www.tecn

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com

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Shear Stud ConnectorsWith Crampons

TIMBER-CONCRETE

COMPOSITE FLOORS

MODERN STRENGTHENING SYSTEMS

x

THE SOLUTION TO A PROBLEM

Old timber floors often need strengthening and stiffening as they were designed to bearmoderate loads and almost always suffer from excessive deflections with respect to currentrequirements. To be sufficiently strong and stiff, new timber floors must be made withhigher beams. In both cases, it is possible to lay a thin concrete slab, adequately reinforcedand connected, over the existing structure either to strengthen and stiffen existing timberfloors or to allow lower beams to be used to build new floors. The connector can also beused to build roofs.The interposition of TECNARIA dowel and cramponconnectors between the timber beams and the concreteslab allows the two materials to collaborate with eachother. The result is structurally efficient structure inwhich, due to the vertical loads applied, the concrete ismainly under compression and the timber mainly undertension.

The composite timber-concrete structure will therefore result stronger andstiffer than a simple timber structure. Dynamic behaviour(vibrations) and sound insulation levels are also greatly improved. Theaddition of a concrete slab is an excellent technical solution in masonrybuildings located in seismic areas, since it enables load bearing walls to beconnected to each other through a rigid floor capable of evenly distributing

horizontal seismic forces.

THE TECNARIA DOWEL AND CRAMPONCONNECTORS have been specially designed andwidely tested in order to join timber structure toconcrete slabs.

The effectiveness of the connector is assured by the strong baseplate supporting the dowel, toothed with crampons so to improve its

grip on the wood and to better contribute to the shear stressabsorption. Numerous laboratory tests have demonstrated the absolute

efficacy of this solution which prevents the occurrence of embedmentwhich is inevitable when common screws or nails are used as connection

system.

Nails, screws and crampons, old and tested elements, have now been given a new task.

Continuous cut of boardingon the beam extrados

TECNARIA CONNECTORS: APPLICATIONS

C Over the boarding

Board core boring TECNARIA has a range of equipment whichsimplifies installation of the connectors;these are also available for hire.

The boards are cut with a circular saw in order to create a continuous corridor abovethe beam. Recommended for new floors. The same situation occurs if hollow floor tilesor flat tiles are interposed.

A waterproof transpiring sheet prevents themortar from percolating, the timber fromabsorbing the cast water and dust fromdepositing on the underlying floor. It must belaid over the boards and under theconnectors.

The connectors are placed directly ontothe boards. This application isrecommended for the complete repairingof existing structures.

The interposition of stiff insulating materialincreases the cross-section of the timber-concrete composite structure without addingweight to the floor.It also increases the strength and stiffness ofthe structure and improves heat and soundinsulation.

A

Dowel and crampons connectors are very easy to install; they neither require skilled workmanship norspecial site conditions. Installing them is as simple as tightening two screws! Connectors can eitherbe fixed directly to the beam or to floorboards.A sheet of waterproof material should be laid under the connectors before casting the concrete. Whenworking with hardwood predrilling is necessary (6 mm diameter for "BASE" connectors with 8 mmscrews) 8 mm diameter holes must always be prepared for "MAXI" connectors with 10 mm diameterscrews. A suitably dimensioned steel mesh should also be placed.There are three installation methods:

Cut the holes in the boards with a milling cutter or acup saw (Ø 65 mm for BASE connectors) (Ø 90 mmfor MAXI connectors). Not recommended forhardwood boards or existing boards fixed with alarge number of nails.

B

FLOOR TYPES

These drawings and other construction details can bedownloaded from the Tecnaria Internet sitewww.tecnaria.com.

DOUBLE-FRAME FLOORS

SINGLE-FRAME FLOORS

MAXI connector base plate 75 x 50 x 4 mm screws Ø 10 mm

18

12

8

8

5

H

4

TECN

AR IAT E C N A RI A

50

75

10 50

18

12

8

5

H

4

TECN

AR

IA

T E C N A R I A

36

50

8 50

BASE connector base plate 50 x 50 x 4 mm screws Ø 8 mm

cm

Mechanical properties of Tecnaria Connectors according to Eurocode 5 EN1995-1-1:2008. Processing of laboratory data as Avis Technique 3/09-603Connector Thick

boardsStrength classes of

structural timberCharacteristic resistance

Fv, RkSlip modulus Kser Slip modulus for ultimate

limit states Ku

kN kN/mm kN/mm

BASE0

C16, GL24and greater classes

17,20 17,90 9,99

D30and greater classes

19,50 16,50 9,87

2

4

C16, GL24, D30and greater classes

C16, GL24, D30and greater classes

8,96 4,00 2,49

5,86 1,43 1,20

cm

Mechanical properties of Tecnaria Connectors according to Eurocode 5 EN1995-1-1:2008. Processing of laboratory data as Avis Technique 3/09-603Connector Thick

