Optimization of composite floors : theory and practice

Abstract

In this paper optimized weight values for a composite metal deck floor system are compared to existing buildings to evaluate current industry performance in regards to material efficiency in steel structures. This comparison is made to demonstrate how optimization can be used to reduce material usage in buildings, thereby driving down the embodied carbon of structures and potentially reducing costs. It is shown that on average, recently constructed buildings contain nearly twice as much structural material as required by structural constraints consistent with a typical office building in North America. A wide range of rectangular bays are examined to demonstrate trends within the flooring system and to yield information that can be applied directly to practice. Existing building information is extracted from a database containing structural material quantities for 640 buildings normalized by their floor area. Optimized values are adjusted to account for the contributions of foundations and lateral resisting systems to the total weight. This results in full building weights of 266 - 342 kg/m² (55 - 70 psf) which are much less than an average 808 kg/m² (166 psf) for the steel commercial buildings surveyed. Finally, hypotheses are proposed to explain the continued disparity between theory and practice.