Guidelines for Designing Curved Roofs Using non-bended Metal Sheets

Abstract

The roof is the covering of a building. Its function is to protect from the sun and rain. Roof styles devive from the structure and roofing materials. For structural buildings with wide spans such as factories and warehouses. Metal sheets are often used as a roofing material because of properties such as being thin, lightweight and having various for examples, forms. Parallel straight sheet, Tapered Straight sheet, Parallel smooth curve sheet, Tapered smooth curve sheet, Crimp curved sheet and S-curved sheet. From this preliminary study, it was found that the production of curved sheets has a complex process. This results in long time construction and cost. Therefore, the objective is to study the current situation and problems for designing curved roofs using metal sheets as material.

In this research, 13 buildings were analyzed. It was observed that 5 of them used non-bended and 8 used bended metal sheets for their roofs. The curvatures of the roofs were then analyzed based on the radius specified in the product manuals, which dictate the non-bending curvature capacity.

The study found that the factors determining curvature include land size, functional requirements, and aesthetic appeal. Land size and functional requirements correlate with the building's width, while the latter also relates to building height. Aesthetic considerations, on the other hand, influence the roof's radius.

Two proposed approaches emerged from the study. The first approach suggests that if curvature is based on width, the roof's height—measured from its tip to its highest point—should be reduced. The second approach, for curvatures based on height, advises increasing the width of the roof's eaves. If the roof's curvature is influenced by its functional requirements, it is recommended to increase the building's height by adjusting the height from the roof's tip to its apex, aligning the curve's radius with the product model. This would enable the use of non-bending curved sheets. Cost analysis revealed that bending curved sheets are 54% more expensive than non-bending ones.