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317 records – page 1 of 32.

Analysis Behavior of Openings on Full-Size Cross-Laminated Timber (CLT) Frame Shear Walls Tested Monotonically

https://research.thinkwood.com/en/permalink/catalogue3335
Year of Publication
2023
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Dungani, Rudi
Sulistyono
Karliati, Tati
Suhaya, Yoyo
Malik, Jamaludin
Alpian
Supriyati, Wahyu
Organization
Institut Teknologi Bandung
Kuningan University
Palangka Raya University
Publisher
MDPI
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Keywords
Monotonic Test
Seismic Resistance
Wood-Frame
Opening
Research Status
Complete
Series
Forests
Summary
Walls, as components of the lateral-force-resisting system of a building, are defined as shear walls. This study aims to determine the behavior of shear wall panel cross-laminated-timber-based mangium wood (Acacia mangium Willd) (CLT-mangium) in earthquake-resistant prefabricated houses. The earthquake performance of CLT mangium frame shear walls panels has been studied using monotonic tests. The shear walls were constructed using CLT-mangium measuring 2400 mm × 1200 mm × 68 mm with various design patterns (straight sheathing, diagonal sheathing/45°, windowed shear wall with diagonal pattern and a door shear wall with a diagonal pattern). Shear wall testing was carried out using a racking test, and seismic force calculations were obtained using static equivalent earthquake analysis. CLT-mangium sheathing installed horizontally (straight sheathing) is relatively weak compared to the diagonal sheathing, but it is easier and more flexible to manufacture. The diagonal sheathing type is stronger and stiffer because it has triangulation properties, such as truss properties, but is more complicated to manufacture (less flexible). The type A design is suitable for low-intensity zones (2), and types B, D, E1 and E2 are suitable for moderate-intensity zones (3, 4), and type C is suitable for severe-intensity zones (5).
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Experimental investigations of a new highly ductile hold-down with adaptive stiffness for timber seismic bracing walls

https://research.thinkwood.com/en/permalink/catalogue3370
Year of Publication
2023
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Maître, K.
Lestuzzi, P.
Geiser, M.
Organization
Bern University of Applied Sciences
École Polytechnique Fédérale de Lausanne
Publisher
Springer
Year of Publication
2023
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Keywords
Hold-Down
Adaptative Stiffness
Buckling Restrained Brace
Capacity Design
CLT Shear Wall
High Ductility
Research Status
Complete
Series
Bulletin of Earthquake Engineering
Summary
An efficient implementation of the capacity design requires high ductility combined with a low overstrength of the critical regions. Conventional timber connections do not generally offer such ideal combination, resulting in modest behaviour and relatively high overstrength factors. Inspired by the Buckling Restrained Brace a new hold-down has been developed where the timber wall directly acts as a casing. The new hold-down has been given an adaptive stiffness allowing the structure to be stiff in the wind, while becoming more flexible in the case of an earthquake. Furthermore, local crushing of the timber members is completely avoided, and the new hold-down could be replaced after an earthquake. Experimental investigations were performed on hold-down specimens. The results show ultimate displacement values vu,c of more than 30 mm in a cyclic test according to EN12512. Eleven Cross Laminated Timber shear walls, in which the new hold-down has been implemented, were tested following monotonic and static-cyclic tests procedures, with and without vertical load. A very high ductility has been achieved with almost no strength degradation, little pinching and limited overstrength.
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Design of a novel seismic retrofitting system for RC structures based on asymmetric friction connections and CLT panels

