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Prof. Massimo Fragiacomo
University of L'Aquila DICEAA - Department of Civil, Construction-Architecture & Environmental Engineering

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0 Earthquake Engineering
0 Timber
0 Timber Frame
0 Timber Structures
0 Wood

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Timber
Wood
Timber Structures
Timber concrete structures
Wood and Concrete
Timber Frame
Timber engineering
Timber composite structure

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Journal article
Published: 23 August 2021 in Symmetry
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Given the growing spread of glass as a construction material, the knowledge of structural response must be ensured, especially under dynamic accidental loads. In this regard, an increasingly popular method to probabilistically characterize the seismic response of a given structure is based on the use of “fragility” or “seismic vulnerability” curves. Most existing applications, however, typically refer to construction and structural members composed of traditional building materials. The present study extends and adapts such a calculation method to innovative structural glass systems, which are characterized by specific material properties and expected damage mechanisms, restraint details, and dynamic features. Suitable Engineering Demand Parameters (EDPs) for seismic design are thus required. In this paper, a major advantage is represented by the use of Cloud Analysis in the Cornell’s reliability method, for the seismic assessment of two different case-study glass systems. Cloud Analysis is known to represent a simple and immediate tool to analytically investigate a given (glass) structure by taking into account variations in seismic motions and uncertainties of structural parameters. Such a method is exploited by means of detailed three-dimensional (3D) Finite Element (FE) numerical models and non-linear dynamic analyses (ABAQUS/Standard). Critical issues and typical failure mechanisms for in-plane seismically loaded glass systems are discussed. The validity of reference EDPs are addressed for the examined solutions. Based on a broad seismic investigation (60 records in total), fragility curves are developed from parametric results, so as to support a multi-hazard performance-based design (PBD) procedure.

ACS Style

Silvana Mattei; Chiara Bedon. Analytical Fragility Curves for Seismic Design of Glass Systems Based on Cloud Analysis. Symmetry 2021, 13, 1541 .

AMA Style

Silvana Mattei, Chiara Bedon. Analytical Fragility Curves for Seismic Design of Glass Systems Based on Cloud Analysis. Symmetry. 2021; 13 (8):1541.

Chicago/Turabian Style

Silvana Mattei; Chiara Bedon. 2021. "Analytical Fragility Curves for Seismic Design of Glass Systems Based on Cloud Analysis." Symmetry 13, no. 8: 1541.

Journal article
Published: 18 August 2021 in Sustainability
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Current standards for seismic-resistant buildings provide recommendations for various structural systems, but no specific provisions are given for structural glass. As such, the seismic design of joints and members could result in improper sizing and non-efficient solutions, or even non-efficient calculation procedures. An open issue is represented by the lack of reliable and generalized performance limit indicators (or “engineering demand parameters”, EDPs) for glass structures, which represent the basic input for seismic analyses or q-factor estimates. In this paper, special care is given to the q-factor assessment for glass frames under in-plane seismic loads. Major advantage is taken from efficient finite element (FE) numerical simulations to support the local/global analysis of mechanical behaviors. From extensive non-linear dynamic parametric calculations, numerical outcomes are discussed based on three different approaches that are deeply consolidated for ordinary structural systems. Among others, the cloud analysis is characterized by high computational efficiency, but requires the definition of specific EDPs, as well as the choice of reliable input seismic signals. In this regard, a comparative parametric study is carried out with the support of the incremental dynamic analysis (IDA) approach for the herein called “dynamic” (M1) and “mixed” (M2) procedures, towards the linear regression of cloud analysis data (M3). Potential and limits of selected calculation methods are hence discussed, with a focus on sample size, computational cost, estimated mechanical phenomena, and predicted q-factor estimates for a case study glass frame.

ACS Style

Silvana Mattei; Marco Fasan; Chiara Bedon. On the Use of Cloud Analysis for Structural Glass Members under Seismic Events. Sustainability 2021, 13, 9291 .

AMA Style

Silvana Mattei, Marco Fasan, Chiara Bedon. On the Use of Cloud Analysis for Structural Glass Members under Seismic Events. Sustainability. 2021; 13 (16):9291.

Chicago/Turabian Style

Silvana Mattei; Marco Fasan; Chiara Bedon. 2021. "On the Use of Cloud Analysis for Structural Glass Members under Seismic Events." Sustainability 13, no. 16: 9291.

Journal article
Published: 12 July 2021 in Engineering Structures
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The aim of this paper is to propose formulations for the slip modulus prediction of timber-to-timber connections (TTC) and steel-to-timber connections (STC) with inclined screws and possible interlayers. The beam on elastic foundation model, previously developed for timber-to-concrete connections, was extended to consider the flexibility of both media where the screw is inserted. Since a significant influence of the fastener diameter on the foundation modulus was observed in tests, an interpolating formula correlating the foundation modulus with timber density and the fastener diameter was derived. The exact solution of the timber-to-timber analytical model was found to agree well with experimental results for total and double thread screws. A parametric study was undertaken to prove that connections with inclined screws have significantly higher slip modulus and lower degradation of performance as the diameter decreases or the thickness of the intermediate layer increases compared to connections with screws perpendicular to the sliding plane. Furthermore, the slip modulus of inclined screws was found to be limited by the weakest timber layer. Closed form expressions for the prediction of the slip modulus were derived by interpolation for the most important cases of technical interest. These formulas can be proposed for the implementations in codes of practice such as the Eurocode 5, since simplified formulas of the slip modulus are currently missing for connections with inclined fasteners and interlayers.

