Experimental Study of Self-Compacted Concrete-Filled Steel Tube (CFST) Truss Girders

This paper studies the performance of steel tube truss girders filled with self-compacting concrete. Four concrete-filled steel tubular (CFST) truss girders specimens were tested. The first novelty in this research was using square tubes to manufacture truss girder. The main parameters were the bottom chord concrete compressive strength and reinforcing steel bar employment in the bottom chord (second novelty). One bar with a nominal diameter 16mm was used to reinforce the concrete in the bottom chord while keeping the concrete in the top chord without reinforcement. This paper shows the load-displacement curves at the midspan, deflections along the span, peak loads, flexural strength, and failure shapes of the tested specimens. The design equation was used to predict the flexural strength of CFST truss specimens. Results show that the flexural strength was increased with the increase in the concrete strength from 29.23MPa to 48.41MPa by about 4.5% and was increased by about 10.27% when using reinforcing the concrete in the bottom chord.