Blast load reinforcement

Reinforced concrete is the most commonly used construction material for structures designed to resist explosive blast loads. It is used extensively in blast hardened structures because of its strength, ductility (when properly designed), mass, penetration resistance, relative economy, and universal availability. Its strength, mass, and ductility provide high resistance to the extreme blast pressure (psi) and impulse (psi-ms) loads. It is important to remember that (unlike in static load design) in the... 

The existing wall only provides 7% of the required resistance for the specified blast loads. For adequate resistance, the existing wall must either be strengthened with steel reinforcement, or a new wall must be added next to the existing wall. 

The analysis of the existing masonry wail revealed that the wall only provides a small percentage of the required resistance for the specified blast. Due to the symmetry of the wall and the reinforcement (for the upgrade system), the analysis for the rebound blast loads was not required. 

CBARCS, CUARCS - Optimum Nonlinear Dynamic Design of Reinforced Concrete Slabs Under Blast Loading, Program No. 713-F3-R0056, US Army Corps of Engineers, Waterways Experiment Station, Vicksburg, MS, 1980... 

The primary failure mechanisms encountered in reinforced concrete buildings arc flexure, diagonal tension, and direct shear. Of these three mechanisms,. flexure is preferred under blast loading because an extended plastic response is provider prior to failure. To assure a ductile response, sections are designed so that the flexural capacity is less than the capacity of non-ductile mechanisms. 

Many petrochemical structures have concrete masonry unit (CMU) walls with little or no steel reinforcement. This type of construction lacks ductility and has relativity low resistance to blast loads. 

This chapter provides an example of the evaluation and retrofit of the masonry walls of an existing reinforced concrete framed building using the principles outlined in Chapter 10. The evaluation of the roof, structural framing and foundation are not covered in this example. The explosion magnitude and front wall blast load are determined by others. The analysis of the exterior walls, and upgrade options, arc presented in this example. 

Yahya et al. [21—24] used a ballistic pendulum to conduct blast tests on a range of glass- and carbon hbre-reinforced composites. The fracture processes in the panels were initially assessed by examining the proximal and distal surfaces of the panels following blast loading. Figure 13.2 shows photographs of a number of 4.2-mm-thick laminates... 

Langdon GS, Nurick GN, Lemanski SL, Simmons MC, Cantwell WJ, Schleyer GK. Failure characterisation of blast-loaded fibre-metal laminate panels based on aluminium and glass-fibre reinforced polypropylene. Compos Sci Technol 2007 67(7-8) 1385-405. 

The motor control center (MCC) and Substation have concrete block load bearing walls of ordinary construction. The control house is of blast resistant construction with reinforced concrete walls and roof designed for 0.2 bar static. All three buildings are 4 m tall. 

Masonry, both reinforced and unrein forced, is a common construction material in petrochemical facilities. However, unreinforced masonry is inappropriate in blast resistant design due to its limited strength and its nonductile failure mechanisms. Reinforced masonry walls with independent structural framing for vertical loads arc commonly used in blast resistant design. 

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