曲线梁桥预应力钢筋合力重心线计算方法

A Method of Calculating the Center Line of Gravity of Prestressing Force of Steel in Plane Curved Girder Bridges

本文把曲线梁桥预应力钢筋合力重心线的保压力线变换定理推广应于多主梁和非常数预加力的连续梁桥,对于已知各主梁弯矩包络图的平面曲线梁桥,只要在它们的压力线限制区内各任选一条合理曲线作为预定压力线,总可以用本方法求得各主梁内的预应力钢筋合力重心线,它们产生的压力线与预定压力线在最小二乘意义上最为靠近,从而保证梁内没有或者只有限定值以下的拉应力。

The Transformation theorem of the center line of gravity of the prestressing force of steel (i. e., the c.g.s.-line) with preserving the compressive line (i.e, the C-line) is extended and used in the design of plane curved girder bridges with multi-main girders and variable prestressing force. For a plane curved girder bridge with a known bending moment envelope, if a resonable curve in the limiting zone of C-line is selected as a predetermined C-line, a corresponding c.g.s.-line can be uniquely obtained by the method. This c.g.s.-line produces a C-line which is close to the one selected before in the meaning of least square. So the method ensures that there will be no tensile stress or only a tensile stress smaller than the alowable one in concrete.