基于能量法的体外预应力梁力筋应力增量研究

Stress increment study of external tendons based on energy method

以体外预应力简支梁为研究对象,针对结构的正常使用阶段,利用能量法推导了典型布筋形式与荷载形式下体外预应筋应力增量的解析计算公式,公式的物理意义明确,包含梁的几何尺寸、截面刚度、预应力筋位置、外荷载大小及位置等必要的参数.在此基础上,通过对解析式的合理简化,给出了实用简化计算公式,并对影响应力增量的外荷载大小和力筋偏心距等关键因素进行了参数分析.此外,还应用能量法推导了体外预应力连续梁的力筋应力增量公式.最后,通过与已有试验结果的对比,验证了本文所推导的解析公式和简化公式的适用性.

Using the principle of energy conservation, analytical formulae for calculating the stress increment of external tendons of externally prestressed beams are derived under service limit states, which are applicable to both simply supported and continuous beams and suitable to two typical load cases. The formulae have clear physical significance, which include some influential factors, such as beam geometry, material properties, tendons profile and load cases. Simplified formulae are also deduced by reasonable simplification to the above analytical ones. Furthermore, parametric studies are carried out based on the simplified formulae. In the end, the accuracy of the proposed formulae is justiffed by comparing the analytical solutions with some experimental results reported in the technical literature.