预制体外预应力混凝土风电塔施工过程监测

分阶变径预制体外预应力混凝土风电塔在钢绞线张拉前,各筒段之间依靠自身重力和摩擦力保持整体性。钢绞线张拉顺序对施工过程中结构受力状态的影响尚缺乏研究。本文采用分层壳单元建立混凝土塔筒的分析模型,模拟了塔筒在钢绞线张拉前及钢绞线张拉过程中的受力状态,并根据分析结果制定了施工方案。同时,采用振弦式应变计对钢绞线张拉过程中关键位置的应变进行跟踪监测。结果显示基于分层壳单元的建模技术所得分析结果和实测结果吻合较好,可以用于预制塔筒的施工过程分析;而且所制定的施工方案合理,结构在钢绞线的张拉过程中保持稳定,可为类似结构提供参考。

Monitoring of construction process for a prefabricated external prestressed concrete wind tower

The prefabricated external prestressed concrete wind tower with split and variable diameters keeps its integrity by its own gravity and friction before the steel strand is stretched. There is no previous research about the influence of the stressing order on the stress state of the tower. A layered-shell element model is built to simulate the unstressed state and the stressing process. Construction procedure is developed according to those results. Vibrational chord strain gauges are adopted for monitoring the strain of key positions during the stressing process. It is found that the results produced by layered-shell element model arecompatible with those from the field test and it is suitable for construction process analysis of the prefabricated tower. The stability of the structure during the stressing process proves the validity of the construction procedure,which can provide a reference for similar projects.