Development of reinforcement of sandwich facade element

This report is concerned with a study of possibilities of developing the reinforcement of sandwich facade elements for the purpose of minimizing the detrimental effects appearing primarily in the service state on the elements subjected to indirect loading; the solutions applicable in this respect to the truss reinforcement used between the panels are introduced. First in the study, behavior, manufacture and structure of the types of walls most frequently being used in Finland as well as loads taken by the walls are examined. Furthermore, functions of the reinforcement in the sandwich walls and functional requirements to be set for the reinforcement are mapped. Secondly, emphasis is placed on the different nature of cracking caused by indirect loading, which differs e.g. from that induced by external mechanical loads. In order to clarify the cracking mechanism of this kind the formation of cracks from the first crack to the stabilization of cracks as well as the determination of the crack distance and crack width by means of calculations are discussed. Dimensioning of the desired crack width is proposed to be carried out by means of the curves, presented for the first time by Falkner in his thesis. In conclusion, a proposal for developing the reinforcement in panels and trusses is presented with the results obtained from the laboratory tests on the elements provided with the reinforcement conforming with the proposed requirements