- Author
- Woodward, K. | Rankin, F.
- Title
- Influence of Vertical Compressive Stress on Shear Resistance of Concrete Block Masonry Walls.
- Coporate
- National Bureau of Standards, Gaithersburg, MD
- Report
- NBSIR 84-2929, October 1984,
- Distribution
- Available from National Technical Information Service
- Keywords
- concrete blocks; masonry; walls; structural analysis; mortars (materials); shear tests; shear properties; axial stress; compressive properties; loads (forces); displacement; cracks; cracking (fracturing)
- Abstract
- The results from tests on eight ungrouted and unreinforced concrete block masonry walls are presented. The emphasis of the research program is the influence of vertical in-plane compressive stress on the lateral in-plane load resistance of the walls. Each wall has nominal dimensions of 64 in. x 64 in. x 8 in. and is fabricated from similar materials by the same experienced mason. The masonry units are hollow concrete block having a nominal compressive strength of 1800 psi based on the gross area. The mortar was proportioned as a Type S. The walls are tested in the NBS Tri-directional Testing Facility using fixed ended boundary conditions at the top and bottom of the wall. Lateral in-plane displacements were applied at the top of the wall while maintaining a constant compressive axial load. The vertical compressive stress varies between 120 and 500 psi (based on net cross-sectional area) in the test program. The test results indicate that there is a linear relationship between increasing amounts of vertical compressive stress and the resulting increased in-plane maximum lateral load resistance.