Research On Anti-overall Collapse Of Prefabricated Simply Supported Beam Bridges

In recent years, due to the impacting action of sudden load, such as explosion and seismic load, building and bridge engineering collapse have happened many times, causing huge economic losses and a large number of casualties. Blast load is ephemeral, under which,three damage forms of reinforced concrete structure will happen, the bending failure, shear failure and bending shear failure. This paper study it that horizontal displacement on the top of pier is beyond its allowable value of code, leading to the upper structure overall collapse,before the several damage happen, under the action of force to which the explosion load transfer the top of pier, and other force. In the view of study above, this paper analyze and select the reasonable calculation model of pier top, deriving the calculation formula of horizontal displacement of top pier, based on Rayleigh-Ritz method of energy principle,verifying the rationality of the formula. Finally, apply this method to practical engineering,analyze the engineering collapse, under the accidental load, and proposing the relevant measures of bridge overall collapse resistance. The result is as follows.(1)When laminated rubber bearings install on the top of pier, the distribution of the horizontal force effecting pier top have to consider the integration situation of support stiffness and pier stiffness, and the axial force on top of pier will give pier a additional deformation ?.In view of this, considering four kinds of circumstances, whether or not the spring support will install on the top of pier, whether or not the bottom of the pier was fixed,from simple to complex, derive the calculation formula of horizontal displacement on the top of pier, based on Rayleigh-Ritz method.(2)Choosing reasonable structure calculation model, the paper modeling and analyze the pier through the finite element software, calculating the displacement of the pier top, and compared it to the results of formula method, analyze the influence of geometric characteristics and mechanical parameters on two kinds of calculation results. The results show that the formula method has certain accuracy and applicability.(3)Based on the actual project case, analyze the collapse of simply supported beam bridge under the accidental load, such as explosion load.(4)Proposing the relevant measures of bridge overall collapse resistance. The bridge deck paving layer integration is the measures to ensure the integrity of the bridges, and verifying the feasibility of the measures. The results show that the overall collapse causing by explosion load is starting by a cross falling beam. Integration tier can make each bridge across collaborative force, improving it’s bearing capacity, overall integrity and ability to resist collapse, thus improving the safety and reliability of the whole bridge system. At the same time, put forward the inhibiting device between the pier and beam at expansion joints to improving the ability to resist the collapse of the bridge.