Title: Torsional Strength of Longitudinally Reinforced Beams Containing an Opening
Author(s): A. E. McMullen and H. R. Daniel
Publication: Journal Proceedings
Appears on pages(s): 415-420
Keywords: angle of twist;beams (supports);bending moments;cracking (fracturing); deflection; deformation; loads (forces);openings;reinforced concrete; shear properties;strains;structural design;torsion;torsion tests.
Equations for predicting the torsional strength of longitudinally reinforced concrete beams that contain an opening to accommodate service ducts are presented and the results are compared with the test results of 29 beams. The strength of beams containing a short opening can be significantly larger than the strength predicted by the theory because the spiral crack extends into the solid portion of the beam. However, the eqautions can be modified emprically so that they satisfactorily predict the torsional strength. Although all the beams tested were subjected to pure torsion, the analysis includes the shear and moment due to self weight of the beam and can thus easily be extended to include members supporting external loads that cause shear and bending.