Minimiarmering i grundplattor : En studie om hur konstruktörsföretag väljer armering och hur valet påverkar den färdiga konstruktionen

Sammanfattning: Purpose: Concrete is a widely used construction material for mainly buildingfoundations. In Sweden Eurocode is used to dimension the minimum reinforcement that is supposed to limit the cracking of the concrete after casting, but cracking is nevertheless a common problem. The aim of this paper is to investigate how structural engineers choose the reinforcement in slabs on ground and how the construction is affected by the choice of reinforcement. Method: In the study, a literature study is made with articles within minimum reinforcement and cracking problems. A document analysis is made of how the Eurocode should be interpreted and used to calculate the minimum reinforcement amounts and crack widths. There are structured interviews with five design companies to investigate how minimum reinforcement is chosen for three different types of slabon ground. Findings: The results of the study show that the final construction might be both physically and economically affected in a negative way due to the fact that the wanted minimum reinforcement levels and crack widths are not always reached. Implications: The findings implicate that the choice of minimum reinforcement is done in different ways among engineers, and a significant difference in the levels could be seen. The recommendations are that the formula for crack width limitation should be used first, lower rebar dimensions should be used and that the communication between building construction engineer and builder should beimproved. Limitations: The study was limited to five interviews with building construction engineers, only three different slab examples were given to the interviewees for calculation of crack limitation reinforcement. Hence the results are not generally useful for all types of slab on ground. Keywords: Crack width, eurocode, eurokod, minimum reinforcement, slab on ground