鋼管支撐架承受非對稱荷重及側向位移之研究

Study of Steel Scaffold Supports Subjected to Unsymmetric Load and Sidesway

本文針對非對稱荷重及側向位移對鋼管架支撐之影響，進行各項試驗工作，並建立理論分析模式，試驗所用之試體皆為雙組三層之門型鋼管架，試驗結果顯示，在底座支承及頂部荷重處有側向束制的情況下，單根鋼管之極限承載能力並不因載重偏心或存在一小量之側向位移而產生明顯的變化；影響支撐架極限承載力之因素有：底座勁度、鋼管套接處之勁度、及鋼管架設之傾斜狀態。研究結果顯示，三項因素造成單根鋼管承載力之影響程度約為20％。綜合試驗及理論分析結果，本計畫提出鋼管架支撐倒塌預警系統發展方向之建議。

Steel scaffolds are often used as temporary support structures in the construction of high clearance structures. This research focuses mainly on the mechanical behavior of steel scaffold supports subjected to unsymmetric loads. Effects of sidesway on the critical load of steel scaffolds were also investigated. Both experimental and theoretical analyses were carried out in order to understand the failure mechanism of steel scaffold support systems. Because of the slenderness in its members, the failure of a steel scaffold is governed by the buckling mode. It is shown that the critical load of a steel scaffold is affected by the jack base stiffness, initial imperfections, and the stiffness of joints between door-typed units. Under the same boundary constraints, experimental results showed that the bearing capacity of an inclined steel scaffold is almost the same as that of the vertical one. Results obtained from this series of studies will be used to develop a warning system for preventing steel scaffolds from sudden collapse during construction.