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Costing Analysis for Common Mass-timber Archetypes

https://research.thinkwood.com/en/permalink/catalogue2812
Topic
Cost
Design and Systems
Energy Performance
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Hybrid Building Systems
Building Envelope
Organization
Morrison Hershield
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Hybrid Building Systems
Building Envelope
Topic
Cost
Design and Systems
Energy Performance
Keywords
Parametric Design
Cost
Mass Timber
Building Code
BC Energy Step Code
National Energy Code of Canada for Buildings
Research Status
In Progress
Notes
Project contact is Eric Wood at Morrison Hershfield
Summary
The project develops building archetypes, cost data and energy modelling to allow users to cost out mass timber buildings from basic, code-compliant buildings to high-performing, energy-efficient, low-emitting buildings. It will help quantity surveyors, designers, and other decisionmakers undertake business-case development by clarifying cost variables associated with mass-timber construction.
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Mass Timber Economics of 7-12 Storey Residential Rental Buildings

https://research.thinkwood.com/en/permalink/catalogue2813
Topic
Cost
Design and Systems
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
NLT (Nail-Laminated Timber)
Application
Wood Building Systems
Organization
Morrison Hershield
BC Housing
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
NLT (Nail-Laminated Timber)
Application
Wood Building Systems
Topic
Cost
Design and Systems
Keywords
Cost Effective
Cost-Competitive
ROI
Building Code
Affordable Housing
Mass Timber
Research Status
In Progress
Notes
Project contact is Eric Wood at Morrison Hershfield
Summary
The study assesses the potential of mass timber multi-unit residential construction as it compares to traditional methods including concrete and steel in terms of cost competitiveness, cost effectiveness, financial value and ROI. The analysis will include potential limitations of existing building codes, how the codes support or constrain the use of mass timber, including impacts to affordability, and whether further industry and government support of tall wood construction is needed to integrate it into Canada’s housing supply. To inform the analysis, the study produces base case archetypes for concrete and steel structures, and then create a series of comparative archetypes mass timber structures and hybrid structures in the range of 7-12 storeys.
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Sustainability Design Considerations for Timber-Concrete Composite Floor Systems

https://research.thinkwood.com/en/permalink/catalogue3090
Year of Publication
2021
Topic
Design and Systems
Material
Timber-Concrete Composite
Application
Floors
Author
Mirdad, Md Abdul Hamid
Daneshvar, Hossein
Joyce, Thomas
Chui, Ying Hei
Organization
University of Alberta
Publisher
Hindawi
Year of Publication
2021
Format
Journal Article
Material
Timber-Concrete Composite
Application
Floors
Topic
Design and Systems
Keywords
Span Table
Embodied Carbon
Serviceability Limite State
Ultimate Limite State
Research Status
Complete
Series
Advances in Civil Engineering
Summary
Over the last few decades, there has been growing interest in the use of low-carbon materials to reduce the environmental impacts of the construction industry. The advent of mass timber panels (MTP), such as cross laminated timber (CLT), has allowed structural engineers to specify a low-carbon material for a variety of floor design considerations. However, serviceability issues such as vibration and deflection are limiting the construction of longer span timber-only floor systems and have encouraged the development of timber-concrete composite (TCC) systems. The use of concrete would negatively impact on the carbon footprint of the TCC floor system and should be minimized. The purpose of this study was to study the impact on embodied carbon in the TCC system, when the ratio of timber and concrete was varied for specific floor spans. Two MTP products were considered, CLT and glued laminated timber (GLT). The floors were designed to satisfy structural, acoustic, and vibration criteria, and the results were presented in the form of span tables. It was found that using thicker MTP instead of adding concrete thickness to meet a specific span requirement can lead to lower embodied carbon values. Increasing concrete thickness for long-span floor systems led to a reduction in allowable floor span due to the vibration criterion being the controlling design parameter. Increasing timber thickness also resulted in higher strength and stiffness to weight ratios, which would contribute toward reducing the size of lateral load resisting systems and foundations, resulting in further reductions in the embodied carbon of the entire structure.
Online Access
Free
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A Review of the Methods for Predicting the Effective In-Plane Shear Modulus of Cross-Laminated Timber (CLT)

