The Effects of Double Openings on the Behaviour of Hollow Concrete Blocks Masonry Panels
Description
This work investigated the influence of double openings to the structural performance of hollow concrete block masonry walls. A full-scale experimental masonry wall was constructed and tested. Additionally, simulation modeling was conducted using ABAQUS software, employing the finite element method to validate the experimental results. Findings revealed that larger opening sizes generally resulted in reduced compressive strength of masonry walls. Similarly, increased aspect ratios and edge-positioned openings, as opposed to centrally placed openings, led to further reductions in compressive strength. Furthermore, masonry prism compressive strength exhibited an inverse relationship with the height-to-thickness (h/t) ratio but positively correlated with the length-to-thickness (l/t) ratio. Walls with fixed boundary conditions at the top and bottom displayed the highest strength. Additionally, a strong predictive relationship was established.
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Steps to reproduce
This study adopted an experimental research approach utilizing various materials in a laboratory setting. Initially, hollow concrete blocks measuring 390 × 190 × 140 mm were procured from the manufacturer, produced according to ASTM C90-16a standards (ASTM C90-16a, 2016). Mortar served as the bonding agent between blocks, facilitating load transfer, with a joint thickness maintained at 10 ± 1 mm. The mortar mix, prepared following ASTM C595/C595M-23 specifications (ASTM C595/C595M-23, 2023), consisted of ordinary Portland cement, sand, lime, and water. Its flow value was maintained within 175 ± 10 to ensure consistent workability and uniform results across variations in block characteristics. Additionally, grout was prepared to fill the joints around horizontal steel reinforcement bars embedded in bond beams. Experimental results were validated through comparative simulations using ABAQUS software. Upon gathering all necessary materials, the initial phase involved constructing masonry prisms and wall panels. Masonry prisms featured varied height-to-thickness (h/t) and length-to-thickness (l/t) ratios, resulting in 17 configurations and 51 specimens for testing, utilizing both staggered (running) and stack bond patterns. The first testing phase included compressive strength assessments of masonry prisms across different h/t and l/t ratios, boundary conditions, aspect ratios, and opening dimensions. Subsequently, full-scale masonry walls were constructed over a period of 28 days, as depicted in Figure 2, to evaluate their compressive strength under various opening conditions, including centrally located openings (WOC), edge-located openings (WOE), and solid walls without openings (WS). Strength testing for masonry walls was performed using a 1000 kN hydraulic testing machine, with strain measurements captured via strain gauges connected to multi-channel data loggers placed on wall panels. Additionally, flexural strength tests were conducted to determine the masonry units' ability to withstand bending forces. The final phase of the research involved finite element analysis (FEA) modeling using ABAQUS software, employing a 40 mm mesh size for prisms and wall panels following a convergence study. The simulations mirrored the experimental procedures, evaluating the compressive strength of masonry prisms and wall panels under varying h/t ratios and opening conditions. Experimental data were analyzed to identify key trends, with corresponding charts generated to elucidate relationships among the investigated variables.