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Advancement of Timber Panels as Structural Elements in Composite Floor Systems of Timber-Steel Hybrid Structures

https://research.thinkwood.com/en/permalink/catalogue2785
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Floors
Hybrid Building Systems
Organization
Auburn University
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Floors
Hybrid Building Systems
Topic
Design and Systems
Keywords
Timber-Steel Hybrid
Research Status
In Progress
Summary
Auburn University’s (AU) School of Forestry and Wildlife Sciences (SFWS) in Alabama actively works to increase awareness of the benefits of CLT along with hybrid systems for more widespread adoption in multiple building segments. AU’s two-year project proposal outlines a plan that will establish a preliminary design for the usage of a timber-steel composite system, utilizing CLT or laminated veneer lumber (LVL), as an option that will replace reinforced concrete slabs to improve the structural performance for buildings six stories or more.
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Advancement of Timber Panels as Structural Elements in Timber-Steel Composite Floor Systems

https://research.thinkwood.com/en/permalink/catalogue2844
Topic
Design and Systems
Material
Steel-Timber Composite
Application
Floors
Organization
Auburn University
Material
Steel-Timber Composite
Application
Floors
Topic
Design and Systems
Keywords
Mass Timber
Timber-Steel Hybrid
Research Status
In Progress
Notes
Project contact is Kadir Sener at Auburn University
Summary
While the emphasis in the timber industry understandably focuses predominately on complete mass timber structures, opportunities to substantially expand the mass timber market exist using composite timber-steel systems. Timber-steel composite systems have a high potential to be an economically, architecturally, and structurally feasible system to expand the usage of timber panels for mid-rise and high-rise structures where mass timber is currently not a feasible option. In this novel system, prefabricated timber panels replace reinforced concrete slabs to provide the floor and diaphragm elements that work compositely with steel beams and to improve the structural performance compared to either individual material. Considerable testing effort outside the US has explored the feasibility and benefits of these composite systems. This has led to implementation of this novel system on a number of international construction projects. However, the topic has not been assimilated by researchers and practitioners in the US. Hence, this proposal focuses on identifying and removing barriers and providing design guidance on using steel-timber composite systems in US construction. The proposal: (i) Engages a diverse body of stakeholders in an advisory panel and workshop, (ii) Completes engineering-based testing and analysis to demonstrate feasibility, (iii) Performs constructability studies (i.e., construction cost, speed, env. impact), and (iv) Establishes preliminary design guidelines and approaches. The goal of the project will be to demonstrate the performance and economy of a timber-steel composite system(s) and establish preliminary design guidelines and approaches for target stakeholders. Ultimately, the project will develop experimentally validated design-detailing configurations and establish design specifications for new mass timber markets in multiple construction sectors.
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Analysis of Mechanical Properties of Cross-Laminated Timber (CLT) with Plywood using Korean Larch

https://research.thinkwood.com/en/permalink/catalogue1806
Year of Publication
2018
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Choi, Chul
Kojima, Erina
Kim, Kyung-Jung
Yamasaki, Mariko
Sasaki, Yasutoshi
Kang, Seog-Goo
Publisher
North Carolina State University
Year of Publication
2018
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Korean Larch
Bending Strength
Hybrid Wooden-Core Laminated Timber (HWLT)
Lamina
Compression
Tensile Strength
Korea
In-Plate Shear Failure
Research Status
Complete
Series
BioResources
Summary
The bending strength of hybrid wooden-core laminated timber (HWLT), a composite material made from existing cross-laminated timber (CLT) and plywood, was analyzed. Using plywood makes it possible to decrease the bending strength of the starting material. Korea Larch (Larix kaempferi Carr.) was used as plywood because of its popularity in Korea. To analyze HWLT’s bending properties, each component (lamina, plywood) was tested for bending, compression, and tensile strengths. The results showed that the HWLT’s bending strength depended on the plywood’s number of plies. With an increased number of plies, plywood’s bending strength decreased, and also HWLT’s bending strength decreased. Most of the failure showed in-plate shear failure of plywood. This result meant that use of reinforced plywood made it possible to increase HWLT’s bending strength for structural material.
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An innovative timber-steel hybrid beam consisting of glulam mechanically reinforced by means of steel rod: Analytical and preliminary numerical investigations

