Research On Seismic Performance Of Frame-supported Multi-ribbed Composite Slab Structure

To cope with function of modern building, the structure with large space at the bottom is developing. This paper introduces Multi-ribbed Composite slab structure (MRC slab structure), whose displays good performance in energy saving and earthquake resistance, environmental protection, at the same time, owing to its lightness, strength, adjustable rigidity, to this structure. The Frame-supported Multi-ribbed Composite slab structure (FSMRC slab structure) is able to realize the reasonable distributions of the stiffness and the bearing forces, expand the application scope of MRC slab structure. Based on the prior related study results and the design of oblique frame-grid, the load-bearing mechanism, seismic design method and damage is studied, through model tests, numerical simulation and theoretical analysis. The main parts of work are as follows:1?Four FSMRC slab specimens with different forms were tested under cyclic loading, the failure process, hysteresis characteristic, the loading-strain curves of the reinforcing bars of the members, as well as the the stiffness-degradation law, strengthen-degradation performance and repairability were anlyzed. The characteristics of mechanical behavior, failure mode and collapse-resistant capacity were obtained, to provide reference for the establishment of the restoring force model.2?The macro model was computed incorporated in the program IDARC, to simulate cyclic loading test of FSMRC slab structure. The calculating results have accordance well with experimental data. And detailed stress characteristics of the specimens in the elastic-plastic stage were simulated by ANSYS. Furthmore, the stiffness ratio of transfer-story was discussed in each control phrase, the unique rule on stiffness ratio of transfer story of FSMRC slab structure was given, moreover, optimal design of stiffness ratio was adviced. The computing models with high-storey FSMRC slab structure was established to make the near-field seismic response analysis, and compare with the nonlinear dynamic response of Frame-supported Shear wall structure (FSS wall structure) under the same terms. The characteristics of energy-dissipation and seismic-response were obtained, to provide the basis for the nonlinear design of the structure.3?Based on the orthogonal design method, the influence factors and calculation formula of FSMRC slab structure were studied. Considering the factors of height-to-span ratio of the frame-supported beam, width-to-height ratio of the aseismic wall, height-to-span ratio of MRC wall and hole-position variation of orthogonal frame-grid, the internal force of frame-supported beam, frame-supported column and maximum angle of the overall structure were analyzed. The significant degree of various influence factors were determined, in addition, the calculation formula of bearing internal-force coefficient of frame-supported beam of the structure was also given.4-Based on the Griffith energy release and Irwin-Orowan energy balance principle in material fracture theory, damage phenomenon and internal mechanism of FSMRC wall were examined. According to the failure features of the wall, a more reasonable improved damage model was set up. The boundary values of the damage index at different destructive state were researched, hysteretic energy dissipation and pinch process of hysteretic curve was analyzed quantitatively, so that the wall damage-evolution law was evaluated accurately.5^Through the structure failure criterion, the structural failure degree was analyzed. Multi lines of defense principle of FSMRC slab structure was revealed. A new definition of structural robustness was given, in accordance with the quantitative analysis on vulnerable index of MRC wall and safety evaluation indicator of FSMRC slab structure, the structural seismic robustness was studied in depth, to provide a new method for structural anti-collapse design.