| Jacketing structure, a construction technique used to add stories around the existing buildings, has been becoming one of the most concerned topics in the circles of civil engineering. A new style of steel reinforced concrete frame structure made up of encased H-shape steel prestressed concrete composite beams and angle-steel concrete columns (ASCC) with 4 or 8 angle-steel is put forward. The H-shape steel can transit among angle-steels of columns, and the prestressing tendons can be laid between the top and bottom flange of H-shape steel, so the prestressing tendons can be tensioned and anchored outside the column. At the same time, for the bottom formwork can be hung from the H-shape steel, on which the side formwork can be installed, the ground floor can be self-supporting during construction. Therefore, this new frame structure is fit for jacketing structures to add stories around the existing buildings. How to ensure this new structure to be in elastic state under frequent earthquake, be mendable under design earthquake and not collapse under infrequent earthquake, especially the last item, is the problem to be solved imminently in engineering field. Center around this problem, 5 aspects of investigation are carried out as following:(1) The experiment of seismic performance of ASCCs in this new frame structure has not been reported, in order to study this problem, 9 ASCC specimens with shear steel plate are tested subjected to the horizontal low cyclic loading, in which, the shear span ratio is 3 and axial compression ratio is different. The hysteretic curves of 9 specimens are obtained. The seismic performance indexes such as energy dissipation, stiffness degradation, strength degradation, skeleton curves and ductility of this kind of column are acquired, and the seismic fortification measures including ultimate values of axial compression ratio under different seismic degree are suggested. Based on the tests, the calculation formula of flexural bearing capacity of the columns is given. Simulation analysis is used to calculate monotone load-displacement curves of the ASCCs, and the calculated results agree well with the test results. Then the influence of factors on the performance of the ASCCs is explored, such as the axial compression ratio, shear steel plate ratio, concrete compression strength, steel ratio, yield strength of steel and shear span ratio, etc. The hysteretic models for the load-displacement and the moment-curvature are established, and this provides reference for the elastic-plastic history analysis of structure.(2) Hysteretic model of encased H-shape steel prestressed concrete composite beams based on mass parameter statistical analysis has not covered, in order to study this problem, using Simulation analysis monotone moment-displacement curves and load-displacement curves based on the encased H-shape steel prestressed concrete composite beams tests by other scholars are calculated, and the results agree well with the test results. Then the influence of two factors on the mechanical performance of the encased H-shape steel prestressed concrete composite beams are researched, which are the ratio of the resistance of the H-shape steel to the total resistance and the ratio of the resistance of the prestressing tendons to the total resistance of the members, and the formulas of the curvature ductility and the displacement ductility are given. Hysteretic models for the load-displacement and the moment-curvature are established for encased H-shape steel prestressed concrete composite beams, this provides reference for elastic-plastic time analysis of structure.(3) Combined with the characteristics of jacketing frame, based on the large-scale finite element method software ANSYS, making use of parameterized design language APDL and Matlab, program for calculating internal force and placing reinforcement of jacketing steel reinforced concrete frame prestressed with bonded tendons is compiled under"Code for seismic design of buildings"(GB50011-2001) and"Technical specification for steel reinforced concrete composite stuctures"(JGJ138-2001). This program can adjust seismic reinforced measures according to different requirements, and provides the tool for the elastic-plastic history analysis of jacketing steel reinforced concrete frame prestressed with bonded tendons.(4) Based on the plane rod model, using IDARC nonlinear analysis program, the different jacketing steel reinforced concrete frames prestressed with bonded tendons designed according to"technical specification for steel reinforced concrete composite structures", and with design earthquake group one, two and three, situated in Class I, II and III soil are analyzed under different earthquake waves. In this case, the height of the ground floor of these frames is 8.1m, 11.7m, 15.3m, 18.9m separately, and the height of the added stories is 4.2m, and the span is 16m. Analysis results indicate: satisfing"technical specification for steel reinforced concrete composite structures",under infrequent earthquake, in the area of earthquake fortification intensity of degree 7, the jacketing steel reinforced concrete frames prestressed with bonded tendons for storey-adding situated in Class I, II and III soil will not collapse; in the area of earthquake fortification intensity of degree 8, the jacketing steel reinforced concrete frames prestressed with bonded tendons for storey-adding situated in Class I soil will not collapse; in the area of earthquake fortification intensity of degree 8, failure occurs in the bottom column of the jacketing steel reinforced concrete frames prestressed with bonded tendons for storey-adding situated in Class II and III soil with the height of ground floor is 8.1m and the number of added stories is 2 to 4, and the ground floor will collapse because of column hinges mechanism. So we suggest in design of the jacketing steel reinforced concrete frames prestressed with bonded tendons for storey-adding, in the area of earthquake fortification intensity of degree 8, steel reinforced concrete frames prestressed with bonded tendons situated in Class II and III soil with the height of ground floor is 8.1m and the number of added stories is 2 to 4, multiplying coefficient of bending moment of column, detail of seismic design of beam, column, and joint, should conform to a higher one earthquake-resistant grade.(5) 7 aspects of design and construction suggestions on jacketing steel reinforced concrete frames prestressed with bonded tendons for storey-adding are presented, they are general principles, general requirements, types of structure, choice of materials, earthquake resistant grade, details of design, and choice of sectional dimension of beam and slab, design of beams and columns and construction of joints, and others, etc. Design process of this type jacketing frame are given associated with a particular example of project, design method and construction details of angle-steel concrete columns and self-supporting floor of the first floor are given.
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