Skip header and navigation

47 records – page 1 of 5.

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.
Online Access
Free
Resource Link
Less detail

Comparing Numerical Results for Seismic Performance of Portal Steel Frames Braced with Steel: HSS Brace, Glulam Timber Brace, and Timber-Steel-BRB

https://research.thinkwood.com/en/permalink/catalogue3163
Year of Publication
2022
Topic
Seismic
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Sabbagh-Yazdi, Saeed-Reza
Mirzazadah, Ainullah
Organization
Toosi University of Technology
Editor
Branco, Jorge
Publisher
Hindawi
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Seismic
Keywords
Portal Steel Frames
Seismic Analyses
Buckling Restrained Brace
Energy Dissipation
Research Status
Complete
Series
Advances in Civil Engineering
Summary
This study involves the application of timber-based bracings elements. For this purpose, seismic analyses are performed on special portal steel frames without the brace and diagonally braced with Glued Laminated Timber (glulam) and Timber-Steel Buckling Restrained Brace (TS-BRB), and the results are compared with the same configuration using steel Hollow Structural Sections (HSS) bracing, using OpenSees structural analyzer. First, to verify the accuracy of the modeling, the numerical results are compared with experimental measurements on several types of elements: (a) diagonally braced frame with steel Hollow Structural Sections with a concentrically steel braced frame which was tested by the quasi-static method under cyclic loading protocol by previous researchers, (b) diagonally glulam braced frame with results of shake table tests on single-story timber braced frames, and (c) Timber-Steel Buckling Restrained Brace (TS-BRB) frame with experimental results of Heavy Timber Buckling-Restrained Braced Frame (HT-BRB). In the second step, the aforementioned timber base bracing alternatives (glulam, TS-BRB) are applied in the special portal steel frame, then the seismic performance of the frame is investigated under pushover, cyclic, time history, and incremental dynamic analysis (IDA), and then the results are compared with the behavior of similar portal frame in two conditions without the brace and diagonally braced with the steel-HSS brace. Results showed that steel-HSS, glulam, and timber-steel buckling restrained braces have significant roles in energy dissipation, increasing shear capacity, decreasing interstory drift, and decreasing weight and cost of estimation of the structure.
Online Access
Free
Resource Link
Less detail

Pinching Effect on Seismic Performance of a SDOF Lightframe Timber Structure

https://research.thinkwood.com/en/permalink/catalogue2542
Year of Publication
2021
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Shear Walls
Author
Eini, Ariya
Zhou, Lina
Ni, Chun
Organization
University of Victoria
Year of Publication
2021
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Shear Walls
Topic
Seismic
Keywords
Pinching Behavior
Energy Dissipation
Hysteresis Loop
Light-frame wood
IDA Analysis
SDOF System
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
Although energy dissipation is one of the key factors in resisting seismic force, current design codes only take into account the ductility of the backbone properties of hysteresis curves, and the energy dissipation is usually not accounted for. This paper focuses on understanding and assessing the influence of energy dissipation due to different pinching levels on the seismic performance of a light-frame wood shear wall system. Timber structures with identical backbone curves but different pinching levels were analyzed. Incremental dynamic analyses were run on a single-degreeof-freedom system with varying pinching stiffness and residual strength. The seismic evaluation is presented by the spectral accelerations causing failure of the structure and the hysteresis energy dissipation under a suite of 22 ground motions (2 components per motion) over a wide range of fundamental periods of typical timber structures. Results show that the effect of pinching on the seismic performance of timber structures is period-dependent. Short period structures are more sensitive to the pinching of hysteresis loops compared to long period structures. The residual strength of pinching loops has a greater influence on the seismic performance than the stiffness of the pinching loops. Hysteretic energy dissipation derived from standard reversed-cyclic tests can provide a better understanding on the seismic resistance of timber structures. However, the hysteretic energy under a seismic event at near-collapse stage neither agrees with quasistatic cyclic test’s energy dissipation nor is well correlated to the maximum seismic capacity of the structure.
Online Access
Free
Less detail

Mechanical performance of timber connections made of thick flexible polyurethane adhesives

https://research.thinkwood.com/en/permalink/catalogue3130
Year of Publication
2021
Topic
Connections
Author
Pecnik, Jaka Gašper
Gavric, Igor
Sebera, Václav
Kržan, Meta
Kwiecien, Arkadiusz
Zajac, Boguslaw
Azinovic, Boris
Organization
University of Primorska
Slovenian National Building and Civil Engineering Institute
Cracow University of Technology
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Topic
Connections
Keywords
Flexible Adhesive
Timber Connection
Polyurethane
Double Lap-shear
Cyclic Loading
Energy Dissipation
Research Status
Complete
Series
Engineering Structures
Summary
This study investigates timber connections with flexible polyurethane adhesives, which prove to have the potential for timber-adhesive composite structures without mechanical connections for seismic regions. Results of conducted cyclic double lap-shear adhesive timber joints tests were compared with available experimental results on timber connections with standard mechanical dowel-type fasteners and with results of numerical finite element analysis. The study found that the shear strength, elastic stiffness and strength degradation capacity of the flexible adhesive connections were significantly higher compared to mechanical fasteners commonly used in seismic-resistant timber connections. The latter, however, manifested larger ultimate displacements but also yielded at lower displacements.
Online Access
Free
Resource Link
Less detail

