拉索线膨胀系数试验研究

Experimental Research of Linear Thermal Expansion Coefficient of Cables

推导了拉索线膨胀系数的测定公式;根据试验原理,研制了水域索线膨胀系数测定仪,验证了该仪器的精确性,并对钢丝绳、钢绞线、半平行钢丝束和钢拉杆4种索材进行了线膨胀系数测定;根据试验得到的拉索线膨胀系数,对预应力钢结构进行了温度作用下的力学性能分析.结果表明:拉索为钢丝绳和半平行钢丝束时结构力学性能受温度的影响较大,而拉索为钢铰线和钢拉杆时则受温度的影响较小,结构设计时需考虑索材选取不同所造成的温度预应力损失影响.

An equation is derived for determination of thermal expansion coefficient. Based on test principles, an water-heated instrument for determination of thermal expansion coefficient was manufactured, and its accuracy was validated. Four types of cables were chosen including steel wire rope cable, steel strand cable, semi-parallel steel tendon cable, and steel rod, and their linear thermal expansion coefficients were determined by the instrument. Finally, the mechanical performance of prestressed steel structure under influence of temperature was evaluated. The results indicate that the temperature has great impact on the mechanical performance of structure, especially on its applicability for using steel wire rope cable and semiparallel steel tendon cable. The impacts are weak when using steel strand cable and steel rod. Therefore, it is necessary to consider the prestress loss in different cable types in design.