Author : Yuying Hu
Publisher :
ISBN 13 :
Total Pages : 664 pages
Book Rating : 4.:/5 (319 download)
Book Synopsis Use of Adhesives to Retrofit Out-of-plane Distortion Induced Fatigue Cracks by : Yuying Hu
Download or read book Use of Adhesives to Retrofit Out-of-plane Distortion Induced Fatigue Cracks written by Yuying Hu and published by . This book was released on 2005 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prior to 1985, it was common practice to avoid welding the connection plates to the tension flange of the girders of steel bridges. However, extensive fatigue cracking has developed in the unstiffened web gaps because of out-ofplane distortion. A new retrofit option was investigated that uses a room-temperature-cured two-part epoxy (3M Adhesive DP460-NS) to join a small length of 3/4-inch thick steel angle to the tension flange and the connection plate. A field test on two skewed bridges showed that the adhesive-angle retrofit system decreased the out-of-plane strain range by 40 to 50% when the original strain range was more than 50 microstrains. The ten adhesive-angle retrofits remained in place and were in good condition after three and a half years, suggesting that the chosen adhesive had good environmental durability. A laboratory large-scale specimen test with 8 web gaps showed that the retrofit system stopped or retarded most cracks even without stop holes when the measured out-of-plane strains were approximately 600 microstrains. Coupon tests conducted to investigate the environmental durability of the chosen adhesive showed that the chosen adhesive is suitable for applications at room or low temperature, even with high relative humidity.