Static plate

The ceiling does not necessarily need to be constructedas a static plate. Larger spatial geometriesor glass facades may require this. Horizontal forcesat right angles to the direction of span are usuallyaccommodated by the outer element itself andpassed on to the bearings via the screw connection. 

On the right are shown corner cutouts of two static plate examples.
1 LIGNATUR box element, OSB t ≥ 15 mm and nail or staple
2 LIGNATUR surface element, LIGNATUR shear connector

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.

Static plate

Dimensioning values

moment
Mz,d (qx,d) = qx,d . ls 2 / 8
Mz,d,4 (qy,d,1) = qy,d,1 . hs 2 / 8

tensile / compressive force

Zd = Nd = Mz,d / hs

shear force / bearing reaction
Ax,d = Bx,d = qx,d . ls / 2
Ay,d,1 = By,d,1 = qy,d,1 . hs / 2

Verification

1 shear connector
Rd,shear connector,EC5 = 4.14 kN
Rd,shear connector,SIA = 3.43 kN
Ax,d ≤ Rd,shear connector . n1


2 bearings in x-direction
Rd,screw = 1.69 kN
Ax,d  ≤ Rd,screw . n2


3 bearings in y-direction
Rd,screw = 1.69 kN
Ed,3 = ((Zd / ls)2 + qx,d 2
Ed,3  ≤ Rd,screw . n3


4 outer element
Mz,d,4 ≤ RM,z,d,4
Ay,d,1 ≤ RV,y,d,4
wy,4 ≤ hs / 1000


5 bearing of outer element
Rd,screw = 1.69 kN
Ay,d ≤ Rd,screw . n5

ni = number of fasteners
screw = timber construction screw Ø 8 mm, slat
thickness 31 mm, point
side penetration 60 mm, kmod = 0.9

The floor bearings need to be dimensioned so that they can take the impact from Nd and Zd and transfer the reactions from the static plate.