Skip header and navigation

Refine Results By

613 records – page 1 of 62.

Experimental analysis of timber-concrete composite behaviour with synthetic fibres

https://research.thinkwood.com/en/permalink/catalogue3396
Year of Publication
2023
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Application
Floors
Author
Buka-Vaivade, K
Serdjuks, D
Zvirina, D
Pakrastins, L
Organization
Riga Technical University
Publisher
IOP Publishing
Year of Publication
2023
Format
Conference Paper
Material
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Keywords
Synthetic Fibre
Bending Test
Conference
5th International Conference: Innovative Materials, Structures and Technologies (IMST 2022)
Research Status
Complete
Series
Journal of Physics: Conference Series
Summary
With the growing importance of the principles of sustainable construction, the use of load-bearing timber-concrete composite structures is becoming increasingly popular. Timber-concrete composite offers wider possibilities for the use of timber in construction, especially for large-span structures. The most significant benefit from combining these materials can be obtained by providing a rigid connection between the timber and concrete layers, which can be obtained by the adhesive timber-to-concrete connection produced by the proposed stone chips method. A sustainable solution involves the abandonment of steel longitudinal reinforcement. The use of such a solution in practice is often associated with fears of a fragile collapse. Therefore, the issue of how to increase the safety factor of the proposed material is topical now. The experimental investigation is made to determine the effect of synthetic fibre use on timber-concrete composite behaviour by testing a series of timber-concrete composite specimens with and without fibres in the concrete layer. The obtained results show that adding 0.5 % of synthetic macro fibres allows to abandon the use of longitudinal steel reinforcement and prevents the formation of large cracks in concrete and the disintegration of the concrete layer in case of collapse.
Online Access
Free
Resource Link
Less detail

Experimental modal analysis of a cross-laminated timber slab

https://research.thinkwood.com/en/permalink/catalogue3009
Year of Publication
2022
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Author
Kawrza, M.
Furtmüller, T.
Adam, C.
Maderebner, R.
Organization
University of Innsbruck
Publisher
Elsevier
Year of Publication
2022
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Acoustics and Vibration
Keywords
Experimental Modal Analysis
Complex Mode Shapes
Modal Parameter Estimation
Conference
37th Danubia Adria Symposium on Advances in Experimental Mechanics
Research Status
Complete
Series
Materials Today: Proceedings
Summary
This paper presents the results of an investigation of the dynamic response of a point-supported cross-laminated timber (CLT) slab without joists with a column grid of 5.0 × 5.0 m and overall dimensions of 16.0 × 11.0 × 0.2 m. The results are based on a detailed experimental modal analysis, identifying seven modes from the dynamic response of 651 measurement points, including natural frequencies, mode shapes and damping ratios. These modal parameters exhibit a time variance that is due to environmental influences during the measurement period of two days. As a result of this disturbance effect, the determined mode shapes have a non-negligible imaginary part, which is eliminated by correcting each of the 73 measurements individually. The findings presented provide in-depth insight into the dynamic behavior of the large-scale CLT structure with point supports realized with a novel steel connector.
Online Access
Free
Resource Link
Less detail

