弧形索塔施工过程风荷载静力效应分析

Analysis on Static Effect of Wind Load during Construction of Arc Cable Tower

弧形索塔造型美观,常应用于独塔斜拉桥中,但索塔施工过程受力复杂,线形控制难度大,受风荷载、温度荷载等因素影响大。本文以某拱门型索塔斜拉桥为工程背景,探究索塔施工过程中风荷载对索塔结构的静力效应及梁柱效应。利用MIDAS有限元软件,建立力学模型,对有无风荷载在索塔施工过程中对结构应力、位移的影响,并运用P-Δ分析控制。计算表明,主动横撑位置处首先出现拉应力且逐渐增至最大,横向静风荷载作用下相比无风荷载作用,最大拉应力增加了35.80%,成塔后位移增大了95.98%。考虑梁柱效应后,索塔的内力和位移的变化量很小。结果表明,静风荷载对索塔施工阶段内力及位移影响很大,风荷载作用下梁柱效应对混凝土索塔的影响可忽略不计。

The curved cable tower has a beautiful shape and is often used in single-tower cable-stayed bridges.However,it is difficult to control the alignment due to complicated forces during the construction of the cable tower and is greatly affected by wind load and temperature load.This paper takes an arched Cable-tower cable-stayed bridge as engineering background to explore the static effect of wind load on Cable-tower structure and beam-column effect during Cable-tower construction.By using MIDAS finite element software,the mechanical model is established,and the effect on structural stress and displacement under wind load and construction load is controlled by P-Δanalysis.The calculation shows that the tensile stress first appears at the active transverse brace position and gradually increases to the maximum.Under the transverse static wind load,the maximum tensile stress increases by 35.80%and the displacement increases by 95.98%compared with the non-wind load.Considering beam-column effect,the variation of internal force and displacement of cable tower is very small.The results show that the static wind load has a great influence on the internal force and displacement during the construction stage of the cable tower,and the beam-column effect under the wind load has a negligible influence on the concrete cable tower.