ACS Style

Yuri De Santis; Massimo Fragiacomo. Timber-to-timber and steel-to-timber screw connections: Derivation of the slip modulus via beam on elastic foundation model. Engineering Structures 2021, 244, 112798 .

AMA Style

Yuri De Santis, Massimo Fragiacomo. Timber-to-timber and steel-to-timber screw connections: Derivation of the slip modulus via beam on elastic foundation model. Engineering Structures. 2021; 244 ():112798.

Chicago/Turabian Style

Yuri De Santis; Massimo Fragiacomo. 2021. "Timber-to-timber and steel-to-timber screw connections: Derivation of the slip modulus via beam on elastic foundation model." Engineering Structures 244, no. : 112798.

Journal article
Published: 07 July 2021 in Soil Dynamics and Earthquake Engineering
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Practice-oriented finite element (FE) modelling strategies represent a fundamental tool for the seismic analysis and design of Cross Laminated Timber (CLT) structures. Although substantial research has been undertaken concerning the seismic behaviour of CLT buildings, practice-oriented FE modelling strategies are still at an early stage. This paper presents an upgrade of an existing practice-oriented FE design model for the seismic design of CLT structures. The upgrade is supported through the same modelling strategy presented by Christovasilis et al. (2020) adding some features of analytical equations models presented by Casagrande et al. (2016). 2D elements are used both for the modelling of CLT panels and for mechanical connections, which are represented by a horizontal strip with a height smaller than 7% of the height of the panel. Analytical equations for determining the elastic modulus of elasticity and the shear modulus of the horizontal strip are reported accounting for both rocking and sliding behaviour for single- and multi-panel CLT shearwalls, including the effect of the vertical loads by using a secant stiffness. The validation of the proposal is carried out in terms of the shearwall lateral stiffness through the results of experimental tests on full-scale shearwalls published by other authors and through a validation/comparison between a detailed non-linear model and the Christovasilis et al. (2020) strategy on two multi-storey seismic-resistant lateral systems configurations with different amount of vertical loads. Finally, a proposal for the initial layout of connections to reduce the iterative seismic design and analysis process for CLT buildings is presented through a case study.

ACS Style

Vincenzo Rinaldi; Daniele Casagrande; Catia Cimini; Maurizio Follesa; Massimo Fragiacomo. An upgrade of existing practice-oriented FE design models for the seismic analysis of CLT buildings. Soil Dynamics and Earthquake Engineering 2021, 149, 106802 .

AMA Style

Vincenzo Rinaldi, Daniele Casagrande, Catia Cimini, Maurizio Follesa, Massimo Fragiacomo. An upgrade of existing practice-oriented FE design models for the seismic analysis of CLT buildings. Soil Dynamics and Earthquake Engineering. 2021; 149 ():106802.

Chicago/Turabian Style

Vincenzo Rinaldi; Daniele Casagrande; Catia Cimini; Maurizio Follesa; Massimo Fragiacomo. 2021. "An upgrade of existing practice-oriented FE design models for the seismic analysis of CLT buildings." Soil Dynamics and Earthquake Engineering 149, no. : 106802.

Journal article
Published: 01 July 2021 in Journal of Structural Engineering
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Due to the high in-plane stiffness and strength capacity of cross-laminated timber (CLT) panels, the mechanical behavior of CLT shear walls is mainly influenced by the mechanical performances of the connections. Several calculation models have been proposed considering the mechanical anchors effectiveness only along their primary direction. However, recent studies showed a relatively high stiffness and capacity of new typologies of angle brackets when subjected to uplift vertical loads, such as for the wall-to-floor Titan V (TTV) angle bracket, developed to obtain high mechanical performances along both the vertical-tensile and horizontal-shear direction. In this paper a study on CLT shear walls anchored with TTV angle bracket is presented. The aim of the work is to investigate the effects of the coupled shear-tension behavior of the connections at the wall level and the effectiveness of TTV as an alternative to traditional mechanical anchors. The paper presents results from full-scale experimental tests and finite-element (FE) numerical analyses in SAP2000, where an innovative macroelement has been developed to model the TTV coupled shear-tension behavior. The effects of the plastic load redistributions of the TTV angle bracket on the global mechanical behavior of the CLT shear wall are discussed.

ACS Style

Giuseppe D’Arenzo; Daniele Casagrande; Andrea Polastri; Marinella Fossetti; Massimo Fragiacomo; Werner Seim. CLT Shear Walls Anchored with Shear-Tension Angle Brackets: Experimental Tests and Finite-Element Modeling. Journal of Structural Engineering 2021, 147, 04021089 .

AMA Style

Giuseppe D’Arenzo, Daniele Casagrande, Andrea Polastri, Marinella Fossetti, Massimo Fragiacomo, Werner Seim. CLT Shear Walls Anchored with Shear-Tension Angle Brackets: Experimental Tests and Finite-Element Modeling. Journal of Structural Engineering. 2021; 147 (7):04021089.

