Experimental Study on Collapse Failure of Concrete Continuous Girder Bridges Under Contact Explosion
The contact explosion test of two columns of the middle pier of the two-span prestressed concrete continuous girder bridge model was carried out successively,and the refined three-dimensional finite element model of the bridge model was established to explore the dynamic response,failure mode and collapse mechanism of the bridge model under contact explosion.The results shows that:① The bottom of the column mainly suffers local breaching under contact explosion.The magnitude of the axial force has a significant influence on the damage degree of the column.After the pier loses its bearing capacity,the bridge model will collapse under the action of its own weight;② Except for the measuring point at the fixed support,the variation trend of acceleration time history curve of other points on bridge deck is basically the same in the two scenarios. The variation trend of the peak acceleration distribution of the bridge deck is basically the same along the longitudinal and transversal direction. The maximum tension fluctuation value of the measuring point in the positive bending moment region is obviously smaller than that in the negative bending moment region;③ The nonlinear numerical model can well simulate the punching shear failure mode of the bottom of the column and the distribution of cracks in the column body under the action of contact explosion,and can reproduce the collapse failure phenomenon of the bridge model under the action of its own weight during the test.The research results can provide references for the global blast-resistant collapse of the continuous girder bridge structure and its explosion safety protection to some extent.
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