Research On Load-Bearing Performance And Design Method Of Frame-Supported Multi-Ribbed Wall Beam

Multi-ribbed slab structure (MRSS) is a new structural system, characterized by saving energy and good seismic performance. At the present time, certain staged achievements have been made in the study of the theoretical and application of conventional multi-storied and high-rise buildings, but the study of this system in buildings with large space at the bottom remains blank. The dissertation is devoted to frame-supported multi-ribbed wall beam (FSMRWB), the main bearing member in the frame-supported multi-ribbed slab structure with large space at the bottom, and mainly studies its load-bearing performance and design method, including its load-bearing mechanism, seismic performance and practical design method. The main studied are as follows.1. The pseudo-static experiments of four large-scale models of FSMRWB are done. The load-bearing performance and composite action of FSMRWB under vertical load are explored, then the failure procedure and the seismic performances under both vertical and horizontal load, such as failure mode, bearing capacity, deformation features, hysteretic characteristic and anti-collapse performance, are studied. Then the influence of the factors, such as is discussed, and FSMRWB is contrasted with frame-supported masonry wall beam and frame-supported shear wall in failure mode, bearing capacity, deformation and energy dissipation.2. Through simulating concrete and blocks with solid element, bars with link element, and using isotropic hardening model and William-Warnke five-parameter failure rule, the nonlinear FEM analysis model of FSMRWB is set up, whose rationality is certificated by experimental data. Through the nonlinear FEM analysis under vertical load, the stress distribution and the influence of span-to-span ratio of the wall beam, height-to-span ratio of the trimmer beam, and the opening in the wall, are simulated. And the distribution proportion of vertical load in different members of the multi-ribbedcomposite wall is obtained.3. Through the nonlinear FEM analysis under vertical and horizontal load, the whole changing process of the internal force and deformation of FSMRWB is simulated truly and simply, and the appearance and development of cracks, the failure procedure and the ultimate strength capacity is described.4. On the basis of experimental study and finite element analysis, the load-bearing mechanism of FSMRWB is studied, and it is contrasted with that of frame-supported masonry wall beam. Then, the theoretical calculation model of FSMRWB is put forward.5. Considering the factors of span-to-span ratio of the wall beam, height-to-span ratio of the trimmer beam, height-to-span ratio of the wall and section height-to-length ratio of the bottom frame column, the orthogonal design is done and the internal force of the trimmer beam is calculated. Through the visual analysis and variance analysis to the results, the significance analysis of the factors influencing the internal force of the trimmer beam of FSMRWB is done. Then, considering the position of the opening in the wall, the internal force coefficient of the trimmer beam is obtained through regression analysis. In addition, the simple drawing for the design and calculation of FSMRWB is put forward, and the practical design calculation formula of the trimmer beam of FSMRWB is also given.6. By referring to the practical formula for oblique section bearing capacity of ordinary multi-ribbed composite wall, and considering the results of the experimental study and theoretical analysis, the practical formula for oblique section bearing capacity of the walls in FSMRWB is given.7. According to the results of the experimental study and theoretical analysis, the possible failure modes of FSMRWB under earthquake are pointed out. With seismic control design method, the seismic detail measures for FSMRWB are proposed. Considering the load-bearing performance of high-rise multi-ribbed slab structures, some problems on the transfer beam in high-rise frame-supported multi-ribbed slab structures are discussed.The originality of this dissertation lies in: 1. Large-scale FSMRWB model experimentsLarge-scale FSMRWB model experiments are done for the first time. Through the experiments, the load-bearing performance of FSMRWB under vertical load and the seismic performances under both vertical and horizontal load, such as failure mode, bearing capacity, deformation, hysteretic characteristic and anti-collapse performance, are studied systematically, which assures the usage of MRSS in buildings with large space at the bottom.2. Establishment of nonlinear numerical model of FSMRWBNonlinear finite element model of FSMRWB is established for the first time. Through the nonlinearFEM analysis, the stress distribution and load-bearing performance of FSMRWB are truly simulated, which provides more detailed data for the comprehension of load-bearing mechanism of FSMRWB.3. Provision of the theoretical calculation model of FSMRWBConsidering the unique structural details of MRSS, the results of the experimental study and theoretical analysis, the load-bearing mechanism of FSMRWB is studied, and the theoretical calculation model of FSMRWB is put forward.4. Establishment of the practical design calculation formula of the trimmer beam of FSMRWB Through the orthotropic experiment design, the significance analysis of the factors infiuencing theinternal force of Ihe trimmer beam of FSMRWB is done for the first time, and the practical design calculation formula of the trimmer beam of FSMRWB is set up through regression analysis.5. Provision of the seismic detail measures of FSMRWBConsidering the load-bearing performance of FSMRWB, and its possible failure mode under earthquake, the seismic detail measures of FSMRWB are provided with seismic control design method.