Chicago/Turabian Style

Giuseppe D’Arenzo; Daniele Casagrande; Andrea Polastri; Marinella Fossetti; Massimo Fragiacomo; Werner Seim. 2021. "CLT Shear Walls Anchored with Shear-Tension Angle Brackets: Experimental Tests and Finite-Element Modeling." Journal of Structural Engineering 147, no. 7: 04021089.

Research article
Published: 30 May 2021 in Advances in Structural Engineering
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Experimental out-of-plane, four-points bending tests were performed on two series of three-layered Cross Laminated Timber (CLT) panels made of Calabrian Beech and Calabrian Beech and Corsican Pine respectively. The predominant failure mechanism was rolling shear alongthe innerlayer and the glue line. A linear elastic model of a three-layered, CLT panel was developed to describe the stress distribution in CLT slabs in bending, with a focus on their load-bearing performance before the propagation of cracks. In the analytical model, each timber layer was defined as an Euler-Bernoulli beam. The two glue lines were modeled using extensional springs, infinitely rigid in the direction perpendicular to the beam’s axis, and with a defined stiffness in the tangential direction. The outer layers are assumed axially flexible whilethe innerone is regarded as axially rigid. The results of the proposed model were thus compared and validated with the experimental evidence and with additional FE numerical predictions given by 3D numerical simulations carried out in Abaqus.

ACS Style

Martina Sciomenta; Angelo Di Egidio; Chiara Bedon; Massimo Fragiacomo. Linear model to describe the working of a three layers CLT strip slab: Experimental and numerical validation. Advances in Structural Engineering 2021, 1 .

AMA Style

Martina Sciomenta, Angelo Di Egidio, Chiara Bedon, Massimo Fragiacomo. Linear model to describe the working of a three layers CLT strip slab: Experimental and numerical validation. Advances in Structural Engineering. 2021; ():1.

Chicago/Turabian Style

Martina Sciomenta; Angelo Di Egidio; Chiara Bedon; Massimo Fragiacomo. 2021. "Linear model to describe the working of a three layers CLT strip slab: Experimental and numerical validation." Advances in Structural Engineering , no. : 1.

Journal article
Published: 26 May 2021 in Infrastructures
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The number of effective factors and their nonlinear behaviour—mainly the nonlinear effect of the factors on concrete properties—has led researchers to employ complex models such as artificial neural networks (ANNs). The compressive strength is certainly a prominent characteristic for design and analysis of concrete structures. In this paper, 1030 concrete samples from literature are considered to model accurately and efficiently the compressive strength. To this aim, a Feed-Forward (FF) neural network is employed to model the compressive strength based on eight different factors. More in detail, the parameters of the ANN are learned using the bat algorithm (BAT). The resulting optimized model is thus validated by comparative analyses towards ANNs optimized with a genetic algorithm (GA) and Teaching-Learning-Based-Optimization (TLBO), as well as a multi-linear regression model, and four compressive strength models proposed in literature. The results indicate that the BAT-optimized ANN is more accurate in estimating the compressive strength of concrete.

ACS Style

Nasrin Aalimahmoody; Chiara Bedon; Nasim Hasanzadeh-Inanlou; Amir Hasanzade-Inallu; Mehdi Nikoo. BAT Algorithm-Based ANN to Predict the Compressive Strength of Concrete—A Comparative Study. Infrastructures 2021, 6, 80 .

AMA Style

Nasrin Aalimahmoody, Chiara Bedon, Nasim Hasanzadeh-Inanlou, Amir Hasanzade-Inallu, Mehdi Nikoo. BAT Algorithm-Based ANN to Predict the Compressive Strength of Concrete—A Comparative Study. Infrastructures. 2021; 6 (6):80.

Chicago/Turabian Style

Nasrin Aalimahmoody; Chiara Bedon; Nasim Hasanzadeh-Inanlou; Amir Hasanzade-Inallu; Mehdi Nikoo. 2021. "BAT Algorithm-Based ANN to Predict the Compressive Strength of Concrete—A Comparative Study." Infrastructures 6, no. 6: 80.

Review
Published: 18 May 2021 in Buildings
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The column buckling problem was first investigated by Leonhard Euler in 1757. Since then, numerous efforts have been made to enhance the buckling capacity of slender columns, because of their importance in structural, mechanical, aeronautical, biomedical, and several other engineering fields. Buckling analysis has become a critical aspect, especially in the safety engineering design since, at the time of failure, the actual stress at the point of failure is significantly lower than the material capability to withstand the imposed loads. With the recent advancement in materials and composites, the load-carrying capacity of columns has been remarkably increased, without any significant increase in their size, thus resulting in even more slender compressive members that can be susceptible to buckling collapse. Thus, nonuniformity in columns can be achieved in two ways—either by varying the material properties or by varying the cross section (i.e., shape and size). Both these methods are preferred because they actually inherited the advantage of the reduction in the dead load of the column. Hence, an attempt is made herein to present an abridged review on the buckling analysis of the columns with major emphasis on the buckling of nonuniform and functionally graded columns. Moreover, the paper provides a concise discussion on references that could be helpful for researchers and designers to understand and address the relevant buckling parameters.

