Mechanical Properties And Calculation Method Of Trimmer Beam Of Frame-supported Multi-ribbed Composite Structure Under Vertical Load

ABSTRACT:Multi-ribbed composite structure is a new structural system, which can be utilized in many fieds. The thesis is devoted to studying on the trimmer beam of the frame-supported multi-ribbed composite structure. On the basis of the previous researches, theoretical analysis and numerical simulation with FEM are used to study the load-bearing performance. The influencing factors of the parameters of wall to the trimmer beam under vertical load are studied, and the trimmer beam theoretical formula and practical internal force calculation formula are put forward. It provides references for the design and engineering practice of the frame-supported multi-ribbed composite structure. The main contents of studies include:(1) Applying elastic foundation beam theory, the deformation governing differential equation of the trimmer beam is established according to the model in which the upper multi-ribbed composite wall is simplified as Pasternak two-parameter elastic foundation with the consideration of shear effect and the material property differences, and the trimmer beam is considered as finite beam inverted on elastic foundation. And then the vertical stress of the interface and the internal force of the trimmer beam are obtained by applying transfer matrix method, with a comparison to FEM analysis.(2) FEM was employed to study frame-supported multi-ribbed wall beam under vertical load. The behavior of trimmer beam under vertical loads is studied on various parameters including elastic module of in-fill block, arrangment of RC rib in wall, robustness of side column, height—to-span ratio of the trimmer beam, the height-to-span ratio of the wall, the position of hole in the wall and the section height-to-length ratio of the bottom frame column.(3) Considering the factors of the height of ribbed beams, the amount of ribbed columns, the width of ribbed columns, height-to-span ratio of the trimmer beam and height-to-span ratio of the wall, the orthogonal design is done and the internal force of the trimmer beam is calculated. The significance analysis of the factors influencing the internal force of the trimmer beam of frame-supported multi-ribbed composite structure is done. Then, considering the position of the hole in the wall, the internal force coefficient of the trimmer beam is obtained through regression analysis. At the same time, the calculation diagram of frame-supported multi-ribbed wall beam is put forward, and the practical design calculation formula of the trimmer beam of frame-supported multi-ribbed composite structure is also given. The detail design suggestions are proposed to provide optimization for the trimmer beam under vertical load.