The Influence Of Seismic Capacity Of Prestressed Concrete Frame Structure By Stiffened Side Column

In the design of the prestressed concrete frame structure (PCFS), Tendon of frame beams usually is designed by crack resistance capacity and it is deployed through the interior beam-column joint. So moment capacity of frame beams has a lot of margin.The bending moment of side column is great under vertical load; the amount of reinforcing steel bars is great. There are two ways to solve this problem. One is to abate the dimension of the side columns. So the moment of the side columns is reduced. The problem brought from this method is the decrease of lateral rigidity and the increase of deformation under the earthquake action. The exterior columns are easy to form hinges before the beams and the column hinge energy dissipation mechanism come into being. The other way is to add symmetric tendon in the exterior column before the insurance of column's lateral rigidity. The axial force and the moment capacity of exterior column increases add much. Tendon can replace some reinforcing steel bars. The crack of exterior column comes forth later. The increase of exterior column lateral rigidity is favor of reducing the force of the interior column under macro quake. The actual horizontal shear of all columns approach the shear gained form "D" value method. This is favor of the increase of seismic behavior of frame structure.Nowadays, a simple and effective method to evaluate aseismic capacity, Pushover method is paid attention to. The author mend and perfect the program of PUSHOVER compiled by engineering graduate school. So the program is more easy to use. The basic principle of pushover analysis method is stated in this paper. In comparison with the program, SAP2000 is used. In SAP2000, Moment hinge is designed to simulate the plastic hinge. User must define the bending moment-angular rotated of member ends in sap2000. The author compiles a program to solve bending moment-angular by way of discrete section method. Pushover method and analytical program become the theoretical basis of scaling PCFS's seismic resistance, realizing the energy dissipation mechanisms (EDM) selected, analyzing the displacement ductility of PCFS concerned with the sequence of plastic hinges.From the engineering examples of one span's, two spans', three spans' PCFS, they are designed by standard method and the method of tendon in side column. The two methods are quantity analyzed. The result point out the lack of the code. The suggestions, which can increase the seismic capacity of PCFS, are put forward.Under the help of energy approach and capacity spectrum, the seismic behavior of examples is evaluated.Through the discussion of the advantage of tendon in side column, this method favors the realization of the change of energy dissipation form column hinge dissipation to the mixed energy dissipation. This method increases the seismic behavior of frame structure and favors the comeback after the earthquake.