Dynamic Analysis Of Structures Response To Blasting Induced Ground Motions

With the development of the blasting technology and the need for the urban construction reform, the application of blasting has developed to the extent which include the demolition of urban large building, the foundation fit excavation, light rail project, subway project, highway, urban road and the leveling construction of airport etc, the environment of blasting change to urban which has large population from the environs which has little people. But the study on the theory of blasting vibration gets far behind the application, the current design methods and safety assessment used empirical and semi-empirical method. It often caused accidents and impedes the development of blasting.Based on the above issues, in this paper, something has been discussed as the following aspects:①Based on the analysis of blasting wave's mechanism, time and frequency domain, results show that the blasting seismic waves have the characteristics of a short time, large amplitude, high frequency and rapid decay while compared with natural seismic waves.②In this paper, four R/C frame structures including two-storey, 7-storey, 12-storey and 16-storey were analyzed with the nonlinear time history analysis. The R/C frame structures were both modeled with three-dimensional coordinated system. On the assumption that spatial building structures may be idealized as the assemblage of planar substructures interconnected by infinitely rigid floors, the nonlinear behavior of reinforced concrete elements may be simulated by a modified planar element model with varied stiffness in different regions. A moment-curvature hysteretic model including the pinching effect resulted from shear deformation, which named modified Otani model, is proposed to determine the elastic-plastic flexural stiffness of reinforced concrete elements. The effects of slippage rotations at the ends of reinforced concrete elements due to non-perfect bond of reinforced bars are also considered in the hysteretic models. Two kinds of blasting seismic waves were adopted in the paper.③Two shear-wall and frame shear-wall structures including 12-storey, 24-storey were analyzed under blasting wave by SAP2000, which also compared with the response of the structures under natural seismic.④The soil-structure interaction effect is included in the analysis of structures located on a soil site by adding springs and dashpots to each support. In this part, three R/C frame structures including single-storey factory, two-storey,12-storey were analyzed by SAP2000.⑤To find the relations between the duration and frequency with the response of the structures, the analysis used the same frequency and vibration peak, but different duration of blasting seismic waves and used the same duration and vibration peak, but different frequency of blasting seismic waves. There are two R/C frame structures including 7-storey, 12-storey were analyzed.