https://research.thinkwood.com/en/permalink/catalogue2912
Year of Publication
2022
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Author
Aloisoio, Angelo
Boggian, Francesco
Tomasi, Roberto
Organization
Università degli Studi dell’Aquila
Università degli Studi di Trento
Norwegian University of Life Science
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Seismic
Keywords
Friction-based Device
Seismic Protection
Structural Design
Reinforced-concrete Structures
Research Status
Complete
Series
Engineering Structures
Summary
Friction-based dampers are a valid solution for non-invasive seismic retrofitting interventions of existing structures, particularly reinforced-concrete (RC) structures. The design of friction-based dampers is challenging: underestimating the slip force prevents the full use of the potential of the device, which attains the maximum admissible displacement earlier than expected. By contrast, overestimating the slip force may cause delayed triggering of the device when the structure has suffered extensive damage. Therefore, designing the appropriate slip force is an optimization problem. The optimal slip force guarantees the highest inter-story drift reduction. The authors formulated the optimization problem for designing a specific class of friction-based dampers, the asymmetric friction connection (AFC), devised as part of the ongoing multidisciplinary Horizon 2020 research project e-SAFE (Energy and Seismic AFfordable rEnovation solutions). The seismic retrofitting technology involves the external application of modular prefabricated cross-laminated timber (CLT) panels on existing external walls. Friction dampers connect the CLT panels to the beams of two consecutive floors. The friction depends on the mutual sliding of two metal plates, pressed against each other by preloaded bolts. This study determines the optimal slip force, which guarantees the best seismic performance of an RC structural archetype. The authors investigate the nonlinear dynamic response of a coupled mechanical system (RC frame-friction damper) under a set of strong-motion earthquakes, using non-differential hysteresis models calibrated on the experimental cyclic responses. The solution of the optimization leads to the proposal of a preliminary simplified design procedure, useful for practitioners.
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CLT Diaphragm Design for Wind and Seismic Resistance

https://research.thinkwood.com/en/permalink/catalogue2967
Year of Publication
2022
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Breneman, Scott
McDonnell, Eric
Tremayne, Donovan
Houston, Jonas
Gu, Mengzhe
Zimmerman, Reid
Montgomery, Graham
Organization
WoodWorks
Holmes
KPFF Consulting Engineers
Timberlab
Publisher
WoodWorks
Year of Publication
2022
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Seismic
Keywords
Diaphragm
Shear Capacity
Diaphragm Flexibility
Panel-to-Panel Connections
Research Status
Complete
Summary
Cross-laminated timber (CLT) has become increasingly prominent in building construction and can be seen in buildings throughout the world. Specifically, the use of CLT floor and roof panels as a primary gravity force-resisting component has become relatively commonplace. Now, with availability of the 2021 Special Design Provisions for Wind and Seismic (SDPWS 2021) from the American Wood Council (AWC), U.S. designers have a standardized path to utilize CLT floor and roof panels as a structural diaphragm. Prior to publication of this document, projects typically had to receive approval to use CLT as a structural diaphragm on a case-by-case basis from the local Authority Having Jurisdiction (AHJ). This paper highlights important provisions of SDPWS 2021 for CLT diaphragm design and recommendations developed by the authors in the upcoming CLT Diaphragm Design Guide, based on SDPWS 2021.
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Innovations in mass timber lateral systems

https://research.thinkwood.com/en/permalink/catalogue3099
Year of Publication
2022
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Bailey, Dawson
Organization
Kansas State University
Year of Publication
2022
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Keywords
Rocking Timber Walls
Lateral Systems
Post Tensioning
Research Status
Complete
Summary
As mass timber becomes increasingly popular in the United States and around the world, there comes more demand for mass timber in larger buildings. With this demand comes a necessity for these buildings to be able to withstand seismic forces; and in some locations, these forces can get quite high. Typical mass timber lateral systems (such as CLT shear walls) have worked fine for lower seismic forces and shorter buildings, but with this new demand comes a need for newer systems. Rocking timber walls is one of these systems. The goal of a rocking timber wall is to allow the lateral wall system to move in the case of high seismic force, thus reducing the loading the wall experiences. This is done with vertical post tensioning (PT) within cross-laminated timber panels (CLT). In addition, easily replaceable energy dissipation devices, such as U-shaped flexural plates (UFPs), allow for concentration of inelastic deformation during rocking of the walls, which keeps the CLT and PT components free from harm. Another system used to handle seismic load in tall mass timber structures are inter-story isolation systems. These systems can isolate the force at separate levels, effectively decreasing the load the foundation takes from the building's movement. Even newer than these systems is the Floor Isolated Re-centering Modular Construction System (FIRMOC), which utilizes rocking timber walls, inter-story isolation, and the addition of prefabricated modular mass timber to create a system capable of effectively and efficiently dealing with large seismic forces. This report seeks to present these innovative, capable, and effective lateral systems for seismic forces in large scale mass timber structures in a manner that provides understanding of how they work and what makes them effective.
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Hybrid simulation of a post-tensioned timber frame and validation of numerical models for seismic design

