Skip header and navigation

Refine Results By

605 records – page 1 of 61.

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
Year of Publication
2021
Country of Publication
Canada
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
Language
English
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

Alternative Load Path Analyses for Mid-Rise Post and Beam Mass Timber Building

https://research.thinkwood.com/en/permalink/catalogue2448
Year of Publication
2020
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Columns
Beams

New Bridge Inspection Approach with Joint UAV and DIC System

https://research.thinkwood.com/en/permalink/catalogue2560
Year of Publication
2020
Topic
Serviceability
Application
Bridges and Spans
Author
Jeong, Euiseok
Seo, Junwon
Wacker, James
Year of Publication
2020
Country of Publication
United States
Format
Conference Paper
Application
Bridges and Spans
Topic
Serviceability
Keywords
UAV
DIC
Inspection
Deterioration
Detection
Language
English
Conference
Structures Congress
Research Status
Complete
Summary
This research aims to develop a new bridge inspection approach using unmanned aerial vehicle (UAV) coupled with digital image correlation (DIC) system. The DIC system incorporating UAV images can measure displacements or strains by analyzing patterns of reference and deformed images. As part of this research, a commercially available UAV, DJI Matrice 210, was integrated with the DIC system using a 3D printed mounting plate, and the joint UAV-DIC system was utilized to inspect a timber bridge girder in the Structure Lab. Then, the UAV-DIC system inspected an existing timber slab bridge in Pipestone, Minnesota, but the system was not able to efficiently identify critical damage due to its instability caused by windy conditions. Therefore, only the UAV equipped with a gimbal camera was operated to perform the bridge inspection. A significant number of images from the UAV were used and analyzed through a conventional image analysis algorithm within ImageJ software for damage quantification. The major conclusion from this research was that the UAV-DIC system was only able to detect and quantify damage (i.e., crack) on the considered girder under almost zero ambient wind conditions, and the UAV integrated with the image analysis algorithm was capable of damage identification and quantification for the inspected bridge.
Online Access
Free
Resource Link
Less detail

Design and Performance of High-Rise Structure using Ultra-Lightweight Cross Laminated Timber Floor System

https://research.thinkwood.com/en/permalink/catalogue2698
Year of Publication
2020
Topic
Mechanical Properties
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Ahmed, Danish
Ayadat, Tahar
Asiz, Andi
Publisher
ISEC Press
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Serviceability
Keywords
Tall Timber Buildings
Lateral Load
Lateral Deflections
Floor Diaphragm
Language
English
Conference
International Structural Engineering and Construction Conference
Research Status
Complete
Series
Proceedings of International Structural Engineering and Construction
Summary
The main objective of this paper is to study the structural performance of a high-rise structure when alternative lightweight material known as cross-laminated timber was used as a slab in floor system in lieu of conventional reinforced concrete slab. A numerical case study was conducted using a highly irregular RC frame building with its two 60-story towers joined at the top. Three major analyses were considered. First, modeling and analyzing the building with an RC slab was conducted to determine the design reference. Second, substituting the RC slab with the CLT slab was performed using the same building skeleton. Third, redesigning and optimizing the building skeleton with that CLT to observe skeleton material saving obtained using the same structural performance criteria. Major lateral loads applicable in the Eastern Province of Saudi Arabia were inputted. Strengths and serviceability requirements for floor diaphragm and lateral load resisting system were checked first before performing a comparative analysis between traditional RC and CLT slabs as floor diaphragm. The structural performance criteria to be used for comparative study between RC and CLT slabs included total drift, inter-story drift due to lateral loads, and base reactions. Structural periods and acceleration responses for each floor were investigated and contrasted with the existing building code. The foundation demand was also investigated based on the structural weight and reactions generated from the RC and CLT floor systems.
Online Access
Free
Resource Link
Less detail

The Numerical Analysis and Experimental Verification on the Thermal Performance of Hybrid Cross-Laminated Timber (CLT)-Glass Facade Elements

https://research.thinkwood.com/en/permalink/catalogue2704
Year of Publication
2020
Topic
Energy Performance
Material
CLT (Cross-Laminated Timber)
Author
Rajcic, Vlatka
Bedon, Chiara
Barbalic, Jure
Perkovic, Nikola
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Energy Performance
Keywords
Structural Glass
CLT-Structural Glass Hybrid Facade
Small-Scale Experiments
Finite Element Modelling
Numerical Modelling
Language
English
Conference
Challenging Glass Conference
Research Status
Complete
Summary
Structural solutions involving the mechanical interaction of timber and glass load-bearing members showed a progressive increase in the last decade. Among others, a multipurpose hybrid facade element composed of Cross-Laminated Timber (CLT) members and glass panels interacting by frictional contact mechanisms only was proposed ion the framework of the VETROLIGNUM project. While demonstrating enhanced load-bearing and deformation capacity performances under seismic loads, facade elements are known to represent a building component with multiple performance parameters to satisfy. These include energy efficiency, durability, lightening comfort and optimal thermal performance. In this paper, a special focus is dedicated to the thermal performance assessment of CLT-glass facade modules under ordinary operational conditions. Based on the thermal-chamber analysis of small-scale prototypes, reliable Finite Element numerical models are developed and applied to full-scale VETROLIGNUM solution. Sensitivity analyses are hence carried out to explore the actual thermal performance of these novel hybrid systems.
Online Access
Free
Resource Link
Less detail

