Studies on seismic performances of the prestressed egg-shaped digester with shaking table test

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The seismic response and performance of a water-filled, prestressed concrete egg-shaped digester (ESD) subjected to various earthquake inputs are investigated by shaking table test. A 1:8 scaled model structure was tested. The tests involve three stages including the empty model digester (EMD1) subjected to accelerations of relatively small peak ground acceleration (PGA), the model digester filled with half volume of water (WMD) subjected to accelerations of medium PGA and the empty model digester with water taken out (EMD2) subjected to acceleration with PGA up to a large value. According to the site condition and seismic background, two scaled ground motion accelerations, the recorded El Centro acceleration (ELA) and the artificial acceleration adopted in Guangzhou (GZA), are employed as the seismic excitations. The natural frequency, seismic responses including the amplification factor of acceleration (AFA), the relative displacement and the strain and stress of the EMD1, WMD and EMD2, are investigated based on the test results. Some features are captured and discussed. The fluid–solid coupling effects on different responses are pointed out. Finite-element modeling computations are conducted. Comparison with the test counterparts shows a fair agreement on the whole, indicating the reasonability as an engineering model. However, detailed stochastic response analysis and reliability assessment are necessary to comprehensively capture seismic performances of the ESD. Some concluding remarks are made.