斜拉型悬索结构形式与受力特性研究

将索桁架和斜拉结构进行组合，构造一种新型索结构体系，即斜拉型悬索结构。张拉背索对结构施加预应力，通过找力和找形得到了结构的初始预应力态，在此基础上进行了结构在满跨和半跨均布荷载作用下的静力、动力特性研究及参数分析，并对该新型索结构体系进行了风振响应计算。研究表明：结构静力荷载 位移关系呈非线性双折线，结构刚度的转折点对应于稳定索边段的退拉松弛；结构的低阶振型表现为桅杆的水平振动叠加屋盖的竖向振动，高阶振型中桅杆水平方向参与很少；增大背索截面面积可有效提高结构刚度和自振频率，稳定索、斜拉索面积对自振频率影响不大；背索预应力值对结构的静力特性影响是线性的，在所有索段具有拉应力时，预应力值对结构动力特性基本无影响，若索出现松弛则结构刚度急剧退化，自振频率陡降；桅杆高度增大，结构刚度下降，桅杆高度对结构的低阶振型和频率影响较大；矢跨比对屋盖竖向对称振动的第2振型有影响，而对反对称的第1振型基本无影响；斜拉型悬索结构的风振系数介于1~2之间。

Structural form and mechanical characteristic of suspended cable-stayed structure

The cable-stayed structure and cable truss structure were combined to form a new structural system named suspended cable-stayed structure.The prestressing force was applied to the cable system by tension back cable.Force-finding and form-finding were adopted to obtain the initial prestressing mode.Based on the initial prestressing mode,static and dynamic characteristics under full-span load and half-span load were analyzed.Parametric analysis was carried out.Wind-induced vibration response was calculated.Research shows that the structural nonlinear static load and displacement relationship is a nonlinear folded line.Structural rigidity turning point is corresponding to the stable cable relaxation.The low order vibration modes are the superposition of mast horizontal vibration and roof vertical vibration,while mast horizontal direction participates little in higher order vibration modes.Enlarging back cable area can effectively improve the structural rigidity and fundamental frequency,while stable cable and stay cable cross sectional areas impact slightly.The prestressing force value of back cable has linear effect on the static characteristics,while has no effect on dynamic characteristics when all cables are in tensile stresses.If a cable loosens the structural rigidity will sharply decrease and the fundamental frequency will drop.If the mast height increases,the structural rigidity will degrade.The mast height influences the low order vibration modes and frequencies.The rise-to-span ratio has effect on the roof symmetric vibration(second order) mode,while has no effect on the un-symmetric vibration(first order) mode.Wind vibration coefficient of suspended cable-stayed structure is between 1~2.