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73 records – page 1 of 8.

Timber Semirigid Frame Connection with Improved Deformation Capacity and Ductility

https://research.thinkwood.com/en/permalink/catalogue3017
Year of Publication
2022
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Johanides, Marek
Lokaj, Antonin
Mikolasek, David
Mynarcik, Petr
Dobes, Pavel
Sucharda, Oldrich
Organization
VSB-Technical University of Ostrava
Editor
Branco, Jorge Manuel
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Connections
Mechanical Properties
Keywords
Ductility
Load-capacity
Frame Connection
Screws
Bolts and Dowels
Research Status
Complete
Series
Buildings
Summary
The present study deals with the innovation and the possibilities of improving the design solution of a frame connection for two selected types of fasteners. All specimens were made of glued laminated timber. Dowel-type mechanical fasteners, a combination of bolts and dowels, and full-threaded screws were used for the connection. The main goal of this research was to replace the typical solution (common dowel-type fasteners) with a more modern, faster, and easier solution in order to improve the load-carrying capacity, ductility, and deformation capacity of this type of frame connection. This article also aimed to provide a detailed evaluation of the mechanical properties of the used glued laminated timber and fasteners in order to comprehensively evaluate the research task. For the design solution, a frame connection created from a system of two struts and a partition was chosen as the basis of the experimental program. Dowel-type mechanical fasteners, as well as combinations of bolts and dowels, were used for the connection; however, in addition to these standardly used mechanical fasteners, full-threaded screws were used. The article describes the use of static destructive testing to determine the ductility of the connection, considering different variations in the strengthening of the individual segments of the mentioned connection means. In the first variation, the individual components of the frame were not reinforced in any way. In the second, the crossbar was reinforced with two full-threaded bolts. In the third, the webs and the crossbar were reinforced with two full-threaded bolts. In the article, these ductility values were compared with each other and the procedure was set by the currently valid standard.
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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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A study on beam-to-column moment-resisting timber connections under service load, comparing full-scale connection testing and mock-up frame assembly

https://research.thinkwood.com/en/permalink/catalogue3116
Year of Publication
2022
Topic
Connections
Application
Frames
Author
Vilguts, Aivars
Nesheim, Sveinung Ørjan
Stamatopoulos, Haris
Malo, Kjell Arne
Organization
Norwegian University of Science and Technology
Publisher
Springer
Year of Publication
2022
Format
Journal Article
Application
Frames
Topic
Connections
Keywords
Moment-resisting Connection
Semi-rigid Connection
Screwed-in Threaded Rods
Experimental Modal Analysis
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
A new timber frame structural system consisting of continuous columns, prefabricated hollow box timber decks and beam-to-column moment-resisting connections is investigated. The hollow box timber decks allow long spans with competitive floor height and efficient material consumption. To achieve long spans, semi-rigid connections at the corners of deck elements are used to join the columns to the deck elements. In the present paper, experimental investigations of a semi-rigid moment-resisting connection and a mock-up frame assembly are presented. The semi-rigid connection consists of inclined screwed-in threaded rods and steel coupling parts, connected with friction bolts. Full-scale moment-resisting timber connections were tested under monotonic and cyclic loading to quantify rotational stiffness, energy dissipation and moment resistance. The mock-up frame assembly was tested under cyclic lateral loading and with experimental modal analysis. The lateral stiffness, energy dissipation, rotational stiffness of the connections and the eigen frequencies of the mock-up frame assembly were quantified based on the experimental tests in combination with a Finite Element model, i.e., the model was validated with experimental results from the rotational stiffness tests of the beam-to-column connections. Finally, the structural damping measured with experimental modal analysis was evaluated and compared with FE model using the material damping of timber parts and equivalent viscous damping of the moment-resisting connections.
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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.
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Numerical Analysis of Masonry-Infilled RC-CLT Panel Connections

