Evaluation and Damage Repair of 23-Year Old Prestressed Bridge Box Girders

在美国里诺市一座有23年历史的混凝土桥梁拆除过程中，大量长69'的预制预应力混凝土箱梁被恢复原状。其中6根大梁已捐赠给内华达大学里诺分校（UNR），用于研究目的。这些梁提供了一个很好的机会来研究现有结构的不同方面的行为，设计，维修和疲劳寿命。能源部提供的研究资金用于测试两根大梁，以确定其实际刚度和强度，并对大梁的修复进行有限的研究。本提案的主要目的是研究另外四个梁，以确定(1)实际预应力，(2)暴露于除冰盐23年后氯化物污染的程度，(3)低水平损伤对剩余寿命的影响，以及(4)碰撞损坏梁的适当修复技术，并调查修复后梁的疲劳性能。

During the demolition of a 23-year old concrete bridge in Reno, a large number of plant-cast prestressed concrete box girders with a length of 69' were recovered in good condition. Six of the girders have been donated to the University of Nevada, Reno (UNR), for research purpose. These girders provide an excellent opportunity to study different aspects of the behavior, design, repair, and fatigue life of existing structures. Research funds have been received from the Department of Energy to test two girders to determine their actual stiffness and strength and to conduct limited studies on the repair of the girders. The primary objective of this proposal is to study four additional girders to determine (1) the actual prestress forces, (2) the extent of chloride contamination after 23 years of exposure to deicing salt, (3) the effect of low-level damage on the remaining life, and (4) appropriate repair techniques for girders damaged by collision, and to investigate the fatigue performance of the repaired girders.