Experimental study on structural performance of new steel-concrete composite beam for both long-span and low-height parking structures

Abstract

Parking structures taller than 8 m in height are difficult to design because both fire and seismic resistance must be considered, whereas structures shorter than this threshold are simpler to design and are subject to fewer construction restrictions. Therefore, to optimize the design of these low parking structures, we propose a novel wide, long-span, steel-concrete composite beam that can be applied to reduce their story height. We investigated flexural and shear-bonding performance of the developed composite beams based on experiments, as well as theoretical and analytical research. Seven flexural beams were loaded at two points prior to monotonic bending tests, and four shear bonding beams were tested using compressive loading schemes. The results of the flexural tests indicated that the flexural strength of the wide composite-steel beams increased by approximately 20% as steel thickness increased by 3 mm (from 6 to 9 mm). Shear-bonding tests showed that all specimens without shear connectors exhibited insufficient shear-bonding strength to resist the mechanical bond mechanism; therefore, they should be reinforced with two or more flat bars. As a result, the novel composite beam system can be applied to reduce construction costs and resources by decreasing floor height in systems with long-span beams.