ACS Style

Manmohan Goel; Chiara Bedon; Adesh Singh; Ashish Khatri; Laxmikant Gupta. An Abridged Review of Buckling Analysis of Compression Members in Construction. Buildings 2021, 11, 211 .

AMA Style

Manmohan Goel, Chiara Bedon, Adesh Singh, Ashish Khatri, Laxmikant Gupta. An Abridged Review of Buckling Analysis of Compression Members in Construction. Buildings. 2021; 11 (5):211.

Chicago/Turabian Style

Manmohan Goel; Chiara Bedon; Adesh Singh; Ashish Khatri; Laxmikant Gupta. 2021. "An Abridged Review of Buckling Analysis of Compression Members in Construction." Buildings 11, no. 5: 211.

Journal article
Published: 14 May 2021 in Buildings
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For engineering applications, human comfort in the built environment depends on several objective aspects that can be mathematically controlled and limited to reference performance indicators. Typical examples include structural, energy and thermal issues, and others. Human reactions, however, are also sensitive to a multitude of aspects that can be associated with design concepts of the so-called “emotional architecture”, through which subjective feelings, nervous states and emotions of end-users are evoked by constructional details. The interactions of several objective and subjective parameters can make the “optimal” building design challenging, and this is especially the case for new technical concepts, constructional materials and techniques. In this paper, a remote experimental methodology is proposed to explore and quantify the prevailing human reactions and psychological comfort trends for building occupants, with a focus on end-users exposed to structural glass environments. Major advantages were taken from the use of virtual visual stimuli and facial expression automatic recognition analysis, and from the active support of 30 volunteers. As shown, while glass is often used in constructions, several intrinsic features (transparency, brittleness, etc.) are responsible for subjective feelings that can affect the overall psychological comfort of users. In this regard, the use of virtual built environments and facial expression analysis to quantify human reactions can represent an efficient system to support the building design process.

ACS Style

Chiara Bedon; Silvana Mattei. Facial Expression-Based Experimental Analysis of Human Reactions and Psychological Comfort on Glass Structures in Buildings. Buildings 2021, 11, 204 .

AMA Style

Chiara Bedon, Silvana Mattei. Facial Expression-Based Experimental Analysis of Human Reactions and Psychological Comfort on Glass Structures in Buildings. Buildings. 2021; 11 (5):204.

Chicago/Turabian Style

Chiara Bedon; Silvana Mattei. 2021. "Facial Expression-Based Experimental Analysis of Human Reactions and Psychological Comfort on Glass Structures in Buildings." Buildings 11, no. 5: 204.

Journal article
Published: 30 April 2021 in Construction and Building Materials
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Cross Laminated Timber (CLT) and Light Timber Frame (LTF) shear walls are widespread constructive technologies in timber engineering. Despite the intrinsic differences, the lateral response of the two structural systems may be quite similar under specific connection layouts, boundary constraints, and size of the shear walls. This paper compares the experimental cyclic responses of CLT and LTF shear walls characterized by the same size 250×250cm, and loaded according to the EN 12512 protocol. The rigid-body rotation of the shear walls prevails over the deformation and rigid-body translation in the post-elastic displacement range. As a consequence, a capacity model of the two systems based on the sole hold-down response accurately seizes the observed cyclic response, despite ignoring the other resisting contributions. The authors examine the differences exhibited by the CLT and LTF shear walls and the related error corresponding to a capacity model based on the sole hold down restraints. Additionally, it is assessed the overstrength of the CLT panel and LTF sheathing to the shear walls collapse due to the hold-down failure. The estimated overstrength factor is the most meaningful difference between the two structural systems in the considered experimental layouts.

ACS Style

Angelo Aloisio; Francesco Boggian; Roberto Tomasi; Massimo Fragiacomo. The role of the hold-down in the capacity model of LTF and CLT shear walls based on the experimental lateral response. Construction and Building Materials 2021, 289, 123046 .

AMA Style

Angelo Aloisio, Francesco Boggian, Roberto Tomasi, Massimo Fragiacomo. The role of the hold-down in the capacity model of LTF and CLT shear walls based on the experimental lateral response. Construction and Building Materials. 2021; 289 ():123046.

Chicago/Turabian Style

Angelo Aloisio; Francesco Boggian; Roberto Tomasi; Massimo Fragiacomo. 2021. "The role of the hold-down in the capacity model of LTF and CLT shear walls based on the experimental lateral response." Construction and Building Materials 289, no. : 123046.

Journal article
Published: 19 April 2021 in The Open Civil Engineering Journal
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Background: Existing Reinforced Concrete (RC) structures and brittle buildings are often exposed to seismic events that may have significant resistance and displacement demand compared to their actual capacity. Accordingly, an optimal retrofit intervention can ensure enhanced and safe structural performances for them. Among the techniques that have been addressed for the retrofit of existing RC frames, steel exoskeletons can notoriously improve the seismic performance of existing buildings due to their input stiffness, ductility and resistance. In this paper, the attention is focused on the interaction of steel exoskeletons with RC frames and the consequent details to achieve a more effective design of the retrofit intervention. Objective: Based on parametric calculations, a new hybrid design concept that takes advantage of traditional steel exoskeletons with additional base sliding devices (at the foundation level of the RC frame to retrofit) is addressed in this paper. Methods: As shown through SDOF and 2D-MDOF calculations, the definition of the optimal operational conditions (and thus mechanical configurations) for the so-assembled hybrid solution can maximize the potential of the retrofit intervention, with marked benefits in terms of ductility, resistance, and overall efficiency, ensuring very low damage in the existing building. Results: Given that the used base sliders are bidirectional, it is expected that the proposed solution could be efficiently extended to 3D structures, once the exoskeleton systems are optimally designed along the two principal directions of the hybrid structure to retrofit. Conclusion: The potential of the hybrid approach is shown based on parametric analyses. Furthermore, general design recommendations are proposed for the hybrid solution.