https://research.thinkwood.com/en/permalink/catalogue3091
Year of Publication
2021
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Khan, Mehsam Tanzim
Chui, Ying Hei
Huang Dongsheng
Organization
University of Alberta
Nanjing Forestry University
Publisher
Hindawi
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Mechanical Properties
Keywords
In-Plane Shear
Effective Shear Modulus
Research Status
Complete
Series
Advances in Civil Engineering
Summary
Cross-laminated timber (CLT) is a type of engineered wood product that offers both high in-plane and out-of-plane load-bearing capacity. It is slowly becoming an alternative material for building high-rise structures. However, there is no current standard or regulation for determining the shear modulus of CLT under in-plane loading condition, which is a very important property for its use as structural members. Few methods have been proposed over the last decade to determine the in-plane shear modulus of CLT. Almost all of the methods proposed until now have their strengths and weaknesses. In this paper, some of the prominent methods for determining the in-plane shear modulus of CLT are described and analysed. The descriptions along with the critical discussions will facilitate a better understanding and might pave the way to further enhancements of the method(s) to determine the in-plane shear modulus of CLT.
Online Access
Free
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Wood Vault: remove atmospheric CO2 with trees, store wood for carbon sequestration for now and as biomass, bioenergy and carbon reserve for the future

https://research.thinkwood.com/en/permalink/catalogue3086
Year of Publication
2022
Topic
Environmental Impact
Author
Zeng, Ning
Hausmann, Henry
Organization
University of Maryland
Publisher
Springer
Year of Publication
2022
Format
Journal Article
Topic
Environmental Impact
Keywords
Wood Harvesting and Storage
Wood Vault
Research Status
Complete
Series
Carbon Balance and Management
Summary
Background Wood harvesting and storage (WHS) is a hybrid Nature-Engineering combination method to combat climate change by harvesting wood sustainably and storing it semi-permanently for carbon sequestration. To date, the technology has only been purposefully tested in small-scale demonstration projects. This study aims to develop a concrete way to carry out WHS at large-scale. Results We describe a method of constructing a wood storage facility, named Wood Vault, that can bury woody biomass on a mega-tonne scale in specially engineered enclosures to ensure anaerobic environments, thus preventing wood decay. The buried wood enters a quasi-geological reservoir that is expected to stay intact semi-permanently. Storing wood in many environments is possible, leading to seven versions of Wood Vault: (1) Burial Mound (Tumulus or Barrow), (2) Underground (Pit, Quarry, or Mine), (3) Super Vault, (4) Shelter, (5) AquaOpen or AquaVault with wood submerged under water, (6) DesertOpen or DesertVault in dry regions, (7) FreezeVault in cold regions such as Antarctica. Smaller sizes are also possible, named Baby Vault. A prototype Wood Vault Unit (WVU) occupies 1 hectare (ha, 100 m by 100 m) of surface land, 20 m tall, stores up to 100,000 m3 of wood, sequestering 0.1 MtCO2. A 1 MtCO2 y-1 sequestration rate can be achieved by collecting currently unused wood residuals (WR) on an area of 25,000 km2, the size of 10 typical counties in the eastern US, corresponding to an average transportation distance of less than 100 km. After 30 years of operation, such a Wood Vault facility would have sequestered 30 MtCO2, stored in 300 WVUs, occupying a land surface of 300 ha. The cost is estimated at $10–50/tCO2 with a mid-point price of $30/tCO2. To sequester 1 GtCO2 y-1, wood can be sourced from currently unexploited wood residuals on an area of 9 Mkm2 forested land (9 million square kilometers, size of the US), corresponding to a low areal harvesting intensity of 1.1 tCO2 ha-1 y-1. Alternatively, giga-tonne scale carbon removal can be achieved by harvesting wood at a medium harvesting intensity of 4 tCO2 ha-1 y-1 on 3 Mkm2 of forest (equivalent to increasing current world wood harvest rate by 25%), or harvest on 0.8 Mkm2 forest restored from past Amazon deforestation at high harvest intensity, or many combinations of these and other possibilities. It takes 1000 facilities as discussed above to store 1 GtCO2 y-1, compared to more than 6000 landfills currently in operation in the US. After full closure of a Wood Vault, the land can be utilized for recreation, agriculture, solar farm, or agrivoltaics. A more distributed small operator model (Baby Vault) has somewhat different operation and economic constraints. A 10 giga-tonne sequestration rate siphons off only 5% of total terrestrial net primary production, thus possible with WHS, but extreme caution needs to be taken to ensure sustainable wood sourcing. Conclusions Our technical and economic analysis shows that Wood Vault can be a powerful tool to sequester carbon reliably, using a variety of wood sources. Most pieces of the technology already exist, but they need to be put together efficiently in practice. Some uncertainties need to be addressed, including how durability of buried wood depends on detailed storage methods and burial environment, but the science and technology are known well enough to believe the practicality of the method. The high durability, verifiability and low-cost makes it already an attractive option in the current global carbon market. Woody biomass stored in Wood Vaults is not only a carbon sink to combat current climate crisis, but also a valuable resource for the future that can be used as biomass/bioenergy and carbon supply. The quantity of this wood utilization can be controlled carefully to maintain a desired amount of CO2 in the atmosphere to keep the Earth’s climate from diving into the next ice age, acting as a climate thermostat. The CO2 drawdown time is on the order of 100 years while the ramp-up time is a decade. A sense of urgency is warranted because the CO2 removal rate is limited by biosphere productivity, thus delayed action means a loss of opportunity. In conclusion, WHS provides a tool for managing our Earth system, which will likely remain forever in the Anthropocene.
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Free
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Inward- versus outward-focused bioeconomy strategies for British Columbia’s forest products industry: a harvested wood products carbon storage and emission perspective

