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

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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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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Experimental Fragility Analysis of Suspension Ceiling Systems

Earthquake Spectra ◽

10.1193/071514eqs109m ◽

2016 ◽

Vol 32 (2) ◽

pp. 881-908 ◽

Cited By ~ 14

Author(s):

Siavash Soroushian ◽

Esmaeel Rahmanishamsi ◽

Ki P. Ryu ◽

Manos Maragakis ◽

Andrei M. Reinhorn

Keyword(s):

Seismic Response ◽

Fragility Curves ◽

Vertical Direction ◽

Fragility Analysis ◽

Code Design ◽

Amplification Factors ◽

Acceleration Amplification ◽

Overall Performance ◽

The University ◽

Early Damage

The seismic response of suspended ceiling systems that were shaken at the University at Buffalo; University of Nevada, Reno; and E-Defense facilities is critically assessed in this paper. After presenting a brief description of each experiment, the most repetitive damage observations in all experiments are discussed. Fragility curves are developed for ceiling perimeter connectors, supporting elements, and overall performance of ceiling systems by using 346 combinations of ceiling configurations and shake intensities. The key findings of these curves are the insufficient support of the 7/8-in. wall angles, unconservative code design capacity of connections for supporting elements, and early damage of ceiling systems because of ceiling-piping interaction. Acceleration amplification factors of ceiling systems with respect to suspending floor are computed. The amplification factors prescribed by the code were found to be unconservative due to the pounding of panels to the ceiling grids and deck vibration in a vertical direction.

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Friction dissipative devices for cladding panels in precast buildings

European Journal of Environmental and Civil engineering ◽

10.1080/19648189.2011.9714857 ◽

2011 ◽

Vol 15 (9) ◽

pp. 1319-1338

Author(s):

Liberato Ferrara ◽

Roberto Felicetti ◽

Giandomenico Toniolo ◽

Carla Zenti

Keyword(s):

Precast Buildings ◽

Cladding Panels

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Experimental investigation of seismic performance of a novel isostatic frame-cladding system

Advances in Structural Engineering ◽

10.1177/13694332211057264 ◽

2022 ◽

pp. 136943322110572

Author(s):

Xun Chong ◽

Pu Huo ◽

Linlin Xie ◽

Qing Jiang ◽

Linbing Hou ◽

...

Keyword(s):

Seismic Performance ◽

Damage Evolution ◽

Failure Modes ◽

Static Load ◽

Precast Concrete ◽

Frame Structure ◽

Deformation Capacity ◽

Load Bearing Capacity ◽

Cladding Panels ◽

Energy Dissipation Capacity

A new connection measure between the precast concrete (PC) cladding panel and PC frame structure is proposed to realize a new kind of isostatic frame-cladding system. Three full-scale PC wall-frame substructures were tested under the quasi-static load. These substructures included a bare wall-frame specimen, a specimen with a cladding panel that has no opening, and a specimen with a cladding panel that has an opening in it. The damage evolution, failure mode, load-bearing capacity, deformation capacity, and energy dissipation capacity of three specimens were compared. The results indicated that the motions of the cladding panels and the main structures were uncoupled through the relative clearance of the bottom connections, and three specimens exhibited approximately identical failure modes and seismic performance. Thus, the reliability of this new isostatic system was validated.

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Innovative structural system consisting of CFT columns and precast concrete beams

Structures and Architecture ◽

10.1201/b20891-148 ◽

2016 ◽

pp. 1069-1076

Author(s):

L Bezerra ◽

M Debs ◽

A Debs

Keyword(s):

Concrete Beams ◽

Precast Concrete ◽

Structural System

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Seismic Behavior of Mid-Rise Precast Reinforced Concrete Building with Effect of Joints and Supports

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.d7846.118419 ◽

2019 ◽

Vol 8 (4) ◽

pp. 3633-3637

Keyword(s):

Reinforced Concrete ◽

Response Spectrum ◽

Precast Concrete ◽

Mode Shapes ◽

Base Shear ◽

Reinforced Concrete Building ◽

Axial Forces ◽

Building Models ◽

Precast Buildings ◽

Concrete Building

Precast concrete structures are widely used in construction. It consists of prefabricated elements casted in industry and connected to each other to form a homogeneous structure. Connections function is to transfer moments and axial forces. Many engineers assume precast connection as pinned, but in reality, they are semi-rigid connections that transfer forces to other members. Lack of design and detailing of connection leads to improper behaviour of the structure, which then leads to the collapse of the building. Past earthquake studies show that many precast buildings performed poorly, and the main reasons were connections. This paper mainly focuses on understanding the seismic behaviour of mid-rise i.e seven-storey precast reinforced concrete buildings with various beam-column joints i.e rigid, semi-rigid, pinned and column-base supports i.e, fixed and hinged supports. Building is modelled and analyzed using ETABS v17 software. Rotational stiffness of precast billet connection is adopted for modelling of semi-rigid beam-column connections. Response spectrum and modal analysis are carried out. Results of displacements, storey drift, storey shear, storey stiffness, base shear, time periods and first mode shapes of models are discussed. It is observed, precast reinforced concrete building models with semi rigid connection performs better than building models with pinned connections and building models with fixed supports reduces the structural response to a great extent.

