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Dynamic Response of an Under-Deck Cable-Stayed Timber-Concrete Composite Bridge Under a Moving Load

https://research.thinkwood.com/en/permalink/catalogue2037
Year of Publication
2018
Topic
Mechanical Properties
Design and Systems
Material
Timber-Concrete Composite
Application
Bridges and Spans
Author
Lyu, Zhan
MÁLAGA-CHUQUITAYPE, Christian
Ruiz-Teran, Ana
Organization
Imperial College London
Year of Publication
2018
Format
Conference Paper
Material
Timber-Concrete Composite
Application
Bridges and Spans
Topic
Mechanical Properties
Design and Systems
Keywords
FE model
Post-Tensioned
Shear Deformations
Deflection
Shear Forces
Dynamic Response
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
Timber-Concrete Composite bridges have the potential to achieve significant levels of structural efficiency through the synergistic use of Engineering Wood Products (EWPs) and reinforced concrete. With the implementation of post-tensioned under-deck tendons, the range of application of TCC bridges can be extended to medium spans. However, little work has been done to date to study the dynamic response of these newly proposed bridges. In this paper, a set of FE models representing 60-m span structures are analysed to gain understanding on the dynamic response of post-tensioned under-deck TCC bridges. Two models with Euler and Timoshenko beam idealizations are considered in order to evaluate the significance of shear deformations on deflection, structural stresses and connector shear forces. Besides, an analytical model is formulated and compared against the numerical predictions. The results show that timber shear deformations should be considered in the design of post-tensioned under-deck TCC bridges. The dynamic characteristics of the bridge models were studied. The dynamic amplification caused by a moving point load on key response parameters such as deflection, stresses and connector shear forces is discussed. Also, a sensitivity study on the speed of moving load is conducted to investigate its influence on the bridge dynamic response.
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Post-Tensioned Timber Frames with Supplemental Damping Devices

https://research.thinkwood.com/en/permalink/catalogue1150
Year of Publication
2014
Topic
Seismic
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Smith, Tobias
Organization
University of Canterbury
Year of Publication
2014
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Seismic
Keywords
Post-Tensioned
Static Response
Dynamic Response
Lateral Loading
Beam-Column Joint
Research Status
Complete
Summary
In recent years the public expectation of what is acceptable in seismic resisting construction has changed significantly. Engineers today live under demands which are far more intensive than their historical counterparts and recent seismic events have shown that preserving life is no longer sufficient, and a preservation of livelihood is now the minimum. This means that after a major seismic event a building should not only be intact but be usable with no or minimal post-quake intervention. In addition to this already high expectation these demands must be met in a green and sustainable fashion with minimal (or even negative) environmental impact. This doctoral project looks to further advance the research into a new and innovative method of timber construction which satisfies (and exceeds) these demands.
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Stability and Dynamic Properties of Tall Timber Structures - A parametric study of the structural response due to wind action

https://research.thinkwood.com/en/permalink/catalogue3096
Year of Publication
2019
Topic
Wind
Author
Alalwan, Ahmad
Larsson, Joakim
Organization
Chalmers University of Technology
Year of Publication
2019
Format
Thesis
Topic
Wind
Keywords
Dynamic Response
Human Occupancy
Tall Timber Structure
Wind-induced Vibration
Research Status
Complete
Summary
The interest in building taller structures in timber is increasing in the building sector. However, the high strength-to-weight ratio of timber leads to a relatively light structure which is often associated with vibrations. The dynamic properties are essential in the design of tall timber structures, where wind-induced vibrations of the building in service state is addressed. The dynamic response is influenced by mass, stiffness and damping. These parameters influence the acceleration of the building which can be perceived as a discomfort for human occupancy. The aim is to find a structural concept that makes a taller structure than the usual today feasible. The objective is to make a parametric study and investigate how a multi-storey residential building of timber can be optimized with respect to dynamic wind loading. With a combination of numerical and analytical methods, accelerations are calculated and evaluated against the criteria for human comfort according to ISO 10137 and ISO 6897. An analytical calculation sheet is set up according to SS-EN-1991-1-4 and EKS 10 to define wind-induced acceleration. Starting from a beam-column structure with a central core, the effect of adding inner walls and exterior bracing is studied to see what limits the number of storeys for an open plan building. Analysis of the dynamic response due to wind shows the fundamental mode shape in torsion before exterior bracing is added. Results have shown that the structure can reach 5-storeys with inner walls of cross-laminated timber and 4-storeys with no walls. Moreover, it’s found that diagonal bracing in the facades improves the torsional stiffness significantly and the fundamental mode becomes a transversal mode. An outrigger bracing system has been found to be the most efficient, leading to a structure of 12-storeys. The parameters mass and stiffness are modified by adding concrete floors and assigning larger sections to the structure. Results show that the building can achieve 15-storeys with pure timber and 21-storeys when concrete floors are added. Secondary parametric action i.e. adding another outrigger generates a gain of one-storey and modifying the truss-work to steel gives a structure of 23-storeys.
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Vibration Response Modelling of Cross Laminated Timber Slabs

https://research.thinkwood.com/en/permalink/catalogue1621
Year of Publication
2016
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Ussher, Ebenezer
Weckendorf, Jan
Smith, Ian
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Finite Element
Dynamic Response
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 2494-2501
Summary
Innovations in timber engineering have led to new slab systems built from engineered wood products like cross-laminated-timber (CLT). High stiffness of CLT can enable attainment of better vibration performances than is possible with traditional shallow profile-long span floors constructed from timber and other materials. However, realization of this depends on engineers being able to accurately predict effects various construction variables have on dynamic responses of CLT slabs. Past physical experiments have provided insights into those effects. However, testing is a very expensive and time consuming means of acquiring necessary knowledge. Discussion here addresses finite element (FE) simulations as a cost effective method allowing engineers to understand and assess relationships between design variables and dynamic responses of CLT floor slabs. Presented modelling techniques are verified by demonstrating close correlation between numerical predictions and experimental modal response characteristics of CLT slabs.
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