https://research.thinkwood.com/en/permalink/catalogue3087
Year of Publication
2021
Topic
Environmental Impact
Author
Xie, Sheng H.
Kurz, Werner A.
McFarlane, Paul N.
Organization
Pacifc Institute for Climate Solutions
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Topic
Environmental Impact
Keywords
Climate Change Mitigation
Emission Reduction
Carbon Dynamics Modeling
Harvested Wood Products
Bioeconomy
Mass Timber Construction
Biofuel
Pulp and Paper
Wood Pellets
Research Status
Complete
Series
Carbon Balance and Management
Summary
Background British Columbia’s (BC) extensive forest resources provide climate change mitigation opportunities that are available to few other jurisdictions. However, as a consequence of the Mountain Pine Beetle outbreak and large-scale wildfires, BC is anticipating reduced roundwood harvest for the next decades. Progress towards more climatically efficient utilization of forest resources is needed. This research quantitatively compared the greenhouse gas emission consequences of nine harvested wood products trade and consumption strategies. Inward-focused strategies use wood products within Canada to achieve emission reduction objectives, while outward-focused strategies encourage exports of wood products. Results In the business-as-usual baseline scenario, average emissions arising from BC-originated harvested wood products between 2016 and 2050 were 40 MtCO2e yr-1. The estimated theoretical boundaries were 11 MtCO2e yr-1 and 54 MtCO2e yr-1, under the scenarios of using all harvests for either construction purposes or biofuel production, respectively. Due to the constrained domestic market size, inward-focused scenarios that were based on population and market capacity achieved 0.3–10% emission reductions compared to the baseline. The international markets were larger, however the emissions varied substantially between 68% reduction and 25% increase depending on wood products’ end uses. Conclusions Future bioeconomy strategies can have a substantial impact on emissions. This analysis revealed that from a carbon storage and emission perspective, it was better to consume BC’s harvests within Canada and only export those products that would be used for long-lived construction applications, provided that construction market access beyond the US was available. However, restricting export of wood products destined for short-lived uses such as pulp and wood pellets would have significant economic and social impacts. On the other hand, inward-focused strategies had a small but politically and environmentally meaningful contribution to BC’s climate action plan. This study also revealed the conflicts between a demand-driven bioeconomy and targeted environmental outcomes. A hierarchical incentive system that could co-exist with other market drivers may help achieve emission reduction goals, but this would require a better quantitative understanding of wood products’ substitution effects. While the analyses were conducted for BC, other regions that are net exporters of wood products may face similar issues.
Online Access
Free
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Cross-Laminated Timber—North American CLT vs. Imported Product

https://research.thinkwood.com/en/permalink/catalogue3088
Year of Publication
2020
Topic
General Information
Material
CLT (Cross-Laminated Timber)
Organization
APA
Year of Publication
2020
Format
Document
Material
CLT (Cross-Laminated Timber)
Topic
General Information
Keywords
Design Property Compatibility
Adhesive Heat Durability
Moisture Durability
Fire Performance
Research Status
Complete
Summary
Cross-laminated timber (CLT) manufactured in North America must meet stringent product standards and be certified to the ANSI/APA PRG 320 Standard for Performance-Rated Cross-Laminated Timber. This publication from APA - The Engineered Wood Association explains the key characteristics that are evaluated in certification process. When comparing North Amarican CLT to products manufactured elsewhere, it is important to recognize that products manufactured outside of North Amarica may not meet the performance expections defined in the ANSI standard.
Online Access
Free
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APA Engineered Wood Construction Guide

