建筑施工脚手架强风响应的实测及抗风设计方法研究

Cladding is widely used for scaffolding because it could suppress the dust and noise problem. However, cladding leads to significant increase of wind loads and make it more complicated, also increases the risk of wind-induced collapse of scaffolding. It is investigated that about 10% of severe collapse accidents are due to strong wind. There is limit information about the study on wind-induced failure and wind-resistant design of scaffolding. Thus, wind-induced response and wind-resistant design for construction scaffolding are proposed to carry out based on field measurement, wind tunnel experiment and finite element analysis. Specific research contents are as follows: (1) Carry out field measurement on stress, strain and wind velocity for scaffolding, study the distribution characteristics of wind-induced response of scaffolding. (2) Carry out wind tunnel experiment and measure the wind pressures acting on scaffolding (considering the most unfavorable condition which the nonporous cladding of the scaffolding is simulated), study the wind pressure characteristics acting on scaffolding.(3)Establish the finite element model for scaffolding with the consideration of load transfer mechanism based on the field measurement. Calculate the wind-induced response of scaffolding by using the data from wind tunnel experiment, study the wind-induced failure mechanism of scaffolding. (4) Propose an optimized method for the wind-resistant design and safety assessment for construction scaffolding.

目前，防尘、降噪效果好的覆面材料被广泛应用于施工脚手架。然而，覆面材料的使用会导致作用在脚手架上的风荷载显著增大且更为复杂，加剧脚手架风致破坏的风险。研究表明，约10%的脚手架倒塌事故是强风引发的。目前对脚手架风致破坏的机理及其抗风设计研究不足，为此本项目以施工脚手架为研究对象，采用现场实测、风洞试验和有限元分析相结合的方法对脚手架的风致响应和抗风设计方法展开研究：（1）针对脚手架连墙件的应力、应变及周边风速进行现场实测，掌握脚手架风致响应分布特点及传递规律；（2）考虑最不利的100%挡风率覆面结构形式，通过风洞试验研究作用在脚手架上的风荷载特性及其分布规律；（3）基于现场实测和风洞试验的结果，构建符合风荷载传递规律的脚手架计算模型并对其开展有限元仿真分析，研究脚手架风致响应特性及其风致破坏机理。（4）为施工脚手架的抗风设计及抗风安全评估提供科学的计算方法。

本项目以建筑覆面施工脚手架为研究对象，通过现场实测、风洞试验和数值模拟相结合的方法，研究作用在脚手架上的风荷载特性、风荷载传递规律等内容，为施工脚手架的抗风设计及抗风安全评估提供科学的计算方法。主要研究内容如下：.（1）基于实测建筑周边风速数据，统计分析风场特性，分析平均风速、紊流度、紊流积分尺度及阵风因子间的变化关系，进行脉动风谱的拟合，确定拟合参数间的关系及取值范围。.（2）基于实测脚手架覆面风压数据，统计分析风荷载的分布规律，分析同一高度下不同测点处平均风压、脉动风压根方差、紊流度以及紊流积分尺度的时程变化。对比根据日本规范求得的积分尺度与泰勒假定所求得的积分尺度，进行风压功率谱拟合，分析实测风谱的能量分布。分析同一高度不同测点处风压在不同时距下的相关性，分析风压的高斯分布特性，研究长时距及短时距内偏度及峰度间的关系，给出判断大容量样本高斯分布的依据。.（3）基于实测连墙件应力数据，分析实测风压与其相邻连墙件应力的关联，探索作用在覆面施工脚手架结构上的风荷载传递特性及简化模型。.（4）通过风洞试验研究不同尺寸、孔隙形状、孔隙率等关键参数对多孔结构风荷载的影响及其抗风设计取值范围。.（5）结合数值仿真与风洞试验结果，研究多孔板的长宽比、孔隙形状对压力降的影响，优化多孔结构的开孔形式及其风荷载之间的变化规律。