| The post-tensioned technique was used broadly because of its advantage, but the good or not of grounting in duct is not to be easy dected. It is of great importance to consider Imact-Echo (IE) method for detecting voids in post-tensioned ducts. IE is a hot reasearch topic in the field of Non Destructive Technology (NDT). In this dissertation, which funded by the Science and Technology Item of West from Ministry of Communications, IE scanning method was performed to study the mechanism of decting voids in ducts and to acquire some rules.Some main achievements of this dissertation are described as follow:(1) Based on lots of literature, the methods and tests about the issue of IE was summarized and commented.,and classified some production by different influence factor.(2) Based on some investigations, the advantage and disadvantage about the IE testing systems at home and abroad were compared, and chose Impact-Echo scanning system to do research.(3) Considered the influences in actual bridge structure, ten mockup specimens were built in lab. The data tested from the specimens had been conducted and the following conclusion were drawn:①The quantity of steel bar in concrete structure influenced the result of Impact-Echo test;②The mode of vibration in the cuneiform structure, caused by stress wave,differed from the mode in plate;③The void in plastic duct would be detected difficultly because of some interspaces between concrete and outside of plastic duct;④The transverse distance between the ducts effected the test result about correlative ducts;⑤The estimation of quality about the grouted duct was influenced by e , S_s/S_d, the wave velocity of grout,and so on;⑥Comparatively analysed the offsets of duct in one test line, IES could detect the grouted,half-grouted and ungrouted duct。...
|
PDF Full Text Request