详情

原文传递 TECHNIQUES FOR MEASURING EXISTING LONG-TERM STRESSES IN PRESTRESSED CONCRETE BRIDGES

题名：	TECHNIQUES FOR MEASURING EXISTING LONG-TERM STRESSES IN PRESTRESSED CONCRETE BRIDGES
作者：	T. R. Overman, N. W. Hanson, B. G. Rabbat, B. J. Morgan, R. I. Zwiers, K. N. Shiu
关键词：	Nondestructive tests, normal stress, strain, residual stress, reinforced concrete, prestressed concrete, field tests, determination of stress
摘要：	This volume summarizes the state-of-the-art, analytical, laboratory, and field studies performed to evaluate the feasibility of the flat-jack direct stress measurement technique to be used on prestressed concrete bridges. Several strain relief methods. Including boring and slitting techniques, were evaluated by performing analytical studies. The flat-jack slitting technique was determined to be the most promising. Laboratory studies Indicated that concrete Internal stress could be measured to within +125 psi with a 90 percent confidence level. Laboratory tests were performed on unreinforced, reinforced, and prestressed concrete specimens. Additional variables Included member thickness, magnitude of stress, and stress distribution. Various linear regression analyses were performed to determine the best relationship between flat-jack canceling pressure and Internal concrete stress. Direct stress measurements taken on a 25-year-old prestressed concrete highwav girder were similar to those determined from laboratory testing on companion girders
报告类型：	科技报告