boardsStrength classes

of structural timberCharacteristic resistance

Fv, RkSlip modulus Kser Slip modulus for ultimate

limit states Ku

kN kN/mm kN/mm

MAXI0

C16, GL24and greater classes

19,30 18,60 10,40

D30and greater classes

24,50 21,20 13,60

2

4

C16, GL24, D30and greater classes

C16, GL24, D30and greater classes

15,00 7,68 4,35

11,30 3,06 2,66

Specifications: dowel connector comprising a 50x50x4 mm base plate with crampons and two holes for 8-mm diameter coach screws with tapered necks, and a 12 mm diameter zinc coated dowel, cold-swaged to the plate. Available dowel heights: 30, 40, 60, 70, 80, 105, 125, 150, 175 and 200 mm. Available screw lengths: 70, 100 and 120 mm

Specifications: dowel connector comprising a 75x50x4 mm base plate with crampons and two holes for 10-mm diameter coach screws with tapered necks, and a 12 mm diameter zinc coated dowel, cold-swaged to the plate. Available dowel heights: 30, 40, 60, 70, 80, 105, 125, 150, 175 and 200 mm. Available screw lengths: 100 , 120 and 140 mm

CALCULATION SOFTWARE: a precious aid for designers

Tecnaria offers designers a useful design tool: a calculation programme for rapidly dimensioningcomposite timber-concrete floors with dowel and crampon connectors. It can be downloaded free ofcharge from www.tecnaria.com

A factor that must be taken into consideration when determining the size of composite timber-concrete floors is thedeformability of the connection system. Both Eurocode 5 and DIN 1052 (Möhler theory) contain a method based on thishypothesis. The calculation programme developed by Tecnaria is based on the method recommended in the above mentioneddocuments.

CA

RLO

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AZZ

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TECNARIA was the first company in Europe to subject its connectors to accurate experimentalanalysis according to the standards quoted by Eurocode 5.Stiffness and strength characteristics of Tecnaria connector fastened to timber havebeen experimentally verified in:- CNR of Florence - Istituto per la Ricerca sul Legno (Wood Research Institute):"Evaluation of the behaviour of Tecnaria connectors in compliance with Eurocode 5standards" [January 2001].- Experimental Laboratory for Building Material Testing of the Faculty of Engineering –Department of Structural and Transportation Engineering - University of Padua:"Evaluation of the behaviour of Tecnaria connectors in compliance with Eurocode 5standards" [March 1995, September 1995, June 1996].- FC BA Institut technologique (10, avenue de Saint-Mandé 75012 Paris) Dossier Technique –Connecteurs pour planchers mixtes bois – béton Juin 2008- CSTB Centre Scientifique et Technique du Bàtiment – Avis Technique 3/09-603Plancher mixte bois-béton – Composite wood-concrete floor TECNARIA Juin 2009

Eurocode 5 (EN1995-1-1) is a standard

that defines the regulationspertaining to the design,

calculation and execution of timberstructures. It is shared by thecountries belonging to the EuropeanCommunity and represents analternative to the various nationalregulations. It is used in connectionwith other European standards

that establish materialcharacteristics and

testing methods.

Eurocode 5. Design of timber structuresTimber structures. Joints made withmechanical fasteners. General principles for thedetermination of strength and deformationcharacteristics.Timber structures. Testing of joints made withmechanical fasteners. Requirement for wooddensity.Structural timber. Strength classes.Timber structures. Testing methods. Generalprinciples for static load tests.

EN 1995-1-1EN 26891

EN 28970

EN 338EN 380/00

The above tests were conducted in compliancewith the following standards:

The Tecnaria connectors have also been tested at:University of Trieste – Department of Civil Engineering: - “Evaluation of the short- and long-term behaviour of timber-concrete mechanical connections”. Astudy of the long-term behaviour of the Tecnaria connection system in timber-concrete composite structures in conditions of constant humidity andtemperature (creep or viscosity tests) and in conditions of variable humidity, under the action of a service load with plain and light-weight concrete. Testterm: 9 months [September 2000].The connectors have also been subjected to experimental testing at:- Universität Leipzig, Institut für Massivbau und Baustofftechnologie (University of Leipzig – German Federal Republic) “Push-out tests with Tecnaria studconnectors in timber-Light weight aggregate concrete composite structures” (November 1999).- Universidade do Minho – Departemento de Engenharia Civil Portugal – “Programa de ensaios em vigas mistas madeira-betão”.In June 2009 Tecnaria has received the technical certification Avis – Technique. Tecnaria products and the whole design method for composite timber andconcrete floors have been approved by independent organisation CSTB, Centre Scientifique et Tecnique du Bâtiment (French Scientific and TechnicalCentre for Building), member of EOTA (European organisation for Technical Approvals)The stud and crampon connector TECNARIA is a product covered by European patent.

THE TECNARIA SYSTEM: tested and certified according to Eurocode 5 standards