Simplistic design and ease of fabrication and installation results in cost efficiency. Steel bridge bearing selection and design guide steel building. 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. The following tests and calculations were completed for both babbitt and ptfe. Steel bridge design handbook bearing design volume 15. This was resolved by redesigning the bearing pads to have a ptfe surface instead of a babbitt surface. The test results are compared with predictions using the genmat analysis software. Pdf test results for ptfefaced thrust pads, with direct. Design development and application of ptfe compound.
Ptfe expansion joints are corrosionresistant and made to withstand the high pressure and temperature in a compact, spacesaving design. Some results from extensive testing of ptfefaced pads are given. In general, bearings should not be designed for dead load rotations if proper camber is provided in the girders. Bearing pads and expansion bearing assemblies sorbtex fabricated pads, washers, and bushings vsb series ptfesteel slide bearings neosorb aashto grade polychloroprene bearing pads fiberlast omnidirectional random oriented fiber rof pads vossco random oriented fiber rof pads.
For most applications, ptfe, 25% glass filled, is adequate when the temperature is less than 400 degrees f. Example 3 type i bearing steel reinforced method b 1 218 design example 3 appendix a example 3 type i bearing steel reinforced method b general information material and section properties bearing dimensions bearing width w 20. The slide bearing possesses an extremely low coefficient of friction, thus enabling the stainless steel plate to slide easily against the ptfe material. Fabreeka product binder and catalogs fabreeka vibration. The assembly is designed to ensure that the ptfe pad is covered by the ss plate throughout the expected design movements. Trbs second strategic highway research program shrp 2 report s2r19arw2. Thrust bearing ptfe redesign for pump storage generator case. Venkat reddy department of mechanical engineering, anurag group of institutions, hyde rabad, telangana, india. Aug 23, 2010 riload is a bearing material which is made by molding tfe on each side and completelly through a sheet of perforated stainles steel. Lrfd steel girder superstructure design example bearing design example design step 6 table of contents design step 6. Hydro tech used bearing design software from genmat to study the babbitted pads. Ptfe bearing pad, also called teflon bearing pads, is an important material in bridge construction. The typical hinge or abutment configuration using many small elastomeric bearing pads has proved highly reliable and redundant.
Dimpled and lubricated ptfe has been shown to provide both improved wear resistance and reduced coefficient of friction. Woven or glassfilled ptfe greatly improves wear resistance, but it has a higher coefficient of. Fabreekaptfe pad is used to accommodate construction irregularities such as rotation and nonparallel load bearing surfaces, while also providing a sliding. Engineering evaluation and design recommendations by dawn e.
Ptfe thrust bearings improve operations at sir adam beck. Bridge bearing are a commonly used modern bridge bearing. Their use has proven beneficial and often may be necessary for satisfactory performance of precast concrete structures. Bridge bearings california department of transportation. Composed of highest quality ptfe sheet, dynalon can be permanently bonded to any size, type or thickness of steel plate, neoprene pad, or preformed fabric pad.
Both hydro techs bearing design software and enenergos bearing design software showed this was still a possibility. Enenergo, based in russia, supported hydro tech in studying the ptfe bearing pad. The two most important design aspects of ptfe are the coefficient of friction. Elastomers are used in both elastomeric bearing pads and steel reinforced elastomeric bearings 10. Elastomeric bearing pads compress on vertical load and accommodate horizontal rotation and provide lateral shear movement. The dynalon slide bearing pad can be used as a highly efficient maintenance free method of accommodating lateral stress in structural components. Steel bridge bearing design and detailing guidelines 39 appendix a recommendations for beam rotation calculations dead load rotations. The ptfe provides a low friction sliding surface on the fabreeka bearing pad, which distributes high compressive loads and accommodates rotations. The latest design software and fea is used to optimise bearing design for efficiency and cost. Our inhouse design engineers work alongside our specialist. Highquality ptfe sheet used to accommodate lateral stress in structural. Vsb series ptfesteel slide bearings on voss engineering, inc. The 1988 fiberlast test program and published design manual.
It is evident from the figure and mathematical model that maximum stress developed in the ptfe disc,elastomer pad and the top plate is considerable as a safe design. Slide bearings fabreeka structural expansion slide bearings. Elastomeric bearings goodco ztech elastomeric bearings are fabricated of natural rubber or neoprene. The basic element is a 5mm ptfe sheet, recessed into a 10mm steel backing plate for. Design capability for rotating and rocking movements as well as translation.
Design of pot ptfe bearing is governed by the minimum average stress on the ptfe disc, elastomer pad and the top plate at which all the system is fixed. Due to seismic design requirements, when lateral movements required for structure are of greater values than the height of bearing it would be ideal to use a ptfe teflon sliding bearing which provide a very low friction coefficient between ptfe and stainless steel surface which will be less. This method will prevent damage to the ptfe, 25% glass filled. Design step 6 design of bearings prestressed concrete bridge design example task order dtfh6102t63032 65 design step 6. Reinforced elastomeric bearing pads, designed in accordance with. Norwesco industries has been involved in the supply and manufacturing of a wide variety of slide bearing pads since 1989. A full weld will help prevent seepage of water between the slide bearing plate and the support structure.
