Shear behaviour and theoretical model of large shear key dry joints in precast concrete segmental bridges using advanced monitoring

Abstract

Keyed dry joints are commonly utilised in segmental bridges for shear stress transmission. The aim of this study is to explore the shear behaviour and capacity of large shear key dry joints. The considered parameters included key base height, key number and concrete strength. The key base heights were found to have a significant impact on the failure mode and shear carrying capacity. When the key base height is increased by 100%, the shear carrying capacity of the joint is increased by 156%. Digital image correlation (DIC) and distributed fibre optic sensing (DFOS) technologies revealed the characteristics of load transfer in the large shear key, validated the principle of inclined strut column and observed the changing angle of inclined column with the increase in shear key size. Moreover, due to the shear transfer at the large key teeth, there is a trend of separation in the lower contact surfaces of the joint. Based on these findings, an improved calculation method for the shear strength of large key dry joints was established. The calculation results show more accurate predictions for large key dry joints than available calculation methods developed for smaller keyed dry joints.

Keywords:

• Design specifications
• dry joints
• large shear keys
• non-destructive testing
• precast concrete segmental bridges
• shear strength
• shear stress transmission

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was funded by National Natural Science Foundation of China [Grant 51979090]. Qinghai Provincial Key R&D and Transformation Plan [Grant No. 2019SF127]. The Fundamental Research Funds for the Central Universities [Grant No. B230205017]. CSC scholarship of China [202206710009].