Abstract
Concrete filled steel tube one of the most important modern innovations in the world. This paper studies the performance of steel tube truss girders filled with self-compacting concrete. Four CFST truss girders specimens tested. The first novelty in this research was using square tubes to made truss girder; the main parameters were bottom chord concrete compressive grade and reinforce steel bar is embedded in the bottom chord (second novelty). One bar with a nominal diameter 16 mm was used to reinforce the concrete in the bottom chord while keeping the concrete in the top chord without reinforced. This paper shows the load-displacement curves at the mid-span, deflections along the span, peak loads, flexural strength, and failure modes of the tested specimens. The design equation was used to predict the flexural strength of CFST truss specimens. Results show that the flexural strength increased with increasing the concrete grade from 29.23MPa to 48.41MPa by about 4.5% and increased by about 10.27% when using reinforce steel bar embedded the concrete in the bottom chord.
