Roads And Bridges Off The Beam To Prevent The Device

Falling-off prevention system of highway bridges is an important type of seismic isolation device. Based on the analysis of the highway bridges' damages in the earthquakes of recently twenty years and the introduction of the development and the present technology of the world, the paper has explored a useful falling-off prevention device. In this paper, the three level fortification criterion , two stage design method and the elastic response spectrum theory are adopted, and the program of NBA (The Program of Nonlinear-Aseismic Analysis for Beam Bridge) is used to calculate. Through gathering , analyzing and calculating a lot of bridge design materials, this paper induces a simple way to calculate the relative displacement of the beam and the pier, and then according to the current design method, it concludes a better design principle of the supporting length of the beams. At the same time the dynamics is adopted to put forward the design method of the carrying capacity and the lengthen of prestress wire(steel bar) falling-off prevention structures of highway bridges. At last, this paper explains the design method of this device. It is anticipated that this paper would have some referential value to the design, application and production of falling-off prevention device, in order to accelerate its process of the practicality.