论文部分内容阅读
一、П形梁的约束扭转我国铁路上目前研制和试用的П形截面无碴无枕预应力混凝土梁,与长期来广泛使用的工字形截面分片道碴桥面预应力混凝土梁,同属于开口截面杆。如所周知,任何截面形状的杆只有当横向力通过横截面上的特定点——弯曲中心A,杆才只发生弯曲(图1、2的a、b),否则还将产生扭转(图1、2c);而仅就扭转而言,横截面正是绕此点在其平面内转动的。正因如此,这个点A也就是扭转中心。图1所示具有两个对称轴的工
First, the restraint of the Π beam reverses the currently developed and tested П-shaped ballastless pillow prestressed concrete beam in China’s railway, and the long-term widely used I-shaped section slab ballasted prestressed concrete beam, both belong to the opening Section bar. As is known, a bar of any cross-sectional shape undergoes only a bending (a, b in FIGS. 1, 2) only when the transverse force passes through a particular point on the cross-section, bending center A, , 2c); whereas in the case of torsion only the cross-section is about its point of rotation in its plane. Because of this, this point A is to reverse the center. Figure 1 shows a work with two axes of symmetry