Experimental and analytical study on structural performance of polyurethane foam-filled built-up galvanized iron members

摘要

The sandwich members are widely adopted in building structures in particular pre-engineered building (PEB) as cladding and roof members due to its light-weight and thermal properties. PEB based Polyurethane foam (PUF) insulated structure is an alternative to the conventional PEB. The PUF filled sandwich structural members significantly reduces the structural steel weight and improves thermal performance. In this study, experiments were carried out to evaluate the flexural, shear and axial compression performance of PUF filled built-up sandwich beam/column, and purlin members which are fabricated with cold-formed sections made of thin galvanized iron (GI) sheets. In total 22 specimens were tested, in which ten beam/column specimens and twelve purlin specimens. The tests were conducted both in bare and PUF filled frames (specimens). The experimental results revealed that the PUF core material prevents premature failures which are common in cold-formed members and enhances the structural performance. As the observed failure mechanisms were not in line with the conventional cold-formed steel members. Hence, the capacity estimation based on the design guidelines given in Indian standard (IS) 801: 1975 (working stress method) and European standard (EN) 1993-1-3: 2006 (limit state method) may not be appropriate as these standards are based on the effective cross-section area. In this study, the applicability of existing design guidelines given in IS 800: 2007 for the hot-rolled section is verified through the estimation of flexural, shear and axial compression capacity. The estimated capacity was found to be in good agreement with the experimental results. Also, this method of estimation is found to be very simple in comparison with conventional cold-formed steel member design guidelines.