Friction dissipative devices for cladding panels in precast buildings

In the presented study, a second-line back-up system for the seismic protection of cladding panels in RC precast buildings is first presented. The system consists of special anchoring elements and a rope restrainer. The latter is activated only in the case when the existing connections between the primary structure and the panel fail, resulting in the occurrence of relatively large impact forces in the restrainer and in the anchoring elements. In order to adequately design the constitutive parts of the system, a simple yet sufficiently accurate procedure for the estimation of the impact forces is needed. A relatively easy-to-use formula was therefore proposed for this purpose. Next, an extensive parametric study, using response history analysis (RHA), was performed and the influence of several parameters affecting the impact forces in the restrainers was studied. The results obtained in the study were used to evaluate the proposed analytical formula. Considering the simplicity of the proposed formula, its accuracy was good. It can therefore be applied to the design of short restrainers which could be used in reinforced concrete (RC) precast buildings for the protection of cladding panels against the effects of earthquakes.

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Seismic Retrofitting Solutions for Precast RC Industrial Buildings Struck by the 2012 Earthquakes in Northern Italy

Frontiers in Built Environment ◽

10.3389/fbuil.2021.631315 ◽

2021 ◽

Vol 7 ◽

Author(s):

Fabio Minghini ◽

Nerio Tullini

Keyword(s):

Fragility Curves ◽

Seismic Retrofitting ◽

Rc Structures ◽

Existing Structures ◽

The North ◽

Industrial Buildings ◽

Precast Buildings ◽

Damage Data ◽

Emilia Romagna Region ◽

Cladding Panels

In 2012, the North of Italy was hit by a seismic sequence characterized by two main events occurred on May 20 and 29 with MW = 6.1 and 6.0, respectively. Those earthquakes were particularly severe toward precast Reinforced Concrete (RC) structures not designed for seismic resistance. In the past years, the authors implemented a database collecting damage data and typological information on the industrial buildings struck by the Emilia earthquakes. That database was used to develop empirical fragility curves, which highlighted the considerable vulnerability of precast buildings conceived in accordance with pre-seismic code provisions. More recently, the interventions of seismic retrofitting on the same buildings, funded by the Emilia-Romagna region and designed by engineers which were directly hired by the companies, were examined in detail and critically revisited. A selection of these interventions is presented in this paper, which analyzes the effectiveness of the various retrofitting solutions, with a specific attention to the force transfer mechanisms between existing structures and strengthening systems. The interventions are divided between column strengthening (based, for example, on RC or steel jacketing) and interventions aimed at providing the building with a suitable earthquake resistant system (based, for example, on either the use of the existing cladding panels or the implementation of new bracing systems). Graphical representations of the analyzed solutions with the relevant construction details are provided.

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Out-of-plane capacity of cladding panel-to-structure connections in one-story R/C precast structures

Bulletin of Earthquake Engineering ◽

10.1007/s10518-020-00962-5 ◽

2020 ◽

Vol 18 (15) ◽

pp. 6849-6882

Author(s):

Giovanni Menichini ◽

Emanuele Del Monte ◽

Maurizio Orlando ◽

Andrea Vignoli

Keyword(s):

Experimental Tests ◽

Structural Safety ◽

Industrial Building ◽

Seismic Load ◽

Materials Testing ◽

Main Structure ◽

Precast Buildings ◽

Out Of Plane ◽

Cladding Panels ◽

Precast Structures

Abstract The interaction between cladding panels and the main structure is a crucial point to assess the seismic response, and above all the structural safety, of RC precast industrial building. In the past, connections were often designed to allow construction tolerances and to accommodate both thermal and wind-induced displacements. The lack of specific details to allow relative in-plane displacements between cladding panels and the main structure often led to the participation of cladding panels in the structure seismic-resistant system with consequent connection failures. In the last decades, a lot of experimental tests were performed to investigate the in-plane performance of panel connections, and some design recommendations have been developed accordingly. In the out-of-plane direction, the connections were often considered to be infinitely rigid and not to suffer any damage by the seismic load. This work deals with the out-of-plane response of panel-to-structure connections for vertical panels typical of industrial and commercial precast buildings. Both standard hammer-head strap and new devices, called SismoSafe, were investigated. Tests were performed in the Structures and Materials Testing Laboratory of the Department of Civil and Environmental Engineering of Florence, where a specific setup was designed to perform cyclic and monotonic tests on the connection devices. Standard connections showed a rather limited resistance, while the innovative connections exhibited a high out-of-plane resistance. Numerical analyses were also performed on a case study building to evaluate the distribution of the out-of-plane demand on the connections.

