التصرف الإنشائي للجسور المركبة الخلوية المعرضة للاحمال الساكنة و تكرارية

Structural Behavior of Composite Castellated Beams Under Monotonic and Repeated Loads

Abstract

The present study focuses on conducting experimental and numerical analyses to examine the performance of composite castellated beams subjected to repeated loading. This study investigates multiple parameters, such as shaped openings (hexagonal, circular, and square) and shear stud spacings of 150 mm and 300 mm, in both the presence and absence of stiffeners. The experimental work involved conducting experiments on materials’ mechanical and chemical properties. The beams underwent repeated (25%Pu-50%Pu-75%Pu-100%Pu, etc.) and monotonic loading. In addition, the extension ratio resulted in a 50% increase in the height of the web. In the experimental phase, fifteen composite sections were fabricated, with three of them serving as control samples. The connection between the concrete deck slab and the steel I-beam was established using headed steel studs welded onto the top flanges. The deck slab has dimensions of 1500 mm in length, 350 mm in breadth, and 70 mm in thickness. The structural element utilized was an I-beam, namely an IPE 140, with a length of 1500 mm. The composite beams were categorized into five groups based on variable factors. Each group is comprised of three beams. The study found that certain factors significantly impact the structural integrity of composite castellated beams. Decreased spacing increased load-carrying capabilities and decreased deflections. The design of the opening significantly affects the performance, with hexagonal configurations regularly surpassing circular and square forms in all groups, which varies from 28.26% to 100.43%, emphasizing the structural superiority of hexagonal apertures. Furthermore, the distance between shear connections significantly impacts the maximum load capacities, resulting in variations ranging from 7.91% to 58.09%. It is crucial to thoroughly evaluate the spacing of shear connectors in the design of castellated steel beams. Finally, reinforcement methods demonstrate efficacy, resulting in percentage increments in maximum load ranging from 17.89% to 66.53%. The study also compares numerical simulations and experimental findings using ABAQUS/Explicit software. The analysis includes parameters like opening configuration, shear connector distribution, and strengthening. Finite element analysis confirms these findings, demonstrating a high level of accuracy of around 94% in predicting ultimate load and load-deflection correlations. The study provides valuable insights into the design of composite castellated beams, emphasizing the need to optimize design parameters to enhance structural efficiency.