Introductions Of Seismic Spherical Bridge Bearing
After summarizing experience in designing, manufacturing, and using spherical bearings over the past decade. We have referred to the design method for spherical bearings specified in the European standard EN1337 and used finite element analysis to optimize the design. This series of spherical bearings is suitable for bridges with seismic fortification intensity of 7 and 8 degrees. Due to the use of metal spraying and heavy-duty anti-corrosion coating system, it can better adapt to corrosive environments such as acidic and marine atmospheres.
Installation Preparation of Seismic Bridge Bearing
How to install the seismic spherical bridge bearings? To install bridge bearings , professional teams are needed, especially the DCFP type bearing, there are some key points should be followed, including some store and transportation details of bridge bearings.
Firstly, The delivered and accepted products should have the manufacturer's factory inspection report, certificate of conformity, packing list, and valid periodic sampling test report. The on-site acceptance shall be carried out in accordance with the relevant provisions of the national standard for seismic spherical bearings.
The warehouse for storing bridge bearings should be dry and well ventilated. The warehouse temperature should be maintained within the temperature range for the use of bridge bearing. Seismic bridge spherical bearing should be sorted and neatly stacked, and kept clean. It is strictly prohibited to come into contact with substances that affect the quality of the support, such as acids, alkalis, oils, and organic solvents, and to be at least 1 meter away from the heat source
During transportation and transfer, the bridge bearing must not be collided or disassembled. The original assembly and packaging status of the supports should be maintained unchanged. And avoid direct exposure to sunlight, rain, and snow,
All above preparation is to ensure the seismic spherical bridge bearings can be kept in good outlook and status before installation, to the new bridge seismic bearings, it should be in good situation, it is not meaning that it can not be used in the bad situation and environment,after all, the steel bridge bearings are with Anti corrosion spray coating, and good steel materials.
Installation Guideliness Of KTQZ Seismic Spherical bearing.
1. Installation Precautions
When using this series of bearings, the concrete grade of the bearing pad stone shall not be lower than C40 (local compressive strength shall not be less than 20MPa).
The height of the cushion stone should consider the convenience of installation, maintenance, and necessary replacement of the support, and effective drainage measures should be taken around the support
The height difference of the four corners of the top surface of the cushion stone shall not exceed 2mm.
2.Before installation, reserved holes should be left at the pad stone or pier area according to the main dimensions of the bridge bearing and the plane connection dimensions in the weight table. The diameter of the reserved hole is the sleeve diameter plus 60mm, and the depth of the reserved hole is the sleeve length plus 60mm. The deviation of the center distance and diagonal length of the reserved holes shall not exceed 10mm.
3.When installing bridge bearings for prefabricated simply supported beam bridges, a force measuring jack should be used as a temporary support, to ensure that each pivot point is reversed,The difference between the force and the average reaction force of the four pivot points shall not exceed ± 5,
4,During the installation process of the support, it is not allowed to dismantle the support arbitrarily. But before the prefabricated beam is erected or the cast-in-place beam is pre-stressed and tensioned,The temporary locking connection device must be removed
5. After unpacking the bridge bearing, the seismic bearings should be kept clean and measures such as collision prevention, pollution prevention, and heat prevention should be considered.
6. When pre embedding steel plates, sleeves, and bolts at the bottom of prefabricated support beams, the accuracy of the connection dimensions with the upper support plate should be ensured. The deviation of heart distance and diagonal length shall not exceed 1mm. And the plane of the embedded steel plate surface in contact with the top surface of the at any seismic bearing position. The degree should not exceed 1/1000.
7, If there is displacement change of seismic bearing before installation, there should have agreement of the bridge bearing factory The displacement and pre deviation of the bridge bearing angle should be approved by the manufacturer and the bridge design institute. And completed under the guidance of the manufacturer. It is recommended to provide a pre deviation amount when signing the contract. The pre deviation amount should be set and locked before the product leaves the factory.
8. Installation steps for seismic isolation bearings for prefabricated simply supported box girder bridges
Before lifting the beam, remove the iron sheet packaging of the support and clean the rivets on the surface of the support. Then install the support
At the bottom of the prefabricated box girder. There should be no gap between the upper support plate and the pre embedded steel plate at the bottom of the beam. If there is a gap, pressure should be applied Fill with grouting method.
9.Chisel the surface of the bridge bearingt pad stone at the position where the support is in place, remove debris from the reserved holes, install the grouting template, and use it Soak the surface of the cushion stone with clean water. The grouting template can be made of prefabricated steel formwork, with a layer of 4mm thick rubber leak proof strip on the bottom surface, fixed to the top surface of the supporting pad stone through expansion bolts
10. Lifting prefabricated box beams with supports Place the box beams on temporary support jacks Adjust the beam body and supports with the jacks
Seat to design position and elevation,Ensure that there is a gap of 20-30mm between the bottom plate of the seismic isolation bearing and the top surface of the support pad stone.
We can see that at every step of installing the seismic spherical bearing of KTQZ SERIES, we must follow the specifications and must do every dimension as the specification request, one step after the other, or once there is mistake, the next step will be wrong, either, then there will be a big problem for the whole process.
