Efficacy of roof-to-beam mechanical connections on the diaphragm behaviour of precast decks with spaced roof elements

Abstract

The diaphragm action of slab/roof decks ensures the collaboration of different parts of the lateral load resisting system of a building. In reinforced concrete precast buildings for industrial/commercial halls, not seldom the deck is not provided with a cast-in-situ topping: this results into diaphragm action to rely upon the floor mechanical connections alone. In this study, the effectiveness of three different typical floor-beam connections, namely hot-rolled angle brackets, cold-formed angle brackets and dowel bars, on the diaphragm action of the deck has been investigated. To this purpose, simplified macroscopic "behaviour models" have been proposed, based on the results of monotonic and cyclic tests carried out within the framework of the research project Safecast (FP7-SME-2007-2; GA 218417/2009). A numerical model of a dry-assembled precast structure with mechanical floor-to-beam connections has been checked against the results of cyclic and pseudodynamic tests carried out on a full-scale prototype within the framework of the Precast Structures EC8 project (GA G6RD-CT-2002-70002). Non-linear dynamic analyses have then been performed to investigate the diaphragm action effectiveness of the three different technological solutions to connect slab and beams as above considering a seismic action orthogonal to the roof elements. Different stiffness distributions of the lateral load resisting system have been considered, investigating the possible bracing effect induced by an integrated connection system of the external cladding panels. A simplified "design-wise" analytical interpretation of the phenomenon is also formulated and checked against the numerical results.

Conceptual design and full‐scale experimentation of cladding panel connection systems of precast buildings

“…FBD [29,30,34] and FPA [28,34] with plastic dissipation have been used. The detailed model criteria and outcomes can be found in Dal Lago and Ferrara [35]. This also allowed for a step-by-step monitoring of the ongoing tests with respect to the expected response, and it supports the final interpretations.…”

“…The problem is that it is presently difficult to find products on the market that fulfill the requirements of large displacements or high forces described earlier; moreover, the dissipative connections are out of the consolidated construction praxis. However, the effectiveness of the walls' contribution within a real building depends on its general lay-out, on the action direction, and on the degree of the roof diaphragm stiffness [35,36]. Enhanced solutions that allow larger displacement capacity were proposed in Refs [22,23].…”

“…However, the effectiveness of the walls' contribution within a real building depends on its general lay-out, on the action direction, and on the degree of the roof diaphragm stiffness [35,36]. However, the effectiveness of the walls' contribution within a real building depends on its general lay-out, on the action direction, and on the degree of the roof diaphragm stiffness [35,36].…”

Seismic performance of precast concrete structures with energy dissipating cladding panel connection systems

“…. Significant research efforts have been also devoted to clarify the role of the roof diaphragm action in the seismic response of precast systems . This paper addresses such problems focusing on the use of energy dissipating connection systems .…”

End support connection of precast roof elements by bolted steel angles

“…Preliminary experimental information about the local behavior of the floor‐to‐beam connections was reported in Reference , and design rules were proposed in Reference . The role of these connections on the efficiency of the diaphragm is described in References .…”