ACS Style

Ljuba Sancin; Chiara Bedon; Claudio Amadio. Novel Design Proposal for the Seismic Retrofit of Existing Buildings with Hybrid Steel Exoskeletons and Base Sliding Devices. The Open Civil Engineering Journal 2021, 15, 74 -90.

AMA Style

Ljuba Sancin, Chiara Bedon, Claudio Amadio. Novel Design Proposal for the Seismic Retrofit of Existing Buildings with Hybrid Steel Exoskeletons and Base Sliding Devices. The Open Civil Engineering Journal. 2021; 15 (1):74-90.

Chicago/Turabian Style

Ljuba Sancin; Chiara Bedon; Claudio Amadio. 2021. "Novel Design Proposal for the Seismic Retrofit of Existing Buildings with Hybrid Steel Exoskeletons and Base Sliding Devices." The Open Civil Engineering Journal 15, no. 1: 74-90.

Journal article
Published: 07 April 2021 in Buildings
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The structural design of glass curtain walls and facades is a challenging issue, considering that building envelopes can be subjected extreme design loads. Among others, the soft body impact (SBI) test protocol represents a key design step to protect the occupants. While in Europe the standardized protocol based on the pneumatic twin-tire (TT) impactor can be nowadays supported by Finite Element (FE) numerical simulations, cost-time consuming experimental procedures with the spheroconical bag (SB) impactor are still required for facade producers and manufacturers by several technical committees, for the impact assessment of novel systems. At the same time, validated numerical calibrations for SB are still missing in support of designers and manufacturers. In this paper, an enhanced numerical approach is proposed for curtain walls under SB, based on a coupled methodology inclusive of a computationally efficient two Degree of Freedom (2-DOF) and a more geometrically accurate Finite Element (FE) model. As shown, the SB impactor is characterized by stiffness and dissipation properties that hardly match with ideal rigid elastic assumptions, nor with the TT features. Based on a reliable set of experimental investigations and records, the proposed methodology acts on the time history of the imposed load, which is implicitly calibrated to account for the SB impactor features, once the facade features (flexibility and damping parameters) are known. The resulting calibration of the 2-DOF modelling parameters for the derivation of time histories of impact force is achieved with the support of experimental measurements and FE model of the examined facade. The potential and accuracy of the method is emphasized by the collected experimental and numerical comparisons. Successively, the same numerical approach is used to derive a series of iso-damage curves that could support practical design calculations.

ACS Style

Alessia Bez; Chiara Bedon; Giampiero Manara; Claudio Amadio; Guido Lori. Calibrated Numerical Approach for the Dynamic Analysis of Glass Curtain Walls under Spheroconical Bag Impact. Buildings 2021, 11, 154 .

AMA Style

Alessia Bez, Chiara Bedon, Giampiero Manara, Claudio Amadio, Guido Lori. Calibrated Numerical Approach for the Dynamic Analysis of Glass Curtain Walls under Spheroconical Bag Impact. Buildings. 2021; 11 (4):154.

Chicago/Turabian Style

Alessia Bez; Chiara Bedon; Giampiero Manara; Claudio Amadio; Guido Lori. 2021. "Calibrated Numerical Approach for the Dynamic Analysis of Glass Curtain Walls under Spheroconical Bag Impact." Buildings 11, no. 4: 154.

Journal article
Published: 06 April 2021 in Infrastructures
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The paper presents an application of the Extended Energy-dependent Generalized Bouc–Wen model (EEGBW) to simulate the experimental cyclic response of Cross-Laminated Timber (CLT) panels. The main objectives of the paper are assessing the sensitivity of the quadratic error between experimental and numerical data to the EEGBW parameters, showing the fitting performance of the EEGBW model in matching the experimental cyclic response of CLT panels, highlighting the stability of the model in nonlinear dynamic analysis with seismic excitation. The research proves that the considered Bouc–Wen class hysteresis model can reproduce the hysteretic response of structural arrangements characterized by pinching and degradation phenomena. The model exhibits significant stability in nonlinear dynamic analysis with seismic excitation. The model’s stability and versatility endorse its application to simulate structural systems’ dynamic response when Finite Element modelling might be an impractical choice.

ACS Style

Angelo Aloisio; Massimo Fragiacomo. Assessment of the Seismic Response of CLT Shear Walls Using the EEGBW, a Bouc–Wen Class Predictive Model. Infrastructures 2021, 6, 55 .