Seismic Design Options for Post-Tensioned Timber Walls

https://research.thinkwood.com/en/permalink/catalogue1853
Year of Publication
2018
Topic
Design and Systems
Seismic
Material
LVL (Laminated Veneer Lumber)
Application
Walls
Author
Iqbal, Asif
Pampanin, Stefano
Palermo, Alessandro
Buchanan, Andrew
Fragiacomo, Massimo
Publisher
New Zealand Timber Design Society
Year of Publication
2018
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
Walls
Topic
Design and Systems
Seismic
Keywords
Earthquake
Post-Tensioned
Energy Dissipation
Multi-Storey
Research Status
Complete
Series
New Zealand Timber Design Journal
Summary
Structural systems made of prefabricated laminated timber members connected by unbonded post-tensioning and additional mild steel reinforcement have recently been proposed for multi-storey timber buildings. The benefits of the use of post-tensioning to assemble prefabricated timber elements are rapid erection, simple connections, and high seismic resistance. It has been shown that prefabricated post-tensioned timber members can be designed to have excellent seismic resistance, with the post-tensioning providing re-centering capacity after major earthquakes, while energy is dissipated through yielding of replaceable steel elements. Both post-tensioning and energy dissipating elements contribute to the stiffness and strength of the overall system. Investigation into the seismic response of twin post-tensioned timber walls, uncoupled and coupled, with and without energy dissipaters has been performed as part of a larger research programme on timber structures at the University of Canterbury. The walls were fabricated from laminated veneer lumber (LVL). A number of special fuses all made of mild steel were used as energy dissipating devices. The energy dissipaters are attached externally so that they can be removed and replaced easily after a major earthquake. Under gravity or low-seismic loading they would be able to provide, as per standard mild steel reinforcement, substantial stiffness and strength. As additional option, plywood sheets have been used to couple the LVL walls in which case the nails dissipated energy through yielding during rocking motion of the walls. This paper discusses the experimental tests and numerical validation of the response of posttensioned timber wall systems. The results show excellent seismic behaviour with very little residual damage. This research also demonstrates the practical feasibility of post-tensioned timber walls for multi-storey timber buildings as well as their versatility of design and use.
Online Access
Free
Resource Link
Less detail

Shaking Table Testing of a Multi-Storey Post-Tensioned Glulam Building: Preliminary Experimental Results

https://research.thinkwood.com/en/permalink/catalogue1854
Year of Publication
2018
Topic
Seismic
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Beams
Columns
Author
Carlo Ponzo, Felice
Di Cesare, Antonio
Nigro, Domenico
Simonetti, Michele
Smith, Tobias
Pampanin, Stefano
Publisher
New Zealand Timber Design Society
Year of Publication
2018
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Beams
Columns
Topic
Seismic
Design and Systems
Keywords
Post-Tensioned
Earthquake
Multi-Storey
Shaking Table Test
Pres-Lam
Hysteretic
Energy Dissipation
Seismic Loading
Research Status
Complete
Series
New Zealand Timber Design Journal
Summary
This paper describes the results of preliminary shaking table testing performed on a post-tensioned glulam framed building in the structural laboratory of the University of Basilicata in Potenza, Italy. This experimental campaign is part of a series of experimental tests in collaboration with the University of Canterbury in Christchurch, New Zealand. The specimen is 3-dimensional, 3-storey, 2/3rd scale and is made up of post-tensioned timber frames in both directions. During the testing programme the specimen was tested with and without the addition of dissipative steel angle reinforcing which was designed to yield at a certain level of frame drift. These steel angles release energy through hysteresis during movement thus increasing damping. The specimen was subjected to a selection of natural earthquake records with increasing (as % of PGA) levels of seismic loading. This paper briefly discusses the testing set-up and then presents the result of the first phase of experimental testing with and without additional reinforcing.
Online Access
Free
Resource Link
Less detail

