Finite Element Analysis On The Behavior Of Prestressed Concrete Wide-flat Beam Joint

The flat beam in the pper what it’s breadth of section is greater than the depth ofsection, width.In the construction of frame,the prestressed beam not only can be used assupported member for the floor,but also can increase the clean hight of storey.So it cansatisfy the requirements of the modern buildings in the structural concept of longspanand large space.because particularity section dirmension of flat beam and imposeprestressed,to make it’s behavior different from the common frame joints,and the jointsdamaged under the seismic load are huge.The article dose some research baced on dimensional parameters of flat beam-column joints through18outer joints and18inner joints numerical tasts. Those tests areunder the combination of vertical and horizontal loads at the column tip by usingelasticity properties in this paper,find out the key factor and important factor ofinfluence the joints behavior,also impact trend.At the same time,the trace anddistribution patterns of principle stresses such as S1、S3have been put forward at thejoint region.Next studying the concrete tensile strain and stirrup tensile stress byconsidering the effection of changing prestressing tendon position.The main conclusionare as follows:(1)By using the prestressing tendon can improve the concrete shear capacity andreduce the tensile stress of the stirrup at the joint region.Changing the prestressingtendon position have little effection on shear capacity of the joint region concrete.(2)The ratio of P/N is the key factor affecting the maximum principle stresses suchas，，. There was significant linear correlation and direct ratio between Thethree stresses and P/N. The length-width ratio of column is the important factor affectingthe three maximum stresses,from the test we can see the ratio of1.5is a betterlength-width ratio.(3)The conclusion of the outer joints are similarity with inner joints, the key factoraffecting the maximum principle stresses is the ratio of P/N.The important factor is thelength-width ratio of column.(4)Analyzing the trace of principle stresses such as S1、S3of the inner joint regioncan get to know that the joint behavior of strength accord with diagonal mechanism. Thestress concentration phenomenon produced at the corner of the joint region. The outerjoint strength behavior is approximate with the diagonal mechanism,at the same time the stress concentration phenomenon produced at the compressive zone.