Hygrothermal Conditions in Cross Laminated Timber (CLT) Dwellings

https://research.thinkwood.com/en/permalink/catalogue2705
Year of Publication
2020
Topic
Moisture
Energy Performance
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Tingstveit, Merethe
Nielsen, Henrik
Risholt, Birgit
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Moisture
Energy Performance
Keywords
Hygrothermal
Low-Rise
Residential
Moisture Content
Relative Humidity
Indoor Air Temperature
Language
English
Conference
Nordic Symposium on Building Physics
Research Status
Complete
Summary
The use of CLT has been increasing the last decade, and a subsequently focus on documentation of the accompanying indoor climate and exposed wooden surfaces on human well-being. This study presents the results of a measurement campaign conducted over one year of a CLT apartment building in Grimstad, Norway. The apartment building consists of three floors with 35 apartments and comply with the Norwegian passive house standard and energy grade A. Measurements of the relative humidity (RH), indoor air temperature and wood moisture content (MC) were performed in the exposed CLT spruce panels in three apartments in two different floors. The results from the three apartments show a relatively small variation in the MC values regardless the residents behavior measured as RH variation through a complete year. Selected periods from a cold period (winter) and a warm period (summer) show the variation in relative humidity (RH) and moisture content in the CLT element. However, results from control measurements showed higher MC values. The gap between the measurements and methods are discussed.
Online Access
Free
Resource Link
Less detail

High Performance Connections to Mitigate Seismic Damage in Cross Laminated Timber (CLT) Structures

https://research.thinkwood.com/en/permalink/catalogue2707
Year of Publication
2020
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Floors
Walls
Author
Smiroldo, Francesco
Gaspari, Andrea
Viel, Davide
Piazza, Maurizio
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Floors
Walls
Topic
Connections
Seismic
Keywords
Finite Element Modelling
Non-linear Analysis
Seismic Engineering
Earthquake
Connection Systems
Language
English
Conference
World Conference on Earthquake Engineering
Research Status
Complete
Summary
The present study proposes a new connection system for Cross Laminated Timber (CLT) structures in earthquake prone areas. The system is suitable for creating wall-floor-wall and wall-foundation connections, where each connection device can transfer both shear and tension forces, thus replacing the role of traditional “hold downs” and “angle brackets”, and eliminating possible uncertainty on the load paths and on the force-transfer mechanism. For design earthquakes intensity, the proposed system is designed to remain elastic without accessing the inelastic resources, avoiding in this way permanent deformations in both structural and non-structural elements. However, in case of unforeseen events of exceptional intensity, the system exhibits a pseudo-ductile behaviour, with significant deformation capacity. Furthermore, in the proposed system the vertical forces are directly transferred through the contact between wall panels, avoiding compressions orthogonal to the grain of the floor panels. In this research, the connection system was analysed via finite element modelling based on numerical strategies with different levels of refinements. Nonlinear analyses were performed in order to investigate the response of the connection to shear, tension and a combination of such forces. The numerical responses were compared with those of full-scale experimental tests performed on the proposed connection subjected to different kind of loading configuration. The results appear as promising, suggesting that the proposed connection system could represent a viable solution to build medium-rise seismic-resistant CLT structures, that minimise damage to structural and non-structural elements and the cost of repair.
Online Access
Free
Resource Link
Less detail

Influence of Openings on the Shear Strength and Stiffness of Cross Laminated Timber (CLT) Panels

