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Shear connector

Shear connectors are used to form a static plate with LIGNATUR surface elements. They are also used to align the LIGNATUR elements.

The shear connector is inserted into the factory-prepared groove from above during installation. Fixing with a 6.0 x 60 mm pan head screw into the web serves to secure the position without a static function. The resulting offset torque is transferred via a pair of forces and introduced into the wood via contact. The force transmission therefore functions without constraint and the elements can swell and shrink freely. During installation, at least two shear connectors should be installed per joint before the next element is laid.

Static system and actions

Geometry:

Length of diaphragm: ls 
Width of diaphragm: hs

Actions:

Wind pressure: q_Druck,x,d respectively q_Druck,y,d
Wind suction: q_Sog,x,d respectively q_Sog,y,d
Stabilisation load: q_H,x,d respectively q_H,y,d 
Seismic action: q_E,x,d respectively q_E,y,d 

Pertinent combination wind:

q_x,d = q_Druck,x,d + q_Sog,x,d + q_H,x,d
q_y,d = q_Druck,y,d + q_H,y,d

Pertinent combination earthquake:

q_x,d = q_E,x,d + q_H,x,d
q_y,d = q_E,y,d / l_s + q_H,y,d

Maximum shear force:  

A_x,d = B_x,d = q_x,d * l_s / 2
A_y,d = B_y,d = q_y,d * h_s / 2

Maximum moment:

M_z,d = q_x,d * l_s² / 8

Maximum compressive / tensile force:

± N_d = M_z,d / h_s

± N_d must be taken up by the supports. Joints must be designed with one and a half times the load-carrying capacity! The support reactions A_x,d, B_x,d, A_y,d and B_y,d must be transmittet through the primary construction.

1 Transfer of shear loads

Verification: A_x,d / F_Rd,tot ≤ 1.00

A_x,d Maximum shear force
F_Rd,tot Total design load-carrying capacity

F_Rd,tot = F_Rd * n

n Number of shear connectors 
F_Rd Design load-carrying capacity per shear connector 

F_Rd = F_Rk * k_mod / γ_M

F_Rk Characteristic load-carrying capacity per shear connector = 10.19 kN
k_mod Modification factor according to EN 1995-1-1 depending on the relevant load case or load duration
γ_M Partial factor

2 Connection to the supports

Verification: A_x,d / F_v,Rd,tot ≤ 1.00

A_x,d Maximum shear force
F_v,Rd,tot Total design load-carrying capacity

F_v,Rd,tot = F_v,Rd * n

n Number of screws per row, SPAX Senkkopf, screw diameter d_S = 8 mm
F_v,Rd Design load-carrying capacity per screw

F_v,Rd = F_v,Rk * k_mod / γ_M

F_v,Rk Characteristic load-carrying capacity per screw = 3.00 kN (pre-drilled)
at:
t₁ Wood thickness (element) = 31 mm
t₂ Penetration in the support = 40 mm

3 Connection parallel to the longitudinal wall

Verification: E_d / F_v,Rd,tot ≤ 1.00

E_d Maximum action parallel to the longitudinal wall
F_v,Rd,tot Total design load-carrying capacity

Ed = √(s_w,v,d² +q_Druck,x,d² ) / 1.00m

s_w,v,d = A_x,d / h_s
s_w,v,d shear flow
q_x,d Maximum shear force

F_v,Rd,tot = F_v,Rd * n

n Numbers of screws per row per m, SPAX Senkkopf, screw diameter d_S = 8 mm
F_v,Rd Design load-carrying capacity per screw

F_v,Rd = F_v,Rk * k_mod / γ_M

F_v,Rk Characteristic load-carrying capacity per screw = 3.00 kN (pre-drilled)
at:
t₁ Wood thickness (element)  = 31 mm
t₂ Penetration in the support = 40 mm

4 Verification of the load-carrying capacity

Verification: σ_m,d / f_m,d  ≤ 1.00

σ_m,d Maximum bending stress
f_m,d Design bending strength

Verification: τ_d / f_v,d  ≤ 1.00

τ_d Maximum shear stress
f_v,d Design shear strength

Maximum horizontal bending: wy ≥ h_s / 1000
at:
b Element width 
h_s Element height
t Slat thickness
d Web thickness = 31 mm

5 Connection of border elements to the supports

Verification: A_y,d / F_v,Rd,tot ≤ 1.00

A_y,d  Maximum shear force
F_v,Rd,tot Total design load-carrying capacity

F_v,Rd,tot = F_v,Rd * n

n Number of screws per row, SPAX Senkkopf, screw diameter d_S = 8 mm
F_v,Rd Design load-carrying capacity per screw

F_v,Rd = F_v,Rk * k_mod / γ_M

F_v,Rk Characteristic load-carrying capacity per screw = 3.00 kN (pre-drilled)
at:
t₁ Wood thickness (element) = 31 mm
t₂ Penetration in the support = 40 mm

Static plate

Dimensioning values

moment
M_z,d (q_x,d) = q_x,d . l_s ² / 8

tensile / compressive force
Z_d = N_d = M_z,d / h_s

shear force / bearing reaction
A_x,d = B_x,d = q_x,d . l_s / 2
A_y,d = B_y,d = q_y,d . h_s / 2

flow of shear forces
s_v,0,d = A_x,d / h_s

Verification
1 fasteners
f_v,0,d = k_v1 . R_d / a_v ≥ s_v,0,d

2 shear strength OSB
f_v,0,d = k_v1 . k_v2 . f_v,d . t ≥ s_v,0,d

3 shear buckling OSB
f_v,0,d = k_v1 . k_v2 . f_v,d . 35 . t² / ar ≥ s_v,0,d

k_v1 = 1.0 (boards are rigidly connected all around)
k_v2 = 0.33 (one-sided sheating)
a_v = distance fasteners
t = 15 mm (thickness OSB)
ar = 800 mm (distance studs)
R_{d,nail,Ø3.1 mm} = 0.53 kN
R_{d,staple,Ø1.8 mm} = 0.60 kN
k_mod = 0.9

The floor bearings need to be dimensioned so that they can take the loads from N_d and Z_d and transfer the reactions from the static plate. The design is performed according to EN 1995-1-1, section 9.2.3.