开洞深梁的拉压杆模型设计方法研究

引入拉压杆理论建立开洞深梁实用设计方法，提出利用承载能力和有效系数进行拉压杆模型方案的比选，并根据最优的拉压杆模型进行配筋设计．为验证其有效性，对一简支开洞深梁实例建立了多种拉压杆模型，详细对比了计算结果和试验结果．研究表明拉压杆模型预测的承载力比实验结果偏安全，能满足工程可靠度的要求；拉压杆模型计算承载力与配筋试件实验值大小变化趋势一致．根据拉压杆模型的计算分析结果，可以看出洞口附近沿主拉应力方向配置斜向钢筋对提高承载力最有效，如不明确构件内主应力分布，在洞口上下部同时配置水平纵筋和竖向钢筋也能达到提高承载能力的目的．

Strut-and-Tie Approach for Deep Beam with Opening

We present a design procedure for deep beam with openings in the strut-and-tie(STM) approach.The reinforcement assembly is based on STM optimized according to the bearing capacity as well as effective coefficients.Multiple STMs are developed for a simply supported deep beam with an opening to verify the validation of STM method.The comparison between theoretical and experimental results shows that the strengths calculated by STMs yield conservative estimates of capacity for the tested structures and it can meet the requirements of engineering reliability.It is concluded that the bearing capacity can be improved effectively by placing diagonal reinforcement near the opening along the principal tensile stress trajectories.When the principal stress distributions are too complex,in order to meet the requirement of bearing capacity,the horizontal and vertical reinforcements can be placed above and beneath the opening simultaneously.