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台座生产预应力砼构件时,必须考虑温差所引起的钢筋应力损失。为了较精确地计算构件的抗裂度和预测其耐久性,以及为了制定减小或完全消除由温差而引起应力损失的施工工艺,必须精确地确定其损失值。因为在台座上生产特大型重荷载构件时,要大大提高其使用安全度。 1975年以前,构件由温差所引起的应力损失是按σ=2.0Δt公式计算的。该公式是由σ=αEΔt 公式计算得来的。式中α和E分别为钢筋的线膨胀系数和弹性模量;Δt为钢筋与台座承受拉力设备之间的温差。后来,研究某些其它因素对温差应力损
When the pedestal produces prestressed concrete components, the stress loss of the reinforcement caused by the temperature difference must be considered. In order to more accurately calculate the crack resistance of a component and to predict its durability, and to develop a construction process that reduces or completely eliminates the stress loss caused by temperature differences, its loss value must be accurately determined. Because the production of extra large heavy load components on the pedestal, its use safety should be greatly improved. Before 1975, the stress loss caused by the temperature difference of the components was calculated according to the σ=2.0Δt formula. This formula is calculated from σ=αEΔt formula. In the formula, α and E are the linear expansion coefficient and elastic modulus of the steel bar, respectively. Δt is the temperature difference between the steel bar and the pedestal bearing tension equipment. Later, some other factors were studied for temperature differential stress loss.