Abstract: This study adopts a combined approach of full-scale local test and numerical simulations to clarify our understanding of the axial damage modes of grouted connections. A modified finite element model is used to examine the influence of shear key height and spacing on the overall mechanical performance and failure patterns of grouted connections, aimed to provide a basis for optimized designs. The results indicate that the axial ultimate bearing capacity manifests limited variation with the shear key spacing, but vertical displacement is more sensitive to it. A small spacing tends to induce localized inclined cracks, while a large one may lead to brittle damage. Shear key height significantly influences the load-bearing mechanism and stiffness of the connection structure; at its minimum, the bearing capacity is relatively low. Its variation imposes a considerable effect on damage distribution and damage modes, but little on primary damage angles, reducing the performance of the connection structure if it is excessively small or excessively large. With a comprehensive consideration of the strength, ductility, failure mode, stress distribution, and construction cost, we recommend the shear key spacings suggested by API and HSE, and the shear key height ranges by NORSOK and ISO.

Key words: grouted connection, axial bearing capacity, damage mode, shear key spacing, shear key height