Compression-shear behavior of a scaled immersion joint with steel shear keys

摘要

The shear behavior of an immersion joint subjected to compressive-shear loads is investigated in this paper. To explore the performance of the immersion joint a scaled specimen, according to a specific protocol of a real project, is designed. A quasi-static shear force is applied horizontally while a constant compression force is maintained on the joint. A hysteresis effect is observed during the test and the area of the hysteretic loop increases with the shear force. An envelope curve of the shear force-displacement of the joint is obtained and divided into four stages based on the observed shear behavior of the joint. The shear stiffness of the immersion joint is calculated, showing a non-linear change with the shear displacement. The shear capacity of the model immersion joint and that of a single steel shear key are evaluated. It is found that the capacity of the joint is smaller than the sum of the capacities of all shear keys. This shows that the shear keys are not activated at the same time. The failure mode of the joint consists of a brittle shear failure in the single shear keys and a step-bystep failure way of the complete joint.