RC Frame Structure Strengthening By Reason Of Insufficient Concrete Strength
Free (open access)
135 - 146
P. Stepanek, I. Lanikova & P. Simunek
During the reconstruction of a university in Olomouc (Czech Republic) it was discovered that the concrete used in one load-bearing structure was of insufficient strength. The university building complex was constructed in the years 1955–1960. It is built from a reinforced concrete skeleton. The four-storey building is founded on RC footings and continuous footing. A detailed structural investigation of the structure of the first floor determined that the strength of the used concrete varied, ranging from concrete class C3/3.5 to C12/15. The original designed concrete class was C10/13.5, while the plain reinforcement utilised according to the original design was steel with a design strength of 180 MPa. Three structural repair variants were designed based on construction surveys: • steel bandages for the columns and girders, and strengthening/supporting of the girders via steel cross-beams fitted to the bandages; • steel bandages for the columns and girders, and strengthening of the girders via prestressing tendons; • additional non-prestressed reinforcement of the structure by covering it with sprayed concrete. Based on the economic (cost), structural and technical aspects (minimising of additional load), the variant using bandages with additional external prestressing of the majority of the girders via tendons was preferred. Keywords: concrete, prestressing, bandage, frame, strengthening.
Keywords: concrete, prestressing, bandage, frame, strengthening.