Verification with flat steel

The flat steel is inserted from above and held in the web with a 6.0 x 60 mm pan head screw. When assembling, install at least one flat steel (in the middle) before the next element is installed.

Geometry flat steel

bst: 20 mm
tst: 12 mm
lst: 180 mm

Static characteristics

Characteristic load-carrying capacity flat steel Fv,Rk = 7.06 kN
Shifting module Kser = 3225 N/mm
Steel quality S235

Structural design according to EN 1995-1-1
The modification factor kmod and the partial factor γM change depending on the relevant load case and load duration:

Wind
kmod 0.9

Earthquake
kmod 1.0

Static system and actions

Geometry:

Length of diaphragm: ls 
Width of diaphragm: hs

Actions:

Wind pressure: qDruck,x,d respectively qDruck,y,d
Wind suction: qSog,x,d respectively qSog,y,d
Stabilisation load: qH,x,d respectively qH,y,d 
Seismic action: qE,x,d respectively qE,y,d 

Pertinant combination wind:

qx,d = qDruck,x,d + qSog,x,d + qH,x,d
qy,d = qDruck,y,d + qH,y,d

Pertinant combination earthquake:

qx,d = qE,x,d + qH,x,d
qy,d = qE,y,d / ls + qH,y,d

Maximum shear force:  

Ax,d = Bx,d = qx,d * ls / 2
Ay,d = By,d = qy,d * hs / 2

Maximum moment:

Mz,d = qx,d * ls2 / 8

Maximum compressive / tensile force:

± Nd = Mz,d / hs

± Nd must be taken up by the supports. Joints must be designed with one and a half times the load-carrying capacity! The support reactions Ax,d, Bx,d, Ay,d and By,d must be trasmittet through the primary construction.

1 Transfer of shear loads

Verification: Ax,d / FRd,tot ≤ 1.00

Ax,d Maximum shear force
FRd,tot Total design load-carrying capacity

FRd,tot = FRd * n

n Number of flat steels
FRd Design load-carrying capacity per flat steel

FRd = FRk * kmod / γM

FRk Characteristic load-carrying capacity per flat steel = 7.06 kN
kmod Modification factor according to EN 1995-1-1 depending on the relevant load case or load duration
γM Partial factor

2 Connection to the supports

Verification: Ax,d / Fv,Rd,tot ≤ 1.00

Ax,d Maximum shear force
Fv,Rd,tot Total design load-carrying capacity

Fv,Rd,tot = Fv,Rd * n

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

Fv,Rd = Fv,Rk * kmod / γM

Fv,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: Ed / Fv,Rd,tot ≤ 1.00

Ed Maximum action parallel to the longitudinal wall
Fv,Rd,tot Total deisgn load-carrying capacity

Ed = √(sw,v,d2 +qDruck,x,d2 ) / 1.00m

sw,v,d = Ax,d / hs
sw,v,d shear flow
qx,d Maximum shear force

Fv,Rd,tot = Fv,Rd * n

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

Fv,Rd = Fv,Rk * kmod / γM

Fv,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: σm,d / fm,d  ≤ 1.00

σm,d Maximum bending stress
fm,d Design bending strength

Verification: τd / fv,d  ≤ 1.00

τd Maximum shear stress
fv,d Design shear strength

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

5 Connection of border elements to the supports

Verification: Ay,d / Fv,Rd,tot ≤ 1.00

Ay,d  Maximum shear force
Fv,Rd,tot Total design load-carrying capacity

Fv,Rd,tot = Fv,Rd * n

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

Fv,Rd = Fv,Rk * kmod / γM

Fv,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
Mz,d (qx,d) = qx,d . ls 2 / 8

tensile / compressive force
Zd = Nd = Mz,d / hs

shear force / bearing reaction
Ax,d = Bx,d = qx,d . ls / 2
Ay,d = By,d = qy,d . hs / 2

flow of shear forces
sv,0,d = Ax,d / hs

Verification
1 fasteners
fv,0,d = kv1 . Rd / av ≥ sv,0,d

2 shear strength OSB
fv,0,d = kv1 . kv2 . fv,d . t ≥ sv,0,d

3 shear buckling OSB
fv,0,d = kv1 . kv2 . fv,d . 35 . t² / ar ≥ sv,0,d

kv1 = 1.0 (boards are rigidly connected all around)
kv2 = 0.33 (one-sided sheating)
av = distance fasteners
t = 15 mm (thickness OSB)
ar = 800 mm (distance studs)
Rd,nail,Ø3.1 mm = 0.53 kN
Rd,staple,Ø1.8 mm = 0.60 kN
kmod = 0.9

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