Development of Seismic Damage Finite Element Code for Reinforced Concrete Framed Structures


In the conventional design of a building, only static analysis in the horizontal and uniaxial directions is commonly carried out, in order to minimize calculation costs. This approach may ensure the structural strength of the building, if there is sufficient strength to support the load in vertical direction. However, the mass system model replaces the building layer in dynamic analysis, and the complicated dynamic behavior of the structure at member level is not sufficiently examined. Therefore, the development of a more precise and more efficient dynamic analysis code is strongly desired. Recently, significant advances in the field of computers have been removing the calculation cost restrictions, and various dynamic analysis codes are being developed. In this study, the Adaptively Shifted Integration (ASI) technique with a linear Timoshenko beam element, which can express a plastic hinge located at an exact position by shifting the numerical integration point in the element, is implemented into the finite element code in order to develop a more precise and less calculation-time-consuming seismic response analytical tool.
The purpose of this study is to verify the validity of the ASI technique in seismic response analysis and to construct a highly efficient structural design tool for RC structures. Analyses considering vertical seismic excitation or the phase difference of seismic-wave propagation, and those involving structural discontinuities such as member fracture are carried out as numerical examples. Member fracture can be expressed by forming a plastic hinge located at an exact position with a simultaneous release of the resultant forces in the element. A contact algorithm is added to the code to reproduce phenomena such as intermediate-layer failure. The results reveal that this technique can be used in the numerical estimation of structural reliabilities.

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