Study on Concrete Quality of Box Girder Based on Acoustic CT Technology

摘要

The twenty-ninth span 1# box girder of grand bridge on a Expressway in Yunnan, China, which is broken suddenly during the hoisting and transportation, resulting in the overturning of the beam and partial breakage. This paper focuses on the study of concrete appearance and concrete strength by CT technology. The results show that the average wave velocity of concrete in the area detected by the left web CT is 4.60 Km/s, and the coefficient of variation is 0.12; the average wave velocity of concrete in the right web area is 4.68 Km/s and the coefficient of variation is 0.11. The concrete pouring quality of the box girder is grade B. There are some abnormal areas in the concrete of the left and right web, which have certain influence on the bearing capacity of the bridge.