AMA Style

Angelo Aloisio, Massimo Fragiacomo. Assessment of the Seismic Response of CLT Shear Walls Using the EEGBW, a Bouc–Wen Class Predictive Model. Infrastructures. 2021; 6 (4):55.

Chicago/Turabian Style

Angelo Aloisio; Massimo Fragiacomo. 2021. "Assessment of the Seismic Response of CLT Shear Walls Using the EEGBW, a Bouc–Wen Class Predictive Model." Infrastructures 6, no. 4: 55.

Journal article
Published: 01 April 2021 in Journal of Structural Engineering
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A full-scale 2-story mass timber building was tested on the University of California San Diego Natural Hazards Engineering Research Infrastructure (UCSD-NHERI) uniaxial shake table during the period from June 2017 to September 2017. The main objective of the experimental program was to test the performance of mass timber building designs with different seismic lateral force–resisting systems. The focus of this study is on a building configuration designed using self-centering post-tensioned cross-laminated timber (CLT) rocking walls with U-shaped steel flexural plate energy dissipators. The shake-table tests were designed to subject the building to a series of earthquake ground motions of increasing intensity, ranging from a service-level earthquake to 1.20 times the maximum considered earthquake intensity. Between each ground motion, low-amplitude white-noise excitations were applied to the building, which responded as a quasilinear system. In this paper, two output-only operational modal analysis methods are used to estimate the modal parameters (frequency, damping, and mode shapes) based on acceleration data collected during the white-noise shake-table tests. The correlations of observed damage and repairs performed during the experimental program with changes in estimated modal features are reported. The modal parameters estimated from the testing program are also compared with a linear finite-element model that is used to validate the modal identification results and study the performance of the two system identification methods for CLT rocking structures.

ACS Style

Ignace Mugabo; Andre R. Barbosa; Arijit Sinha; Christopher Higgins; Mariapaola Riggio; Shiling Pei; John W. Van De Lindt; Jeffrey W. Berman. System Identification of UCSD-NHERI Shake-Table Test of Two-Story Structure with Cross-Laminated Timber Rocking Walls. Journal of Structural Engineering 2021, 147, 04021018 .

AMA Style

Ignace Mugabo, Andre R. Barbosa, Arijit Sinha, Christopher Higgins, Mariapaola Riggio, Shiling Pei, John W. Van De Lindt, Jeffrey W. Berman. System Identification of UCSD-NHERI Shake-Table Test of Two-Story Structure with Cross-Laminated Timber Rocking Walls. Journal of Structural Engineering. 2021; 147 (4):04021018.

Chicago/Turabian Style

Ignace Mugabo; Andre R. Barbosa; Arijit Sinha; Christopher Higgins; Mariapaola Riggio; Shiling Pei; John W. Van De Lindt; Jeffrey W. Berman. 2021. "System Identification of UCSD-NHERI Shake-Table Test of Two-Story Structure with Cross-Laminated Timber Rocking Walls." Journal of Structural Engineering 147, no. 4: 04021018.

Journal article
Published: 01 April 2021 in Journal of Structural Engineering
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This paper presents the behavior of floor diaphragms of a shake-table experiment of a full-scale 2-story mass-timber building structure. The structure consists of glued-laminated timber beams and columns, and floors and walls were designed and built making use of cross-laminated timber panels. Two different floor systems were designed, where the roof consists of a topped cross-laminated timber (CLT)-concrete composite system, and the floor level consists of untopped CLT panels connected with plywood single-surface splines. The CLT floor systems were designed to remain essentially elastic over the whole series of shake-table tests, which included testing of three lateral force–resisting systems tested at three different seismic intensity levels (service level, design basis, and maximum considered earthquake) for a total of 34 shake-table earthquake tests. Results from the testing indicate that CLT diaphragms designed to remain essentially elastic based on basic principles of structural mechanics and existing test data can achieve desired seismic performance objectives. In addition, sources of overstrength in certain elements of the diaphragm need to be explicitly considered for a holistic diaphragm design.

ACS Style

Andre R. Barbosa; Leonardo G. Rodrigues; Arijit Sinha; Christopher Higgins; Reid B. Zimmerman; Scott Breneman; Shiling Pei; John W. Van De Lindt; Jeffrey Berman; Eric McDonnell. Shake-Table Experimental Testing and Performance of Topped and Untopped Cross-Laminated Timber Diaphragms. Journal of Structural Engineering 2021, 147, 04021011 .

AMA Style

Andre R. Barbosa, Leonardo G. Rodrigues, Arijit Sinha, Christopher Higgins, Reid B. Zimmerman, Scott Breneman, Shiling Pei, John W. Van De Lindt, Jeffrey Berman, Eric McDonnell. Shake-Table Experimental Testing and Performance of Topped and Untopped Cross-Laminated Timber Diaphragms. Journal of Structural Engineering. 2021; 147 (4):04021011.

Chicago/Turabian Style

Andre R. Barbosa; Leonardo G. Rodrigues; Arijit Sinha; Christopher Higgins; Reid B. Zimmerman; Scott Breneman; Shiling Pei; John W. Van De Lindt; Jeffrey Berman; Eric McDonnell. 2021. "Shake-Table Experimental Testing and Performance of Topped and Untopped Cross-Laminated Timber Diaphragms." Journal of Structural Engineering 147, no. 4: 04021011.

