Investigations on the wind uplift behaviour of standing seam cold formed steel roofing sheets

Abstract

There is a steady rise in the usage of cold formed sheets made as standing seam panels in the roofs of pre-engineered buildings. Nevertheless, there are also reports of failure of these roof panels while in service. The behaviour of these panels cannot be captured analytically. A literature study is carried out on the testing and design methods of the cold formed steel (CFS) metal roof system. It is seen from literature survey that none of the international codes of practice specifies the procedure for the calculation of structural capacity of a standing seam roof system unless supported by experimental evidence. In view of that, the structural performance of a standing seam CFS metal roof system under wind uplift is tested in a vacuum chamber as per ASTM E1592. The objective of the presented work is the study of the behaviour and failure modes of the rigid purlin-sheeting system with standing seam CFS panel under uplift. The paper presents the details of an experimental investigation to achieve this objective. This study and the experimental infrastructure is first of its kind in India. The paper also presents various limit states of sheeting – purlin interaction failure based on experimental evidences. It is concluded that in order to treat the sheet-purlin dual load resisting behaviour, the disengagement of the sheet with purlin through the halter must be avoided. One of the main conclusions of the work is the concept of adjustable halter length in regions of high pressure in the roofs.