空间主缆自锚式悬索桥成桥状态确定及其科学实现的理论与方法

On the basis of experiment and theoretical analysis, the mechanical properties, especially the torsional of main cable made from steel wire ropes under spatial loading are firstly considered and investigated to build analytical model, determine related parameters, as well as establish corresponding calculation theory. Based on the above work, on one hand, the rule of interaction between structural members in typical kinds of self-anchored suspension bridge with spatial cable is revealed, and on the other hand, is the combined criterion in quantity for loading distribution along structural members in bridge after completion is further developed. Taking into account the related feature for each structural member, the method to determine the reasonable final state of self-anchored suspension bridge with spatial cable plane is also outlined. Moreover, considering the phase change during assembly and the geometry deviation of girder segments to be assembled on the launching bed, and with the introduction of new conception and mathematical correction method as basis, the mathematical models to evaluate the geometry of assembled girder segments and to determine the elevation of girder segments are proposed, which leading to the theory with high precision to efficiently achieve the objective unstressed geometry of incrementally launched segments. At the same time, by studying the uplift tolerance at each central bearing point in stiffening girder, and along with analyzing the mechanical behavior (including the effect of torsional deformation in spatial main cable) under construction stages of self-anchored suspension bridge with spatial main cable, and also considering the value range of chain block's physical and mechanical parameters, the possible optimal resolution of system transformation is put forward after combining variety of means. Finally, by checking four conditions to be fulfilled for system transformation and with the aid of numerical simulation throughout whole process, the mechanism and methodology for determining the resolution of system transformation in self-anchored suspension bridge with spatial cable plane are proposed.

在试验与理论分析基础上,研究钢丝绳主缆在空间荷载作用下的力学特性,特别是扭转特性,构建分析模型,确定相关参数,建立相应计算理论；以此为基础,揭示各典型空间主缆自锚式悬索桥各构件间作用规律，研究成桥状态各构件合理受力评判的综合量化准则,考虑各构件相关特性，建立空间主缆自锚式悬索桥合理成桥状态确定的方法；考虑接拼梁相位变化和顶推平台上梁体组拼线形偏差，在引入新概念和实现组拼线形偏差修正数学表示的基础上，建立已拼梁体线形评价与待拼梁段就位高程确定的数学模型，形成顶推梁体无应力线形高效高精度实现的理论与方法；研究加劲梁各中支点相对抬升量容许值和空间主缆自锚式悬索桥施工阶段的力学特性(考虑空间主缆扭转效应影响)，考虑手拉葫芦物理力学参数常用范围等,提出基于多种方式结合的可能较优体系转换方案，通过全过程仿真，考察其满足体系转换条件的状况，形成空间主缆自锚式悬索桥体系转换方案确定的机理和方法。

空间主缆自锚式悬索桥因抗风性能好、地基要求低、造型美观特别而在城市具有广阔应用前景。其成桥状态确定与科学实现的理论及方法是该桥型合理设计和高效高精度安全架设的前提。项目围绕钢丝绳主缆的力学特性、空间主缆自锚式悬索桥合理成桥状态确定方法、顶推钢箱梁无应力构型高精度实现、合理体系转换方案开展理论与试验研究。取得了多方面具有科学意义和工程价值的研究成果：1）获得了钢丝绳空间主缆扭转特性。即，其扭转刚度介于单根钢丝扭转刚度之和与全截面整体转动的扭转刚度之间；可取为整体扭转刚度的2/3，且主缆抗扭刚度系数对主缆扭转角影响不大；主缆的扭转角主要取决于索夹安装时的横向预偏角。2）建立了空间缆索悬索桥水平母线鞍座设计位置的确定方法，确保了水平母线索鞍设计位置的迭代计算快速收敛于真实值。3）发明了基于“吊索张拉”的双塔三跨“边中共进”的逐步推进体系转换技术，明确了包括空间主缆在内的双塔三跨自锚式悬索桥合理成桥状态确定方法。4）提出了一种包括空间主缆在内的混合梁自锚式悬索桥“无临时地锚的缆梁同步”的实现方法，改变了传统方法主梁施工与主缆架设的先后关系为部分平行关系，缩短了工期，节约成本，减小了安全风险。5）研究了小孔径吊索锚管双塔单跨自锚式悬索桥体系转换优化方案，避免了吊索在其锚固导管口弯折。6）发明了包括空间主缆悬索桥在内的顶推钢箱梁的梁段制造构形确定的“等高等邻边梯形法”，克服了传统方法不足。7）创立了变曲率竖曲线梁顶推过程支点标高调整方案确定的单步模数搜索合成法，解决了穷举法计算量太大、试算法需要丰富经验的不足。8）改进了包括空间主缆悬索桥在内的薄壁箱梁剪力滞翘曲位移函数，提高了精度。9）得到了无铺装层 PK 断面混凝土梁日照温度场及其变化，为相应的空间主缆悬索桥采集数据剔除加劲梁日照温变影响创造了条件。