The present research is aimed at evaluating the influence of different modelling assumptions, such as crane-load and beam-column connections, on the local seismic response of precast RC buildings. The considered case study is a one-story industrial building designed in accordance with the Italian building code NTC 2008. Typical pinned beam-column connections are investigated. They are made by dowels protruding from the column inserted into holes in the beams, which are subsequently grouted. This technique ensures stability during the construction process and allows the horizontal seismic load transfer from the beam to the column. Different structural layouts have been modeled considering various types of beamcolumn joint models, namely a perfect hinge, an elastic hinge and a non-linear spring with a degrading hysteretic force-displacement model; the last model reproduces the results of recent experimental campaigns. Non-linear dynamic time history analyses allow to evaluate displacements, drifts, deformations and ultimate curvatures. The results are analyzed in terms of both global quantities, i.e. roof maximum displacements and rotation at the base of the columns, and local quantities, i.e. force or displacement demand at the beam-column connections, for the various implemented models. Depending on the considered model, it is observed that the effects of higher vibrating modes may increase the load in the connections.
This research evaluates the influence of different modelling assumptions on the global and local seismic risk assessment of code-conforming precast reinforced concrete buildings, specifically single-story industrial buildings. In particular the modelling of the system mass, the overhead crane, the beam-to-column and roof-to-beam connections and the cladding system are investigated. For this purpose, a case study resembling a new industrial building designed in accordance with the current Italian building code was selected. Typical dowel beam-to-column connections were considered and the influence of various modelling strategies investigated: perfect hinges, linear elastic connections and non-linear connections with a degrading hysteretic force-displacement model which was calibrated from available data on experimental tests. Three different types of roof-to-beam connections were investigated removing the assumption of rigid diaphragm, namely hot-rolled, cold-formed and socket welded connections. Initially, simplified planar models of single frames were considered to evaluate the influence of the different modelling strategies, then 3D models of the entire building were analyzed. Multiple-stripe non-linear dynamic time history analyses allowed to evaluate displacements, drifts, deformations and ultimate curvatures of the main elements and connections for various intensity measure levels. The seismic risk was assessed in terms of failure rate considering the collapse of both the columns and of the connections. The results show that the beam-to-column connections fail right after reaching yielding due to their low displacement ductility, leading to the loss of support of the beam and therefore increasing the collapse rate of the investigated structural typology.
The 2012 Emilia earthquakes caused significant damage to existing precast reinforced concrete (RC) industrial buildings not specifically designed to resist seismic actions. The main failure mechanisms were related to the loss of support of beams and roof elements caused by high relative displacements, to the failure of the mechanical connections and consequent fall of cladding panels, to the damage at the base of the columns and to the collapse of RC forks at the top of the columns. In all cases, the behavior of the connections, and specifically of beam-to-column connections, demonstrated to be crucial, given that they may inhibit the exploitation of strength and ductility reserves in precast elements. This paper presents a beam-to-column connection restraint-device for precast industrial buildings. The device can be applied to existing structures to transfer horizontal seismic forces between beams and columns and to increase the energy dissipation of the system. Design criteria were defined with the aim to limit the relative maximum displacement at the beam-to-column interface and to mitigate the out-of-plane overturning of the beam. Numerical analyses were carried out to define a suitable shape of the device and to investigate its effectiveness in terms of both local and global behavior. To validate the computational results, experimental tests have been also carried out. The tests allowed to classify the device as “dissipative” according to UNI EN 15129. Finally, the design procedure has been validated considering a one-story industrial building case study designed in accordance with the Italian building code.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.