Clt mtb seminar_presentation_two

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Modern screw connectors

Design and use in CLT, Gluelam and LVL

By Michael Koenig

TopicsPictures of projects• Expo Roof• Airport Paris• Mt Ruapehu• Waitomo Caves

Modern screw connectors• Partial thread and full thread and field of use• Head shape and recess• Samples of connections • Pre drilling• Corrosion issues

Technical information• Where to get information from

The roof of the Expo 2000 in Germanyapprox. 10,000,000 screws are in use here, to ensure the permanent

strength of the wood.

Charles de Gaulle Airport, Paris

Cologne Zoo Elefant House

Steel to Timber connection

Knoll Ridge Cafe, Whakapapa NZ

Knoll Ridge Cafe, Whakapapa NZ

Waitomo Caves Visitor Centre

Waitomo Caves Visitor Centre


Modern screw connectors today are:

• Self-tapping screws for use in timber structures• No pre drilling is required (except hardwoods)• The main characteristics are:

- thread: full or partial threaded- head shapes


Full thread or Partial threadFull thread- for long screws no clamping effect- with remarkably high load bearing capacityin tension as well as in compression- inclined screws can work as framed truss

Partial thread- with clamping effect, pull together- clamping effect is depending on head shape and size

Modern Screw Connectors

Main head shapes and recess

Washer headCountersunk SPAX T-STAR plus recess for best driving home performance


Countersunk head

• Main use for full threaded screws• Flush counter sinking in timber• Small head diameter for reduced visibility• For partial threaded screws small load bearing

capacity in tension due to head diameter• Can be used also in counter sunk steel plates for steel to

timber connections

Application examples: Countersunk ScrewsWall fastening, timber frame construction

Secure joining of wall elements, for example


Washer head

• Best use for partial thread screws• Plain contact to timber• Big head diameter• For partial threaded screws high load bearing

capacity in tension due to big head diameter

Application examples: Wascher Head Screws

Fastening rafters, purlin

Fastening the rafters, pulled tightly together using the washer head screw.

No purlin anchors / triple grip necessary

High wind uplift load bearing capacity


Cylindrical head

• Only use for full thread screws• Flush counter sinking with timber, or

slightly deeper sinking possible• Very small head diameter for reduced visibility• Is not recommended for use in

steel to timber connections • Also data on screw reinforcement available from Expan

Application examples: Fully Threaded ScrewsTransverse tensile reinforcement in accordance with DIN 1052:2008

Reliable alternative to bonded reinforcement boards and glued thread rods

Work can be performed by any carpenters shop

No bonding approval required

Work can also be reliably performed on site (e.g. restoration of buildings)

Roller coaster Liseberg Stockholm, SwedenSplit control of engineered dowel connections

EXPAN Quick-Connect

R afte r

S leev es(s tee l ro d s in s id e )

S c rew s

B earin g p la te s

C o lu m n

Design of connection detail

Spacing of screws

CLT – standard details

Corner jointExterior wall

partial thread

sealing tapes forair tight shell

Picture: Building with cross laminated timber of Studiengemeinschaft Holzleimbau e.V.


Ceiling connectionPlatform framing

partial thread




Roof connectionEave detail

partial thread




Wall connection verticalPartial thread with connection splice plate

Picture: Building solutions of Stora Enso


Ceiling connection with connection splice platePartial thread


j

J g

cv



J g

cv

J g

cv

Ceiling connection Full thread with reinforcement, full thread



Top bearer connection with steel beamFull thread

J v

J v



Top bearer connection with upper CLT wallFull thread

J v

J v

Pre-Drilling

Do not exceed maximum drive torque

Pre-drill size should be shank Ø of the screw

Pre-drilling as a locating guide for easy installation

Corrosion control

Zinc: for internal use only

Hot dip galvanize: for external use in low corrosive areas. (Low tensile fasteners only)

Delta-Seal: ideal for treated timber in low corrosive areas

Stainless Steel: in exposed high corrosive areas

Technical Information

www.spaxpacific.com

Download the European Technical approvals

Download a SPAX Design guide (based on EC5 and ETA)

E-mail details to [email protected]

Full range of SPAX timber construction program available in Australia and New Zealand

Design software available soon

http://www.spaxpacific.com/

mailto:[email protected]

THANK YOU VERY MUCH