https://research.thinkwood.com/en/permalink/catalogue3107
Year of Publication
2022
Topic
Seismic
Application
Frames
Author
Ogrizovic, J.
Abbiati, G.
Stojadinovic, B.
Frangi, A.
Organization
MWV Bauingenieure
University of Aarhus
ETH Zurich
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Application
Frames
Topic
Seismic
Keywords
Post-tensioned Timber Frame
Seismic Analysis
Hybrid Simulation
Finite Element Modeling
Research Status
Complete
Series
Engineering Structures
Summary
The post-tensioned frame is one of the recently emerged structural systems for multi-story timber buildings. It is characterized by a high level of prefabrication and quick erection on the construction site. The post-tensioned frame developed at ETH Zurich is based on post-tensioned beam–column connections with hardwood reinforcement of the column in the connection region and column base connections with glued-in steel rods. Such a construction system is suitable for low- and mid-rise buildings that are located in regions characterized by low to moderate seismicity. This paper presents a series of hybrid simulations of the response of a two-story two-bay post-tensioned timber frame subjected to ground motion excitation. Nonlinear numerical models of both beam–column and column base connections to be used for design purposes are validated based on the experiments.
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Seismic strengthening of existing RC buildings with external cross-laminated timber (CLT) walls hosting an integrated energetic and architectural renovation

https://research.thinkwood.com/en/permalink/catalogue3114
Year of Publication
2022
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Badini, Lorenzo
Ott, Stephan
Aondio, Patrik
Winter, Stefan
Organization
Technical University of Munich
Publisher
Springer
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Seismic
Keywords
Existing Building
Seismic Retrofit
Target Displacement
Energy Retrofit
Numerical Analyses
Research Status
Complete
Series
Bulletin of Earthquake Engineering
Summary
In this study a timber-based integrated solution is presented to solve at once common issues affecting typical reinforced concrete (RC) existing buildings, such as seismic and energy performances, providing an eco-friendly alternative to steel external bracing systems. Cross-laminated timber (CLT) walls are provided perpendicularly to the external façades as strengthening elements while interposed CLT slabs are foreseen at each floor level to host new architectural units together with a new envelope. While the connections to the foundations and to the existing RC frames are provided respectively with steel brackets and axial-connectors distributed along the height of the building, a post-tensioned connection, between CLT panels (PT-CLT connection), is implemented in the system to guarantee resistance to horizontal actions acting parallel to existing façades with consequent structural independence and architectural freedom. On this regards a first look at the findings of an experimental campaign carried on the Technical University of Munich are presented. A numerical model is developed with finite element software characterizing each type of connector for linear and non-linear analyses. Modal analyses with response spectrum are performed to verify structural elements and connectors, while pushover analyses with target displacement checks are performed to assess the obtained seismic improvement. Finally, the preassembled architectural components that allow to renovate the envelope and the provided assembly procedure are revealed.
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Seismic performance evaluation of innovative balloon type CLT rocking shear walls

https://research.thinkwood.com/en/permalink/catalogue3133
Year of Publication
2022
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Yang, T.Y.
Lepine-Lacroix, S.
Guerrero, J.A. Ramos
McFadden, J.B.W.
Al-Janabi, M.A.Q.
Organization
The University of British Columbia
National Research Council Canada
Al-Nahrain University
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Keywords
Rocking Shear Walls
CLT Shear Walls
Seismic Performance
Nonlinear Finite Element Model
Research Status
Complete
Series
Resilient Cities and Structures
Summary
Balloon type cross laminated timber (CLT) rocking shear walls are a novel seismic force resisting system. In this paper, the seismic performance of four 12-story balloon type CLT rocking shear walls, designed by a structural engineering firm located in Vancouver (Canada) using the performance-based design procedure outlined in the technical guideline published by the Canadian Construction Materials center (CCMC)/National Research Council Canada (NRC), is assessed. The seismic performance of the prototype CLT rocking shear walls was investigated using nonlinear time history analyses. Robust nonlinear finite element models were developed using OpenSees and the nonlinear behavior of the displacement-controlled components was calibrated using available experimental data. A detailed site-specific hazard analysis was conducted and sets of ground motions suitable for the prototype buildings were selected. The ground motions were used in a series of incremental dynamic analyses (IDAs) to quantify the adjustable collapse margin ratio (ACMR) of the prototype balloon type CLT rocking shear walls. The results show that the prototype balloon type CLT rocking shear walls designed using the performance-based design procedure outlined in the CCMC/NRC technical guideline have sufficient ACMR when compared to the acceptable limits recommended by FEMA P695.
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Effects of Ground Motion Duration on the Seismic Performance of a Two-Storey Balloon-Type CLT Building

