Evo Design - structural engineering Calculation No.
001-WOOD BEAM
CALCULATION SHEET Project No.
onlinestructuraldesign.com SAMPLE CALCULATION
Project Title: Wood beam -interactive design spreadsheet   Calc. By Date Rev.
MN 16.04.2014 0
Subject Wood Element Bending Capacity (EC5)   Checked By Date
CN 16.04.2014

Input Output
Element section and dimensions Element verification
Material

Wood Element Bending Moment Capacity Calculation   per EN 1995-1-1:2004* & EN 338*
Maximum working loads (Ultimate Limit State)
My,Ed= kN*m bending moment y-y
Mz,Ed= kN*m bending moment z-z

Element dimensions - Rectangular cross section
h = 20 cm height
d = 10 cm width
(parameters that can not be modified in the demo version)
Section Properties
A = d*h = cm2 section area
IY = d*h3/12 = cm4 moment of inertia about y-y axis
Iz = d3*h/12 = cm4 moment of inertia about z-z axis

Material characteristics           per EN 338-97 - Table 1
Wood strength class:

fm,k = N/mm2           Characteristic bending strength
gm =             per EN 1995-1-1 - Table 2.3
1.3 for solid timber, 1.25 for glued laminated timber
kh = min( (150/h)0.2 ; 1.3) =       per EN 1995-1-1 - Section 3.2 (3), formula (3.1)
for timber with density less than 700 kg/m3 and
h < 150mm the characteristic valus of fm,k andÂ
ft,0,k may be increased by the factor kh
kmod =             per EN 1995-1-1 - Table 3.1
Load duration classes per EN 1995-1-1
Section 2.3.1.2 - Table 2.1 and 2.2
Service classes per EN 1995-1-1 - Section 2.3.1.3

fm.y.d = fm.y.d = kmod *kh * fm,k / gm = N/mm2   design bending strength about y and z axis
per EN 1995-1-1 - Section 2.4.1, formula (2.14)
sm.y.d = My,Ed * (h/2) / Iy = N/mm2       Design bending stress about the principal y axis
sm.z.d = Mz,Ed * (d/2) / Iz = N/mm2       Design bending stress about the principal z axis

km = 0.7 for rectangular sections       per EN 1995-1-1 - Section 6.1.6 (2)

Check on for y-y axis
( sm.y.d / fm.y.d ) + km * ( sm.z.d / fm.z.d ) =     per EN 1995-1-1 - Section 6.1.6, formula (6.11)

Check on for z-z axis
km * ( sm.y.d / fm.y.d ) + ( sm.z.d / fm.z.d ) =     per EN 1995-1-1 - Section 6.1.6, formula (6.12)

References:
EN 1995-1-1:2004 - Eurocode 5: Design of timber structures - Part 1-1: Common rules and rules for buildings
EN 338 : 2003 - Structural Timber; Strength Classes