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Recent Advances in the Research of the Seismic Response of RC Precast Buildings at the University of Ljubljana

Frontiers in Built Environment ◽

10.3389/fbuil.2021.630952 ◽

2021 ◽

Vol 7 ◽

Author(s):

Blaž Zoubek ◽

Anže Babič ◽

Matjaž Dolšek ◽

Matej Fischinger ◽

Tatjana Isaković

Keyword(s):

Seismic Response ◽

Fragility Curves ◽

Precast Concrete ◽

Structural System ◽

Design Procedures ◽

Cyclic Behaviour ◽

Displacement Capacity ◽

Precast Buildings ◽

Cladding Panels ◽

The University

Although in Europe, precast concrete buildings had been built for decades, their seismic response was poorly understood, which is reflected in ambiguous code requirements and conservative design approaches. Therefore, this structural system was the main focus of several European research projects in the past 2 decades. The University of Ljubljana was actively involved in these projects. The key results of the work performed at the University of Ljubljana are presented and discussed in this paper. The main contributions include: a) the development of a new capacity model of beam-column dowel connections, which are one of the critical parts of the RC precast structural system, b) new insight into the cyclic behaviour of fastening systems of concrete cladding panels, and new design procedures for the estimation of strength and displacement capacity of cladding fasteners, c) the development of a methodology for seismic fragility analysis of RC precast buildings, and the fragility curves of precast RC building classes, which can be used for the safety-calibration of the new design procedures of RC precast buildings, and d) the development of a relatively simple and economically attractive back-up (strengthening) system to prevent the falling of panels in case of a strong earthquake.

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Friction dissipative devices for cladding panels in precast buildings. An experimental investigation

European Journal of Environmental and Civil engineering ◽

10.3166/ejece.15.1319-1338 ◽

2011 ◽

Vol 15 (9) ◽

pp. 1319-1338

Author(s):

Liberato Ferrara ◽

Roberto Felicetti ◽

Giandomenico Toniolo ◽

Carla Zenti

Keyword(s):

Experimental Investigation ◽

Precast Buildings ◽

Cladding Panels

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Seismic Behavior of Precast Buildings With Dissipative Connections

Frontiers in Built Environment ◽

10.3389/fbuil.2021.639777 ◽

2021 ◽

Vol 7 ◽

Author(s):

Lorenzo De Stefani ◽

Roberto Scotta

Keyword(s):

Sensitivity Analyses ◽

Plastic Behavior ◽

Seismic Action ◽

Axial Forces ◽

Precast Buildings ◽

Non Linear ◽

Frame System ◽

Cladding Panels ◽

Recent Earthquakes ◽

Precast Structures

Recent earthquakes in southern Europe highlighted that the connections of cladding panels to R.C. frames in precast buildings had a major role in the structural collapse. For this reason, there is an urgent need for a review of the design methods for these connections as well as for an improvement in the manufacturing technology. This article aimed to assess the efficiency of dissipative panel-to-structure and roof connections in R.C. precast buildings. A parametric study consisting of linear and non-linear analyses on one case-study building is performed. Different sensitivity analyses are performed varying their mechanical properties (i.e., stiffness, strength, and ductility) to analyze the behavior of the CP/frame connections. The study focuses on dissipative connections with an elastic–plastic behavior, placed between cladding panels (CPs) and frames in precast buildings with stacked horizontal cladding panels. The introduction of dissipative CP/frame connections implies the inclusion of panels in the global seismic resisting system. The “panels + frame” system highlights a high stiffness until the yield strength of the CP/frame connections is reached. The results, obtained from non-linear dynamic analyses (NLDAs), clearly show how the proposed connection improves the structural seismic performance. By contrast, this is no longer true for R.C. precast structures with flexible diaphragms, especially for intermediate columns, far from panels aligned to seismic action. In this case, significant and unexpected axial forces arise on out-of-plane connections between panels and columns. The integration of an efficient diaphragm is essential to prevent these critical issues both on intermediate columns and CP/column connections; it enables the dissipative capacity of the “panels + frame” system, and it significantly limits the forces and displacements of intermediate alignments. Unfortunately, the achievement of a rigid diaphragm is not always feasible in precast buildings. A possible alternative to activate dissipative capacities of the roof diaphragm with limited in-plane stiffness is the use of dissipative connections linking roof beams and main beams. The solutions described in this article can be applied both in the design of new buildings and for the seismic upgrading of existing ones with easy-to-install and low-impact applications.

