Performance of Partially Grouted, Minimally Reinforced CMU Cavity Walls against Blast Demands. II: Performance under Impulse Loads
Publication: Journal of Performance of Constructed Facilities
Volume 29, Issue 4
Abstract
This paper presents the results of full-scale blast load testing of partially grouted single-wythe and multiwythe insulated masonry walls. Three design sections were evaluated, as follows: (1) a 150-mm (6-in.) standard block masonry wall reinforced with 10-mm (No. 3) rebar at 80-cm (32-in.) maximum spacing, (2) a 200-mm (8-in.) standard block masonry wall reinforced with 13-mm (No. 4) rebar at 122-cm (48-in.) maximum spacing, and (3) a cavity wall consisting of 200-mm (8-in.) standard reinforced concrete masonry unit (CMU) wythe plus a 102-cm (4-in.) clay facing brick veneer with 52-mm (2-in.) thick extruded polystyrene rigid board insulation and a 25-mm (1-in.) air gap between the structural wythe and the veneer. Each test panel was 285 cm (112 in.), seven blocks, in (136 in.), 17 courses, in height. Only the cells containing reinforcement were grouted. Three blast load experiments were conducted; each experiment tested one each of the three test panel designs. The loading varied significantly between each of the three experiments. Dynamic displacement at several locations through the height (quarter points) of each panel was recorded. The reflected pressures, free field pressures, and internal pressures were recorded at several locations. Interior and exterior videography was also used to record the response. A detailed posttest forensic evaluation was conducted to determine predominant failure mechanisms. The measured transient deflection responses were then compared to analytical responses calculated using the static resistance functions generated from the test results presented in the companion paper as well as by typical blast design methodologies. The comparisons demonstrated that the design resistances used in blast analysis single degree of freedom methodology are conservative. However, the blast testing demonstrated that potentially dangerous modes of localized failure between the grouted cells can occur at scaled distances that are significantly greater than scaled distances that would be assumed to cause breaching.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The experimental components of the research reported in this paper were sponsored by the Airbase Technologies Division, Engineering Mechanics Section of the Air Force Research Laboratory (AFRL) at Tyndall Air Force Base, Florida. The AFRL program manager during the experimental phase of the research reported in this paper was Dr. Robert Dinan. Experimental samples were provided through a Cooperative Research and Development Agreement (CRADA) with the Portland Cement Association (PCA; CRADA No. 05-119-ML-01). Mr. Dennis Graber from the National Concrete Masonry Association (NCMA) and Mr. Greg Borchelt from the Brick Industry Association (BIA) assisted throughout the planning and execution of the research reported in this paper. Static experiments were conducted at the National Center of Explosive Research and Design (NCERD), University of Missouri-Columbia, under the supervision of Dr. Hani Salim and Mr. Aaron Saucier. Masonry material tests were conducted by NCMA. Employees of Black and Veatch, and Applied Research Associates, contributed to the execution of the research reported in this paper. Auburn University researchers in the Department of Civil Engineering, under the guidance of Dr. James Davidson, provided pretest support of the research reported in this paper, as well as posttest analysis of the experimental data, which was partially sponsored through an NCMA Education and Research Foundation Grant. In addition the writers thank the Geotechnical and Structural Laboratory of the U.S. Army Engineer Research and Development Center for efforts in revising this paper. Citation of manufacturers or trade names does not constitute an official endorsement or approval of the use thereof. The U.S. government is authorized to reproduce and distribute reprints for government purposes notwithstanding any copyright notation in this paper.
References
American Concrete Institute (ACI). (2008). “Building code requirements and specification for masonry structures.”, Farmington Hills, MI.
American Welding Society (AWS). (2006). “Structural welding code—Steel.” D1.1/D1.1M, Miami, FL.
ASTM. (2010). “Standard specification for grout masonry.” C476-10, West Conshohocken, PA.
ASTM. (2011). “Standard specification for steel wire for masonry joint reinforcement.” A951/A951M-11, West Conshohocken, PA.
ASTM. (2012a). “Standard specification for mortar for unit masonry.” C270-12a, West Conshohocken, PA.
ASTM. (2012b). “Standard test method for compressive strength of masonry prisms.” C1314-12, West Conshohocken, PA.
ASTM. (2013a). “Standard specification for deformed and plain carbon-steel bars for concrete reinforcement.” A615/A615M-13, West Conshohocken, PA.
ASTM. (2013b). “Standard specification for facing brick (solid masonry units made from clay or shale).” C216-13, West Conshohocken, PA.
ASTM. (2013c). “Standard specification for loadbearing concrete masonry units.” C90-13, West Conshohocken, PA.
ASTM. (2013d). “Standard specification for steel wire, plain, for concrete reinforcement (withdrawn 2013).” A82/A82M-07, West Conshohocken, PA.
ASTM. (2013e). “Standard test methods and definitions for mechanical testing of steel products.” A370-13, West Conshohocken, PA.
ASTM. (2013f). “Standard test method for sampling and testing grout.” C1019-13, West Conshohocken, PA.
ASTM. (2014a). “Standard specification for deformed and plain low-alloy steel bars for concrete reinforcement.” A706/A706M-14, West Conshohocken, PA.
ASTM. (2014b). “Standard test method for preconstruction and construction evaluation of mortars for plain and reinforced unit masonry.” C780-14, West Conshohocken, PA.
ASTM. (2014c). “Standard test methods for sampling and testing concrete masonry units and related units.” C140/C140M-14, West Conshohocken, PA.
Biggs, J. M. (1964). Introduction to structural dynamics, McGraw-Hill, New York.
Browning, R. S., Davidson, J. S., and Dinan, R. J. (2008). “Resistance of multi-wythe insulated masonry walls subjected to impulse loads–Volume 1.”, Air Force Research Laboratory, Panama, FL.
Davidson, J. S., et al. (2011). “Full-scale experimental evaluation of partially grouted, minimally reinforced CMU walls against blast demands.”, Air Force Research Laboratory, Panama, FL.
Dept. of Defense (DoD). (2005). “Masonry structural design for buildings.”, Washington, DC.
Dept. of Defense (DoD). (2008). “Structures to resist the effects of accidental explosions.”, Washington, DC.
Hoemann, J. M., Shull, J. S., Salim, H. H., Bewick, B. T., and Davidson, J. S. (2015). “Performance of partially grouted, minimally reinforced CMU cavity walls against blast demands. I: Large deflection static resistance under uniform pressure.” J. Perform. Constr. Facil., 04014113.
Protective Design Center (PDC). (2005). “Single-degree-of-freedom blast effects design spreadsheets (SBEDS).”, U.S. Army Corps of Engineers, Vicksburg, MS.
Single Degree of Freedom Blast Effects Design Spreadsheets (SBEDS) version 4.2 [Computer software]. Omaha, Nebraska, U.S. Army Corp of Engineers.
Slawson, T. R. (1995). “Wall response to airblast loads: The wall analysis code (WAC).”, U.S. Army Engineer Research and Development Center, Vicksburg, MS.
Wall Analysis Code (WAC) version 2 [Computer software]. Vicksburg, MS, U.S. Army Engineer Waterways Experiment Station.
Information & Authors
Information
Published In
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Mar 23, 2013
Accepted: Aug 14, 2013
Published online: Sep 2, 2014
Discussion open until: Feb 2, 2015
Published in print: Aug 1, 2015
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.