Study of Causes and Preventive Measures of the Support System Settlement Accident during Cast-In-Situ Bridge Construction: A Case Study

• Published in: Journal of bridge engineering Vol. 29; no. 3
• Main Authors: Luo, Yufan, Yan, Quansheng, Jia, Buyu, Yu, Xiaolin, Zhang, Xiang, Chen, Yangwen
• Format: Journal Article
• Language: English
• Published: New York American Society of Civil Engineers 01-03-2024
• Subjects: Accidents; Beams (radiation); Box girder bridges; Bridge construction; Bridge failure; Bridges; Components; Construction; Design; Failures; Finite element method; Highway construction; Mathematical models; Onsite; Piles; Pipe piles; Steel; Steel pipes; Steel plates; Stress concentration; Struts; Support systems; System failures; Vulnerability; Welding
• ISSN: 1084-0702; 1943-5592
• DOI: 10.1061/JBENF2.BEENG-6479

The failure of the support system is one of the primary reasons for bridge failures during construction. Existing research on support system failures primarily focused on falsework, with less attention given to other components such as Bailey beams, transverse beams, and steel pipe piles. This study focused on an incident where the support system of a cast-in-situ box girder bridge experienced settlement due to the failure of Bailey beams, transverse beams, and steel pipe piles. To thoroughly analyze the accident's causes, a multiscale elastic–plastic finite-element model of the support system was developed based on the actual on-site layout. By combining the results of the finite-element model with comprehensive on-site data, it was found that the support system settlement accident was caused by a series of construction errors, including the incorrect placement of the Bailey beams, excessive vulnerability in the steel pipe piles' support positions, and inadequate welding strength between the transverse beams. To prevent similar accidents from recurring, the design, construction, and supervisory parties should collectively ensure the consistency between design and construction and increase their attention to potential stress concentrations in certain components of the support system. When the possibility of stress concentration exists, Bailey beams should be reinforced with vertical or diagonal struts depending on their actual support positions, while steel pipe piles should be reinforced with annular steel plates higher than 500 mm.