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为改善斜拉桥平行钢绞线拉索以索力控制张拉时需多次重复张拉的复杂操作工序,并减少由此产生的累计误差,同时使得张拉完成后每股钢绞线拉力分布更均匀,选择以钢绞线的无应力长度作为控制张拉的对象,设计了以无应力长度控制钢绞线逐根一次张拉到位的施工方案,并对其进行优化。考虑拉索的几何非线性,建立单根钢绞线的几何状态方程,确定其在目标索力下控制张拉的无应力长度;在实际施工中以该无应力长度控制张拉单根钢绞线,运用分阶段局部寻优的数值方法,考虑实际施工误差和塔、梁变形等因素,对实际施工索力与设计目标索力之间存在的误差进行修正,寻求对应实际工况的控制张拉无应力长度,以实现一次张拉到位、张拉完成后每根钢绞线拉力相等且成桥索力也更精确的目的;最后,通过计算机仿真算例模拟实际工况进行验证。结果表明:对给定的设计成桥目标索力,采用无应力长度控制张拉方案可一次张拉到位,考虑施工误差进行优化后控制张拉的无应力长度与对应实际工况的无应力长度相差较小,经过二次优化后,施工张拉索力与设计目标索力的相对误差为0.72%,且张拉完成后每根钢绞线拉力相等,满足施工要求;相关计算程序经固化后嵌入智能千斤顶可用于斜拉索张拉施工。
In order to improve the cable-stayed bridge parallel strands of cable tension control tension required to repeat the operation of multiple steps and reduce the resulting cumulative error, while making tension after each strand tension The distribution is more uniform, and the stress-free length of strand is selected as the object of tension control. The construction scheme of tension-free strand tension control is designed and optimized. Considering the geometrical nonlinearity of the cable, the geometrical equation of the single strand is established and the stress-free length of the tension is controlled under the target cable force. During the actual construction, Line, using the method of partial optimization in stages, taking into account factors such as actual construction error, tower and beam deformation, the error between the actual construction cable force and the designed target cable force is corrected and the control sheet corresponding to the actual working condition Pull the stress-free length in order to achieve a tension in place, the tension of each strand after the completion of equal tension and the cable tension is also more accurate purpose; Finally, the computer simulation examples to simulate the actual operating conditions for verification. The results show that for a given design goal, the tension-free tension control scheme can be tensioned once. After considering the construction error, the stress-free length of the tension control and the stress-free length corresponding to the actual working condition After the second optimization, the relative error between the construction tension force and the designed target force is 0.72%, and the tensile force of each strand is equal after the tension is completed to meet the construction requirements. After the relevant calculation program is cured Embedded smart jacks can be used for tension cable tensioning construction.