Effects of Cyclic Fatigue Loading on Partially Prestressed Beams - Phase 2

这是对这种行为的两部分研究调查的第二部分。 部分预应力混凝土梁的建模 循环疲劳载荷 部分预应力梁的定义如下 作为混凝土梁，用预应力和非预应力的组合加固， 预应力钢筋，设计为允许在全应力下开裂 工作荷载（静荷载加活荷载）。 疲劳的以下方面 将调查：疲劳寿命的成员，开裂和 疲劳时裂纹宽度增加，挠度和挠度 随着加载循环次数的增加而增加。 第一阶段 矩形截面恒压试验研究 振幅疲劳载荷 第二阶段处理T段 在模拟真实的活载的变幅疲劳载荷下， 桥梁. 本研究包括一个实验和分析 程序. 实验变量包括三个水平， 钢筋，并为每个，四个部分预应力水平， 包括完全配筋和完全预应力两个界限。 总的实验程序和要记录的测量结果是 旨在提供关于开裂挠度的综合数据基础， 随着循环疲劳载荷的增加， 分析 一个预测疲劳裂纹宽度和挠度的程序， 旨在生成合理的模型，这些模型在 边界，以完全钢筋和完全预应力为代表 混凝土

This is the second of a two-part research investigation of the behavior and modeling of partially prestressed concrete beams subjected to cyclic fatigue loading. Partially prestressed beams are defined here as concrete beams reinforced with a combination of prestressed and non- prestressed reinforcement, designed to allow cracking under full service load (dead plus live load). The following aspects of fatigue will be investigated: the fatigue life of the members, cracking and crack width increases under fatigue, and deflection and deflection increases with the number of cycles of loading. The first phase of the research dealt with rectangular sections tested under constant amplitude fatigue loading. The second phase deals with T sections under variable amplitude fatigue loading simulating real live loads on bridges. The research comprises an experimental and an analytical program. The experimental variables include three levels of reinforcement and, for each, four levels of partial prestressing which include the two boundaries of full reinforcing and full prestressing. The total experimental program and the measurements to be recorded are designed to provide a comprehensive data base on cracking deflections, and their increases with cyclic fatigue loading. The analytical program to predict crack widths and deflections under fatigue is designed to generate rational models that remain valid at the boundaries, represented by fully reinforced and fully prestressed concrete.