钢筋混凝土深梁受力不同于浅梁,梁腹开孔后受力更趋复杂。现有的设计方法对深梁行为的解释不够完备,设计结果的适用性难以判断,设计规范也没有给出开孔深梁的设计条文。为研究深梁设计方法的有效性,本文采用了非线性有限元分析方法,引入适合混凝土结构非线性分析的断裂塑性模型,并考虑钢筋粘结滑移效应,对一系列开双孔或偏孔钢筋混凝土深梁试验进行仿真分析,所得结果与试验结果吻合良好,能够准确预测深梁在裂缝、破坏形态及承载力等方面的受力特征。研究表明现有的深梁设计方法中,压拉杆模型方法相较内力法和应力图形法更加经济有效。在仿真分析的基础上,提出了一种对开孔深梁具有普遍适用性的非线性设计方法,其设计结果具有高承载力、较好延性、经济的配筋量和充分的材料利用率的优点。
The behavior of reinforced concrete (RC) deep beams is different from shallow beams and the situation becomes more complex since the presence of web openings. All codes presented are short of explaining the exact behavior of deep beams and the scope of application. However, no code provision exists for the deep beams with openings. In this paper, nonlinear finite element analysis method is used to the effectiveness of design methods for RC deep beams, including reinforcement bond-slip model and fracture-plastic model,which is suitable for nonlinear analysis of concrete structures. A series of RC deep beams with openings, are analyzed and the simulation results are found agreed well with test results. And it can exactly predict such as cracks, failure modes and limit strengths. It finds out that strut-and-tie model (STM) method is more optimized than the internal forces method and the stress graphical method among the present design methods. Based on these results, a new nonlinear design method, generally applying to all deep beams with opening, is presented and proved the most optimized one when compared capacity, ductility, steel amount and material utilization with the others.