Rehabilitering av antikvarisk betongkonstruksjon fra perioden 1926-1938 : Vurdering av rehabiliteringstiltak og restkapasitet for Ingierstrand bad, basert på prøveresultater, dagens standard og standarden gjeldende i 1926-1938

Abstract

Traditionally restoration of antiquarian concrete constructions has been a prominent topic in Norwegian context. This topic has been given more attention, as more concrete constructions and reinforced concrete constructions have been preserved. In this thesis a case-study were done of Ingierstrand bad. A central part of the restoration of antiquarian concrete constructions is to control the capacity of the concrete against occurring stresses. We have in this thesis theoretically controlled the capacity of the standard being used during projecting and building, and that of today’s standard. We suggested the actions of restoration we think suitable for the chosen construction parts in Ingierstrand bad, based on test results and calculations. The results from the calculations has been compared and discussed. The technical information of the building substance for the old constructions was insufficient. Thus, we had to do well considered assumptions repeatedly, based on information from field survey, in addition to observations and information from the standard of 1926. This makes it more challenging to decide the capacities and the carrying capacity of the constructions. In restoring antiquarian concrete constructions there is ordinarily not a request to comply with the regulations and standard of today. Therefore, it is not necessary calculate the constructions according to the standard of today when restoring antiquarian concrete constructions, unless there will be a change in usage. Thus, it is not usual to do any comparison between the standard of today and the standard at that time. For this cause the task is professional interesting, since the correlation of the residual capacity (or lack of correlation) between the standard of today and the standard used from 1926 – 1938. Suggestions of simple pre-treatment action with a following electro-chemical realkalizing has been suggested for the main building. Mechanical repair and hydrophobation are suggested for the constructions of the diving-tower and the pier. These actions of restoration will provide that the original carrying capacity of the constructions are recovered, and at the same time the antiquarian principles are fulfilled. The weaknesses of the original constructions in relation to durability is renovated with a complete mechanical change and electro-chemical realkalizing. The four constructions are calculated with regard to capacity according to today’s standard aswell as the standard from 1926. It is not possible to make a collection of generalizations for these constructions based on these calculations. We observe that the constructions capacity with regard to moment and axialforce has less residual capacity when calculated according to the standard from 1926. For shear capacity the standard of today results in the lowest residual capacity. Our information is quite ensuring but still there could be many presumptions. We don’t have a lot of data directly from the construction parts considered, which cause a uncertainty related to the certainty of the calculations