Effect of existing holes under the loading plate on local compressive strength of plain concrete blocks: An experimental and numerical study
Year: 2024
Type: article
Abstract: For structural safety, concrete's bearing strength is a critical design factor. Column base plates are essential for transferring forces to concrete supports, distributing the structure's self-weight and applied loads to the foundation, which affects stability and durability. During installation, holes must be drilled beneath the base plate to insert bolts that secure it to the footing. This paper presents the first experimental and numerical study investigating the effect of vertical and horizontal holes existing under the loading plate on bearing strength of concrete blocks. A total of eighteen numbers of concrete blocks measuring 250 by 250 mm and 200 mm in height were cast to represent the concrete support, with a steel plate measuring 60 by 60 mm positioned in the middle of the top surface of each concrete block. For vertically drilled holes, the variables included hole diameter (6, 10, 12, 16 and 18 mm) and hole depth (20, 40, 60, and 100 mm). For horizontally drilled holes, the variables were hole diameter (12, 16, and 18 mm) and the distance of the hole from the loaded plate (40, 60, 100, and 150 mm). The tested concrete block' crack patterns, ultimate bearing strength, and bearing stress-slip relationships were reported. The test results indicate that for vertically drilled holes, as the hole diameter increases, the loaded area on the concrete surface decreases. This reduction in the loaded area leads to a higher concentration of bearing stresses on a smaller region, accelerating bearing collapse. Consequently, this results in a decrease in the bearing strength of the concrete and an increased likelihood of loaded plate slippage. For horizontally drilled holes, the presence of a transverse hole passing through the bottom of the loading plate does not significantly affect the decrease in the bearing resistance of the concrete. The results confirm that the hole diameter has a greater impact on increasing the ultimate slip than the hole distance. Furthermore, a finite element model (FEM) was developed using ABAQUS software to simulate the behavior of the tested concrete blocks and was validated against the experimental results. The FEM was also used to conduct further parametric investigations. Additionally, the performance of existing design formulas in estimating the ultimate bearing strength for concrete blocks is examined.
Language: English
Subfield: Building and Construction
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,110
OpenAlex ID: W4404338920