In situ repair technique of infill masonry walls in steel frames damaged after an earthquake

摘要

The present paper first reviews the scientific information about masonry buildings in terms of the structural performance of different masonry walls, usual pre-earthquake retrofitting methods, and post-earthquake repair methods. From this, it is found that limited information is available on applicable repair methods for damaged masonry walls after the occurrence of an earthquake event. There is an essential need from the perspective of disaster management strategies to provide urgent aid to casualties of moderate seismic events well before preparing damage assessment data and a comprehensive retrofitting program for the earthquake-affected area. For this reason, three experiments were designed to investigate the effect of brick masonry infill on a simple steel frame and the success rate of a new method of repairing damaged infill. In the proposed repair method, cracks in the damaged masonry infill are stitched by crimped wire meshes in the shape of Band-Aids and cementitious plaster is used to coat the attached wire meshes. The crimped wire meshes must be fastened to the infill with hooked driven nails and must be attached perpendicular to diagonal crack paths and the four corners and centre of the infill. This method is presented for efficient and simple in situ repair interventions to provide temporary residency for casualties. Usage of plasters including accelerated cement or application of accelerated curing methods can reduce the time of repair construction and prepare the proposed method for urgent aids against aftershocks. No inappropriate structural effects of the steel frame-infill interaction were observed during these tests. Furthermore, the results indicated that the repair method not only restored the lost strength of the damaged infill but also recovered the stiffness and ductility of the reference specimen based on the experimental evidence. Following the experiments, a practical design methodology for the required crimped wire mesh specification based on the length of the infill diagonal cracks was recommended.