https://research.thinkwood.com/en/permalink/catalogue3135
Year of Publication
2021
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Wang, Tianxiang
Wang, Yue
Crocetti, Roberto
Franco, Luca
Schweigler, Michael
Wålinder, Magnus
Organization
KTH royal institute of technology
Univiersità IUAV di Venezia
Linnaeus University
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Hybrid Structure
Mechanical Connection
Shear Key
Timber-Steel Hybrid Beam
Analytical Model
Numerical Analysis
Retrofitting Techniques
Research Status
Complete
Series
Journal of Building Engineering
Summary
There is an increasing interest in large-dimensional timber structural elements within the construction sector in order to fulfil the combined demand of sustainability, open spaces and architectural flexibility. Current timber technology allows for efficient production of long-size beams, but many problems are related to their overall high costs due to difficulties in transportation, manufacturing on site and handling during the mounting phase. Hence, the aim of this work is to propose and study an innovative timber-steel hybrid structural element composed of shorter pieces of beams connected and reinforced by means of a system consisting of steel shear keys and steel rods. The small timber elements and steel devices can be prefabricated with low costs and easily assembled into large elements at the construction sites. The proposed system can also be used for retrofitting of existing timber members when it is necessary to increase their strength, stiffness and ductility. The structural behavior of the proposed system was therefore studied both as a connection and as a retrofitting technique, which were analyzed via two types of hybrid beams, one with a splice at mid-span and one without, separately. A simple glulam beam with the same geometrical characteristics of the two hybrid structures was also investigated for the comparison of the structural behavior. The analytical results show that the hybrid beams with and without splice have both obtained significant increasement in the stiffness, strength and ductility. The numerical analyses are limited in the elastic stage due to the elastic mechanical properties assigned to the structural components. The numerical results show good agreement with the analytical ones for each type of beam in terms of the stiffness in the elastic stage. Finally, the influence of the parameters such as the distance between shear keys, slip modulus of shear keys and diameter of rod, on the structural behavior of hybrid beams is discussed in this paper.
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Braced Frame System for Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2527
Year of Publication
2020
Topic
Design and Systems
Seismic
Material
Glulam (Glue-Laminated Timber)
Application
Hybrid Building Systems
Frames
Author
Iqbal, Asif
Organization
University of Northern British Columbia
Year of Publication
2020
Format
Report
Material
Glulam (Glue-Laminated Timber)
Application
Hybrid Building Systems
Frames
Topic
Design and Systems
Seismic
Keywords
Lateral Load Resisting Systems
Sustainability
Post-Tensioned
Connections
Braced Frame Model
Timber-Steel Hybrid
Research Status
Complete
Summary
Advanced sustainable lateral load resisting systems that combine ductile and recyclable materials offer a viable solution to resist seismic load effects in environmentally responsible ways. This paper presents the seismic response of a post-tensioned timber-steel hybrid braced frame. This hybrid system combines glulam frame with steel braces to improve lateral stiffness while providing self-centreing capability under seismic loads. The proposed system is first presented. A detailed numerical model of the proposed system is then developed with emphasis on the connections and inelastic response of bracing members. Various types of braced frames including diagonal, cross and chevron configurations are numerically examined to assess the viability of the proposed concept and to confirm the efficiency of the system. A summary of initial findings is presented to demonstrate usefulness of the hybrid system. The results demonstrate that the proposed system increases overall lateral stiffness and ductility while still being able to achieve self-centring. Some additional information on connection details are provided for implementation in practical structures. The braced-frame solution is expected to widen options for lateral load resisting systems for mid-to-high-rise buildings.
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Carbon Value Engineering: Integrated Carbon and Cost Reduction Strategies for Building Design

