Article

A King-Post Truss Applied to a Wooden Bridge in a New Way

January 2001
IABSE Symposium Report 85(8)

DOI:10.2749/222137801796348584

Authors:

In this paper a new way to apply a king-post truss without any wind bracing is presented. The main diagonals of the structure have been made of wood and concrete and they are working together as a composite structure. The secondary diagonals have been made of wood. The deck consists of transversal planks connected on the longitudinal glued laminated timber girders. The glued laminated girders are supported by transverse steel girders hanging from the truss system. The main diagonals have been developed and designed so that their transverse stiffness is so big that there is no need for the transverse bracing between the trusses. The absence of wind bracing enables to use king-post truss without any vertical height limit in design of medium and small span bridges as well.

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Article

Composite Effect of Bolt-Laminated Sweetgum and Mixed Hardwood Billets

September 2008 · Journal of Bridge Engineering

Industrial hardwood laminated billets and mats were proposed, manufactured, and tested. The raw material for the mats was structural composite lumber billets manufactured from sweetgum and mixed hardwood lumber. Each mat consisted of three bolt-laminated billets. Both billets and mats were tested in third-point bending across a 1.87-m span. The span-to-depth ratio was 21. Results showed that bolt ... [Show full abstract] laminating contributes significantly to mechanical performance as compared to that of individual billets.

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Mechanically jointed CLT panels for wall, floor and timber-concrete composite structures

January 2014

Cross laminated timber (CLT) has become very popular for all types of structures all around the world in last years. CLT consists of uneven number of plank layers oriented in 90° angle to each other and bonded together. Various types of adhesives and technologies are used for bonding and manufacturing of final product. In some cases, gluing is not ideal manufacturing method and there is a demand ... [Show full abstract] of other manufacturing processes. Mechanical jointing is logical result of current research at the Czech Technical University. Research is focused on developing and verifying mechanical behaviour of mechanically jointed CLT solid wood panels. Sets of experiments focused on mechanical behaviour of these mechanically jointed CLT panels were performed. This paper summarizes results of wall, floor and timber-concrete composite elements, which have been tested.

Article

Ein Walfisch aus Stahl, Holz und Glas – die Fassade des Kaufhauses Peek und Cloppenburg in Köln

November 2005 · Stahlbau

Mit dem neuen Kaufhaus Peek und Cloppenburg ist ein Bau von herausragender architektonischer Qualität mitten im Herzen der Kölner Altstadt entstanden. Seine Fassade, über die in diesem Aufsatz berichtet wird, war in vielfacher Hinsicht eine besondere Herausforderung für die Tragwerksplanung. Dies betrifft die komplexe Geometrie, die Lagerung auf dem Rohbau vor allem aber die ungewöhnliche und ... [Show full abstract] neuartige Kombination der Werkstoffe Stahl und Holz. Aufgelöste vertikale Holzbinder und horizontale Stahlrohre bilden mit diagonalen Stahlseilen eine freitragende Stabschale. Dazu mußten zahlreiche Konstruktionsdetails, insbesondere die Holzverbinder, erstmals gelöst werden. The facade structure of the department store Peek und Cloppenburg in Cologne. The new department store Peek and Cloppenburg in the heart of the city of Cologne is a building of outstanding architectural quality. It's façade structure, which is highlighted in this paper, was for many reasons an exceptional challenge for structural engineering. This holds for the complex geometry, for the interaction between the façade and the concrete substructure and especially for the new and unusual combination of the structural materials glass and timber. Vertical oriented spaced laminated wooden trusses and horizontal steel tubes form together with diagonal steel cables a load bearing grid shell. To do so, many structural details, especially the connections between the timber trusses and the steel members had to be resolved for the first time.

