容许开裂的B类部分预应力混凝土梁,由于在荷载作用下梁的受拉区混凝土退出工作,其性能尤如普通钢筋混凝土梁。计算时,一般将其预应力筋中的预拉力视作一偏心力作为大偏心受压构件进行。需要指出的是,梁体施加了预应力之后,预应力即成为一种内力储存于梁内。对外力来说,梁体本身仍属于受弯构件,只不过由于梁内的预应力筋在承受外力之前已有了初始内力, Class B partially prestressed concrete beams that are allowed to crack may perform as well as ordinary reinforced concrete beams due to the withdrawal of concrete from the tensile zone of the beam under load. Calculation, the prestress tendons tendon in general as a eccentric force as a large eccentric compression member. It should be pointed out that after the prestressed girder is applied, the prestress becomes an internal force stored in the girder. For external forces, the beam body itself still belongs to flexural members, but because of the prestressed tendons in the beam before they have the initial internal force,