Journal article
Published: 01 April 2021 in Journal of Structural Engineering
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This paper attempts to formulate an expression for the estimation of equivalent viscous damping (EVD) for cross-laminated timber (CLT) structural archetypes as a function of ductility. The paper aims at contributing toward the direct displacement-based design procedure (DDBD) of CLT structures, which makes use of equivalent viscous damping and secant stiffness estimations as proxies for the estimation of the nonlinear behavior of structures. The available hysteretic models of CLT structures are very elaborate, and the inelastic time-domain simulations using hysteretic models are not easily manageable. Hence, the adoption of equivalent viscous damping is a crucial feature of any DDBD method. In this paper, the authors estimate the EVD of a set of 16 typologies of CLT buildings with an increasing slenderness ratio. The minimum of the squared error between the maximum drift of the elastic time-history and the hysteretic response gives the EVD. The extended energy-dependent generalized Bouc Wen (EEGBW) model, calibrated on experimental data, is used to predict the inelastic seismic response of the single CLT shear wall. The correlation between EVD and ductility is compared to existing EVD formulations referring to concrete and steel structures.

ACS Style

Angelo Aloisio; Rocco Alaggio; Massimo Fragiacomo. Equivalent Viscous Damping of Cross-Laminated Timber Structural Archetypes. Journal of Structural Engineering 2021, 147, 04021012 .

AMA Style

Angelo Aloisio, Rocco Alaggio, Massimo Fragiacomo. Equivalent Viscous Damping of Cross-Laminated Timber Structural Archetypes. Journal of Structural Engineering. 2021; 147 (4):04021012.

Chicago/Turabian Style

Angelo Aloisio; Rocco Alaggio; Massimo Fragiacomo. 2021. "Equivalent Viscous Damping of Cross-Laminated Timber Structural Archetypes." Journal of Structural Engineering 147, no. 4: 04021012.

Journal article
Published: 30 March 2021 in Engineering Structures
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Self-Tapping Screws (STSs) are commonly used to realize many geometrical configurations for connections that are characterized by enhanced stiffness and load-carrying capacity. The analysis of STS joints and composite systems, however, usually requires designers to account for several aspects in their actual load transfer mechanisms, and most of them require refined calculation tools. In this paper, an extended Finite Element (FE) investigation is proposed for timber-to-timber slabs with STS joints, based on full 3D brick models inclusive of Cohesive Zone Modelling (CZM) techniques and damage constitutive laws for the materials in use. The final goal of the study takes advantage of the global and local performance assessment of a selection of STS joints, with careful consideration for their response under a conventional Push-Out (PO) test setup or a full-size bending configuration. As shown, major FE outcomes are discussed to elaborate a design procedure that can be developed on the base of correlation coefficients for maximum force and stiffness calculations in a given slab and loading condition. Major effects due to variable loading configurations are in fact explored at the screw level. Further, geometrically simplified spring-based FE models, that hardly capture the complex behaviour of the examined systems but are largely used in design practice, are presented in comparison to refined FE approaches and literature efforts. As shown, the variation of maximum force and stiffness parameters for STSs is emphasized in the paper for a selection of configurations, and fitting curves are proposed to estimate the STS performance along a given full-size slab, thus suggesting the feasibility and possible generalization of the procedure.

ACS Style

Chiara Bedon; Martina Sciomenta; Massimo Fragiacomo. Correlation approach for the Push-Out and full-size bending short-term performances of timber-to-timber slabs with Self-Tapping Screws. Engineering Structures 2021, 238, 112232 .

AMA Style

Chiara Bedon, Martina Sciomenta, Massimo Fragiacomo. Correlation approach for the Push-Out and full-size bending short-term performances of timber-to-timber slabs with Self-Tapping Screws. Engineering Structures. 2021; 238 ():112232.

Chicago/Turabian Style

Chiara Bedon; Martina Sciomenta; Massimo Fragiacomo. 2021. "Correlation approach for the Push-Out and full-size bending short-term performances of timber-to-timber slabs with Self-Tapping Screws." Engineering Structures 238, no. : 112232.

Research article
Published: 24 March 2021 in Mathematical Problems in Engineering
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Within multiple design challenges, the lateral torsional buckling (LTB) analysis and stability check of structural glass members is a well-known issue for design. Typical examples can be found not only in glass slabs with slender bracing members but also in facades and walls, where glass fins are used to brace the vertical panels against input pressures. Design loads such as wind suction give place to possible LTB of fins with LR at the tensioned edge and thus require dedicated tools. In the present investigation, the LTB analysis of structural glass fins that are intended to act as bracers for facade panels and restrained via continuous, flexible joints acting as lateral restraints (LRs) is addressed. Geometrically simplified but refined numerical models developed in Abaqus are used to perform a wide parametric study and validate the proposed analytical formulations. Special care is spent for the prediction of the elastic critical buckling moment with LRs, given that it represents the first fundamental parameter for buckling design. However, the LR stiffness and resistance on the one side and the geometrical/mechanical features of the LR glass members on the other side are mutually affected in the final LTB prediction. In the case of laminated glass (LG) members composed of two or more glass panels, moreover, further design challenges arise from the bonding level of the constituent layers. A simplified but rational analytical procedure is thus presented in this paper to support the development of a conservative and standardized LTB stability check for glass fins with LR at the tensioned edge.