https://research.thinkwood.com/en/permalink/catalogue3089
Year of Publication
2019
Topic
Design and Systems
General Information
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
LSL (Laminated Strand Lumber)
PSL (Parallel Strand Lumber)
OSL (Oriented Strand Lumber)
Application
Floors
Walls
Roofs
Organization
APA
Year of Publication
2019
Format
Book/Guide
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
LSL (Laminated Strand Lumber)
PSL (Parallel Strand Lumber)
OSL (Oriented Strand Lumber)
Application
Floors
Walls
Roofs
Topic
Design and Systems
General Information
Keywords
Selection and Specification
Structural Composite Lumber
I-Joist
Engineered Wood Products
Construction
Research Status
Complete
Summary
Comprehensive guide to engineered wood construction systems for both residential and commercial/industrial buildings. Includes information on plywood and oriented strand board (wood structural panels), glulam, I-joists, structural composite lumber, typical specifications and design recommendations for floor, wall and roof systems, diaphragms, shear walls, fire-rated systems and methods of finishing.
Online Access
Free
Resource Link
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Analysis and Tests of Lateral Resistance of Bolted and Screwed Connections of CLT

https://research.thinkwood.com/en/permalink/catalogue2956
Year of Publication
2022
Topic
Mechanical Properties
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Huo, Liangliang
Zhu, Enchun
Niu, Shuang
Wu, Guofang
Organization
Harbin Institute of Technology
China Academy of Forestry
Editor
Ozarska, Barbara
Monaco, Angela
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Mechanical Properties
Connections
Keywords
Lateral Resistance
European Yield Model
Bolt Connection
Screw Connectors
Emdedment Stress
Research Status
Complete
Series
Forests
Summary
The lateral resistance of dowel-type connections with CLT is related to its lay-up, species of the laminations and even the manufacture method. Treating the CLT as homogeneous material, current methods develop new equations through test results or make use of the existing equations for the embedment strength already used in design codes; thus, the lateral resistance of dowel-type connections of CLT can be calculated. This kind of approach does not take the embedment stress distribution into account, which may lead to inaccuracy in predicting the lateral resistance and yield mode of the dowel-type connections in CLT. In this study, tests of the bolted connections and the screwed connections of CLT were conducted by considering the effects of the orientation of the laminations, the thickness of the connected members, the fastener diameter and strength of the materials. The material properties including yield strength of the fasteners and embedment strength of the CLT laminations were also tested. Using analysis of the dowel-type connections of CLT by introducing the equivalent embedment stress distribution, equations for the lateral resistance of the connections based on the European Yield Model were developed. The predicted lateral resistance and yield modes were in good agreement with the test results; the correctness and the feasibility of the equations were thus validated.
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Free
Resource Link
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Effects on Global Forests and Wood Product Markets of Increased Demand for Mass Timber

https://research.thinkwood.com/en/permalink/catalogue2886
Year of Publication
2021
Topic
Market and Adoption
Author
Nepal, Prakash
Johnston, Craig
Ganguly, Indroneil
Organization
Forest Products Laboratory
University of Washington
Editor
Rosen, Marc
Publisher
MDPI
Year of Publication
2021
Format
Journal Article
Topic
Market and Adoption
Keywords
Timber Price
Timber Harvest
Forest Stock
Production
Consumption
Trade
Research Status
Complete
Series
Sustainability
Summary
This study evaluated the effects on forest resources and forest product markets of three contrasting mass timber demand scenarios (Conservative, Optimistic, and Extreme), up to 2060, in twelve selected countries in Asia, Europe, North America, and South America. Analyses were carried out by utilizing the FOrest Resource Outlook Model, a partial market equilibrium model of the global forest sector. The findings suggest increases in global softwood lumber production of 8, 23, and 53 million m3 per year by 2060, under the Conservative, Optimistic, and Extreme scenarios, respectively, leading to world price increases of 2%, 7%, and 23%, respectively. This projected price increase is relative to the projected price in the reference scenario, altering prices, production, consumption, trade of forest products, timber harvest, forest growth, and forest stock in individual countries. An increase in softwood lumber prices due to increased mass timber demand would lead to the reduced consumption of softwood lumber for traditional end-use (e.g., light-frame construction), suggesting a likely strong market competition for softwood lumber between the mass timber and traditional construction industries. In contrast, the projected effect on global forest stock was relatively small based on the relatively fast projected biomass growth in stands assumed to be regenerated after harvest.
Online Access
Free
Resource Link
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Mass Timber Building Life Cycle Assessment Methodology for the U.S. Regional Case Studies

