Research On Seismic Performance Of Steel Reinforced High-strength Concrete Frame Prestressed With Bonded Tendons

The maintenance, reinforcement and modification of the existing buildings have been becoming a hot topic in the circles of civil engineering with the development of construction technology in China. Jacketing structure is a new structural type, which is a kind of construction technique used to add stories around the existing buildings. Due to the conventional structure cannot meet the needs of Outer-jacketing and Adding-story, the formulation of a new structure system is necessary. A new style of steel reinforced concrete frame structure made up of encased H-shape steel prestressed high concrete composite beams and angle-steel high concrete columns is put forward in this paper. This kind of structure can effectively solve the following problems in practical engineering. First, the roof of exciting building is hard to bear the gravity load of fluid concrete during construction. It can be achieved by hanging formwork under the H-shape steel. Second, the H-shape steel and prestressing tendons can transit among angle-steels of columns, so the prestressing tendons can be tensioned and anchored outside the column avoiding the column steel weakened. Third, the height of beam section and building can be reduced by applying the prestressing tendons.There are few researches about this structure in the domestic and overseas. As a result, four aspects of work are carrying out for providing the technical support to practical engineering and writing the relevant specification.1. The single-span and single-layer SRCF and PSRCF 3D finite element model are established by using ABAQUS software. The load-displacement curve is obtained to compare with the date from two test frames and both are in good agreement. Then the rationality of established finite element model is verified in this paper. At the same time, the method for establishing the finite element model is given through the comparison of different high concrete constitutive model and different size of concrete grid.2. The static analysis of single-span and single-layer PSRCF under monotonic horizontal load is carried out with slenderness ratio, span ratio, axial compression ratio, column steel ratio, prestressing degree and high strength concrete grade for the parameter. Then the bearing capacity characteristics of structure and the regularity of plastic hinge are given.3. The hysteretic curve is got by carrying out the quasi static simulation analysis of PSRCF to study the skeleton curve, ductility, energy dissipation performance, stiffness degradation, such as seismic indicators, to the structure. Then the design method of PSRCF is put forward.4. Based on the parameters, the P- skeleton curve of PSRCF is extracted. Then the P- restoring force model is established to provide the reference for elastic-plastic time history analysis of the PSRCF structure.