Investigation of flexural behaviors of hybrid beams formed with GFRP box section and concrete

► We developed five different hybrid GFRP-Concrete beams groups. ► We applied physical and mechanical experiments on the beams. ► Flexural strength and fracture toughness of developed hybrid beams increased about 3 and 10times. ► It becomes possible to produce elements with smaller sections with the same strength. This study investigated the use of concrete, which is known to have high compressive strength, as a hybrid beam with GFRP box sections which have a high tensile stress. Hybrid construction elements were formed by placing concrete in plastic form inside GFRP box profiles and experimental tests were performed on the materials. Firstly, the properties of the GFRP profiles were determined and the flexural behaviors of the hybrid beams produced with different profiles were analyzed. The developments of the hybrid material to its components, which are concrete and GFRP profiles, were examined. To increase the adherence of concrete to GFRP profile, sand particles were pasted in the interior surface of the profile using epoxy and the hybrid beams were improved by increasing the profile felt. Study results showed that in addition to many advantages due to its formation, the hybrid design showed superior physical and mechanical properties. It was found that the flexural strength and fracture toughness values of hybrid beams significantly increased when compared to reference values.