Article

Comparison of ASTM D 198 and five-point bending for elastic constant ratio determination

July 2006 · Forest Products Journal

Current design of structural composite lumber (SCL) assumes that the ratios of Young's modulus (E) to in-plane shear modulus of rigidity (G) are equivalent to values associated with solid-sawn lumber. Yet there is no published research presenting a direct comparison of the elastic constants for SCL and solid-sawn lumber. Accordingly, a study was conducted to better define elastic constants and ... [Show full abstract] appropriate E:G ratios evaluated for three kinds of SCL, including laminated veneer lumber (LVL), parallel strand lumber (PSL), and laminated strand lumber (LSL), and one type of solid-sawn lumber. This paper reports on data collected applying the ASTM D 198 test standard and the non-standard five-point bending test (FPBT) for elastic and shear moduli determination. Data collection included edgewise and flatwise loading in the longitudinal direction to determine the modulus of elasticity (E 1) and planar shear moduli (G 12 and G 13). The edgewise E 1:G 12 from LVL was the only SCL elastic constant ratio comparable to solid-sawn lumber values. Large differences in the SCL shear moduli values were observed compared to solid-sawn lumber. This research concludes that there are differences between the E:G ratios of solid-sawn lumber and SCL materials. Comparison of solid-sawn and LVL ASTM E:G ratios with previously published literature was favorable. A comparison of the ASTM D 198 and FPBT results shows that all solid-sawn lumber elastic constants as well as the SCL elastic moduli were less than 10 percent different. The FPBT yielded less test measure variability than the ASTM testing. The FPBT was felt to provide an accurate and simple evaluation of the shear modulus properties for wood and wood composites.

Article

Full-text available

Flexural behavior of FRP strengthened concrete-wood composite beams

November 2018 · Ain Shams Engineering Journal

Yehia A. Zaher Ali

An experimental investigation was conducted to study the structural performance of concrete-timber composite beams provided with systems of semi-rigid connectors of various configurations and stiffness. Eleven concrete-timber composite beams and one concrete-steel composite beam were tested in three-point flexure test. The construction of the beam web and the type of shear connector were the ... [Show full abstract] basic parameters of investigation. The feasibility of boosting the flexural performance of these beams when wrapping their webs with GFRP laminates was examined. Comparison of the flexural behavior of the proposed composite concrete-timber beams with that of both of post-stressed beams using external steel longitudinal rods and a concrete-steel composite beam was also evaluated. Test results showed that vertical glulam timber web is superior to both horizontal glulam and massive block timber webs in providing higher stiffness and load carrying capacity and larger toughness. Also, dovetail shear connector enhanced with insertion of a steel dowel at the center of the groove imparts a full composite action between concrete and timber web. Use of GFRP laminates wrapping along the full span of timber web is a highly effective method to take advantage of the use of enhanced dovetail shear connector. The behavior of the proposed concrete-timber composite beam was comparable to that of the concrete-steel web beam.

Book

Materials and Joints in Timber Structures: Recent Developments of Technology

January 2014 · RILEM Bookseries

Conference Paper

Investigation on Failure Behavior of Mixed-Species Glued Laminated Timber Beams

September 2003

The reported research aims to provide means to improve the performances of timber structures, particularly when brittle behavior of timber elements can represent an obstacle in adopting timber structures. Several technological approach solutions are under investigation within the frame of a three-year national research project: the first solution analyzed is the mixed glulam beam manufactured ... [Show full abstract] coupling laminations of different wood species, featuring a better performance as far the global ductile behavior is concerned. A numerical iterative approach has been adopted to determine the moment-curvature relationship in the plastic field up to failure. The tests performed so far confirm the expected behavior on the basis of the numerical analysis.

Conference Paper

Full-text available

INNOVATIVE CONNECTIONS BETWEEN HYBRID FLOOR PANELS AND TIMBER COLUMNS ABLE TO REDUCE THE DEFLECTION...

