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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 !