https://research.thinkwood.com/en/permalink/catalogue2887
Year of Publication
2021
Topic
Environmental Impact
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Gu, Hongmei
Liang, Shaobo
Pierobon, Francesca
Puettmann, Maureen
Ganguly, Indroneil
Chen, Cindy
Pasternack, Rachel
Wishnie, Mark
Jones, Susan
Maples, Ian
Organization
Forest Products Laboratory
University of Washington
Population Research Center
Editor
Jasinskas, Algirdas
Publisher
MDPI
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Environmental Impact
Keywords
Life-Cycle Assessment
Mass Timber
Whole-building LCA Methodology
Research Status
Complete
Series
Sustainability
Summary
The building industry currently consumes over a third of energy produced and emits 39% of greenhouse gases globally produced by human activities. The manufacturing of building materials and the construction of buildings make up 11% of those emissions within the sector. Whole-building life-cycle assessment is a holistic and scientific tool to assess multiple environmental impacts with internationally accepted inventory databases. A comparison of the building life-cycle assessment results would help to select materials and designs to reduce total environmental impacts at the early planning stage for architects and developers, and to revise the building code to improve environmental performance. The Nature Conservancy convened a group of researchers and policymakers from governments and non-profit organizations with expertise across wood product life-cycle assessment, forest carbon, and forest products market analysis to address emissions and energy consumption associated with mass timber building solutions. The study disclosed a series of detailed, comparative life-cycle assessments of pairs of buildings using both mass timber and conventional materials. The methodologies used in this study are clearly laid out in this paper for transparency and accountability. A plethora of data exists on the favorable environmental performance of wood as a building material and energy source, and many opportunities appear for research to improve on current practices.
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Free
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Increasing Mass Timber Consumption in the U.S. and Sustainable Timber Supply

https://research.thinkwood.com/en/permalink/catalogue2888
Year of Publication
2022
Topic
Market and Adoption
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Comnick, Jeff
Rogers, Luke
Wheiler, Kent
Organization
University of Washington
Editor
Lauteri, Marco
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Market and Adoption
Keywords
Mass Timber
Embodied Carbon
Sustainable Timber Supply
Forest Inventory
Reforestation
Research Status
Complete
Series
Sustainability
Summary
Mass timber products are growing in popularity as a substitute for steel and concrete, reducing embodied carbon in the built environment. This trend has raised questions about the sustainability of the U.S. timber supply. Our research addresses concerns that rising demand for mass timber products may result in unsustainable levels of harvesting in coniferous forests in the United States. Using U.S. Department of Agriculture U.S. Forest Service Forest Inventory and Analysis (FIA) data, incremental U.S. softwood (coniferous) timber harvests were projected to supply a high-volume estimate of mass timber and dimensional lumber consumption in 2035. Growth in reserve forests and riparian zones was excluded, and low confidence intervals were used for timber growth estimates, compared with high confidence intervals for harvest and consumption estimates. Results were considered for the U.S. in total and by three geographic regions (North, South, and West). In total, forest inventory growth in America exceeds timber harvests including incremental mass timber volumes. Even the most optimistic projections of mass timber growth will not exceed the lowest expected annual increases in the nation’s harvestable coniferous timber inventory.
Online Access
Free
Resource Link
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Flexible and transportable robotic timber construction platform – TIM

https://research.thinkwood.com/en/permalink/catalogue2889
Year of Publication
2020
Topic
Market and Adoption
Application
Wood Building Systems
Author
Wagner, Hans
Alvarez, Martin
Kyjanek, Ondrej
Bhiri, Zied
Buck, Matthias
Menges, Achim
Organization
University of Stuttgart
Publisher
Elsevier
Year of Publication
2020
Format
Journal Article
Application
Wood Building Systems
Topic
Market and Adoption
Keywords
Robotic Fabrication
Robotic Timber Construction
Local Manufacturing
Reconfigurable Automation
Sustainable Production
Wood Architecture
Research Status
Complete
Series
Automation in Construction
Summary
This paper presents a new approach to robotic fabrication in the building industry through the conceptualization, development and evaluation of a largescale, transportable and flexible robotic timber construction platform – named TIM. Novel solutions are necessary to make robotic fabrication technologies more accessible for timber construction companies. The developed robotic system is location independent and reconfigurable. It can be rapidly integrated into existing fabrication environments of typical carpentries on a per-project basis. This allows the exploitation of emerging synergies between conventional craft and specialized automation technologies and benefits both quality and productivity of the trade. We portrait how the platform enabled the effective robotic prefabrication of a complex segmented wood shell structure and discuss the fabrication system based on critical performance parameters. Further research is needed to disentangle the mutual dependencies of building-systems and respective automation technologies.
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Free
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Assessment of effect of climate change on hygrothermal performance of cross-laminated timber building envelope with modular construction

