The influence of non-uniform shrinkage creep on vertical cracking of the web in a small box girder bridge
ZHAO Shengjie
ZHANG Yunqing
SUN Tao
Abstract：The study aims to analyze the causes of the vertical cracks concentrated at the mid-span web of a pre-stressed concrete box girder bridge,which has been in service for many years,and investigates the mechanism behind the continued development of cracks even after the application of sealing and bottom slab reinforcement using carbon fiber sheets.A section-layered model of the box girder bridge is established to represent the physical and mechanical behaviors of the top slab,web,and bottom slab.The differential concrete shrinkage and creep between the web and the top/bottom slabs is taken into account which due to variations in theoretical thickness and reinforcement ratio.A calculation method is derived to estimate the self-induced stresses in the cross-section of the box girder bridge caused by non-uniform shrinkage and creep.The effectiveness of this method is validated by applying it to an actual bridge,which shows that the maximum tensile stress occurs in the mid-section of the web,and it attenuates along the top and bottom slabs,which is consistent with the observed crack pattern of the real bridge.The calculated timing of crack initiation aligns well with the actual occurrence of cracks in the bridge.The research demonstrates that non-uniform shrinkage and creep is important contributing factors to vertical cracking in the web of box girder bridges.
Keywords：bridge engineeringnon-uniform shrinkage and creepstratified cross-sectionvertical cracks of webtensile stress
Publication Date：2023-12-30
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：6( 122-126,162 )