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The Use of Moment-Resisting Frames and Braced Frames for Lateral Stability of Multy-Storey Precast Concrete Structures

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.259.173 ◽

2017 ◽

Vol 259 ◽

pp. 173-177

Author(s):

Arthur L. Rocha ◽

Marcelo de A. Ferreira ◽

Wilian dos S. Morais ◽

Bruna Catoia

Keyword(s):

High Performance ◽

Precast Concrete ◽

Tall Buildings ◽

Shear Walls ◽

Order Effects ◽

Lateral Stability ◽

Infill Walls ◽

Precast Buildings ◽

Moment Resisting ◽

Lateral Displacements

Precast structures for multi-storey buildings can be designed with economy, safety and high performance. However, depending on the height of the building and the intensity of the lateral loads, the lateral stability system must be carefully chosen in order to maximize the global structural performance. In Brazil, the most common method for lateral stability is achieved by moment resisting precast-frames, wherein the moment-rotation response of the beam-column connections are responsible to provide the frame action, which will govern the distribution of internal forces and the sway distribution along the building height. On the other hand, in Europe, bracing systems comprised by shear walls or infill walls are mostly used, wherein beam-column connections are designed as hinged. The aim of this paper is to present a comparison between these methods for lateral stability, applying nine structural simulations with moment resisting precast-frames, shear walls and infill walls solutions, divided in three groups - 3 building with 5 storeys (21 meters high), 3 buildings with 10 storeys (41 meters high) and 3 building with 20 storeys (81 meters high). All first storeys are 5 meters high, while all the others are 4 meters high. The results from all structural analyses are compared. As conclusion, while moment-resisting beam-column connections are more feasible for applying in low-rise precast buildings, the use of shear walls and infill walls are more efficient for tall buildings due to decrease of lateral displacements, having a reduction of second order effects but also increasing the reactions at the foundations of bracing elements.

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PRODUCTIVITY AND STRUCTURAL PERFORMANCE OF STEEL/PRECAST CONCRETE HYBRID STRUCTURAL SYSTEM USING FLAT-STEEL-PLATE-CONNECTIONS

AIJ Journal of Technology and Design ◽

10.3130/aijt.5.157 ◽

1999 ◽

Vol 5 (7) ◽

pp. 157-160

Author(s):

Koichi SUZUKI ◽

Tomohiro YOSHIDA ◽

Akio TOMITA ◽

Yukitada OGIHARA

Keyword(s):

Steel Plate ◽

Precast Concrete ◽

Structural Performance ◽

Structural System ◽

Flat Steel ◽

Plate Connections

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Stochastic Vulnerability Assessment of Masonry Structures: Concepts, Modeling and Restoration Aspects

Applied Sciences ◽

10.3390/app9020243 ◽

2019 ◽

Vol 9 (2) ◽

pp. 243 ◽

Cited By ~ 42

Author(s):

Panagiotis G. Asteris ◽

Antonia Moropoulou ◽

Athanasia D. Skentou ◽

Maria Apostolopoulou ◽

Amin Mohebkhah ◽

...

Keyword(s):

Cultural Heritage ◽

Seismic Vulnerability ◽

Fragility Curves ◽

Methodological Approach ◽

Seismic Action ◽

Masonry Structures ◽

Structural System ◽

Brittle Behavior ◽

Masonry Material ◽

Probabilistic Nature

A methodology aiming to predict the vulnerability of masonry structures under seismic action is presented herein. Masonry structures, among which many are cultural heritage assets, present high vulnerability under earthquake. Reliable simulations of their response to seismic stresses are exceedingly difficult because of the complexity of the structural system and the anisotropic and brittle behavior of the masonry materials. Furthermore, the majority of the parameters involved in the problem such as the masonry material mechanical characteristics and earthquake loading characteristics have a stochastic-probabilistic nature. Within this framework, a detailed analytical methodological approach for assessing the seismic vulnerability of masonry historical and monumental structures is presented, taking into account the probabilistic nature of the input parameters by means of analytically determining fragility curves. The emerged methodology is presented in detail through application on theoretical and built cultural heritage real masonry structures.

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