1986

Tanskanen, Kalle; Nykyri, Pekka; Sarja, Asko

The aims of the research are to determine the static behaviour of prefabricated welded reinforcing units and to prepare instructions for their design which are in agreement with the column reinforcement systems previously developed at the Concrete and Silicate (Laboratory of the Technical Research Centre of Finland (VTT). The behaviour of reinforcements was examined by laboratory tests and on the basis of experimental and theoretical data obtained from the literature. The research results indicate that the welded reinforcements, in which two or four main bars are joined together with ties without encircling hoops, are as suitable as the traditional loose bars and the encircling hoops for statically loaded columns. The individual main bar zones determined in the cross-section of the columns make, in conformity with parallel research, the interlocking of beam reinforcements at the beam-to-column intersection possible as well as in the zone of change in the column cross-section. Since to fire tests on columns were carried out in conjunction with this research project, it is recommended that the fire resistance time of new reinforcements not exceed 30 minutes, if the fire resistance is not examined separately.