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CCL Bridge bearings.pdf

Text of CCL Bridge

Bridge Bearings

and Expansion Joints

CCL Bridge Bearings

CCL Bridge BearingsCCL bearings are widely used in structural, marine and civil engineering applications, and particularly bridges, to transfer vertical forces from one structural member to another. They are also required to restrict or permit linear or rotational movement in the horizontal plane. Where horizontal movement is restricted the horizontal forces will be transferred through the bearing to the lower structure. Bearings are available in carbon steel as standard, and in stainless steel for applications where corrosion is a potential problem or life cycle costing benefits are sought. As standard CCL bearings are designed to meet the requirements of BS 5400 : Section 9.1 and 9.2: 1983 Design Due to the complexity of bridge bearing design CCL provide technical assistance on the selection of the most appropriate bearings. Our technical staff will be pleased to discuss individual applications. In order to facilitate the design process relevant information should wherever possible be supplied in accordance with BS5400 section 9.1 table 9. Special Bearings CCL can also manufacture bearings to suit loadings, rotational and movement requirements outside the scope of the standard range. These can include factors such as uplift, environmental conditions, seismic effects and temporary constructional requirements. Testing CCL has well equipped in-house facilities, which are regularly used for testing bearings. In-house testing is carried out in accordance with BS 5400: Section 9.2: 1983 and BS EN ISO 9001: 1994. Our compression test frame is one of the largest in the UK. An imposed rotation of the bearing can be accommodated when this is required. Tests can be observed by independent witnesses when this is required.

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Selection of Bearings

Selection of BearingsThere are many factors to be considered before the most appropriate arrangement of bearings can be determined for a particular application. The table below provides an overall indication of the features of each type of bearing.Direction of ForceBearing Type Fixed Pot Free Sliding Pot Guided Sliding Pot Fixed Pin Uniguide Laminated Elastomeric Plain Pad & Strip Vertical Longitudinal Transverse

Rotation PermittedLongitudinal Transverse

Movement PermittedLongitudinal Transverse

Key

Suitable Not suitable Limited Indicates that either Longitudinal or Transverse loads/movements can be permitted, not both.

Mechanical Pot Bearings Mechanical pot bearings are available in three types; fixed, guided sliding and free sliding, and in a variety of capacities. All three types allow rotation. Fixed bearings provide restraint in all horizontal directions. Guided bearings allow movement in one horizontal direction and provide restraint in the other direction. Free Sliding bearings allow movement in all horizontal directions. Fixed Pin or Removable Dowel Bearings The Fixed Pin bearing provides restraint in all horizontal directions and can be used with Laminated Elastomeric bearings, the Elastomeric bearing supporting the vertical load and the Fixed Pin bearing taking the horizontal loads. Uniguide or Shear Key Bearings Uniguide bearings can be used at the opposite end to Fixed Pin bearings to allow expansion from the fixed end, but provide restraint in the other direction. Uniguide bearings can be used in conjunction with Laminated Elastomeric bearings, the Elastomeric bearings supporting the vertical load, the Uniguide bearing taking the lateral horizontal load. Laminated Elastomeric Bearings Laminated Elastomeric bearings allow horizontal movement by shear deflection, and allow rotation by angular deformation. Where horizontal movement needs to be controlled or large horizontal loads resisted, Laminated Elastomeric bearings should be used in conjunction with Fixed Pin or Uniguide bearings. If required laminated elastomeric bearings can be fitted with a vulcanised PTFE sheet and slider plate to accommodate large translations. Plain Pad and Strip Bearings Un-reinforced elastomeric pads and strips are used where low loads and small movements are expected. They are the simplest type of bearing, readily available and easy to install.

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Arrangement of Bearings

Arrangement of BearingsMechanical Pot Bearings Elastomeric, Fixed Pin & Uniguide Bearings

Fixed Pot Bearing All translations are fixed, rotation possible Guided Sliding Bearing Horizontal movement in one direction, rotation possible. Free Sliding Bearing Horizontal movement in all directions, rotation possible. Elastomeric Bearing Rotation and movement possible in all directions. Uniguide Bearing Movement allowed in one direction only, no vertical load. Fixed Pin Bearing All translations are fixed, rotation possible, no vertical load. 4

PF Fixed Pot Bearing

PF Fixed Pot BearingFixed bearings carry vertical load whilst providing restraint in all horizontal directions. There are three types of mechanical pot bearings, all of which are available in a range of capacities and sizes. Each type utilises a piston, rubber disc and pot base, with variations to suit.

