Vibration Serviceability and Environmental Impact of Steel-Concrete Composite Floors Featuring Openings and Partitions

Abstract

Floor openings and nonstructural full-height partitions are often ignored in both finite-element modeling of long-span office floors and calculations of vertical footfall-induced vibrations, despite quite a few research studies pointing out that nonstructural elements may affect floor response. The consideration of layouts of partitions on the stiffness of the floor was not present in most design guides such as those for vibration serviceability, which only recommend the increase of modal damping to account for partitions. The absence of such a consideration is due to the existence of uncertainties for modeling partitions. This study assessed the effects of openings (also referred to as “voids” in this paper) and partitions, by parametrically studying finite elements (FE) models of steel-concrete composite floors featuring three configurations: (1) unpartitioned floors without voids; (2) unpartitioned floors with voids; and (3) floors featuring partitions and voids. All floor models were parametrically generated, by changing the size of supporting steel beams and the deck depth. It is found that, in floors with partitions, walking-induced vibration levels can be as high as twice the levels of vertical vibration across unpartitioned floors. If structural modifications across the whole floor area are then introduced to control such vibrations, that can lead to up to 40% higher carbon footprint. However, it was also shown that alternative layouts of partitions can significantly reduce floor vibrations due to their stiffening effect in hotspot areas, requiring fewer structural modifications of steel beams and concrete deck sizes to meet vibration serviceability, thus reducing considerably the floor carbon footprint (20% less), structural mass (47% less steel and concrete), and floor cost (13% less).