https://research.thinkwood.com/en/permalink/catalogue2710
Year of Publication
2020
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Shear Walls
Author
Aljuhmani, Ahmad
Ogasawawra, A.
Atsuzawa, E.
Alwashali, Hamood
Shegay, A. V.
Tafheem, Zasiah
Maeda, Masaki
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Shear Walls
Topic
Mechanical Properties
Keywords
Diagonal Compression Test
Openings
Lateral Strength
In-Plane Shear Stiffness
Panels
Language
English
Conference
World Conference on Earthquake Engineering
Research Status
Complete
Summary
In the last decade, cross laminated timber (CLT) has been receiving increasing attention as a promising construction material for multi-storey structures in areas of high seismicity. In Japan, application of CLT in building construction is still relatively new; however, there is increasing interest in CLT from researchers as well as construction companies. Furthermore, the Japanese government is providing construction cost subsidies for new CLT structures as it is a carbon neutral and sustainable material. The high shear and compressive strength of CLT makes it a good candidate for use as shear walls in mid-rise buildings. One important aspect of CLT walls, and one that is presently poorly understood, is the influence of openings on the shear carrying capacity. Openings are often necessary in CLT panels either in form of windows, doors, lift shaft openings or installation of building services. Concerning this aspect, the code regulations in Japan are relatively strict, such that if openings exceeded certain prescribed limits, the entire CLT panel is considered as a non-structural element, and its contribution to lateral strength is totally ignored. Furthermore, as the maximum opening size is usually governed by edge distance constraints, the size of openings that designers can use is inevitably limited by the standard sizes supplied by the manufacturers. As a result, designers are obligated to adopt very small opening size. This is thought to be a very conservative approach. The main purpose of this paper is to experimentally evaluate the influence of openings on seismic capacity; strength and stiffness reduction, as well as failure mode with changing opening size and opening aspect ratio. In addition, check the validity of the Japanese code regulations with regards to openings in CLT panels. In this study, six 5-layer CLT panels containing different openings were tested. The parameters considered include the size and layout of the opening. The panels were specifically designed with openings that would render them ineffective in resisting lateral loads according to the Japanese standard. However, in addition to the six panels, one panel without openings and one panel with openings that meet the Japanese standard was designed. All the CLT panels were tested in uniaxial diagonal compression in order to simulate pure shear loading. The CLT panels and the loading setup were designed such that the resulting failure mode will be governed by a shear mechanism. The main focus of the experiment was to relate the deterioration of the lateral strength and stiffness of the panels to the size and layout of the opening. The results showed that the panels with openings with the same area have relatively different failure direction and reduction factors for panel shear strength and stiffness, and that is due to the shear weak and strong direction that CLT panels have. Also, the effect of openings on the reduction of stiffness for CLT panels was found to be greater than their effect on the reduction of shear strength. The prescribed equation in the Japanese CLT Guidebook underpredicts stiffness reduction, and has discrepancies with regard to strength as the difference of panel strengths in weak and strong directions are not considered.
Online Access
Free
Resource Link
Less detail

Wetting and Drying Performance of Cross-Laminated Timber Related to On-Site Moisture Protections: Field Measurements and Hygrothermal Simulations

https://research.thinkwood.com/en/permalink/catalogue2711
Year of Publication
2020
Topic
Moisture
Site Construction Management
Material
CLT (Cross-Laminated Timber)
Author
Wang, Lin
Wang, Jieying
Ge, Hua
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Moisture
Site Construction Management
Keywords
Hygrothermal
Simulation
Hygrothermal Models
On-site Wetting
Language
English
Conference
Nordic Symposium on Building Physics
Research Status
Complete
Summary
Cross-laminated timber (CLT) panels are increasingly used in mid-rise buildings or even taller structures in North America. However, prolonged exposure to moisture during construction and in service is a durability concern for most wood products including CLT. To investigate practical solutions for reducing on-site wetting of mass timber construction, CLT specimens with a range of moisture protection measures, in six groups were tested in the backyard of FPInnovations’ Vancouver laboratory from Oct. 2017 to Jan. 2018. This study investigates the wetting and drying behaviours of the tested CLT specimens through 2-D hygrothermal simulations. The simulations are performed for base specimens (no protection measures) of group 1 (without joint or plywood spline) and group 2 (with a butt joint and plywood spline). For group 1, three data sources of material properties are used to create the models, and the data that led to the best agreement between simulations and measurement are used for creating the models of group 2. For group 2, two types of hygrothermal models are created with or without considering the differences in water absorption between the transverse and the longitudinal grain orientations. In addition, rain penetration is taken into account for the joint area. It is found that the model with considering the differences between transverse and longitudinal grain orientations shows a better agreement than that without considering such differences.
Online Access
Free
Resource Link
Less detail

Structural Reliability Analysis of Cross Laminated Timber Plates Subjected to Bending

https://research.thinkwood.com/en/permalink/catalogue2713
Year of Publication
2020
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Vilela, Ramon
Mascia, Nilson
Santos, Luciano
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Bending
Structural Reliability
Monte Carlo Simulation
Failure Mode
Probability of Failure
Load Capacity
Four Point Bending Test
Language
English
Conference
Society of Wood Science and Technology International Convention
Research Status
Complete
Summary
Failure modes of Cross Laminated Timber (CLT) plates reach by an excess of tensile stress on finger joints, shear stress on transverse layer due to rolling shear effect and by natural vibration. The Probability of Failure (POF) of CLT plates can be estimated from the probability distribution of their ruptures and stiffnesses, as well as their correlation coefficients. In this context, the aim of this paper is to estimate the load capacity of Cross Laminated Timber plates from a specific probability of failure and the experimental results of mechanical and physical properties. For this purpose, CLT plates were manufactured with wood species of Pinus taeda L., from Brazilian reforestation plantations. Four-point bending tests were conducted to investigate the failure behavior of the CLT plates. Density and moisture content were obtained from small specimens extracted from these plates. Monte Carlo simulation was carried out to predict the probabilistic loads that produce the failure of CLT plates, considering the failure occasioned by natural vibration as well. Experimental and numerical results of the failure modes were compared and the maximum loads to an acceptable probability of failure of the several CLT lengths were estimated too.
Online Access
Free
Resource Link
Less detail

605 records – page 1 of 61.