The arrangement of rubber pads
is mainly related to the structure of the bridge. Usually when arranging bearings, the following basic principles need to be considered:
(1) When the superstructure is a space structure, the rubber spacers should be able to adapt to the deformation of the bridge including both vertical direction (X direction) and horizontal direction (Y direction) at the same time;
(2) The rubber pad must be able to reliably transmit vertical and horizontal reaction forces;
(3) The rubber pads shall be used the longitudinal displacement and lateral displacement resulting from deformation of the beam body, and longitudinal and constant rotation angles are to be as unconstrained as possible;
(4) When the bridge is located on a flat slope, the fixed rubber pad should be set on the front abutment in the main direction of travelling;
(5) The rubber pad should be set in place with a larger pad reaction force;
(6) Several rubber pads on the same pier should have similar rotational stiffness;
In short, the principle of the layout of the bridge rubber pad is to facilitate the transfer of the bearing reaction force, but also to make the rubber pad can fully adapt to the free deformation of the beam body.
Rubber pad's installation
(1) Before the spacer is installed, the installation position of the bearing shall be measured and verified. The mounting plane of the bearing shall be parallel to the sliding plane or the rolling plane of the bearing, and the deviation of the parallelism shall not exceed 2‰.
(2) Check the relative position of the top of the movable support and the bottom plate before installation.
(3) After the spacers are installed, the rolling and sliding planes should be horizontal, and their slope from the theoretical plane should not be greater than 2‰. On the support and center of the lower board should be aiming, and the deviation is not more than 2‰.
(4) In order to ensure the smooth installation of the pad, a dry hard non-shrinking mortar cushion with a thickness of 20 to 50 mm should generally be built between the underside of the support and the top surface of the title pad. The arrangement of rubber pads is mainly related to the structure of the bridge.