Cyclic Load Behaviour of Beam-to-Column Glulam Joints Combining Glued-in Rods with Steel Brackets

https://research.thinkwood.com/en/permalink/catalogue2028
Year of Publication
2018
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Ling, Zhibin
Liu, Weiqing
Yang, Huifeng
Xiang, Zhe
Year of Publication
2018
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Beam-to-Column
Joints
Glued-In Rods
Steel Brackets
Cyclic Loading
Monotonic Loading
Failure Modes
Stiffness
Ductility
Energy Dissipation
Hysteresis Loop
Douglas-Fir
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
This paper presents an experimental campaign conducted on the beam-to-column glulam joints combing glued-in rods and steel brackets (BCGS glulam joints) aiming to investigate the mechanical behaviour of these glulam joints under low cyclic loading. Three types of steel brackets were designed for connecting the beam and column combing with glued-in rods and to work as energy dissipaters. In each group of specimens (except for group MJ4), two specimens were tested under monotonic loading and the others were subjected to low cyclic loading. The test results were summarized comprehensively in terms of failure modes, joint stiffness, hysteresis loops, ductility and energy dissipation ability. Generally, the difference of load capacity between BCGS glulam joints and the beam-to-column glulam joints only with glued-in rods (BCG glulam joints) was not significant. The joint stiffness of BCG glulam joints was higher than that of the BCGS glulam joints, while the stiffness degradation of the later is slower than the former. The hysteresis loops of the BCGS glulam joints exhibited less pinching effect obviously compared with the BCG glulam joints, which indicated that the energy dissipation ability of the glulam joints with glued-in rods could be improved significantly by using the steel brackets as energy dissipaters. Moreover, it should be noted that the hysteresis loops of groups CJ1 showed slipping effect obviously during testing. This might due to the insufficient shear resistance of these two groups, so that further investigations on BCG glulam joints with shear-resisting components are urgently needed.
Online Access
Free
Resource Link
Less detail

Experimental and Numerical Analysis of Flexible Polymer Connections for CLT Buildings

https://research.thinkwood.com/en/permalink/catalogue2057
Year of Publication
2018
Topic
Connections
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Azinovic, Boris
Kramar, Miha
Pazlar, Tomaž
Gams, Matija
Kwiecien, Arkadiusz
Weckendorf, Jan
Sustersic, Iztok
Organization
Cracow University of Technology
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Connections
Mechanical Properties
Seismic
Keywords
Pull-Pull Tests
Cyclic Loading
Energy Dissipation
Glued-In Rods
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
This paper explores the possibility of using flexible adhesives to dissipate energy in CLT buildings during earthquakes. In the first series of tests, a rod glued in a CLT panel with flexible adhesive was investigated. The connection was tested in pull-pull configuration using cyclic, tension-only loading. Different rod diameters and different thicknesses of the glue layer were tested. The tests have shown that the adhesive can resist large deformations and exhibits fairly large energy dissipation capacity. Based on the test results the numerical analyses were performed to test the behaviour of the connection when applied in CLT buildings. Existing constitutive models available in OpenSees software were used to simulate the specific hysteretic behaviour of the connection. The results have shown that the CLT wall anchored with "flexible" glued-in rods would have a significant energy dissipation capacity if a sufficient number of them were used as the hold-down devices. Such system could be used to dissipate energy in seismic areas.
Online Access
Free
Resource Link
Less detail

In-Plane Strength and Stiffness of Cross-Laminated Timber Shear Walls

https://research.thinkwood.com/en/permalink/catalogue2180
Year of Publication
2018
Topic
Mechanical Properties
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls

Investigating the Hysteretic Behavior of Cross-Laminated Timber Wall Systems due to Connections

https://research.thinkwood.com/en/permalink/catalogue1230
Year of Publication
2018
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Izzi, Matteo
Polastri, Andrea
Fragiacomo, Massimo
Publisher
American Society of Civil Engineers
Year of Publication
2018
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Connections
Mechanical Properties
Keywords
Numerical Model
Mechanical Behavior
Failure Mechanisms
Anchoring
Joints
Load-Displacement
Energy Dissipation
Research Status
Complete
Series
Journal of Structural Engineering
Summary
Cross-laminated timber (CLT) wall systems are composed of massive timber panels that are fastened together and to the horizontal elements (foundations or intermediate floors) with step joints and mechanical connections. Due to the high in-plane stiffness of CLT, the shear response of such systems depends strongly on the connections used. This paper proposes a numerical model capable of predicting the mechanical behavior and failure mechanisms of CLT wall systems. The wall and the element to which it is anchored are simulated using three-dimensional (3D) solid bodies, while the connections are modeled as nonlinear hysteretic springs. Typical racking tests of wall systems are reproduced by varying the assumptions used to schematize the behavior of the connections. Results are compared with test data published in the literature, and the differences are discussed. The influence of the boundary conditions (vertical load applied on top of the wall and friction at its base) and aspect ratio of the panel are investigated via a parametric numerical study. Finally, the performance of a wall system assembled with two CLT panels is analyzed, highlighting how the properties of the anchoring connections and vertical step joints affect the load-displacement response and energy dissipation.
Online Access
Free
Resource Link
Less detail

47 records – page 1 of 5.