Research On Shaking Table Test Of SMA-FPB Isolated Single-layer Reticulated Spherical Shell

In order to study the seismic performance of seismically isolated lattice shell structures,a 1/10 scaled single-layer spherical lattice shell model with surrounding columns was designed and fricated.Friction pendulum bearings(FPBs)and shape memory alloy-friction pendulum bearings(SMA-FPBs)were installed on the top of the substructure to support the lattice shell roof.Shaking table tests on the structural model under tri-directional seismic excitations were conducted.The natural dynamic property,accelerations,displacements,and strains of the tested model with and without the isolation systems were measured.Moreover,numerical models of the controlled and uncontrolled models were conducted using OpenSees software.The established numerical model was validated with experimental results.The main work of this thesis is as follows:(1)A single-layer spherical lattice shell structure with a span of 30 m was used as the prototype structure.Based on the full-scale structure,a 1/10 scaled structural model and its isolation bearings were designed and manufactured.Furthermore,the testing program such as the arrangement of measurement points,measurement methods of acceleration and displacement,and preprocessing of seismic input data was developed,and this laid a solid foundation for the following formal experiments.(2)Shaking table tests on the structural model with and without FPB system were carried out.The effectiveness of the FPB system were assessed using accelerations,displacements,and strains of the measured points in the structural models.The experimental results show that the FPB system is effective in reducing structural seismic responses.Meanwhile,the FPBs at the bottom of the lattice shell roof can return to their original locations after completing the dynamic tests.(3)Four and eight NiTi-alloy wires were utilized in each curved sliding bearing,respectively,and two types of SMA-FPB were formed.The isolation effects of the SMA-based sliding isolators in lattice shell structures were examined using shaking table tests,and typical dynamic responses of the structural model were recorded and analyzed.The seismic responses of the structural model with SMA-FPBs were effectively depressed compared with the uncontrolled structural model.Subsequently,the seismic responses of the controlled structure models were compared.The results reveal that the SMA-FPB system provides superior bearing displacement control capacity over the FPB system,which contributes to the development of effective seismic protection for isolated structures.(4)According to the design scheme of structural model and loading program for the shaking table test,numerical modeling of the lattice shells was implemented into OpenSees.The tri-axial seismic responses of the structural models were numerically simulated.The simulation results were compared with the experimental results collected from the aforementioned dynamic tests.The comparisons reveal that the errors between the simulation and experimental results are less than 15 %,indicating that the accuracy and reliability of the proposed numerical modeling method is verified.