https://research.thinkwood.com/en/permalink/catalogue3258
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Frames
Author
Mehdipour, Zabih
Poletti, Elisa
Branco, Jorge M.
Lourenço, Paulo B.
Organization
University of Minho
Editor
Tullini, Nerio
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Frames
Topic
Mechanical Properties
Keywords
RC-CLT Connectors
Optimum Arrangement of Connections
Masonry-infilled RC Frame
Research Status
Complete
Series
Buildings
Summary
CLT panels have been investigated for reinforcement of existing masonry-infilled RC framed buildings through the increase of the overall lateral stiffness of the structure, thus reducing the story drift demand. The contribution of CLT panels depends on the connection to the RC frame elements. This paper evaluates the role of connectors by which CLT is attached to RC frames for capacity, ductility, and energy dissipation of the structure and its elements separately using different kinds of RC-CLT connections, and ultimately finds and compares the optimum number and arrangement of connectors. The results show that the geometry of connections plays a greater seismic role in RC frames than their mechanical properties. Regarding masonry infills, they allow a higher strength capacity but reduce the efficacy of CLT strengthening. However, strong connectors decrease the ability of infills in dissipation. Finally, in the optimum arrangement of connectors, they are distributed equally along the upper and lower beams at equal spacing, where CLT is added, starting in the middle of the beams and moving to the frame corners.
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Direct Displacement-based Seismic Design of Glulam Frames with Buckling Restrained Braces

https://research.thinkwood.com/en/permalink/catalogue3265
Year of Publication
2022
Topic
Seismic
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Dong, Wenchen
Li, Minghao
Sullivan, Timothy
MacRae, Gregory
Lee, Chin-Long
Chang, Theodore
Organization
University of Canterbury
University College London
Publisher
Taylor&Francis Online
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Seismic
Keywords
Glulam Frame
Buckling Restrained Braces
Direct Displacement-Based Design
BRB-Timber Connections
Nonlinear Time-history Analyses
Research Status
Complete
Series
Journal of Earthquake Engineering
Summary
This paper presents a direct displacement-based design (DDBD) approach for the buckling restrained braces (BRBs) braced glue-laminated timber (glulam) frame (BRBGF) structures. First, the critical design parameters of the DDBD approach were derived for BRBGFs. Then, using experimentally verified numerical models, pushover analyses and nonlinear time-history analyses (NLTHAs) were conducted on a series of one-storey BRBGFs to calibrate the stiffness adjustment factor for BRB-timber connections and the spectral displacement reduction factor . Finally, the DDBD approach was verified as a prospective approach for the seismic design of multi-storey BRBGF buildings by NLTHAs of the case study buildings.
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The wall–frame interaction effect in CLT-steel hybrid system

https://research.thinkwood.com/en/permalink/catalogue3260
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Frames
Shear Walls
Author
Vogiatzis, Tzanetis
Tsalkatidis, Themistoklis
Efthymiou, Evangelos
Organization
Aristotle University of Thessaloniki
Norwegian University of Life Sciences
Publisher
Frontiers
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Frames
Shear Walls
Topic
Mechanical Properties
Keywords
Steel-moment Resisting Frame
Steel-timber Hybrid Structure
Seismic Behavior
Numerical Analysis
Ductility
Research Status
Complete
Series
Frontiers in Built Environment
Summary
Behaviour and capacity of cross-laminated timber (CLT) infills built inside steel frames have been given increasing research attention in recent years. It is widely accepted that when the CLT wall panel is built in tight contact with the bounding steel frame to participate in the load sharing, its inherently large in-plane stiffness will attract additional forces to the frame area and change the behaviour of the hybrid system. If not designed properly, the structural integrity of both the infill and the frame will be compromised. It is thus crucial to accurately evaluate the contribution of the infill CLT wall panel to the stiffness and strength of the hybrid system. To that end, a finite element study was performed to investigate the frame-wall interaction effect on the behaviour of hybrid systems. The lateral stiffness, lateral load capacities and hysteretic characteristics of the hybrid systems with frictional and connected interfaces were investigated. The load-sharing effect between the CLT wall and the steel frame was studied. The numerical results showed that the connected models were very effective as the infill absorbed a substantial part of the lateral load, during the initial stages of loading.
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Carbon Impact and Cost of Mass Timber Beam–Column Gravity Systems

