Slender precast voided slabs underwalking‐inducedvibration

Abstract

Disturbance/discomfort caused by vibrations, induced by pedestrian walking on slabs in residential/office buildings, is a typical design issue for lightweight slender slabs, including prestressed concrete ones. Precast slabs are typically made with pretensioned members which allow for only partial collaboration in the transverse slab direction, which becomes even less effective when they are dry-assembled without cast-in-situ topping since it relies on the arrangement of mutual mechanical connections only. This study investigates through tests and numerical analyses the response of slender precast long-span slabs made with voided members, dryassembled with mechanical connections, when subjected to vibrations generated by human activities. A parametric set of dynamic modal and time-history analyses encompassing floor member geometry, connection arrangement, mass, and damping, is carried out. The numerical models are validated against results from an experimental test program carried out on two decks of a prototype precast building. The tests and the numerical models allowed to characterize the fundamental dynamic properties of the slab and its vibrational performance, identifying the most efficient technological solutions among those investigated to mitigate human-induced vibrations

Vibration Performance of Flat Plate Concrete Floors With Codified Minimum Thickness

“…Similarly, Dal Lago et al recently performed heel-drop and walking tests on a number of concrete floors made with voided members and found that the floors had a fundamental frequency of around 8 Hz and an equivalent viscous damping ratio of just 1% in the absence of finishes, furnishing and partitions. The measured root-mean-square acceleration response due to walking was up to 0.051 m/s 2 which exceeded the recommended thresholds for human comfort in an office environment [20]. In another study, the dynamic tests performed on 26 waffle concrete floors revealed a modal damping of at least 3.4% thanks to the contribution of non-structural elements such as partition walls [21].…”