Knowledge of Bridge Engineer: installation of Isolation Rubber Bearing
1. connection between bearing and box girder bottom
a. Bearing with box girder bottom connection installed in the beam pedestal, Should be in accordance with the line longitudinal slope support and fixed support position is in line with the design review activity, especially a one-way bearing unidirectional activity direction should be paid attention to.After bearing installed on the bottom of the box girder, should tighten the bearing and the beam body connecting bolts.
b. After installation of bearing, fixed support seat base plate and anchor plate center under longitudinal and lateral direction momentum and activities that support the centerline transverse momentum fault shall be greater than 3 mm, vertical fault bearing the centerline of the momentum and the design calculation value of allowable deviation of plus or minus the sum of 3 mm, fixed support and movable support were the centerline of the reverse bias is 1 mm.
c. Erection of the box girder, according to measure the position of the location and elevation, box girder Liang Yingxian falls on the jack, and accurate in place, then under the bearing plate and bearing pad stone, gravity grouting anchor bolt hole.
d. Support anchor embedment depth and bolts exposed length must comply with the design requirements, should be in support and anchor bolt support anchor consolidation construction after accurate position adjustment
2. Inspection after falling beam
After falling the beam shall be immediately check whether bearing reticle and bridge expansion jointmeet the following requirements:
Beam body centerline position error and the design shall not be more than 3 mm, bearing bottom center line and pier bearing pad at the top of the stone crosshair error should not be more than 3 mm.
Bearing base and pier bearing pad at the top of the rock should be stick, beam body same side pivot relative elevation difference is not more than 2 mm, entire box girder are not allowed to have three legs phenomenon, to eliminate reaction
3. adjust bearing
after falling beam if it doesn’t meet the above conditions, especially the girder with side pivot relative relief more than 2 mm, should be the beam to lift, adjustment in place after the fall, liang box girder is in place to meet above requirement.
4. grout for bearing
Grouting with template and pad at the top of the stone and reliable measures should be taken, such as a layer of rubber underside set leakproof, template by adopting the way of expansion screws, prevent leakage occurred while gravity grouting slurry. Grouting should support center around, until all filling grouting material.
Reserved bolt hole, bearing pad at the top of the stone and pedestal filled grouting at the bottom clearance should be adopted, grouting pressure shall not be less than 1.0 MPa. In the absence of reliable heat preservation measures, grouting material heat preservation performance during the test, it is strictly prohibited under negative temperature conditions for grouting construction. Grouting material after reaching intensity, dismantling templates, flowability of slurry for repair.
5. Finally tighten the anchor bolt support plate, remove the temporary connection Angle steel bearing plate up and down