Robustness of Dry-Assembled Precast Wall and Coupled Wall-Frame High-Rise Structures With Voided Prestressed Slabs

Precast concrete structures are recognized among the structural typologies that may mostly suffer from progressive collapse as a consequence of local unpredicted damage, also due to past accidents occurred in buildings employing old precast technologies neglecting the basic robustness criteria and characterized by poorly detailed and/or executed joints and connections. Although vertical ties may relatively easily be provided in both frame and wall panel structures by employing ductile connection devices, dry-assembled precast systems avoiding concrete pouring in the whole superstructure typically struggle to provide horizontal ties as strong as required by the current standards concerning progressive collapse, in which they are not fully framed yet. Nevertheless, these systems may exploit alternative sources of robustness to stop collapse progression arising from their structural arrangement, the shape of the slab elements employed, and the slab mechanical connections. This article presents the results of a numerical investigation focused on the structural behavior of a dry-assembled precast floor system consisting of prestressed box-section slab elements employed in either wall panel or coupled wall-frame structural systems following the loss of one or multiple primary load-bearing vertical elements. Nonlinear static simulations of different loss scenarios occurring in prototypes of 100-m-tall high-rise buildings were carried out based upon spread plasticity modeling of the structural elements and experimentally calibrated nonlinear behavior of mechanical connections.