Behavior of timber-concrete composite with defects in adhesive connection

https://research.thinkwood.com/en/permalink/catalogue3108
Year of Publication
2022
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Application
Floors
Author
Buka-Vaivade, Karina
Serdjuks, Dmitrijs
Organization
Riga Technical University
Publisher
Elsevier
Year of Publication
2022
Format
Conference Paper
Material
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Keywords
Adhesive Connection
Rigid Connection
Conference
ICSI 2021 The 4th International Conference on Structural Integrity
Research Status
Complete
Series
Procedia Structural Integrity
Summary
Rigid timber to concrete connection is the most effective solution for timber-concrete composite members subjected to the flexure which provides full composite action and better structural behaviour. One of the most used technologies to produce glued connection of the timber-concrete composite is “dry” method, which includes gluing together of timber and precast concrete slab. This technique has high risk of forming a poor-quality rigid connection in timber-concrete composite, and there are difficulties in controlling the quality of the glued connection. The effect of the non-glued areas in connection between composite layers on the shear stresses and energy absorption were investigated by finite element method and laboratorian experiment. Three timber-concrete composite panels in combination with carbon fibre reinforced plastic composite tapes in the tension zone with the span 1.8 m were statically loaded till the failure by the scheme of three-point bending. Mid-span displacements were measured in the bending test. One specimen was produced by dry method, by gluing together cross-laminated timber panel and prefabricated concrete panel. Timber-concrete qualitative connection of the other two specimens was provided by the granite chips, which were glued on the surface of the cross-laminated timber by epoxy, and then wet concrete was placed. Dimensions of the crushed granite pieces changes within the limits from 16 to 25 mm. The investigated panel with different amount and sizes of non-glued areas in the timber to concrete connection was numerically modelled. Obtained results shown, that the increase of shear stresses is influenced not so much by a total amount of non-glued areas, but by the size of the individual defective areas. Moreover, large non-glued areas significantly reduce the energy absorption of elements subjected to the flexure, which was observed experimentally for defective panel produced by the classical dry method with almost 4 times larger mid-span displacements than for panel with full composite action provided by the proposed production technology of the timber to concrete rigid connection. So, the proposed technology based on the use of granite chips, provides a high-quality connection between timber and concrete layers, with insignificant ration between possible defect and total connection surface area, which is equal to the area of one granite chips edge.
Online Access
Free
Resource Link
Less detail

Influence of the connector shape parameters in the structural behaviour of the adhesive-free timber floor panels

https://research.thinkwood.com/en/permalink/catalogue3125
Year of Publication
2022
Topic
Mechanical Properties
Application
Floors
Author
Moltini, Gonzalo
Baño, Vanesa
Organization
Universidad de la República
Publisher
Elsevier
Year of Publication
2022
Format
Conference Paper
Application
Floors
Topic
Mechanical Properties
Keywords
Adhesive-free Connection
Structural Yield
Timber-to-timber Panels
Conference
ICSI 2021 The 4th International Conference on Structural Integrity
Research Status
Complete
Series
Procedia Structural Integrity
Summary
Timber-to-timber panels (TTPs) are adhesive- and steel-free structural components formed by carpentry joints of Scots pine to be used as floors. A numerical model simulating bending tests on TTPs and considering timber as an orthotropic and bi-modulus material was validated from experimental results of deflection, and rolling shear strength. Since the serviceability and ultimate limit states of the TTPs was mainly defined by the rolling shear properties of the connectors, this paper aims to study the influence of different connector shape parameters in the structural behavior of the panels. For that, values of the connector height (hc varying between 40 and 100 mm), width (b1 varying between 40 and 100 mm) and the dove-tail angle (a varying between 45º and 75º) were introduced in the numerical models to obtain both failure load and stiffness for different span TTPs. Results showed that TTP deflection and shear stresses on the connectors decreases with the increase of the height and the width of the connectors. As the width of the connector (b1) increases, the maximum shear stress decreases up to 42%. For a same connector height, the angle of the dove-tail shows low influence in the maximum shear stress; however, it plays a greater role in the deflection of the panels. For the connectors of 40 mm of height TTP deflection was barely influenced by connector width; however, for higher connectors (hc = 60 mm), TTP deflection decreased up to 41% as width increases. So, new TTPs configurations varying the connector parameters showed an improvement on the deflection and on the shear stresses of the connectors.
Online Access
Free
Resource Link
Less detail

Post-layup protection of mass timber elements in above ground protected exposures: 2-year results