https://research.thinkwood.com/en/permalink/catalogue3154
Year of Publication
2022
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Jafari, Maral
Pan, Yuxin
Shahnewaz, Md
Tannert, Thomas
Organization
University of Northern British Columbia
Fast + Epp
Editor
Bento, Rita
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Keywords
Ground Motion
Collapse Capacity
Dynamic Analysis
Research Status
Complete
Series
Buildings
Summary
The effects of long duration ground motions on the seismic performance of a newly constructed two-storey balloon-type cross-laminated timber (CLT) building located in Vancouver, Canada, was studied. A three-dimensional numerical model of the building was developed in OpenSees. The connection and shear wall models were validated with test data. Twenty-four pairs of long and short duration records with approximately the same amplitude, frequency content, and rate of energy build-up were used for nonlinear dynamic analyses. Fragility curves were developed based on the results of incremental dynamic analysis to assess the building’s collapse capacity. At design intensity level, ground motion duration was shown not to be a critical factor as the difference in inter-storey drift ratio between the two sets of records was negligible. However, due to the larger number of inelastic cycles, the long duration motions increased the median probability of collapse by 9% when compared with the short duration motions. Further research is required to evaluate the duration effects on taller and platform-type CLT buildings.
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Shaking table investigation of a low-cost and sustainable timber-based energy dissipation system with recentering ability

https://research.thinkwood.com/en/permalink/catalogue3161
Year of Publication
2022
Topic
Seismic
Author
Tsiavos, Anastasios
Kolyfetis, Dimitrios
Panzarasa, Guido
Burgert, Ingo
Stojadinovic, Bozidar
Organization
ETH Zurich
Publisher
Springer
Year of Publication
2022
Format
Journal Article
Topic
Seismic
Keywords
Low-cost Seismic Isolation
Geotechnical Seismic Isolation
Large-scale Shaking Table Tests
Energy Dissipation
Sustainability
Research Status
Complete
Series
Bulletin of Earthquake Engineering
Summary
The aim of this paper is to demonstrate the efficiency of a low-cost and sustainable timber-based energy dissipation system with recentering ability, which can be used as a seismic isolation system or a tuned mass damper for the seismic protection of structures in developing or developed countries. The system, defined as Dovetail with SPrings (Dove-SP), utilizes the attractive properties of timber to store CO2, thus reducing the carbon footprint of the existing energy dissipation systems: It comprises two timber slabs that are designed to slide against each other in a motion that is restrained by a dovetail sliding joint. Two sliding interfaces that allow this sliding motion at an attractively low friction coefficient are experimentally investigated: A PVC sand-wich (PVC-s) sliding interface, comprising a thin layer of sand that is sand-wiched between two PVC layers and a timber sand-wich sliding interface consisting of a thin layer of sand encapsulated between two beech timber surfaces. A set of low-cost steel springs is designed and installed on both sides of the dovetail joint to recenter the structure back to its original position after the end of an earthquake ground motion excitation. A novel, low-cost and deformable wood material fabricated from delignified balsa wood is used to reduce the pounding effects before the activation of the steel springs. The seismic behavior and the recentering ability of the novel timber-based energy dissipation system subjected to an ensemble of recorded earthquake ground motion excitations was experimentally investigated through a large-scale shaking table investigation at ETH Zurich.
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317 records – page 1 of 32.