Lateral Displacement Restrainer of Beam Based on Elastic Deviation Prevention and Plastic Unloading Mechanism

In order to alleviate the lateral deflection or overturning of the beam under various factors, and improve the rigid blocking defect of the existing anti-offset equipment, a lateral-movement limiting device of beam body based on the elastic anti-deflection and plastic unloading concept is designed by referring to the mechanical shock absorption and isolation device. In this device, spring parameters (for elastic deviation prevention under normal conditions) are selected according to the reduced data of bending strength of the pier bottom and the maximum allowable transverse displacement of the beam, and the number of anchoring bolts in the weak layer (for unloading pier protection under large loads) is calculated using the reduced data of support reaction force. Taking a curved continuous girder bridge in Shaanxi Province as an example, the displacement and stress increments of the bridge with and without equipment of the device under static and dynamic actions are simulated using the finite element analysis software Midas Civil. Data comparison shows that the radial displacement restriction effect of the equipment under various static loads is remarkable (the average displacement limit rate is more than 70%, and the main displacement inducement limit rate is more than 80%); in most time-histories of the El Centro Site waves, the displacement and stress increments of the beam with equipment are smaller than those without equipment, and the peak displacement (the reduction rate is above 90%) and the peak stress (the average reduction rate is about 50%) are significantly reduced after installing the equipment. This shows that the equipment can effectively reduce the dynamic displacement increment of the beam without stress concentration and has good seismic deviation prevention effect.