The projecting piston of the top plate is fully retained by the metal pot of the bottom plate to provide full restraint in the horizontal plane. The deformation of the elastomeric disc allows multi-directional rotation to take place.f h

Top Plate a Seal Elastomeric Disc Pot Base d b

PF Fixed Pot BearingIndicative Table of DimensionsPF 50 SLS Permanent Vertical Load (kN) SLS Total Vertical Load (kN) SLS Horizontal Load (kN) ULS Vertical Load (kN) ULS Horizontal Load (kN) Overall Height a Base Length and Width b Base Bolt Ctrs (Square) d Top Plate Length and Width f Top Bolt Ctrs (Square) h Bolt Size 330 500 110 650 140 54 180 145 180 145 M12 PF100 670 1000 210 1300 270 71 245 200 245 200 M16 PF150 1000 1500 225 2000 300 84 300 255 300 255 M16 PF200 1330 2000 255 2660 330 89 350 305 350 305 M16 PF250 1660 2500 350 3330 470 103 385 320 385 320 M20 PF300 2000 3000 380 4000 500 115 415 360 415 360 M20 PF400 2670 4000 545 5330 710 131 485 420 485 420 M24 PF500 3330 5000 810 6500 1050 140 545 460 545 460 M30 PF750 PF1000 PF1500 PF2000 5000 7500 930 9750 1200 166 670 590 670 590 M30 6660 10000 1300 13000 1690 202 770 675 770 675 M36 10000 15000 1850 19500 2400 247 940 830 940 830 M42 13330 20000 2100 26000 2700 282 1085 975 1085 975 M42

Assumptions: 1. Minimum load is at least 20% of total load 2. 30% of minimum load is used as frictional resistance to horizontal load 3. Total rotations are up to 0.015 rads 4. Lower and upper seating pressures approach 20N/mm2 at SLS 5. Lower and upper seating pressures approach 30N/mm2 at ULS 6. 25mm mortar under base. 5

PS Free Sliding Pot Bearing

PS Free Sliding Pot BearingFree sliding bearings carry vertical loads whilst allowing horizontal movement and rotation in all directions. Within the base plate a rocker is fully retained in the pot. This rocker has a lubricated, dimpled PTFE disc, which slides against the stainless steel plate. The high quality, polished stainless steel plate is fitted to the machined top plate allowing free horizontal movement between the two sections of the bearing. The deformation of the elastomeric disc under the rocker plate allows multi-directional rotation to take place.g/f h/j Top Plate Stainless Steel Slider PTFE Disc Rocker Plate Seal Elastomeric Disc d b Pot Base

PS Free Sliding BearingIndicative Table of DimensionsPS 50 SLS Permanent Vertical Load (kN) SLS Total Vertical Load (kN) ULS Vertical Load (kN) Overall Height a Base Length and Width b Base Bolt Ctrs (Square) d Top Plate Length f Top Plate Width g Top Plate Bolt Ctrs longitudinally h Top Plate Bolt Ctrs Transversely j Bolt Size 330 500 650 62 180 145 210 290 175 255 M12 PS100 670 1000 1300 85 245 200 260 370 215 325 M16 PS150 1000 1500 2000 95 300 255 300 425 250 380 M16 PS200 1330 2000 2660 101 350 305 335 475 290 430 M16 PS250 1660 2500 3330 113 385 330 365 530 310 475 M20 PS300 2000 3000 4000 128 415 360 385 560 330 505 M20 PS400 2670 4000 5330 144 485 430 440 630 375 575 M20 PS500 3330 5000 6500 158 550 470 480 700 425 645 M20 PS750 PS1000 PS1500 PS2000 5000 7500 9750 190 665 600 570 825 505 760 M24 6660 10000 13000 208 775 650 720 960 640 880 M30 10000 15000 19500 253 940 840 890 1160 790 1060 M36 13330 20000 26000 296 1190 995 960 1300 865 1205 M36

Assumptions: 1. Minimum load is at least 20% of total load 2. Total rotations are up to 0.015 rads 3. Lower and upper seating pressures approach 20N/mm2 at SLS 4. Lower and upper seating pressures approach 30/mm2 at ULS 5. 25mm mortar under base. 6. Movements +/- 25mm SLS. 6

PG Guided Sliding Pot Bearing

PG Guided Sliding Pot BearingGuided sliding bearings carry vertical loads whilst allowing movement in one direction and providing restraint perpendicular to this movement. They also allow rotation in all directions. Within the base plate a rocker is fully retained in the pot. This rocker has a lubricated, dimpled PTFE disc, which slides against the stainless steel plate. The high quality, polished stainless steel plate is fitted to the machined top plate between two guide rails, which resist the horizontal load in one direction. Horizontal movement occurs along the length of the guide rails. The deformation of the elastomeric disc under the rocker plate allows multi-directional rotation to take place.g/f h/j Top Plate Stainless Steel Slider PTFE Disc Guide Bar Rocker Plate Seal d b Elastomeric Disc Pot Base

PG Guided Sliding Pot BearingIndicative Table of DimensionsPG50 SLS Permanent Vertical Load (kN) SLS Total Vertical Load (kN) SLS Horizontal Load (kN) ULS Vertical Load (kN) ULS Horizontal Load (kN) Overall Height a Base Length and Width b Base Bolt Ctrs (Square) d Top Plate Length f Top Plate Width g To

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