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7 records – page 1 of 1.

Influence of Steel Properties on the Ductility of Doweled Timber Connections

https://research.thinkwood.com/en/permalink/catalogue2789
Year of Publication
2021
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Author
Geiser, Martin
Bergmann, M.
Follesa, Maurizio
Publisher
ScienceDirect
Year of Publication
2021
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
Ductility
Strength
Monotonic Test
Cyclic Tests
Dowel Type Fastener
Serial Yielding
Doweled Connections
Capacity Design
Strain Hardening Ratio
Steel
Seismic
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
In the seismic design of structures according to the dissipative structural behaviour, the connection ductility is crucial in order to ensure the desired level of energy dissipation of the overall structure. Therefore, in case of ductile zones composed of dowel-type fasteners arranged in series, it is important to ensure that all the fasteners can fully develop their energy dissipation capacity by plastic deformations. However, when different types of connections made of two symmetrical and serially arranged assemblies of dowel-type fasteners are tested, it often appears that only few fasteners fully work in the plastic region while most of the remaining ones exhibit very low yielding. Looking at the causes of this dysfunction, a possible explanation is due to the fact that the rules for the seismic design of dissipative zones in timber structures given in international codes and used in common practice often make reference only to the steel quality of the dowel-type fasteners specifying a minimum tensile strength or sometime, like is the case of the current version of Eurocode 8, only to maximum values of the dowel-type fastener diameter and of the thickness of the connected timber or wood-based members. Also, the research conducted so far about the ductile behaviour of serially arranged connections was not focused on the post-elastic properties of steel. However, for the seismic design of ductile zones of other materials, such as for example is the case of reinforced concrete walls, post-elastic characteristics of steel are required for the reinforcing bars, in order to achieve the desired dissipative behaviour. Inspired by this fact, timber connections composed of serially arranged dowels made of steel grades with different hardening ratio and elongation at maximum tensile stress were fabricated and tested. The purpose of this work is to understand if the use of steel with significant post-elastic properties may help to solve the problem of limited yielding in serially arranged dowel-type connections. The tested specimens were composed of two symmetrical timber members made of Glulam and LVL connected to two 6 mm thick slotted-in steel plates by means of 9 steel dowels with a diameter of 6.0 mm, which were subjected to monotonic and cyclic tests carried out by implementing dowels made of steel with favourable post-elastic properties. The results showed that the simultaneous yielding of two serially arranged dowelled assemblies is possible, although not fully. Moreover, assuming as reference the steel grade with the lowest post-elastic properties, the connection ductility and strength measured through monotonic and cyclic tests increased by about 30% for the steel grades with the highest hardening ratio and elongation at maximum tensile stress, whereas the displacement at maximum strength was about five times higher. In addition, it was found that confinement of the timber members and shaping of holes were crucial in order to avoid undesired and premature brittle failures and to increase the connection strength and ductility. The results obtained may be useful in order to bring a reassessment of the code requirements regarding the steel properties of ductile connections as well as of certain principles of dimensioning and detailing.
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Seismic Behaviour of Cross-Laminated Timber Structures: A State-of-the-Art Review

https://research.thinkwood.com/en/permalink/catalogue1284
Year of Publication
2018
Topic
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Author
Izzi, Matteo
Casagrande, Daniele
Bezzi, Stefano
Pasca, Dag
Follesa, Maurizio
Tomasi, Roberto
Publisher
ScienceDirect
Year of Publication
2018
Country of Publication
Netherlands
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Seismic
Keywords
Seismic Behaviour
Finite Element Model
Q Factor
Capacity-Based Design
Language
English
Research Status
Complete
Series
Engineering Structures
Summary
Cross-Laminated Timber (CLT) structures exhibit satisfactory performance under seismic conditions. This ispossible because of the high strength-to-weight ratio and in-plane stiffness of the CLT panels, and the capacity ofconnections to resist the loads with ductile deformations and limited impairment of strength. This study sum-marises a part of the activities conducted by the Working Group 2 of COST Action FP1402, by presenting an in-depth review of the research works that have analysed the seismic behaviour of CLT structural systems. Thefirstpart of the paper discusses the outcomes of the testing programmes carried out in the lastfifteen years anddescribes the modelling strategies recommended in the literature. The second part of the paper introduces theq-behaviour factor of CLT structures and provides capacity-based principles for their seismic design.
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Seismic Design of a 10-Storey CLT Building

