Title: Tests of Reinforced Concrete Continuous Deep Beams with Web Openings

Author(s): A. F. Ashour and G. Rishi

Publication: Structural Journal

Volume: 97

Issue: 3

Appears on pages(s): 418-426

Keywords: codes; continuous beams; cracks; deep beams; deflection; fail-ure mechanisms; plasticity; reinforced concrete; shear strength; web openings; web reinforcement.

DOI: 10.14359/4636

Date: 5/1/2000

Abstract:
Test results of 16 reinforced concrete two-span continuous deep beams with web openings are reported. All test specimens had the same geometry and main longitudinal top and bottom reinforcement. The main parameters considered were the size and position of the web openings, and web reinforcement arrangement. Two modes of failure were observed, depending on the position of then web openings. For beams having web openings within interior shear spans, the failure is developed by diagonal cracks between the web opening corners and the edges of the load and central support plates. For beams having web openings within exterior shear spans, the mode of failure is characterized by major diagonal cracks with-in interior and exterior shear spans. The diagonal cracks that occurred in the interior shear span extended to join the edges of the load and central support plates, and at the same time, the diagonal cracks that formed at the web opening corners propagated both ways towards the edges of the load and end support plates. Web openings within interior shear spans caused more reduction on the beam capacity than those within exterior shear spans. The vertical web reinforcement had more influence on the beam capacity than the hor-izontal web reinforcement. An upper-bound analysis of the two fail-ure mechanisms that occurred in the experiments is introduced, and design equations are developed.