The Elastic-plastic Analysis On The Light Steel And Concrete High-rise Mixed Structure

At present, there is a lot of research on the light steel structure system, but the application of light steel structure is limited in china, one more important reason is that the light steel structures are usually used in low-rise structures. In view of the development situation of light steel structure, our research group puts forward the light steel and concrete high-rise mixed structure. The idea of mixed structure is from mega structures, the concrete structure as the main structure, and the light steel structure as the subordinate structure. The combination of light steel structure and concrete structure forms a new structure form. In this paper, the writer has made different research, which include the reduction of period on the mixed structure, the mixed structures' performance state in frequent or rare earthquake, as well as the research about the economy of this mixed structures. The main research contents and conclusions are as follows:(1)The writer have deduced the period time reduction factor in theory, and obtained the formula of period time reduction factor. For different height models and different ratios between light steel wall with the main concrete structure, the writer has compared the difference between the formula results and the finite element calculation results. The comparison results show that the formula method is consistent with the calculated values by software, which proved that the formula is right to calculate the factor of period time reduction.(2)The writer has made a comparison between the mixed structure and the main concrete structure in six degrees zone and seven degrees zone, and the earthquake include frequent earthquake and rare earthquake. The results show that: the light steel structures have the reducing effect on the story drift of main concrete structure, especially in the upper floors. The reducing value is related with the ratio between light steel structure stiffness and the main concrete structure stiffness. The light steel wall has taken part shear force on the horizontal seismic action. The light steel walls constituted by gypsum panel have taken the proportion of the floor shear force is about 6% to 10%, and the light steel walls consisted by OSB panel have taken the proportion of the floor shear force is about 15% to 20%. The light steel walls have taken the proportion of the floor shear force is more in rare earthquake than in frequent earthquake.(3) In the rare earthquake of six degrees zone, the concrete main structures and the mixed structures are only slightly damaged, and the degree is of the nonlinear state is not high. In the rare earthquake of seven degrees zone(0.15g), the concrete structure and the mixed structure enter into high state of elastic-plastic, but the light steel structure have played an important role contribution in the concrete main structure. The light steel wall which consisted by OSB panel can realize the concrete main structure turn from the “not failed in big earthquake” state to “repairable” state. Time-history analysis results show that the light steel wall enter into the state of nonlinear when the concrete main structure generate large deformation.(4)The amounts of concrete and steel are less when comparison between the mixed structure and the traditional concrete structure, and the advantage is more evident, especially in the area with high seismic intensity.