https://research.thinkwood.com/en/permalink/catalogue2890
Year of Publication
2021
Topic
Moisture
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Building Envelope
Author
Chang, Seong Jin
Kang, Yujin
Yun, Beom Yeol
Yang, Sungwoong
Kim, Sumin
Organization
Gyeongsang National University
Yonsei University
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Building Envelope
Topic
Moisture
Serviceability
Keywords
Climate Change
Modular Construction
Hygrothermal Performance
Mock-up Experiments
Research Status
Complete
Series
Case Studies in Thermal Engineering
Summary
Cross-laminated timber (CLT) modular construction possesses the advantages of wood, such as excellent carbon storage and thermal insulation, and of modular construction, such as considerably reduced construction period and cost as well as high productivity. This study evaluates the hygrothermal performance of CLT walls considering modular construction in future climatic conditions. Firstly, CLT walls with plywood applied to a core layer were manufactured. A mock-up of a CLT building was produced and its construction process was analyzed. Hygrothermal behavior of the CLT walls was simulated using WUFI simulation program, and the predicted results were verified against measurements obtained from the mock-up experiment. Finally, the hygrothermal performance of the CLT wall was evaluated for four types of insulation and future climate in eight cities of USA. The coefficient of variation—root mean square error (CV(RMSE))—of the temperature and relative humidity inside the ply-lam CLT wall from mock-up experiments and simulation evaluation were 6.43% and 7.02%, respectively, which met the validation criteria. Based on the hygrothermal performance, the ply-lam CLT wall with extruded polystyrene insulation was evaluated as safe from moisture problems in all the eight cities considered in this study. However, the risk of mold growth in all regions and insulation types increased under climate change with a rise of average annual temperature.
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Free
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Stress-laminated timber decks in bridges: Friction between lamellas, butt joints and pre-stressing system

https://research.thinkwood.com/en/permalink/catalogue2891
Year of Publication
2020
Application
Decking
Author
Massaro, Francesco Mirko
Malo, Kjell Arne
Organization
Norwegian University of Science and Technology
Publisher
Elsevier
Year of Publication
2020
Format
Journal Article
Application
Decking
Keywords
Stress Laminated
Timber Bridges
Butt-Joint
Stiffness
Friction
Pre-Stress
Research Status
Complete
Series
Engineering Structures
Summary
Stress-laminated timber (SLT) decks in bridges are popular structural systems in bridge engineering. SLT decks are made from parallel timber beams placed side by side and pre-stressed together by means of steel rods. SLT decks can be in any length by just using displaced butt joints. The paper presents results from friction experiments performed in both grain and transverse direction with different levels of pre-stress. Numerical simulations of these experiments in addition to comparisons to full-scale experiments of SLT decks presented in literature verified the numerical model approach. Furthermore, several alternative SLT deck configurations with different amounts of butt joints and pre-stressing rod locations were modelled to study their influence on the structural properties of SLT decks. Finally, some recommendations on design of SLT bridge decks are given.
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Free
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Cross-Laminated Timber and Cold-Formed Steel Hybrid System: A New Approach

https://research.thinkwood.com/en/permalink/catalogue3165
Year of Publication
2021
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Author
Malczyk, Robert
Bita, Hercend Mpidi
Organization
Timber Engineering Inc.
Year of Publication
2021
Format
Report
Material
CLT (Cross-Laminated Timber)
Topic
Design and Systems
Keywords
Cold-Formed Steel
Hybrid Mass Timber System
CLT/CFS System
Platform-Type Construction
Research Status
Complete
Summary
The report presents structural considerations of the novel cross-laminated timber and cold-formed steel hybrid system, also referred to as the CLT/CFS system. This novel hybrid system uses CLT floor panels and CFS walls in a platform-type construction to carry all gravity loads, whereas the lateral loads are carried by conventional systems, typically concrete cores or steel braced frames. The CLT/CFS system is a new costeffective and structurally efficient system that helps meet the demand for taller mass timber buildings. The first section of the report introduces timber as a material and the new trends towards mass timber construction. The second section describes typical and conventional structural systems for hybrid mass timber buildings. The third section explains the combinations of CLT and CFS as structural components to make up the CLT/CFS system, including structural system optimisations and a typical building example. The fourth section outlines the main advantages of the system; and the fifth section presents the key structural considerations of the new CLT/CFS system by means of a worked example.
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Free
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Innovative Technology for Mass Timber and Hybrid Modular Buildings