ACS Style

Chiara Bedon. Simplified Lateral Torsional Buckling (LTB) Analysis of Glass Fins with Continuous Lateral Restraints at the Tensioned Edge. Mathematical Problems in Engineering 2021, 2021, 1 -21.

AMA Style

Chiara Bedon. Simplified Lateral Torsional Buckling (LTB) Analysis of Glass Fins with Continuous Lateral Restraints at the Tensioned Edge. Mathematical Problems in Engineering. 2021; 2021 ():1-21.

Chicago/Turabian Style

Chiara Bedon. 2021. "Simplified Lateral Torsional Buckling (LTB) Analysis of Glass Fins with Continuous Lateral Restraints at the Tensioned Edge." Mathematical Problems in Engineering 2021, no. : 1-21.

Journal article
Published: 17 March 2021 in Buildings
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Masonry towers, located in seismic zones, are vulnerable and prone to damages up to compromise their stability. The scatter of data on the mechanical properties of masonry, geometry and boundary conditions determine a lack of building knowledge on their expected behaviour. Therefore the assessment of the seismic capacity represents a critical task. This paper contributes to the issue of seismic analysis of masonry towers, focusing a meaningful case study: the St.Silvestro belfry in L’Aquila, Italy. The tower, severely damaged by the 2009 earthquake sequence, underwent extensive restoration works, endeavoured to mitigate its vulnerability. The observed seismic damage, the performed no-destructive testing campaign and the accomplished rehabilitation measures are described in the paper. The authors appraised the actual seismic performances of the St.Silvestro belfry, reinforced by the last restoration works. At first, the Operational Modal Analysis (OMA) is carried out to enhance building knowledge. In a second step, a refined finite element model is calibrated on the results from OMA to seize the actual dynamic response. Ultimately, by using the updated finite element model, the authors estimate the fragility curves in terms of peak ground acceleration using truncated incremental dynamic analyses.

ACS Style

Ilaria Capanna; Riccardo Cirella; Angelo Aloisio; Rocco Alaggio; Franco Di Fabio; Massimo Fragiacomo. Operational Modal Analysis, Model Update and Fragility Curves Estimation, through Truncated Incremental Dynamic Analysis, of a Masonry Belfry. Buildings 2021, 11, 120 .

AMA Style

Ilaria Capanna, Riccardo Cirella, Angelo Aloisio, Rocco Alaggio, Franco Di Fabio, Massimo Fragiacomo. Operational Modal Analysis, Model Update and Fragility Curves Estimation, through Truncated Incremental Dynamic Analysis, of a Masonry Belfry. Buildings. 2021; 11 (3):120.

Chicago/Turabian Style

Ilaria Capanna; Riccardo Cirella; Angelo Aloisio; Rocco Alaggio; Franco Di Fabio; Massimo Fragiacomo. 2021. "Operational Modal Analysis, Model Update and Fragility Curves Estimation, through Truncated Incremental Dynamic Analysis, of a Masonry Belfry." Buildings 11, no. 3: 120.

Journal article
Published: 17 March 2021 in Applied Sciences
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Bonded-in rods (BiR) represent a structural connection type that is largely used for new timber structures and rehabilitation (repair or reinforcement) of existing structural members. The technology is based on steel / Fiber Reinforced Polymer (FRP) / Glass Fiber Reinforced Polymer (GFRP) rods bonded into predrilled holes in timber elements. The mechanical advantages of BiRs include high local force capacity, improved strength, a relatively high stiffness and the possibility of ductile behaviour. They also offer aesthetic benefits, given that rods are hidden in the cross sections of wooden members. As such, BiR connections are regarded as a solution with great potential, but still uncertain design formulations. Several research projects have dealt with BiRs, but a final definition of their mechanics and a universal design procedure is still missing. This research study explores the typical fracture mechanics modes for BiR connections. A special focus is given to the evaluation of the impact of adhesive bonds under various operational conditions (i.e., moisture content of timber). A total of 84 specimens are tested in pull-out setup, and investigated with the support of digital image correlation (DIC). The reliability of empirical equations and a newly developed analytical model in support of design, based on linear elastic fracture mechanics (LEFM), is also assessed.

ACS Style

Jure Barbalić; Vlatka Rajčić; Chiara Bedon; Michal Budzik. Short-Term Analysis of Adhesive Types and Bonding Mistakes on Bonded-in-Rod (BiR) Connections for Timber Structures. Applied Sciences 2021, 11, 2665 .

AMA Style

Jure Barbalić, Vlatka Rajčić, Chiara Bedon, Michal Budzik. Short-Term Analysis of Adhesive Types and Bonding Mistakes on Bonded-in-Rod (BiR) Connections for Timber Structures. Applied Sciences. 2021; 11 (6):2665.

Chicago/Turabian Style

Jure Barbalić; Vlatka Rajčić; Chiara Bedon; Michal Budzik. 2021. "Short-Term Analysis of Adhesive Types and Bonding Mistakes on Bonded-in-Rod (BiR) Connections for Timber Structures." Applied Sciences 11, no. 6: 2665.