Evaluation and rehabilitation of a building affected by a gas explosion



The paper deals with efficient solutions for rehabilitation of a block of flats affected by a gas explosion in December 2002. The first part of the paper is devoted to general aspects of the effects of explosions on buildings and personnel. The characteristic of the peak incident pressure as well as maximum reflected pressure are presented. The design procedures and rehabilitation solutions of the buildings subjected to blast loads are described. Rehabilitation solutions for general structural vulnerabilities as well as specific solutions for rehabilitation are presented for RC structures, steel structures and masonry structures. These solutions have been adopted from those already used to develop seismic retrofits. Special attention has been paid to carbon-fibre-reinforced plastic (CFRP) materials.

The second part presents a case study analysis and rehabilitation of a block of flats. The damage due to the explosion is presented for the different structural elements: those in direct contact with blast pressure and the surrounding structural members. Structural analysis comprises two important aspects: the behaviour of the structural members subjected to direct blast pressure and the analysis of the state stresses in the entire building.

The rehabilitation solutions were chosen in accordance with the actual stage of the building. New elements have been used instead of the completely destroyed structural members. RC coatings and columns were necessary to assure continuity and stability of vertical members with serious damage after explosion. Longitudinal beams have the role of connecting the new vertical members. Utilization of CFRP for strengthening of slightly damaged elements has the advantages of easy technology and short time of erection. The other technical and economical advantages of the rehabilitation solutions are: safe behaviour under seismic action; slight change of general stiffness of the structure; small cost of rehabilitation. The consolidation and finishing works were completed by the middle of 2003.