions. 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. Elastomeric bearings for construction industry in neoprene and natural rubber compound. Ccl advanced solutions help create innovative bearings that anticipate. 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. A large variety of bearings have evolved using various combinations of these mechanisms. 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. Load load aa b ad ae g h kn kn mm mm mm mm mm mm kg. Bridge bearings indian association of structural engineers.
In the years immediately preceding the turn of the twentieth century, several types of concrete piles were devised. Fuller descrip tions of some bearing types, with illustrations, are given in lee. Over 30,000 references with bridge bearings in 65 countries. 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. It permits a relative motion between the contact surfaces of the members, while carrying the load. Apr 23, 2015 bridge bearings until the middle of this century, the bearings used consisted of following types. A bridge is a structure providing passage over an obstacle without closing the way beneath. Bridge bearings are used to transfer forces from the superstructure to the substructure, allowing the following types of movements of the superstructure. 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. A more detailed analysis in bridge bearing design considers the following. Bridge bearings support structures at a constant elevation, carrying forces from the superstructure into the substructure and allowing necessary superstructure motions to take place. Types of elastomeric bearing pads plain and laminated elastomeric bearings pads. There are many types of bearings, each used for different purposes. Pot bearing, made of elastomeric pad embedded into the steel plate is divided into fixed bearing, guided bearing and free pot bearing.
The rolling elements distinguish the two basic bearing types ball bearings and roller bearings. Bridge bearing bearing is a mechanical device placed between superstructure and substructure to transmit vertical and horizontal load allowing some translational and rotational movement. This module provides practical information for efficient bearing design and. The average bearing pressure on the concrete is 20 mpa. 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. Section 2 special design requirements for different bearing types. Types of beam bridges are girder bridge, box girder bridge, plate girder bridge etc. Pot bearings for bridges and structures plain bearing products.
The separator, which retains the balls or rollers, is also called the cage. The designer must determine which bearing type is best suited to cost effectively accommodate the design. Bearing pads are either plain or reinforced with respect to the loads defined. The bearing can be secured against horizontal sliding by means of shear dowels for example.
A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts. Trbs second strategic highway research program shrp 2 report s2r19arw2. An elastomeric bridge bearing is a commonly used modern bridge bearing. The same principles apply to all types of structure where forces are exerted. A bridge is structure which allows passage over an obstruction. The construction layout sheet in the plans will show the designers intent. Translational and rotational movement of bridge superstructure may be due to shrinkage of concrete elastic shortening of concrete due to prestressing. Although many different types of bridge bearings have been used by the nysdot, elastomeric and multirotational bearings are the. The designer must determine which bearing type is best suited to cost effectively accommodate the design requirements. A pin bearing is a type of fixed bearings that accommodates rotations through the use of a steel. Steel bridge design handbook bearing design volume 15. Bridge bearings are devices for transferring loads and movements from the deck to the substructure and foundations. A support with a f will have a bearing device that will resist longitudinal movements. Collectively, these bearings are known as high load multi.
Bearing is the component of bridge on which the girder in case of girder bridge, or solid slabin case of slab bridge rests. The submerged timber piles of this bridge, which were driven in 900 ad, were found in good condition and were reused. In highway bridge bearings movements are accommodated by the basic mechanisms of internal deformation elastomeric, sliding ptfe, or rolling. 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. Wisdot bridge manual chapter 27 bearings july 2019 273 27. Ball bearings, as shown below, are probably the most common type of bearing. Plain and reinforced elastomeric bearings have become the most common type of bearing in recent years because of their desirable performance characteristics.
They are found in everything from inline skates to hard drives. Bridge design bridge design and assessment bridge bearings. Generally, the roadway of bridge lies on the arch structure. 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. Steel bridge bearing selection and design guide steel building. Substructure guidelines bridge substructure types are determined during the preliminary design phase of the bridge design. In all instances, the use of intermediate expansion joints should be avoided wherever possible. Although many different types of bridge bearings have been used by the. Rail bridge that connects piermont, ny hudson river to dunkirk. These early concrete piles were the castinplace type. A valuable tool for selecting bearing types is presented in lrfd table 14. In a tapered roller bearing, the center lines do not converge at a common point. These bearing types provide limited horizontal movement.
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. Plain bearing, consisting of a shaft rotating in a hole. The obstructions may be river, valley, rail route or road way etc. Bridge bearings introduction aashto defines a bearing as a structural device that transmits loads while facilitating translation andor rotation. Types of elastomeric bearing pads construction rubber. 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. In general, it is best to use a fixed or semi expansion bearing utilizing an unreinforced. Bridge bearings types of bearings for bridge structures and details. There are many factors to consider when deciding on the most appropriate substructure. These include ball bearings, roller bearings, ball thrust bearings, roller thrust bearings and tapered roller thrust bearings.
The required passage may be for a road, a railway, pedestrians, a canal or a pipeline. Types of bridges based on span, materials, structures. Possible causes of movement are thermal expansion and contraction, creep, shrinkage, or fatigue due to the properties of the material used for the bearing. However, the span restriction for sliding bearing utilization can be disregarded when it is used in combination with other bearing types. All bearings do, however, have at least the bearing or bearing surface. Bearings gives the supporting conditions to super structure. 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. Another type of bridge bearing is the mechanical bridge bearing. Steel bridge bearings may be divided into three general types. There are bridge lengthskew limitations when considering this abutment type.
A common form of modern bridge bearing is the elastomeric bridge bearing. Bearings used at that time were metal plates sliding one on the other or, of rollers or, of a combination of both. There are various types of bridges classified based on span, materials, types of bridge structures, functions, utility and position etc. In general, there are two types of supports shown on plans, fixed f or expansion e. Pin bearing a pin bearing is a type of fixed bearings that accommodates rotations through the use of a steel. A bearing is a machine element which supports another moving machine element known as journal. 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. This iricen publication is a result of the desire to fill the gap. Effective isolation in all seismic zones and soil types no corrosion, stickslip, wear or aging effects. Bridges are classified into so many types based on different criterias. Pot bearings are often regarded as suitable for use when bridge bearing rotations are too large. We have been focusing on research and development in recent years and we have made great achievement in this industry. 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. Seismic isolation bearing systems bridge the world with leading infrastructure solutions bridges 300 east cherry street north baltimore, oh 45872 telephone.