Pounding Analysis And Experimental Investigation Of Curve Bridges Underearthquake Excitation

Curve bridge is a kind of civil infrastructure to meet the functional requirements in the specific terrain conditions. Because of the complexity of the terrain and the limitation of the urban space, curve bridge, with its unique advantageous, has been widely used all over the world. Seismic-induced pounding of bridge structure is induced by the asynchronous vibration between the adjacent segments due to the difference of dynamic characteristics. For the curve bridges, the existence of the bridge deck curvature induces the rotation effect, resulting a more serious pounding, even unseating, than straight bridges. Aiming at the the multi-dimensional pounding problem of the curve bridges, this paper investigated the the seismic response of the curve bridge based on a practical curve bridge.The main contents of the study include:(1). Several pounding model was introduced firstly. Aiming at two adjacent irregular structure with multi-degree of freedom, the mechanical model considering the pounding effects was derived. Based on the spatial structural form and the mass distribution of the prototype, a multi-dimensional mechanical model with multi-degree of freedom is developed. For the irregular rigid bodies, the stiffness, mass and damping matrice of the structural were obtained by both using the lump mass method and considering the torsion effect. Considering the depth of the contact area and the material characteristics of the contact bodies, an impact model was established according to the three-dimensional contact slip model with the corresponding pounding force, imact damping and stiffness.(2). Based on a practical curve bridge, a computing program was developed based on the Matlab software and the derivation of the governing equation of motion of the structure with pounding effects. The effects of the main parameters for the pounding responses were also analyzed to provide the basis for the model design of the shaking table test. According to the similarity criterion, the geometry size and mass et al. of the test model were determined, and the manufractured model was assmebed with the measurement system. Shaking table tests were conducted for the test model under the harmonic excitations with different frequency, amplitude and direction, and the earthquake excitations.(3). The test data of the shaking table experiment was analyzed and numerical simulation was conducted to investigate the dynamic response regulity of the straight and curve bridge with and without pounding effects under different earthquake direction angle. According to identified impact parameters, the test results were compared with the simulation results to validate the accuracy and rationality of the pounding theory.