https://research.thinkwood.com/en/permalink/catalogue2801
Topic
Design and Systems
Seismic
Wind
Connections
Application
Wood Building Systems
Hybrid Building Systems
Organization
Oregon State University
Application
Wood Building Systems
Hybrid Building Systems
Topic
Design and Systems
Seismic
Wind
Connections
Keywords
Mass Timber
Modular Construction
Ductility
Overstrength
High-Rise
Tall Wood Buildings
Interdisciplinary Research
Wind Tunnel Test
Research Status
In Progress
Notes
Project contact is Erica Fischer at Oregon State University
Summary
This Faculty Early Career Development (CAREER) award will create innovative building technology that will enable mass timber modular construction as a building solution to many of the issues the nation's major cities face today. The architecture, engineering, and construction (AEC) sector is on the cusp of a significant disruption that will change the way buildings are manufactured, assembled, and designed, the catalyst of which is the integration of building information models (BIM) and automated construction and manufacturing. This disruption will significantly impact structural engineers. With the streamlining of building manufacturing, assembling, and design, engineers will need to take advantage of three opportunities: (1) design for constructability, (2) design for manufacturing, and (3) design for the whole life of the building (considering future modifications, maintenance, and easily replacing parts of the building). Modular construction, as one method to take advantage of these three opportunities, can address labor and housing shortages that exist in almost every U.S. city today and also can provide rapid construction methods for post-disaster reconstruction and additional patient care facilities. This research will contribute to the state of Oregon’s economy, which has made significant investments in mass timber production, manufacturing, and research. This research will be complemented through the development of best practices for using interdisciplinary, collaborative classroom environments to enhance engineering identities of underrepresented minorities and women at the graduate level. This award will support the National Science Foundation (NSF) role in the National Earthquake Hazards Reduction Program and the National Windstorm Impact Reduction Program. The specific goal of this research is to develop a novel framework for robust and ductile mass timber modular construction that can be applied to buildings with varying lateral force resisting systems. Through this framework, the relationship between the rigidity of modular interconnections and overall structural behavior will be investigated. The research objectives of this project are to: (1) quantify the demands in interconnections that provide ductility when the building framing is subjected to combined gravity and lateral forces (seismic and wind); (2) quantify the impact of interconnection configuration and design on the ability of interconnections to meet the strength and serviceability performance criteria for mass timber high-rise modular buildings; (3) quantify ductility and overstrength for mass timber modular construction and explore applicability of conventional seismic performance factors and how these factors influence the adjusted collapse margin ratio for archetype buildings; (4) explore the influence of interconnection stiffness on the behavior of high-rise modular mass timber buildings subjected to wind demands; and (5) explore the relationship between team-focused and interdisciplinary educational practices with engineering identity and knowledge retention. New connection technology will be created and its contribution to the overall building behavior will be investigated through a rigorous testing plan and complex physics-based numerical simulations of archetype buildings subjected to combined gravity and lateral loads (seismic and wind). This research is a critical first step to develop innovative technology that will change how buildings are designed, manufactured, and assembled. This project will enable the Principal Investigator to establish interdisciplinary research, teaching, and mentorship in the area of mass timber and hybrid construction. This research will use the NSF-supported Natural Hazards Engineering Research Infrastructure (NHERI) Boundary Layer Wind Tunnel facility at the University of Florida. Experimental datasets will be archived in the NHERI Data Depot (https://www.DesignSafe-ci.org) and made publicly available.
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Achieving Sustainable Urban Buildings with Seismically Resilient Mass Timber Core Wall and Floor System

