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采用基于割线刚度的等效线性化方法拓展了次弯矩概念,使其能够运用于非线性阶段。进行了4根无粘结预应力混凝土两跨连续梁受力全过程试验。研究结果表明,运用等效线性化方法可以将连续梁非线性阶段的支座反力分解成为预应力等效荷载引起的以及外荷载引起的两个部分,从而分离出次弯矩和外荷载弯矩。非线性阶段,无粘结预应力连续梁的次弯矩随预应力筋拉力的增长而增长。次弯矩折减系数随中支座截面受压区相对高度的增大而增大。承载力极限状态,非线性次弯矩在数值上大于初始次弯矩。
Using the equivalent linearization method based on secant stiffness, the concept of secondary moment is expanded so that it can be applied in the nonlinear phase. Four full tests of stress on two continuous beams of unbonded prestressed concrete were carried out. The results show that the equivalent linearization method can be used to decompose the bearing reaction force of nonlinear beam in continuous beam into two parts caused by prestressed equivalent load and external load, so as to separate secondary moment and outer load bend Moment. In the non-linear phase, the secondary moment of unbonded prestressed continuous beams increases with the prestressing force. The secondary bending moment reduction coefficient increases with the increase of the relative height of the compression zone of the middle bearing. The bearing capacity limit state, the nonlinear secondary moment is numerically larger than the initial secondary moment.