| The R.C. frame with special-shaped columns is a new structural system. Its aseismatic behavior is always being focused. T he research on the aseismatic behavior and the d esign method is of great theoretical significance and practical value.There are many researches on the special-shaped columns, but less on the R.C. frame with special-shaped columns. The seismic design of the frame is a force-based seismic design method, while the displacement-based seismic design of the frame remains blank and unsolved, and the latter will be the main seismic design method for the future. The aseismatic behavior and displacement-based design method of R.C. frames with special-shaped columns are studied here. Such work have been done as follows:1. The pseudo-static tests of three 1/2-scale models R.C. frames with special-shaped columns have been conducted. The load-bearing properties, deformation and energy dissipation capacity and the mechanism of failure for the R.C. frames with special-shaped columns are studied. It makes a comparison in ductility between frames with special-shaped columns and single column. The interaction between infilled-wall and frame with special-shaped columns and its influence to the load bearing capacity and lateral stiffness are studied. Seismic behavior of the structure is evaluated.2. Research has been done on the calculating methods of lateral stiffness and bearing capacity of the frame. According to experimental studies, finite element analysis and theoretical analysis, it develops to calculate lateral stiffness of frame with special-shaped columns of greater height-width ratio by using frame with rigid zones, and considering shear deformation of beam and columns. Without considering the torsion of the whole structure, assuming the special-shaped column in the RC frame is flexural failure under uniaxial eccentricity force, putting forward the calculation method of flexural strength of special-shaped columns and the shear strength in a story for R.C. frame with special-shaped columns. Bringing forwarding the calculating method of shear bearing capacity in a story according to the failure mode.3. Research has been made on pushover analysis. Developed herein is an improved pushover analysis procedure based on structural dynamics theory. Which retains the conceptual simplicity and computational attractiveness of current procedures with invariant force distribution. In this modal pushover analysis, the seismic demand due to individual using the inertia force distribution for each mode. Combining these modal demands due to the first two or three terms of the expansion provides an estimate of the total seismic demand on inelastic systems. This method is applicable to the designof muti-story buildings; it's an improvement to the current method.4. The concept of performance-based seismic design is introduced into design of the new structure. According to the fact of seismic design of our country, a practical displacement-based seismic design method is put forward. The seismic performance level is divided into three: serviceability, life-safety, and collapse protection, hi order to control the performance level of the structure, the three levels are quantified with story drift angles. Applying the inverted triangular distribution of lateral force to the cantilever column with identical section, and the displaced shape of it is regarded as initial lateral displacement mode. On the basis of the theory, the muti-degree-of-freedom system is transformed into single-degree-of-freedom system; the corresponding equivalent parameter is deduced. And then calculate the base shearing and earthquake effect of each mass element. The paper analyze the structure with pushover method, check the displaced shape of it, and evaluate the deformation and strength demand of the element, then prove the method with elasto-plastic dynamic history analysis. It is demonstrated the method is accurate enough to practical application in building evaluation and design.
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