Shaking table tests on structures, poundings and soil-pile-structure interactions

This paper summarizes some of our shaking table tests to be carried out at the Hong Kong Polytechnic University on a MTS shaking table of dimension 3mx3m and with a maximum capability of Ig acceleration at a working load of 10 tons. Our proposed tests are related to structural dynamics of buildings under seismic ground excitation. The proposed experiments can be classified into three categories: the pounding effect, soil-pile-structure interactions and torsional effect. First, seismic poundings between buildings will be modeled by nonlinear impacts of two single-degree-of-freedom oscillators, and the results of these experiments will be compared to our new analytical and numerical solutions (Chau and Wei, 2000), which are extensions of the work by Davis (1992). The main emphasis here will be on the sensitivity of the contacts of the nonlinear impact on various levels of ground shaking to sec whether Hertz contact law can be applied during poundings. Second, a laminated tank, which can be made either flexible or rigid (corresponding to either soft soil or hard soil condition), will be manufactured. Micropiles will be installed into the rank and subject to horizontal ground shaking. The soil-pile-structure interaction will be examined by observing the amplitude of the shaking at the structure levels versus various level of ground shaking input (simulating linear to nonlinear soil responses). Analytical solutions will be used to compare with these experiments. The main focus here is the calibration and validation of various numerical and experiments] models. Third, the torsional effect induced by unsymmetric arrangement of stiffness of structures will be examined.