Blast-Retrofit of CMU Walls Using Steel Sheets

Blast resistant design has come to the forefront of engineering concerns in the wake of recent terrorist threats to the United States. Safety and security are of utmost concern when designing structures, and there has been a significant rise in the demand of researching new methods of reinforcing and retrofitting structures to provide better resistance to blast loading. The focus of this research paper is on the use of steel sheathing as a method of such retrofit. Research is done to ascertain the steel strength, analyze the response of the steel to static pressure, explore strength and ductility limits, investigate connection details, and develop an analytical model of the static resistance function, which will be verified by experimental data. The analytical model for the resistance function will be used in a single-degree of freedom (SDOF) dynamic model to predict the response of steel sheathing blast-retrofitted wall systems. Coupon tests were performed to establish the stress-strain behavior of the steel material, and component beam tests were used to determine the response of the sheathing under static pressure. In addition, connection methods were analyzed and tested in an effort to determine the most suitable blast-retrofit design for a given blast, without exceeding strength or ductility limits for the steel sheets, and to develop the limit states for the retrofit system. The results of the experimental program and the analytical static and dynamic models were incorporated into a user-friendly wall analysis code for the design of steel sheathing for blast retrofit of CMU walls.