https://research.thinkwood.com/en/permalink/catalogue2268
Year of Publication
2019
Topic
Environmental Impact
Cost
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Floors
Walls
Beams
Author
Robati, Mehdi
Oldfield, Philip F.
Nezhad, Ali Akbar
Carmichael, David
Organization
UNSW Sydney
Multiplex Australasia
Publisher
Cooperative Research for Low Carbon Living
Year of Publication
2019
Format
Report
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Floors
Walls
Beams
Topic
Environmental Impact
Cost
Keywords
Value Engineering
Embodied Carbon
Hybrid Life Cycle Assessment
Capital Cost
Environmentally-extended Input-Output Analysis
Research Status
Complete
Summary
The research presents a Carbon Value Engineering framework. This is a quantitative value analysis method, which not only estimates cost but also considers the carbon impact of alternative design solutions. It is primarily concerned with reducing cost and carbon impacts of developed design projects; that is, projects where the design is already a completed to a stage where a Bill of Quantity (BoQ) is available, material quantities are known, and technical understanding of the building is developed. This research demonstrates that adopting this integrated carbon and cost method was able to reduce embodied carbon emissions by 63-267 kgCO2-e/m2 (8-36%) when maintaining a concrete frame, and 72-427 kgCO2-e/m2 (10-57%) when switching to a more novel whole timber frame. With a GFA of 43,229 m2 these savings equate to an overall reduction of embodied carbon in the order of 2,723 – 18,459 tonnes of CO2-e. Costs savings for both alternatives were in the order of $127/m2 which equates to a 10% reduction in capital cost. For comparison purposes the case study was also tested with a high-performance façade. This reduced lifecycle carbon emissions in the order of 255 kgCO2-e/m2, over 50 years, but at an additional capital cost, due to the extra materials. What this means is strategies to reduce embodied carbon even late in the design stage can provide carbon savings comparable, and even greater than, more traditional strategies to reduce operational emissions over a building’s effective life.
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Free
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CLT Infill Panels in Steel Moment Resisting Frames as a Hybrid Seismic Force Resisting System

https://research.thinkwood.com/en/permalink/catalogue107
Year of Publication
2013
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Dickof, Carla
Organization
University of British Columbia
Year of Publication
2013
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Keywords
National Building Code of Canada
Timber-Steel Hybrid
Seismic Force Resisting System
Research Status
Complete
Summary
This paper examines CLT-steel hybrid systems at three, six, and nine storey heights to increase seismic force resistance compared to a plain wood system. CLT panels are used as infill in a steel moment frame combining the ductility of a steel moment frame system with a stiffness and light weight of CLT panels. This system allows for the combination of high strength and ductility of steel with high stiffness and light weight of timber. This thesis examines the seismic response of this type of hybrid seismic force resisting system (SFRS) in regions with moderate to high seismic hazard indices. A detailed non-linear model of a 2D infilled frame system and compared to the behavior of a similar plain steel frame at each height. Parametric analysis was performed determining the effect of the panels and the connection configuration, steel frame design, and panel configuration in a multi-bay system. Static pushover loading was applied alongside semi-static cyclic loading to allow a basis of comparison to future experimental tests. Dynamic analysis using ten ground motions linearly scaled to the uniform hazard spectra for Vancouver, Canada with a return period of 2% in 50 years as, 10% in 50 years, and 50% in 50 years to examine the effect of infill panels on the interstorey drift of the three, six, and nine storey. The ultimate and yield strength and drift capacity are determined and used to determine the overstrength and ductility factors as described in the National Building Code of Canada 2010.
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Free
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Combination of Steel Plate Shear Walls and Timber Moment Frames for Improved Seismic Performance

