中文摘要：

针对系杆拱桥的特点,提出了基于应力平衡法的确定合理吊杆力的方法.该方法的思路是以恒载作用下拱肋的截面上下缘的应力为控制条件,从而给出恒载作用下拱肋截面应力和弯矩的可行域.提出单位荷载法,以恒载作用下拱肋截面弯矩的可行域为目标,以吊杆力为变量,采用最小二乘法原理,确定合理的吊杆力,并指出为加快收敛速度可采用拱肋的最小弯曲应变能原理确定吊杆力的初始值.通过一算例验证了该算法的可行性.研究表明：采用该法可以使得拱肋截面弯矩位于拱肋截面弯矩可行域内,可确定合理吊杆力,并能使整个拱梁组合结构的受力状态处于最优状态.

英文摘要：

Aiming at the mechanical behavior of tied-arch bridges, a new method based on stress balanced method is put forward to optimize the hanger forces. The method followed the idea that the normal stresses on the top and bottom of arch rib section under dead load are controlling condition and the feasible regions of the dead stress and moment are deduced. A unit-load method is put forward; and the least square principle-based optimal method uses the feasible region of moment distribution under dead load as an objec- tive and the hanger forces as optimized variables and then was adopted to optimize hanger forces. In order to accelerate the convergence, the initial value of the hanger forces can be determined by the minimum ben- ding energy of the arch rib. The optimization theory is examined by a case study. The results indicate that the arch rib section moment meets the feasible region by the above method to optimize the hanger forces; and the tie-arch bridges can reach the optimal state.