timber structures and building...

KIT – University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association

TIMBER STRUCTURES AND BUILDING CONSTRUCTION

www.kit.edu

Connections for timber structuresHans J. Blass

Timber Structures and Building Construction2 09.08.2010 Hans J. Blass

Timber bridge in Sneek, NL

Timber Structures and Building Construction3 09.08.2010 Hans J. Blass

Timber joints

Glued jointsJoints with mechanical fastenersCarpenter joints

Glued joint

Timber Structures and Building Construction4 09.08.2010 Hans J. Blass

Timber joints

Glued jointsJoints with mechanical fastenersCarpenter joints

Joint with mechanical

fasteners

Timber Structures and Building Construction5 09.08.2010 Hans J. Blass

Carpenter joint

Timber Structures and Building Construction6 09.08.2010 Hans J. Blass

Joints with mechanical fasteners

Dowel type timber jointsConnector jointsTruss plate joints

Timber Structures and Building Construction7 09.08.2010 Hans J. Blass

Connector joint

Timber Structures and Building Construction8 09.08.2010 Hans J. Blass

Timber Structures and Building Construction9 09.08.2010 Hans J. Blass

Timber Structures and Building Construction10 09.08.2010 Hans J. Blass

Johansen‘s model

Timber Structures and Building Construction11 09.08.2010 Hans J. Blass

Plug shear

Timber Structures and Building Construction12 09.08.2010 Hans J. Blass

Splitting

a1

a3

a4a2

Timber Structures and Building Construction13 09.08.2010 Hans J. Blass

Reinforcement using screws with continuous thread

Timber Structures and Building Construction14 09.08.2010 Hans J. Blass

Screws stop crack growth

Timber Structures and Building Construction15 09.08.2010 Hans J. Blass

Screws loaded in shear

0,5·F 0,5·F

F

Timber Structures and Building Construction16 09.08.2010 Hans J. Blass

Inclination of fastener axis

Timber Structures and Building Construction17 09.08.2010 Hans J. Blass

Truss action

0,5·F 0,5·F

F

Timber Structures and Building Construction18 09.08.2010 Hans J. Blass

Fax

Fc,90

F0

Ffr

Truss action

Timber Structures and Building Construction19 09.08.2010 Hans J. Blass

Bolted steel connections in shear

Source: Project KI-Smile

Timber Structures and Building Construction20 09.08.2010 Hans J. Blass

Bolted steel connections in shear

Source: Project KI-Smile

Timber Structures and Building Construction21 09.08.2010 Hans J. Blass

Timber Structures and Building Construction22 09.08.2010 Hans J. Blass

Truss connection

Photo: Wiehag

Timber Structures and Building Construction23 09.08.2010 Hans J. Blass

Frankfurter Messehalle 11

Photo: Atlas Copco

Timber Structures and Building Construction24 09.08.2010 Hans J. Blass

Inclined screws in steel-to-timber joints

Photo: Atlas Copco

Timber Structures and Building Construction25 09.08.2010 Hans J. Blass

Inclined screws in steel-to-timber joints

Photo: Atlas Copco

Timber Structures and Building Construction26 09.08.2010 Hans J. Blass

Connection test Stuttgart University

Ultimate load per shear plane:Test 1: FU = 6200 kNTest 2: FU = 6600 kN

Photo: Universität Stuttgart

Timber Structures and Building Construction27 09.08.2010 Hans J. Blass

Failure mode: screw tensile failure

Photo: Universität Stuttgart Photo: Universität Stuttgart

Timber Structures and Building Construction28 09.08.2010 Hans J. Blass

Screws parallel to member axis

A

B

B

A

glulam

glulam

CLT

A-AB-B

Timber Structures and Building Construction29 09.08.2010 Hans J. Blass

Glulam

CLT

Threaded rods

Timber Structures and Building Construction30 09.08.2010 Hans J. Blass

Screws parallel to member axis

A A

B

BB-B

A-A

glulam

CLT

Timber Structures and Building Construction31 09.08.2010 Hans J. Blass

Axially loaded screws

Preliminary tests led to timber splitting or screw withdrawal after timber reinforcement

Timber Structures and Building Construction32 09.08.2010 Hans J. Blass

Timber is anisotropic

Avoid perpendicular to the grain stressesDesign for low strength and stiffness perpendicular to the grainReinforcement

Timber Structures and Building Construction33 09.08.2010 Hans J. Blass

Shear failure parallel to grain

Timber Structures and Building Construction34 09.08.2010 Hans J. Blass

Fax

Fax

τ σc,90

σc,90

Shear reinforcement

Timber Structures and Building Construction35 09.08.2010 Hans J. Blass

Crack

Timber Structures and Building Construction36 09.08.2010 Hans J. Blass

Curved and pitched cambered beams

Timber Structures and Building Construction37 09.08.2010 Hans J. Blass

Tensile failure perp. to grain

Timber Structures and Building Construction38 09.08.2010 Hans J. Blass

Curved and pitched cambered beams

Timber Structures and Building Construction39 09.08.2010 Hans J. Blass

Notched beam supports

Timber Structures and Building Construction40 09.08.2010 Hans J. Blass

Reinforcement with screws

A

A-A

fully threaded screws

A

Timber Structures and Building Construction41 09.08.2010 Hans J. Blass

Compression perp. to grain

Photo: Kreuzinger

Timber Structures and Building Construction42 09.08.2010 Hans J. Blass

Fc,90

σc,90 = fc,90

Compression perp. to grain

Timber Structures and Building Construction43 09.08.2010 Hans J. Blass

Fc,90

σc,90 < fc,90

Timber Structures and Building Construction44 09.08.2010 Hans J. Blass

Fc,90

σc,90 < fc,90

Timber Structures and Building Construction45 09.08.2010 Hans J. Blass

Fc,90

σc,90 < fc,90

Timber Structures and Building Construction46 09.08.2010 Hans J. Blass

0

50

100

150

200

250

300

0 1 2 3 4 5

displacement in mm

load

R90

in k

N

non-reinforced

8 x 400 mm 8 x 260 mm

7,5 x 180 mm

Bottom view

Bottom view

Reinforcement using screws

Timber Structures and Building Construction47 09.08.2010 Hans J. BlassThank you very much for your attention !