June 2019

This study experimentally investigates the mechanical response of seval new types of hybrid connections between glulam timber-concrete panels and glulam timber columns. Each panel is composed of glued laminated wood beams and/or concrete constituting the floor and wooden beams constituting the supporting framework for the façade elements. The dimensions of the hybrid panels are defined to ensure ... [Show full abstract] appropriate implementation and transport conditions. For these reasons, the width of the panels is fixed at 1.20 m, and the length is 7.5 m. The experiments are conducted at the Laboratory for Composite Materials and Composite Structures at the University Claude Bernard Lyon I. The experimental setup, connection configurations, and material properties are introduced, followed by a detailed analysis of the test results and observations. The obtained results reveal the overall mechanical behavior of the connections. All of the connections are designed to support the same load combination until failure. Based on the results, the new connections are able to reduce the deflection of the floor panel in the middle of the span by 45% in comparison with the common bolted connections that have been designed to support the same load combination and have the same dimensions .

Article

Wood to concrete connections

January 2006

This is an ongoing study, which focuses on the development of connection models of dowel type connections between wood and concrete. Only preliminary results of experimental testing are presented here. Experimental tests were conducted on three single-shear connection types, two grades of structural composite lumber (SCL) and one grade of Glued Laminated Timber (glulam). Three connector types ... [Show full abstract] were investigated; lag screws, steel dowels (rebar), and headed studs. All of the connector types were installed perpendicular to the wood interface in undersized holes. Concrete was cast in-place to form the other side member of the connection. Specimens were tested in a special jig to prevent rotation due to the eccentricity of the applied loads in these single shear connections and both load and displacement data were recorded. The results of the tests will be used in the development of a connection model to predict connection stiffness and strength.

Article

CHARRING RATE OF COMPOSITE TIMBER PRODUCTS

January 1970

Robert H. White

Increasingly, wood members used in wood structures are structural composite lumber products. Such products include laminated veneer lumber, parallel strand lumber, and lami- nated strand lumber (Green 1998). To apply the calculation procedures to composite timber products, it is critical that char rate data for such products be available in the public domain. Charring data on composite lumber ... [Show full abstract] products in the public domain has been limited (Mikkola 1991, Getto 1998, Uesugi and others 1999). The test program reported in this paper provides these char rate data. Laminated veneer lumber (LVL) is produced by laminating veneers with the grain of each veneer parallel to the longitudinal direction of the member. Approximately 3-mm-thick lam- inates are glued together. Laminated strand lumber (LSL) is produced by gluing and pressing strands of wood together to form the lumber product. The strands are oriented to be parallel to the logitudinal direction of the member. In parallel strand lumber (PSL), veneers are clipped to produce 19-mm-wide strands that are aligned and pressed into the lumber product

Article

Proposal for design method of the composite steel-timber structure using buckling-restrained knee br...

June 2014 · Journal of Structural and Construction Engineering (Transactions of AIJ)

In the field of building construction, mass consumption of wood materials contributes to reforestation as well as to reduce environmental burden. At present, a composite steel-timber structure has been used in several building structures and is expected to be used even more widely in the future. The authors proposed the composite steel-timber structure which system is based on a damage-controlled ... [Show full abstract] structure. This structural member is composed of steel and glued laminated timber. In this paper, a design method of the composite steel-timber structure using buckling-restrained knee braces is proposed on the previous experimental tests. A trial design is conducted where applicability of the design method is shown.

Article

Full-text available

Design, construction and testing of a composite glued timber-concrete structure to be used in bridge...

December 2010 · Revista de la construcción

This paper addresses a theoretical and experimental research conducted on glued laminated timber-concrete composite structures. It focuses on the validation of simple wood screws to be used as connectors in bridges. Beams are designed on the basis of the gamma method, described in the standards NCh 1198 and Eurocode 5. To validate this analysis model, a number of tests were performed consisting ... [Show full abstract] on the one hand of shear tests on composite specimens and on the other hand of a bending test on a composite beam test specimen. The results of these tests, regarding the rigidity of the connection, are very positive. Said rigidity showed values 2 to 3 times bigger than that theoretically calculated. The research study demonstrates the structural efficacy of the glued laminated timberconcrete composite system with wood screw-type connectors and its suitability to bridges.