- Author
-
Schultz, A. E.
|
Hutchinson, R. S.
- Title
- Seismic Behavior of Partially-Grouted Masonry Shear Walls. Phase 2. Effectiveness of Bed-Joint Reinforcement.
- Coporate
- Minnesota Univ., Minnaepolis
- Sponsor
- National Institute of Standards and Technology, Gaithersburg, MD
- Report
-
NIST GCR 01-808; Structural Engineering Report ST-98-6,
February 2001,
440 p.
- Keywords
-
seismic behavior
|
masonry
|
walls
|
effectiveness
|
beams
- Identifiers
- horizontal reinforcement; specimen designations; masonry wall panel; vertical reinforcement; precase concrete header/footer beams; fabrication procedure; general behavior of shear wall specimens; crack patterns; mode of response; force-displacement response to cyclic loading; local response to cyclic loading; assessment of shear resistance characteristics
- Abstract
- A recently completed project on partially-grouted masonry shear walls is documented. This project forms part of an ongoing research program on masonry structures at the Building and Fire Research Laboratory of the National Institute of Standards and Technology (NIST). This report and project draw from and build upon previous work conducted at NIST, including a comprehensive literature review (Yancey et al., 1991), simulated seismic load tests of unreinforced masonry walls (Woodward and Rankin, 1983; 1984a; 1984b; 1985a; 1985b) and reinforced masonry walls (Yancey and Scribner, 1989), and numerical analyses employing empirical formulations (Fattal and Todd, 1991; Fattal, 1 993a; Fattal, 1 993c) and finite element models (Yancey). The previous NIST research culminates with a preliminary draft outlining a research program on partially-grouted masonry shear walls (Schultz, 1994; Fattal, 1993b). This program calls for simulated seismic load experiments of partially-grouted masonry walls, and numerical analyses, both empirical and finite element modeling of shear wall behavior. The current research project on partially-grouted masonry shear walls addresses walls which have vertical reinforcement concentrated at a few locations, such as jambs, and only these cells are grouted. In the present project, all horizontal reinforcement is provided by welded wire grids that are placed in the bed joints of the masonry. The construction and testing of a series of six partially-grouted concrete masonry shear walls is described. The principal variables are height-to-length aspect ratio and horizontal reinforcement ratio. Specimen configuration, test setup, instrumentation, and testing procedure, are presented, along with a detailed discussion of observed behavior of the partially-grouted shear walls and measured response to the cyclic loading histories. The discussion includes modes of response, global force-displacement characteristics, and local deformation response. An assessment of the shear resistance characteristics of the test specimens is also summarized. The shear resistance characteristics studied include initial stiffness, shear strength at first cracking, and shear strength at ultimate. In addition, a discussion on minimum horizontal reinforcement ratio for adequate seismic performance is also discussed.