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This paper presents a simple procedure for the analysis of strengthened and unstrengthened reinforced concrete slabs under close-in blast loadings. The simplified procedure provides a tool to quickly check a slab or verify the results of a more advanced computer analysis. The procedure divides the response of the slab into breach, direct shear, flexural, and membrane behaviors and provides equations and references on how to calculate the capacity of each behavior. The procedure first checks the most severe failure modes, then progresses to other modes. The procedure was used to analyze the response of four slabs subjected to blasts; two of the slabs were strengthened with carbon-fiber reinforced polymer (CFRP) on the back face. The procedure was also used to analyze the response of a reinforced concrete box specimen strengthened with CFRP. The simple procedure accurately predicted the peak deflection of the slabs to close-in blast loadings.

This paper summarizes a research program undertaken to develop cost-effective solutions aimed at protecting new and existing bridge column bents against multiple natural and manmade treats such as earthquakes and blast. Concrete-Filled Double Skin Tube (CFDST) column and Modified Steel Jacketed Column (MSJC) designs were proposed and tested for new bent construction and retrofit, respectively. While CFDSTs maintained their cross-section geometry in dissipating energy under cyclic loading, under severe blast loading, they deformed locally to dissipate the applied impulse and have enough residual strength to prevent collapse. MSJC, on the other hand, were developed to eliminate a deficiency observed in the form of direct shear failure near the top and/or the bottom of the jacket for steel jacketed column (SJC) subjected to blast loading. The proposed modification increases direct shear resistance in the shear-deficient areas and does not interfere with the ability of the jacketed columns to resist earthquake loading.