https://research.thinkwood.com/en/permalink/catalogue3234
Year of Publication
2022
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Author
Mankowski, Mark E.
Shelton, Thomas
Kirker, Grant T.
Morrell, Jeffrey J.
Organization
Forest Products Laboratory
University of the Sunshine Coast
Year of Publication
2022
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Moisture
Keywords
Mass Panel Plywood
AWPA Standard E21
Above Ground Testing
Soil Termiticide
Borate
Field Test
Durability
Decay
Termite
Conference
Proceedings IRG Annual Meeting (ISSN 2000-8953)
Research Status
Complete
Summary
Mass timber has seen increased use as a building material for low and mid-rise construction in recent decades. The durability of mass timber elements has not been fully examined and the effects of wood destroying organisms on this these materials merits attention. The effectiveness of currently labeled soil termiticides and passively applied biocides at post-construction or as remedial agents needs to be evaluated for mass timber used in structures, particularly in areas with elevated risk of termite attack. The ability of soil insecticidal drenches or spray-on insecticide/fungicide treatments for protecting mass timber in service was assessed with a modified AWPA Standard E21 above-ground test using three ply Douglas-fir or southern pine cross-laminated timber as well as Douglas-fir mass plywood panels. Samples of each material (305 x 102 x 102 mm) were installed in an above ground protected test at the Harrison Experimental Forest (HEF) (Saucier, Mississippi) in September, 2019. Six replicates of five treatments including soil termiticide, no treatment, spray-on borate at initiation, borate rods and remedial treatment, using spray on borate of attacked material after two years, were tested. Samples were left undisturbed for two years and then examined and rated. Near surface moisture content increased to levels approaching the fiber saturation point over the two-year non-disturbance period. Untreated control samples were attacked by both decay fungi and termites. Samples treated with borates at test initiation showed limited decay or termite attack. Soil termiticide treated plots showed no sign of termite attack, but some samples had heavy decay compared to non-soil termiticide treated plots.
Online Access
Free
Resource Link
Less detail

Assessment of Termite and Decay Damage to Mass Timber Elements in AWPA Ground Proximity and Above Ground Field Tests in Southern Mississippi

https://research.thinkwood.com/en/permalink/catalogue3236
Year of Publication
2022
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Author
Mankowski, Mark E.
Shelton, Thomas
Kirker, Grant
Morrell, Jeffrey J.
Organization
Forest Products Laboratory
Year of Publication
2022
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Serviceability
Keywords
Mass Panel Plywood
Ground Proximity Test
Above Ground Test
Soil Termiticide
Field Test
Durability
Decay
Termite
Conference
Proc. of 118th annual meeting of American Wood Protection Association
Research Status
Complete
Summary
The ability of soil insecticidal drenches or spray-on insecticide/fungicide treatments to protect mass timber elements was assessed using two modified AWPA ground proximity tests established in 2017 and 2019. The 2017 test evaluated 3-ply Douglas-fir cross-laminated timber using a modified AWPA Standard E26 while the 2019 test used a modified AWPA E21 protocol to evaluate 3-ply Douglas-fir or southern pine cross-laminated timber as well as Douglas-fir mass plywood panels. Both tests were installed at the Harrison Experimental Forest (Saucier, Mississippi) and will be assessed for five years. Treatments include an initial soil termiticide drench, spray-on borate at initiation, borate rods at initiation, remedial boron spray treatment two years after installation, and untreated controls. Samples were left undisturbed for one or two years and then rated for degree of termite and fungal damage. Moisture content of the test materials increased greatly over the non-disturbance period. Untreated control samples were attacked by both decay fungi and termites within the first year after test initiation. Soil termiticide treated plots showed no sign of termite attack, but decay was evident on some samples compared to non-soil termiticide treated plots. Samples treated with borates at test initiation showed limited decay or termite attack. The tests will continue to be evaluated for a period of at least 5 years or longer and serve as critical baseline data for field evaluation methods of mass timber in areas of high subterranean termite and decay pressure.
Online Access
Free
Resource Link
Less detail