https://research.thinkwood.com/en/permalink/catalogue384
Year of Publication
2013
Topic
Design and Systems
Seismic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Follesa, Maurizio
Vassallo, Davide
Christovasilis, Ioannis
Organization
FPInnovations
Year of Publication
2013
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Seismic
Connections
Keywords
Finite Element Model
Equivalent Seismic Force Procedure
Modal Response Spectrum Method
Language
English
Research Status
Complete
Summary
This report presents the seismic design of a 10-storey Cross Laminated Timber (CLT) building in Vancouver, BC, conducted according to the National Building Code of Canada. The multi-storey condominium consists of 20 apartments for a total floor area of about 2000 m2. First, a preliminary simplified model is formulated assuming the same stiffness per meter for each wall of the building. The Equivalent Seismic Force Procedure is applied and the results serve for a preliminary design of all the major connections that play a significant role on the lateral stiffness of the building, assuming rigid in plane floor diaphragms and well-anchored CLT walls. Based on the results of the preliminary design, a 3 dimensional finite element model is created, describing analytically the modelling approach adopted, and both the Equivalent Seismic Force Procedure (referred as static analysis) and the Modal Response Spectrum Method (referred as dynamic analysis) are applied to obtain the design forces for each wall of the building. Based on the results from the dynamic analysis, the final seismic design of the building is performed and the results are presented for connections dedicated to transfer (i) shear forces from floor diaphragms to walls below and from walls to diaphragms below, (ii) uplift forces for each wall, (iii) boundary forces between CLT panels within the same walls, (iv) boundary forces between perpendicular walls, and (v) boundary forces between CLT floor panels. All connections prescribed to provide ductility and energy dissipation are designed to fail in ductile failure mode according to the CSA 086-09 while connections that should remain within the elastic range to allow the ductile connections to yield are designed with overstrength factor.
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Seismic Design of Cross-Laminated Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue1971
Year of Publication
2018
Topic
Seismic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Tannert, Thomas
Follesa, Maurizio
Fragiacomo, Massimo
González Soto, Paulina
Isoda, Hiroshi
Moroder, Daniel
Xiong, Haibei
van de Lindt, John
Publisher
Society of Wood Science and Technology
Year of Publication
2018
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Design and Systems
Keywords
Seismicity
Design Standards
Platform-Type Construction
Ductility
Connections
Language
English
Research Status
Complete
Series
Wood and Fiber Science
Summary
The increasing interest in cross-laminated timber (CLT) construction has resulted in multiple international research projects and publications covering the manufacturing and performance of CLT. Multiple regions and countries have adopted provisions for CLT into their engineering design standards and building regulations. Designing and building CLT structures, also in earthquake-prone regions is no longer a domain for early adopters, but is becoming a part of regular timber engineering practice...
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Seismic Design of Mixed CLT/Light-Frame Multi-Storey Buildings

https://research.thinkwood.com/en/permalink/catalogue1666
Year of Publication
2016
Topic
Seismic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Shear Walls
Author
Follesa, Maurizio
Fragiacomo, Massimo
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Shear Walls
Topic
Seismic
Mechanical Properties
Keywords
Multi-Storey
Q Factor
Eurocode 8
Nonlinear Time History Analysis
Dynamic Analysis
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 3750-3759
Summary
This paper presents a study on the seismic design of hybrid multi-storey wood buildings made of CLT and Light-Frame shear walls acting at the same level. Within the framework of the force-based method, the aim of this study is to propose a simple formulation in order to establish the value of the q-factor of the hybrid system which could be also implemented in seismic design codes such as Eurocode 8. This was achieved by analysing the results of nonlinear dynamic (time-history) analyses performed on a four storey case-study building with different combinations of CLT and Light-Frame shear walls.
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Seismic Design of Multi-Storey Cross Laminated Timber Buildings According to Eurocode 8

https://research.thinkwood.com/en/permalink/catalogue392
Year of Publication
2013
Topic
Seismic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Follesa, Maurizio
Christovasilis, Ioannis
Vassallo, Davide
Fragiacomo, Massimo
Ceccotti, Ario
Year of Publication
2013
Country of Publication
Italy
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Connections
Keywords
Eurocode 8
Multi-Storey
Language
English
Research Status
Complete
Series
International Journal of Earthquake Engineering
Summary
Cross Laminated Timber (CLT) structures are nowadays increasingly used worldwide and mostly in Europe where the system originated. However, in spite of this diffusion which led to the construction of a great number of multi-storey buildings all over Europe, still Eurocodes are almost completely missing provisions for CLT designers, especially regarding the seismic design. Nevertheless, Eurocode 8 requires in most cases, due to the regularity criteria being not fulfilled for most of the buildings, the use of the modal response spectrum analysis method, i.e. the linear dynamic analysis. This method requires the correct estimation of the lateral stiffness of the building in order to accurately calculate the design seismic forces in the building, which may be significantly underestimated or overestimated depending on the size of the building and the shape of the design spectrum. This can be done by modelling each connection with different methods that are often based on available test results, which are not easily accessible by a practicing engineer. This paper provides a design approach for dynamic linear modelling of CLT structures using SAP 2000. Equations are proposed based on available design codes and literature references, and used to design a 3-storey case study building. Further provisions for the seismic design of CLT buildings which are not included in Eurocode 8 are also given. Finally, the proposed design model is also compared with the results of the shaking table tests conducted in 2006 in Japan by CNR-IVALSA on a three-storey CLT building.
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7 records – page 1 of 1.