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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.

本文是关于部分预应力混凝土梁在循环疲劳荷载作用下的行为和模型的两部分研究中的第二部分。部分预应力梁在这里被定义为用预应力和非预应力钢筋的组合加固的混凝土梁，旨在允许在完全使用荷载(静载和活荷载)下开裂。疲劳试验将从以下几个方面进行研究：疲劳下构件的疲劳寿命、裂缝和裂缝宽度增加，挠度和挠度随着加载循环次数的增加而增加。研究的第一阶段是在恒幅疲劳载荷下进行的矩形截面试验。第二阶段采用变幅疲劳荷载作用下的T形截面，模拟桥梁上的实际活荷载。这项研究包括实验和分析程序。试验变量包括三个水平的钢筋和四个水平的部分预应力，其中包括完全加固和完全预应力两个边界。总的试验计划和要记录的测量旨在提供关于裂缝挠度的全面数据基础，以及它们随着循环疲劳载荷的增加而增加。用于预测疲劳状态下裂缝宽度和挠度的分析程序旨在生成合理的模型，这些模型在以全钢筋和全预应力混凝土为代表的边界处仍然有效。