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

循环疲劳载荷对部分预应力梁的影响 - 第 2 阶段

基本信息

批准号：
8613440
负责人：
Antoine Naaman
金额：
$ 17.63万
依托单位：
Regents of the University of Michigan - Ann Arbor
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1987
资助国家：
美国
起止时间：
1987-03-01 至 1990-02-28
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=8613440&HistoricalAwards=false
关键词：
Effects Cyclic Fatigue Loading Partially

项目摘要

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.

这是对经环状疲劳负荷的部分预应力混凝土梁的行为和建模的两部分研究研究的第二次研究。部分预应力的梁在这里定义为混凝土梁，并结合了预应力和非预应力的加固，旨在允许在全服务负载下进行开裂（死亡加上活载荷）。将研究疲劳的以下各个方面：成员的疲劳寿命，疲劳下的裂纹和裂纹宽度增加，偏转和偏转随载荷的循环次数而增加。研究的第一阶段处理在恒定振幅疲劳载荷下测试的矩形切片。第二阶段涉及可变振幅疲劳加载下的T部分，模拟桥梁上的真实活载荷。该研究包括一个实验和分析计划。实验变量包括三个级别的加强级别，对于每个级别的部分预应力，包括全面加强和充分预应力的两个边界。总体实验程序和要记录的测量值旨在提供有关开裂挠度的全面数据基础，并随着环状疲劳负荷的增加而增加。预测疲劳下裂纹宽度和挠度的分析程序旨在生成在边界上保持有效的有效模型，该模型由完全加固和完全预应力的混凝土表示。