| Double steel-concrete composite(DSC) structure,formed by core concrete encased by steel plate, has the advantages in construction convenience, air/water tightness and shock resistance compared to traditional reinforced concrete structure, thus it was applied in the safety shell structure in the China 3rd nuclear power plant. However, research on DSC structure in China is not very comprehensive and the corresponding design method is not clear. Hence, the out-of-plane mechanical performance, hysterical loop characteristic and local buckling of exterior steel plate are first studied in this paper by specimen test on DSC elementary components and, furthermore, to evaluate the aseismic performance, an integral finite element model of DSC safety shell structure is established and its elastic-plastic time-history analysis is performed. The main works and research results are listed below:(1) Static load test of seven DSC specimens with various construction details of steel plate(single or double), shear connection degree, thickness of steel plate are performed, from which similar behavior to reinforced concrete structure is found except the slip effect on the steel-concrete bonding surface and local buckling of steel plate subjected to compression load.(Chapter 2).(2) Quasi-static test of three scaled cantilever DSC shear wall specimens are performed with different shear span ratio and thickness of steel plate. Mechanical performance and hysterical characteristic are examined, and rationality of stud spacing distance-steel plate thickness ratio of original structure and the beneficial effect provided by tensile reinforcement to out-of-plane shear resistance are verified.(Chapter 3).(3) Taking account of both the nonlinear material behavior and slip effect between steel and concrte, a separated layered-shell FEM model of DSC to simulate the static test is established and then verified, which shows good argrement to the test results. Then the formula of out-of-plane bearing capacity and stiffness of DSC is derived.(Chapter 4).(4) The local buckling behavior of exterior steel plate is studied by performing uniaxial compression tests on ten DSC shear walls with different spacing-thickness ratio, steel plate thickness and stud arrangement. In addition, the upper bound of stud spacing distance-steel plate thickness ratio of exterior steel plate can be derived via the test results from other researchers.(Chapter 5).(5) Taking into account of single-side constrain effect of concrete on steel plate, the stud anchorage deformation and slip effect, a finite element model of DSC specimens in uniaxial compression test is established not only to quantify the influence of stud anchorage stiffness, spacing-thickness ratio and initial imperfection of steel plate on the critical buckling stress but also to verify the precision of the proposed formula to get the upper bound of the stud spacing-steel plate thickness ratio. Moreover, a more comprehensive mechanism of stud arrangement acting on buckling behavior of steel plate is analyzed.(Chapter 6).(6) The design parameters of a DSC component in a safety shell structure are checked by the test results, then the entire model is established by layered shell element and elastic-plastic time history analysis under severe earthquake excitation is performed. As a conclusion, the distribution of internal force, deformation and weak components in the DSC safety shell structures are evaluated and an analysis on the aseismic margin of the whole structure is performed.(Chapter 7). |
PDF Full Text Request