What is a friction pendulum ball bearing for highway bridges
1. Definition
Friction pendulum ball bearings for highway bridges are a type of bearing device used for highway bridges. It mainly consists of upper support plate, lower support plate, ball crown liner plate, PTFE sliding plate, stainless steel sliding plate and other components. The spherical contact between the crown liner plate and the upper support plate forms a spherical rotation mech
1. Definition
Friction pendulum ball bearings for highway bridges are a type of bearing device used for highway bridges. It mainly consists of upper support plate, lower support plate, ball crown liner plate, PTFE sliding plate, stainless steel sliding plate and other components. The spherical contact between the crown liner plate and the upper support plate forms a spherical rotation mechanism, and the low friction characteristics of polytetrafluoroethylene sliding plate and stainless steel sliding plate are utilized between the sliding surfaces to achieve frictional pendulum displacement function.
2. Working principle
Rotation function: When the bridge generates a beam end angle due to factors such as vehicle load and temperature changes, the spherical contact between the spherical crown liner plate and the upper support plate can adapt well to this rotation. Just like a ball rotating in the socket, it can flexibly adjust the angle change of the beam, ensuring good contact and force transmission between the beam and the bridge pier.
Sliding displacement function: In the horizontal direction, when the bridge undergoes expansion and contraction deformation, the low friction coefficient between the PTFE sliding plate and the stainless steel sliding plate allows the support to easily generate sliding displacement. Moreover, this friction pendulum design can effectively dissipate energy under dynamic forces such as earthquakes. For example, during an earthquake, the bearings will swing within a certain range, consuming seismic energy through frictional work and providing isolation.
3. Characteristics
Good adaptability: able to adapt to the displacement caused by temperature deformation, shrinkage and creep of the bridge under normal use. For example, when there is a large temperature difference between day and night or seasonal changes, the expansion and contraction of bridges can be well adapted through the sliding and rotation of supports, and their displacement can reach a certain value according to different design requirements. Generally, the horizontal displacement can reach several centimeters or even more.
Excellent seismic performance: Under earthquake action, friction pendulum ball bearings can reduce the impact of earthquakes on bridge structures by dissipating energy through friction. Its oscillation characteristics can extend the natural vibration period of bridge structures, avoid the dominant period of seismic motion, and reduce the input of seismic forces. For example, compared to ordinary bearings, it can significantly reduce the force transmitted to bridge piers and foundations under earthquake action, protecting the safety of bridge structures.
Reliable bearing capacity: The bearings can withstand the dead load (such as the self weight of the beam) and live load (such as vehicle load) of the bridge. Its design bearing capacity can be determined based on the size of the bridge and traffic flow, ranging from hundreds to thousands of tons, ensuring that the beam is stably supported on the bridge pier or abutment.
Good durability: The materials that make up the support, such as stainless steel and polytetrafluoroethylene, have good durability. Stainless steel skateboards are corrosion-resistant, while polytetrafluoroethylene skateboards have good wear resistance and chemical corrosion resistance, which can maintain good working condition during the long-term use of bridges and reduce the frequency of maintenance and replacement.
4. Application scenarios
Widely used in various highway bridges, especially in areas with frequent seismic activity and large-span bridges with high requirements for displacement adaptability. For example, in some cross sea bridges or large highway bridges between valleys, friction pendulum ball bearings can well meet the stress and deformation requirements of bridge structures in complex environments.