Study On The Shear-enhanced Coefficient Of Prestressed Concrete Frame

As prestressed concrete structures are widely used in seismic area, and it hasn‘t been reserched enough on earthquake resistant design, it' s an urgent to carry out more research on it for civil engineering. Therefore, based on ther topic of the project for National Natural Science Foundation of China(51278218), the problem about the values of shear-enhanced coefficient of prestressed concrete frame, which is definded in the current of China, Specification for Seismic Design of Prestressed Concrete Structures(JGJ40-2004), were studied in this paper.In this research, four prestressed concrete frame structures were designed according to the current codes of China, representing the four different seismic level definded by the current codes. Then, analysis models were established in SAP2000. Static elasto-plastic and dynamic elastic-plastic analyses were proceeded. The geometric nonlinearity was considered by P-Delta effect, and matearal nonlinearity was considered by the PMM fiber hinge. Since it is hard to simulate the shearing failure, it wasn't applied in this research. The shear-enhanced coefficients of elements needed in rare earthquake were obtain by combined the formulas in the current code and the capacities the structrues needed indeed, which were the shears of elements in the analyses.In static elasto-plastic analysis, turn-triangle distributed load was applied for the feature of concrete frames. The shears of elements around performance points were regarded as the shearing resistant capacities needed.In dynamic elastic-plastic analysis, Seismo Mathc and Seismo Artif were applied to choose natural acceleration records and sumilate artificial ones. 2 natural and 1 artificial records were used in every structures and the results were the maximum of them.Finally, the conclusion of static elasto-plastic analysis is basically identical with that of dynamic elastic-plastic analysis. For the prestressed concrete frames of seismo level 1 to 4, the suggested shear-enhanced coefficients of beams are 1.55, 1.35, 1.2 and 1.1. And the ones for columns are 1.65, 1.45, 1.3 and 1.2.