Shear walls with double plasterboards : evalutation of design models

Sammanfattning: This thesis presents a part of the ECSC-project Development of dry composite construction systems based on steel in residential application that focus on design recommendations for stabilizing buildings by using shear resistance in the walls. The existing design method suggested and used by the Swedish plasterboard manufacturer Gyproc AB is considered as a bit conservative and it does not consider double plasterboards properly. A work within the frame of the ECCS-project performed by Swedish participants was conducted in order to investigate the possibilities for improvements of design recommendations for shear wall design. Therefore a number of tests concerning the behaviour of the connection between plasterboards and steel studs have been carried out. Background information necessary for the project is presented in this report. Experimental investigations and finite element modelling of characteristic specimens and a design model for a shear wall with double plasterboards are described in the report. Furthermore, a short description of a newly established design recommendations proposed in the project are given. The experimental investigation covered various cases of connections between either one layer or two layers plasterboard to a frame made of steel studs. Nine different set-ups using a single fastener herein referred to as fastener tests were tested to get an indication of the fastener resistance in various situations. Three specimens were tested for each setup. Six types of small-scale wall tests (900x900mm) were performed. Different boards are used in specimens, one layer plasterboard or board made of constructional plywood, and two layers plasterboards were fastened with fasteners to both sides of the frame. The full-scale test was performed on the two-storey wall with a door opening. This test was performed to find out the resistance of a shear wall built up by several units using double plasterboards. A structural model for design of shear walls with double plasterboards is given. A MathCad script was written in order to perform a parametric study of the wall. A complete text of the script is given in Appendix B. A comparison between results obtained from the FE model computed using commercially available code, ABAQUS, and results from the structural model were accomplished to validate assumptions used in the structural model. Two types of the small-scale wall test and the full-scale test were modelled by ABAQUS to gain more knowledge about force distribution between the plasterboards and steel frame. Usefulness of the fastener test to provide reliable data for the non-linear analysis was determined since those data were used in the finite element analysis.