https://research.thinkwood.com/en/permalink/catalogue2735
Year of Publication
2020
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Frames
Author
Iqbal, Asif
Todorov, Borislav
Billah, Muntasir
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Frames
Topic
Seismic
Keywords
Timber Moment Frames
Steel Plate Shear Walls
Hybrid
Seismic Performance
Interstory Drifts
Conference
World Conference on Earthquake Engineering
Research Status
Complete
Summary
Recent interests in adopting sustainable materials and developments in construction technology have created a trend of aiming for greater heights with timber buildings. With the increased height these buildings are subjected to higher level of lateral load demand. A common and efficient way to increase capacity is to use shearwalls, which can resist significant part of the load on the structures. Prefabricated mass timber panels such as those made of Cross-Laminated Timber (CLT) can be used to form the shearwalls. But due to relatively low stiffness value of timber it is often difficult to keep the maximum drifts within acceptable limit prescribed by building codes. It becomes necessary to either increase wall sizes to beyond available panel dimensions or use multiple or groups of walls spread over different locations over the floor plan. Both of the options are problematic from the economic and functional point of view. One possible alternative is to adopt a Hybrid system, using Steel Plate Shear Walls (SPSW) with timber moment frames. The SPSW has much higher stiffness and combined with timber frames it can reduce overall building drifts significantly. Frames with prefabricated timber members have considerable lateral load capacity. For structures located in seismic regions the system possesses excellent energy dissipation ability with combination of ductile SPSW and yielding elements within the frames. This paper investigates combination of SPSW with timber frames for seismic applications. Numerical model of the system has been developed to examine the interaction between the frames and shear walls under extreme lateral load conditions. Arrangements of different geometries of frames and shear walls are evaluated to determine their compatibility and efficiency in sharing lateral loads. Recommendations are presented for optimum solutions as well as practical limits of applications.
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Comparison of the Seismic Performance of Different Hybrid Timber-Steel Frame Configurations

https://research.thinkwood.com/en/permalink/catalogue1775
Year of Publication
2016
Topic
Seismic
Design and Systems
Application
Hybrid Building Systems
Shear Walls
Author
Marin, Jose Alberto
He, Minjuan
Year of Publication
2016
Format
Conference Paper
Application
Hybrid Building Systems
Shear Walls
Topic
Seismic
Design and Systems
Keywords
Finite Element Model
Timber-Steel Hybrid
Deformation
Lateral Loading
Abaqus
Displacement
Inter-Story Drift
Diaphragm
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 5401-5408
Summary
This paper presents a finite element modeling case study of three different designs of hybrid timber-steel 6-story buildings. One of the buildings is composed by steel frames and timber diaphragms while the other two cases consist of the initial design with timber shear walls added in different dispositions, one with outer walls and the other...
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Free
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Conventional and Novel Timber Steel Hybrid Connections: Testing, Performance and Assessment

https://research.thinkwood.com/en/permalink/catalogue187
Year of Publication
2015
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Schneider, Johannes
Organization
University of British Columbia
Year of Publication
2015
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Connections
Seismic
Keywords
Timber-Steel Hybrid
Fasteners
Quasi-Static
Monotonic Loading
Cyclic Loading
Brackets
Tube Connections
Research Status
Complete
Summary
The focus of this research is the connection between steel frame and the infill wall. Over 100 conventional bracket-type connections with various combinations of bracket and fasteners with cross-laminated timber were tested, investigated and assessed for damage under seismic loading protocols for a hybrid application. An energy-based formulation according to Krätzig was applied to calculate the development of the damage index, and the resulting index was validated with visual observation. Six of the connections were modeled in OpenSees. For the modeling, a CUREE-10 parameter model was chosen to reproduce the test curves. The load-displacement results from both test and model were analyzed; the first method according to ASTM standards, where the envelope curve of the hysteretic results are considered and plotted in an equivalent energy elastic-plastic curve (EEEP). The second analyzing method used, was Krätzig’s damage accumulation model. Throughout all six combinations and both loading directions (parallel- and perpendicular-to-the-grain) a major difference was found in the analyzing methods. The EEEP curve roughly approximates the performance but with the damage accumulation method showed that analysis of the subsequent cycles is required to better reflect the empirical performance of the connections. To avoid the extensive destruction of a bracket type connection after completion of seismic loadings, a new approach was chosen. It was found that a tube connection can obtain comparably similar strength results as a conventional bracket connection. The computed mechanical properties of bracket-type and tube-type connections were compared and evaluated. The new tube connection showed great potential for future timber-steel hybrid structures and their connecting challenge. A total of 27 connection assemblies were tested under quasi-static monotonic and reversed cyclic loads. The tube connections showed two major differences when compared to traditional bracket connections: i) the completely linear elastic behaviour at the beginning, and ii) the continued load increase after yielding. Both phenomena are founded in the geometry of that connector effectively making the novel connector a very promising alternative.
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70 records – page 1 of 7.