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Influence of cladding panels on the first period of one-story precast buildings

Bulletin of Earthquake Engineering ◽

10.1007/s10518-014-9657-2 ◽

2014 ◽

Vol 13 (5) ◽

pp. 1531-1555 ◽

Cited By ~ 26

Author(s):

Gennaro Magliulo ◽

Marianna Ercolino ◽

Gaetano Manfredi

Keyword(s):

Precast Buildings ◽

Cladding Panels

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Seismic Performance of Single-Story Precast Buildings: Effect of Cladding Panels

Journal of Structural Engineering ◽

10.1061/(asce)st.1943-541x.0002114 ◽

2018 ◽

Vol 144 (9) ◽

pp. 04018134 ◽

Cited By ~ 1

Author(s):

Marianna Ercolino ◽

Gennaro Magliulo ◽

Gaetano Manfredi

Keyword(s):

Seismic Performance ◽

Precast Buildings ◽

Cladding Panels

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Effects of Precast Cladding Systems on Dynamic Characteristics of Steel Frame Buildings by Ambient and Free Vibration Tests

Shock and Vibration ◽

10.1155/2017/5231727 ◽

2017 ◽

Vol 2017 ◽

pp. 1-20 ◽

Cited By ~ 1

Author(s):

Jun Ma ◽

Shinji Nakata ◽

Akihito Yoshida ◽

Yukio Tamura

Keyword(s):

Free Vibration ◽

Dynamic Characteristics ◽

Steel Frame ◽

Ambient Vibration ◽

Test Cases ◽

Vibration Method ◽

External Wall ◽

Wide Range ◽

Cladding Panels ◽

Vibration Tests

Full-scale tests on a one-story steel frame structure with a typical precast cladding system using ambient and free vibration methods are described in detail. The cladding system is primarily composed of ALC (Autoclaved Lightweight Concrete) external wall cladding panels, gypsum plasterboard interior linings, and window glazing systems. Ten test cases including the bare steel frame and the steel frame with addition of different parts of the precast cladding system are prepared for detailed investigations. The amplitude-dependent dynamic characteristics of the test cases including natural frequencies and damping ratios determined from the tests are presented. The effects of the ALC external wall cladding panels, the gypsum plasterboard interior linings, and the window glazing systems on the stiffness and structural damping of the steel frame are discussed in detail. The effect of the precast cladding systems on the amplitude dependency of the dynamic characteristics and the tendencies of the dynamic parameters with respect to the structural response amplitude are investigated over a wide range. Furthermore, results estimated from the ambient vibration method are compared with those from the free vibration tests to evaluate the feasibility of the ambient vibration method.

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Effect of Weathering on Surface Functional Groups of Charred Norway Spruce Cladding Panels

Forests ◽

10.3390/f11121373 ◽

2020 ◽

Vol 11 (12) ◽

pp. 1373

Author(s):

Maija Kymäläinen ◽

Hannu Turunen ◽

Lauri Rautkari

Keyword(s):

Norway Spruce ◽

Functional Groups ◽

Future Research ◽

Process Conditions ◽

Feed Speed ◽

Cladding Panels ◽

Prototype Device ◽

Modified Lignin ◽

Charred Wood ◽

Poor Stability

Norway spruce cladding panels were surface charred with a prototype device utilizing a hot plate method. The panels were used to construct a test wall that was exposed to natural weathering for a period of two years. The changes in functional groups were evaluated with photoacoustic FTIR spectroscopy. The analysis revealed degradation of the thermally modified lignin component, indicating poor stability in weathering. Improvements in the prototype device process conditions, such as increased surface pressure and slower feed speed, and future research needs regarding surface charred wood are discussed.

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