Rubber bearing pads dampen vibration and permit for the natural thermal expansion and contraction of structures, whether precast concrete or steel, which aids in prolonging their lifespan. Bearing pads are used to distribute concentrated loads and reactions over the bearing area and to allow limited horizontal and rotational movements to provide stress relief. The structural bearing is the key element that creates freedom of movement between a structure and its foundation while ensuring the transfer of vertical loads and rotation. Babbitt bearing pads for even a split second, the bearing will wipe at every contact. Design step 6 design of bearings prestressed concrete. Most websites use some sort of analytics program like this. Ptfe bearing design configurations slide bearings and skidway plates weve documented some of our typical configurations for ptfe slide bearings and skidway plates below but have expertise in tailoring specifications for bespoke projects.
Browse vsb series ptfesteel slide bearings in the voss engineering, inc. Enenergo has an exclusive agreement with north american ptfe bearing to supply ptfe bearing pads in north america. The basics of tilting pad bearing design are discussed to include limits of operation for load, speed, and metal temperature. Department of transportation federal high way administration bearing design. Steel bridge design handbook bearing design volume 15 fhwa. The smaller pad surface area of a ptfe bearing can result in. In a structural bearing design, polished stainless steel is typically used as the smooth surface that the ptfe slides against. In general, the coefficient of friction between the mating surface and the ptfe slide bearing pad will be at a. Ccl commitment committed to providing a first class service across the globe, ccl has a reputation for handson approachability, going further to. A ptfe bearing pad is a slide plate made up of ptfe, 25% glass filled, material that provides a low coefficient of friction for most combinations of temperature and load. The bearing design is based on a girder that provides a level surface for the bearing to support.
Feb 18, 2016 midas e learning midsa civil bearings, piers and abutments part 1. The dimpled ptfe sheet bonded to the laminated bearing pad for structure friction coefficient reduction and displacement capacity improvement. Dynamic positioning conference september 2830, 2004 6. Ptfe sliding surface to a steel reinforced elastomeric bearing. The babbitt study was completed by hydro tech using genmat bearing design software, and the ptfe bearing pad study was completed by enenergo.
Two surfaces with low coefficients of friction are allowed to slide against each other. Ccls quality management system complies with en iso 9001. Fabreeka designs and manufactures several types of expansion bearings for a wide. Between stainless steel and ptfe, the coefficient is less than that between any other two solid engineering materials. Hanna rubbers ptfe slide bearing pads are optimal for commercial structures involving long spans sustained without columns or posts. Plain elastomeric bearing pads pep rely upon friction at the contact. Riload combines the sliding properties of tfe with the. They support vertical loads with minimal compression, allow expansion and contraction of.
The flexibility of ptfe bearing is between a rubber bearing and urethane bearing due to the unique structure. Bearing pads fablon masticated neoprene ptfe slide. Bridge design specifications, section 14, should be considered the preferred type of bearing for all structures. Seiji yamajo, development and application of ptfe compound bearings kobelco eagle marine engineering fumitaka kikkawa, mikasa corporation. Thrust bearing ptfe redesign for pump storage generator. Hanna rubber company produces ptfe slide bearing pads, composed of high quality ptfe sheeting that can be secured to a variety of different materials such as. Warco biltrite manufactures a full line of elastomeric bearing pads for bridge, building and reservoir construction markets. Fabreeka designs and manufactures several types of expansion bearings for a wide range of applications, also including teflon bridge bearing pads. Lrfd steel girder superstructure design example lrfd. Reinforced elastomeric bearing pads, designed in accordance with bridge design. They can have a sliding surface of ptfe and stainless steel for a sliding expansion bearing see example or can be plain without sliding surfaces. Roeder, russell larson, and kevin curtin department of civil and environmental engineering 233b more hall university of washington, box 352700 seattle, washington 981952700 washington state transportation center. Bearing pads elastomeric bearing pot bearing ptfe sliding surface. They go by many names such as fabric bearings, preformed fabric bearings, cotton duck pads and cotton duck bearings.
Ptfe structural bearings ptfe tubes, ptfe bearings. Fabreeka structural expansion bearings or slide bearings are used on buildings. Find your ptfe bearing pad easily amongst the 11 products from the leading brands on archiexpo, the architecture and design specialist for your professional purchases. Bs 5400 design is 2062 mild steel a36 carbon steel aisi 304 stainless steel astm 4894 ptfe. Elastomers are used in both elastomeric bearing pads and steel reinforced elastomeric bearings10. Optimum temperature sensor locations are recommended for selfaligning and nonaligning tilting pads. On this page you may also download any of our individual catalogs in pdf format. Avoid overheating, which may destroy the bonding of the ptfe, 25% glass filled to the base plate.
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