CFRP strengthening of existing building structures

Sammanfattning: Most of the building structures needed in twenty years from now is already built. Building structures are ageing and they deteriorate and often the demands on the structure changes over time. It is often needed to reinforce the structure, especially when reconstructing, repairing or renovating a building. The traditional strengthening methods that are used today are strengthening the structure with beams and columns of steel. The beams and columns often require much space and problems might occur if there are a lot of installations. There is another more modern technique where a composite plate, sheet, grid or bar of relatively small thickness is bonded with an epoxy adhesive to the structure. These reinforcements don’t change the cross-section of the structure. The most common type of fibre reinforcement that is used for strengthening in the building industry is carbon fibre. The carbon fibre products are much more expensive when comparing to steel. Therefore the object of this report is to show when it is economically motivated to use carbon fibre instead of the more traditional material steel. To do this I have studied five real cases brought to me by WSP Construction in Linköping, Sweden. The study shows that in the cases where it’s possible to use composites strengthening the building structure it is also economically motivated to do so. Even if the material is more expensive than the more traditional materials the total cost is in the same price class as the traditional ones because of the short time of construction. But there is still a problem with only a few consultants and entrepreneurs that have the knowledge and the experience to work with composites when strengthening a structure. If the knowledge will be spread to the consultants I will say that carbon fibre composites are the materials of tomorrow even in the building industry.