Study On Seismic Behavior Of Specially Shaped Columns With Different Reinforcement Form

Reinforced concrete special-shaped columns used in residential construction in recent years, for their unique qualities, are widely welcome by users and have been gained a wide development. The national trade standard, Technical Specification for Concrete Structures with Specially Columns, which is used to guide the design and construction of structures with specially shaped columns, has already promulgated and implement. If the T–shaped column with common reinforcement form is compressed on its web, the axial force ratio corresponding with the balanced failure will be on the low side. Therefore, the plasticity plastic hinge occurs at the end of column so early that the structure is easily collapsed in the rare earthquake. More longitudinal steel will be required to avoid that circumstance if the reinforcement form isn't changed. Under the different reinforcement form's condition, moving the reinforcing steel bar at the inward folding angle to the end of the web, which doesn't change the reinforcement ratio, this paper studies the method which raises the axial force ratio corresponding with the balanced failure and makes the plastic hinge occurred later. The main research contents are as follows:1. The paper investigates the seismic behavior of RC frame with special-shaped columns and analyzes the seismic behavior of special-shaped columns, beam-column joint in brief.2. Based on the calculation principle of specially shaped columns' normal section bearing capacity subjected to biaxial compression the vary regulation of T-shaped and十-shaped columns' normal section bearing capacity is analyzed by MyNc program under the different reinforcement form's condition. And the N-Mx- My interaction curves of two reinforcement forms is compared. The result indicates that the axial force ratio corresponding with the balanced failure, and T-shaped and十-shaped columns' normal section bearing capacity are raised when the compression zone totally is on the web.3. Dynamic elastic-plastic time-history analysis is an important method to evaluate the seismic behavior of structures. A different reinforcement form's RC frame with special-shaped column is calculated by NDAS2D which is a finite element analysis of nonlinear dynamic elastic-plastic analysis computer program, and compared with the common reinforcement form. The result indicates that the plastic hinge is delayed and the realization of"strong column weak beam"ensures better. Finally, some suggest for design and structural measures for residence system of RC frame with special-shaped columns are put forward from the above study.