Experimental and Numerical Assessments of Slab-Column Connections Strengthened Using Bonded Hemp Fiber Fabric Sheets

Abstract The replacement of synthetic fibers with natural fibers in concrete has been recently investigated to counter the growing environmental and sustainable issues. Hemp fibers are environmentally friendly and are used in the manufacturing of composite materials. This paper reports on the experimental assessment of using hemp fiber reinforced polymer (HFRP) fabric sheets as an alternative to carbon fiber reinforced polymer (CFRP) sheets to strengthen interior slab-column connections. Small-scale interior slab-column connections were loaded centrally through the column stub up to failure. The main test variables were slab thickness, HFRP sheet width, number of HFRP layers, type of strengthening material (HFRP or CFRP sheets), and HFRP sheet's location relative to the column’s face. Assessment of the strengthening material was based on a comparison of load capacity, mode of failure, load–displacement history, and cracking patterns. The experimental results demonstrated that HFRP strengthening sheets led to improvement in the structural behavior of the slab-column connections depending on the slab thickness, width and configuration for HFRP sheets. Although the HFRP sheets led to lower improvement as compared to the synthetic CFRP sheets, however, the same improvement could be reached by the HFRP sheets if they are applied in larger width or different configurations. A finite-element model was developed using ABAQUS software to predict the behavior of simulated specimens. The numerical findings showed that the models predicted the connection behavior in good agreement with the experimental test results. In addition, an analytical model was calibrated to simulate the behavior of the tested specimens.