Seismic performance of steel-encased composite members with strengthening cross-inclined bars

Concrete structural members are usually vulnerable to earthquake-induced torsion due to the low tensile and shear strengths of the material. Premature cracks in concrete due to torsion usually results in inadequate flexural performance when the members are subjected to loads coupled with torsion. Therefore, a remedy to improve member torsional resistance and enhance bearing performance is essential for concrete-related designs. This study is focused on the flexural-torsional behavior of steel-encased composite members strengthened with cross-inclined bars. The test results show that the torsional rigidities of members with inclined bars were significantly increased. From test comparisons, the strengthened member flexural-torsional performance was significantly improved when subjected to combined bending and torsion.