Experimental study on bending capacity of partially-encased steel-concrete composite reinforcement truss open-web beams

To study the bending capacity of partially-encased steel-concrete composite reinforcement truss open-web beams, four-point bending tests were carried out on four specimens of open-web PEC reinforcement truss beams with variable parameters such as section height, flange thickness and web opening rate of main steel parts. Through the analysis of failure phenomenon, load-deflection curves, concrete strain and steel strain, and bearing capacity and deformation, the influence laws of section height, flange thickness and web opening rate of main steel parts on the bending performance of specimens were explored. Research shows that all specimens are subjected to bending failure with good ductility. The load-deflection curve presents two working stages of elastic and elastic-plastic, and the strains of steel and concrete in mid-span basically satisfy the plane section assumption. With the increase of section height from 400 mm to 500 mm, the flexural bearing capacity of the specimen increases by 29. 3%. With the decrease of flange thickness from 10 mm to 8 mm, the flexural bearing capacity of the specimen decreases by 25. 9%. The web opening rate has little effect on the bearing capacity. Based on the test results and basic assumptions, calculation formula of flexural capacity of open-web PEC reinforcement truss beams was given. The calculation results agree well with the experimental results. © 2024 Science Press. All rights reserved.