Research On Cooperative Effect Of Hybrid Structure With Long Span Steel Roof And Supporting Concrete Frame

The hybrid structure of long span steel roof with supporting concrete frame is a common form of long span structures. At present, most design institutes analyze the hybrid structure by modeling it into two parts. Simplified supporting conditions are used to simulate the supporting concrete structure when the upper steel structure is analyzed. However, this method may not be able to reflect the real situation of the structure. Therefore, it is necessary to conduct the integral analysis to consider cooperative effects for hybrid structures.Four engineering projects: a certain cultural monument project, Beijing Jiangtai winter garden, Wuhan Yinhehui center and the swimming pool of Wugang sports center, are analyzed to compare the differences of analysis results between stand-alone steel roof and the whole structure with supporting concrete frame. Using spring supports model to simulate the supporting concrete frames, and modeling different range of supporting structures to consider the different influence on cooperative effect are also discussed. The main conclusions of this thesis are as follows:(1) Calculation results between stand-alone steel roof and the whole structure with supporting concrete frame show differences in natural periods, vibration modes, support reaction forces, element inner forces, element stresses, structure displacements and overall buckling. And in most conditions, results from the whole structure are in the position of disadvantage, which demonstrates the importance of cooperative effect for hybrid structures.(2) In static analysis, response spectrum analysis, dynamic time history analysis and overall buckling analysis, the results from the spring supports model are close to the whole structure model than the stand-alone upper long span steelstructure model, which demonstrates that it is acceptable to consider the cooperative effect by using spring supports method in such hybrid structure.(3) It is reasonable to take a part of the supporting concrete structure to consider cooperative effect if the supporting concrete structure is much larger than the upper steel structure in size. The model with part of supporting concrete structure and the model with the whole supporting concrete structure have the same trend in calculation results. And there are little differences in magnitudes of results.(4) The influences on the supporting concrete structure by considering cooperative effect are evidenced by the increase in story drift ratio and torsional displacement ratio. Axial compressive ratios of the supporting concrete columns are also different. This also indicates the importance of cooperative effect for hybrid structures.(5) The spring supports model and the structure model with part of supporting concrete structure are not the accurate simulation for the cooperative effect of long span steel structure with supporting concrete structure. There is still some differences compared to the results from the whole structure model. Therefore it is still recommended to analyze the structure behavior by considering the whole supporting structure.