https://research.thinkwood.com/en/permalink/catalogue2883
Year of Publication
2021
Topic
Environmental Impact
Application
Frames
Author
Chaggaris, Rachel
Pei, Shiling
Kingsley, Greg
Feitel, Alexis
Organization
Colorado School of Mines
Editor
Ganguly, Indroneil
Publisher
MDPI
Year of Publication
2021
Format
Journal Article
Application
Frames
Topic
Environmental Impact
Keywords
IBC
Tall Wood Buildings
Gravity Framing System
Embodied Carbon
Mass Timber
Biogenic Carbon
Research Status
Complete
Series
Sustainability
Summary
The need to lower the embodied carbon impact of the built environment and sequester carbon over the life of buildings has spurred the growth of mass timber building construction, leading to the introduction of new building types (Types IV-A, B, and C) in the 2021 International Building Code (IBC). The achievement of sustainability goals has been hindered by the perceived first cost assessment of mass timber systems. Optimizing cost is an urgent prerequisite to embodied carbon reduction. Due to a high level of prefabrication and reduction in field labor, the mass timber material volume constitutes a larger portion of total project cost when compared to buildings with traditional materials. In this study, the dollar cost, carbon emitted, and carbon sequestered of mass timber beam–column gravity system solutions with different design configurations was studied. Design parameters studied in this sensitivity analysis included viable building types, column grid dimension, and building height. A scenario study was conducted to estimate the economic viability of tall wood buildings with respect to land costs. It is concluded that, while Type III building designations are the most economical for lower building heights, the newly introduced Type IV subcategories remain competitive for taller structures while providing a potentially significant embodied carbon benefit.
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A theoretical study of the dynamic response of planar timber frames with semi-rigid moment-resisting connections subjected to wind loads

https://research.thinkwood.com/en/permalink/catalogue2960
Year of Publication
2021
Topic
Wind
Application
Frames
Author
Cao, Alex Sixie
Stamatopoulos, Haris
Organization
Norwegian University of Science and Technology
ETH Zurich
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Application
Frames
Topic
Wind
Keywords
Moment-resisting Timber Frames
Semi-rigid Connection
Wind-induced Vibrations
Time-domain Analysis
Frequency-domain Analysis
Serviceability
Tall Timber Buildings
Research Status
Complete
Series
Engineering Structures
Summary
The dynamic response of semi-rigid timber frames subjected to wind loads is investigated numerically in this paper. The dynamic response of more than one million unique frames with different parameters was assessed with the frequency-domain gust factor approach, which is currently adopted by Eurocode 1, and the time-domain generalized wind load method. In the generalized wind load method, the frames were simulated for three different wind velocities with five simulations per unique combination of parameters, resulting in more than twelve million simulations in total. Qualitative and quantitative observations of the dataset were made. Empirical expressions for the accelerations, displacements, and fundamental eigenfrequency were proposed by the use of nonlinear regression applied to the obtained numerical results and a frequency reduction factor was developed. The wind-induced accelerations obtained by the two methods were compared to the corresponding serviceability criteria according to ISO10137, providing insight about the feasibility of moment-resisting frames as a lateral load-carrying system for mid-rise timber buildings. Comparison between the theoretical gust factor approach and the generalized wind load method showed that the gust factor approach was nonconservative in most cases. Finally, the effect of uniform and non-uniform mass distributions was investigated, with a theoretical reduction in top-floor accelerations of 50% and 25% respectively.
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Earthquake Damage Reduction in Timber Frame Houses Using Small-Size Fluid Damper

https://research.thinkwood.com/en/permalink/catalogue2975
Year of Publication
2021
Topic
Seismic
Application
Frames
Author
Nakamura, Yutaka
Fujii, Hinako
Organization
Shimane University
Editor
Raheem, Shehata
Publisher
Frontiers
Year of Publication
2021
Format
Journal Article
Application
Frames
Topic
Seismic
Keywords
Earthquake Damage
Timber Frame House
Fluid Damper
Response Analysis
Inter-Story Drift
Wall Ratio
Research Status
Complete
Series
Frontiers in Built Environment
Summary
Timber frame structures are common traditional methods of housing construction, which use squared-off timber beams, columns, and walls as lateral load-bearing members. The seismic performance of timber frame houses can be secured by the load-bearing capacity of erected braces and walls; however, past major earthquakes have caused severe damage to earthquake-resistant timber frame houses. This study investigates the effect of small-size fluid dampers on the earthquake damage reduction in a timber frame house through earthquake response analyses. A detailed analytical model was generated based on an actual two-story timber frame house, which was designed for the highest seismic grade using the latest Japanese standards. Time-history response analyses were carried out for the analytical model subjected to the 2016 Kumamoto earthquake with and without small-size fluid dampers. The small-size fluid damper is equipped with a relief mechanism for the damping force, and its damping property can be expressed using the Maxwell model. Four or seven fluid dampers were installed in the first story of the model to investigate their effect on the earthquake damage reduction. The results of the earthquake response analyses show that the four and seven fluid dampers can reduce the maximum first-story drift angle by approximately one-third and half, respectively. The dampers suppress the residual deformation, control the elongation of the fundamental period during the response, and restrain the amplitude growth. A small-size fluid damper has an equivalent quake resistance to a conventional structural wall with a wall ratio of 3 plus.
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73 records – page 1 of 8.