A risk-based approach for timber building decay prediction

https://research.thinkwood.com/en/permalink/catalogue3255
Year of Publication
2022
Topic
Serviceability
Application
Wood Building Systems
Author
Gaspari, Andrea
Giongo, Ivan
Piazza, Maurizio
Organization
University of Trento
Publisher
Elsevier
Year of Publication
2022
Format
Conference Paper
Application
Wood Building Systems
Topic
Serviceability
Keywords
Decay Prediction
TSafe Project
Biotic Attack
Conference
ICSI 2021 The 4th International Conference on Structural Integrity
Research Status
Complete
Series
Procedia Structural Integrity
Summary
The durability of timber structures subjected to biotic attacks is becoming of increasing concern due to several recent examples of failures caused by early degradation. Therefore, the design process of a timber building cannot prescind from accounting for the possible degradation due to biotic attack, especially in light of the recent spread of high-rise timber buildings. Furthermore, it is of extreme importance that reliable models to foresee possible sources of degradation in existing buildings are made available so that retrofit interventions can be programmed before it is too late. In the work presented herein, the decay due to fungal attack was predicted through a risk-based approach where decision trees were created to address all the possible scenarios where water or moisture can intrude within the construction details that most affect the durability. These decision trees allow to assign a risk class, defined based on a thorough review of the major European standards addressing timber “use-classes”. The trees also lead to the selection of a proper prediction function for estimating the decay depth, chosen among suitable functions available in the literature. The proposed methodology was applied to selected case studies where a good correlation was found between the decay level detected onsite and the results from the prediction model. To facilitate the application of the methodology to both the design of new durable timber buildings and the assessment of existing timber structures, an ad hoc software tool named TSafe was developed. In the present paper, due to the length limit, the focus is on the decision trees and the risk classes, while just a brief description of the case study used for the procedure validation is given.
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

Design and simulation of an automated robotic machining cell for cross-laminated timber panels

https://research.thinkwood.com/en/permalink/catalogue2966
Year of Publication
2021
Topic
Market and Adoption
Material
CLT (Cross-Laminated Timber)
Author
Villanueva, Emanuel Martinez
Mamledesai, Harshavardhan
Martinez, Pablo
Poostchi, Peyman
Ahmad, Rafiq
Organization
University of Alberta
University of Calgary
Publisher
Elsevier
Year of Publication
2021
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Market and Adoption
Keywords
Automation in Construction
Industrial Design
Offsite Construction
Robotic Simulation
Conference
31st CIRP Design Conference 2021
Research Status
Complete
Series
Procedia CIRP
Summary
Cross-laminated timber (CLT) is an innovative construction material that has brought advantages over traditional wood structures, reducing cost and lead time of buildings in recent years; yet CLT benefits primarily from offsite construction methods instead of automation or safety, while keeping the human onsite. The few advancements in automation for CLT panels have been in the implementation of dedicated CNC machines. Nevertheless, using CNC machines for machining CLT panels have disadvantages like clamping batches of massive panels with individual profiles, lacking the flexibility to access all acute machining angles, and struggling with the extraction of dust while the cutting spindle moves through large tight spaces. These disadvantages can be overcome with industrial robots’ help, which the construction industry has not been traditionally favorable on their application, giving then the research gap in this study. This paper explores the introduction of a robotic cell for the machining of cross-laminated timber panels. The robotic cell is designed using 3D modeling and validated through motion simulation in a virtual environment. The proposed cell design is based on a minimum viable product and compared against a minimum throughput benchmarked on the Canadian market. This study aims to research the feasibility of CLT’s automated machining by providing clear production characteristics of the designed robotic cell, such as material and tool utilization rates, lead time, or production efficiency.
Online Access
Free
Resource Link
Less detail

North American Research Needs Assesment for Mass Timber

https://research.thinkwood.com/en/permalink/catalogue3222
Year of Publication
2021
Topic
General Information
Material
CLT (Cross-Laminated Timber)
Author
Zelinka, Samuel
Williamson, Tom
Martinson, Karen
Ritter, Michael A.
Organization
Forest Products Laboratory
Year of Publication
2021
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
General Information
Keywords
Mass Timber
North America
Seismic Performance
Fire Performance
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
The 2nd Mass Timber Research Needs Assessment Workshop was held on November 13-14, 2018 at the US Forest Service, Forest Products Laboratory (FPL). The purpose of the workshop was to convene a group of experts on cross laminated timber and mass timber to develop a list of prioritized research needs for the North American mass timber industry. The workshop had over 100 attendees including design professionals, academics, industry leaders, and government employees. The attendees generated a list of over 117 research needs. After the workshop, the list of 117 research needs was prioritized through the use of an online survey. This paper presents highlights of the top research needs generated at the 2nd Mass Timber Research Needs Assessment Meeting.
Online Access
Free
Resource Link
Less detail

613 records – page 1 of 62.