Experimental study for the bearing capacity calculation of concrete expanded plates in squeezed branch piles

Abstract

Abstract Small-scale model specimens of concrete expanded plates at a scale of 1 : 5 were prepared based on the normal sizes of squeezed branch piles used in engineering applications. Load tests were conducted on the model specimens using an electro-hydraulic compression-testing machine. Through the tests, the complete load-displacement curves of expanded plates were obtained. The test results indicate that the failure mode of expanded plates under the experimental conditions is generally inclined to compression failure and that the major factors affecting the expanded plate's bearing capacity are the compressive strength of concrete, the height-to-width ratio of the expanded plate, and the disc diameter ratio of the expanded plate. Based on the test results, a bearing capacity calculation model for the expanded plate was established. Additionally, a practical calculation formula for the expanded plate's ultimate bearing capacity was derived, where a correlation coefficient (β) was considered to reflect the effects of the expanded plate's failure modes and forces on its bearing capacity. Considering the approximations of the failure modes and forces of expanded plates, a β value of 0.625 may be suggested. The computed bearing capacity values from the derived formula are in good agreement with the test results, as evidenced in the comparison and verification analyses. This study demonstrates the improvement in strength design and calculation theory of expanded plates.