https://research.thinkwood.com/en/permalink/catalogue2802
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Cores
Walls
Floors
Wood Building Systems
Organization
Portland State University
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Cores
Walls
Floors
Wood Building Systems
Topic
Design and Systems
Seismic
Keywords
Hold-Down
Seismic Performance
Core Walls
Parametric Analysis
Deformation Capacity
Overstrength
Mid-Rise
High-Rise
Tall Wood Buildings
Research Status
In Progress
Notes
Project contact is Peter Dusicka at Portland State University
Summary
The urgency in increasing growth in densely populated urban areas, reducing the carbon footprint of new buildings, and targeting rapid return to occupancy following disastrous earthquakes has created a need to reexamine the structural systems of mid- to high-rise buildings. To address these sustainability and seismic resiliency needs, the objective of this research is to enable an all-timber material system in a way that will include architectural as well as structural considerations. Utilization of mass timber is societally important in providing buildings that store, instead of generate, carbon and increase the economic opportunity for depressed timber-producing regions of the country. This research will focus on buildings with core walls because those building types are some of the most common for contemporary urban mid- to high-rise construction. The open floor layout will allow for commercial and mixed-use occupancies, but also will contain significant technical knowledge gaps hindering their implementation with mass timber. The research plan has been formulated to fill these gaps by: (1) developing suitable mid- to high-rise archetypes with input from multiple stakeholders, (2) conducting parametric system-level seismic performance investigations, (3) developing new critical components, (4) validating the performance with large-scale experimentation, and (5) bridging the industry information gaps by incorporating teaching modules within an existing educational and outreach framework. Situated in the heart of a timber-producing region, the multi-disciplinary team will utilize the local design professional community with timber experience and Portland State University's recently implemented Green Building Scholars program to deliver technical outcomes that directly impact the surrounding environment. Research outcomes will advance knowledge at the system performance level as well as at the critical component level. The investigated building system will incorporate cross laminated timber cores, floors, and glulam structural members. Using mass timber will present challenges in effectively achieving the goal of desirable seismic performance, especially seismic resiliency. These challenges will be addressed at the system level by a unique combination of core rocking combined with beam and floor interaction to achieve non-linear elastic behavior. This system behavior will eliminate the need for post-tensioning to achieve re-centering, but will introduce new parameters that can directly influence the lateral behavior. This research will study the effects of these parameters on the overall building behavior and will develop a methodology in which designers could use these parameters to strategically control the building seismic response. These key parameters will be investigated using parametric numerical analyses as well as large-scale, sub-system experimentation. One of the critical components of the system will be the hold-down, a device that connects the timber core to the foundation and provides hysteretic energy dissipation. Strength requirements and deformation demands in mid- to high-rise buildings, along with integration with mass timber, will necessitate the advancement of knowledge in developing this low-damage component. The investigated hold-down will have large deformation capability with readily replaceable parts. Moreover, the hold-down will have the potential to reduce strength of the component in a controlled and repeatable way at large deformations, while maintaining original strength at low deformations. This component characteristic can reduce the overall system overstrength, which in turn will have beneficial economic implications. Reducing the carbon footprint of new construction, linking rural and urban economies, and increasing the longevity of buildings in seismic zones are all goals that this mass timber research will advance and will be critical to the sustainable development of cities moving forward.
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Field Hygrothermal Performance of R22+ Wood-Frame Walls in Vancouver

https://research.thinkwood.com/en/permalink/catalogue2775
Year of Publication
2021
Topic
Moisture
Energy Performance
Material
Light Frame (Lumber+Panels)
Application
Walls
Author
Wang, Jieying
Organization
FPInnovations
Year of Publication
2021
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Walls
Topic
Moisture
Energy Performance
Keywords
Hygrothermal Performance
Exterior Wall
Mid-Rise
Panels
Research Status
Complete
Summary
A test program was conducted to generate hygrothermal performance data for light-wood-frame exterior walls meeting the R22 effective (RSI 3.85) requirement for buildings up to six storeys in the City of Vancouver. Six types of exterior wall assemblies, with 12 wall panels in total, were tested using a test hut located in the rear yard of FPInnovations’ Vancouver aboratory. This document provides a brief summary of the test and performance of these walls based on the data collected over the 19 months’ period from October 2018 to May 2020
Online Access
Free
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Le Rendement Hygrothermique de Murs à Ossature de Bois R22+ à Vancouver

https://research.thinkwood.com/en/permalink/catalogue2776
Year of Publication
2021
Topic
Moisture
Energy Performance
Material
Light Frame (Lumber+Panels)
Application
Walls
Author
Wang, Jieying
Organization
FPInnovations
Year of Publication
2021
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Walls
Topic
Moisture
Energy Performance
Keywords
Hygrothermal Performance
Exterior Wall
Mid-Rise
Panels
Research Status
Complete
Summary
Un programme d’essais a été réalisé en vue de générer des données sur le rendement hygrothermique des murs à ossature légère de bois qui répondent à l’exigence R22 (RSI 3,85) pour les bâtiments d'au plus six étages à Vancouver. Six types d’assemblage de mur extérieur, avec un total de 12 murs extérieurs, ont été mis à l’essai à l’aide d’une hutte d’essai située dans la cour arrière du laboratoire de FPInnovations à Vancouver. Le présent document présente un court résumé de l’essai et du rendement de ces murs en se basant sur les données recueillies sur une période de 19 mois, soit d’octobre 2018 à mai 2020 (Wang 2021).
Online Access
Free
Resource Link
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