Cross calculation

Cross calculation N+M+V

With the Cross calculation module, a cross-section of a steel profile can be calculated, where a combination of a normal force, a bending moment and a shear force simultaneously prevails. The result is a code check of the cross-section.

Cross calculation

Timber cross calculation taking into account bending moments (My + Mz), shear forces (Vy + Vz), axial forces (N) and torsion (Mx).

General options

Option

Unit

Description

Section

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Name of cross section or section group is supported by EN 1995-1-1 and related national annexes such as NEN-EN 1995-1-1. Items listed in the Sections Definition dialog window depend on the chosen code or/and national annex

Material

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Strength classes: characteristic values for softwoods

		C14	C16	C18	C20	C22	C24	C27	C30	C35	C40	C45	C50
Strength properties [N/mm²]
Bending	f_m,0,k	14	16	18	20	22	24	27	30	35	40	45	50
Tension parallel	f_t,0,k	8	10	11	12	13	14	16	18	21	24	27	30
Tension perpendicular	f_t,90,k	0.4	0.5	0.5	0.5	0.5	0.5	0.6	0.6	0.6	0.6	0.6	0.6
Compression parallel	f_c,0,k	16	17	18	19	20	21	22	23	25	26	27	29
Compression perpendicular	f_t,90,k	2.0	2.2	2.2	2.3	2.4	2.5	2.6	2.7	2.8	2.9	3.1	3.2
Shear	f_v,0,k	1.7	1.8	2.0	2.2	2.4	2.5	2.8	3.0	3.4	3.8	3.8	3.8
Stiffness properties [kN/mm²]
Mean E parallel	E_0,mean	7	8	9	9.5	10	11	11.5	12	13	14	15	16
5% E parallel	E_0,0.05	4.7	5.4	6.0	6.4	6.7	7.4	7.7	8.0	8.7	9.4	10.0	10.7
Mean E perpendicular	E_90,mean	0.23	0.27	0.30	0.32	0.33	0.37	0.38	0.40	0.43	0.47	0.50	0.53
Mean G	E_mean	0.44	0.50	0.56	0.59	0.63	0.69	0.72	0.75	0.81	0.88	0.91	1.00
Density [kg/m³]
Density	ρ_k	290	310	320	330	340	350	370	380	400	420	440	460
Mean density	ρ_mean	350	370	380	390	410	420	450	460	480	500	520	550

These properties relate to timber at a temaperature 20°C and a relative humidity of 65%.

		D30	D35	D40	D50	D60	D70
Strength properties [N/mm²]
Bending	f_m,0,k	30	35	40	50	60	70
Tension parallel	f_t,0,k	18	21	24	30	36	42
Tension perpendicular	f_t,90,k	0.6	0.6	0.6	0.6	0.6	0.6
Compression parallel	f_c,0,k	23	25	26	26	32	34
Compression perpendicular	f_t,90,k	8.0	8.4	8.8	9.7	10.5	13.5
Shear	f_v,0,k	3.0	3.4	3.8	4.6	5.3	6.0
Stiffness properties [kN/mm²]
Mean E parallel	E_0,mean	10	10	11	14	17	20
5% E parallel	E_0,0.05	8.0	8.7	9.4	11.8	14.3	16.8
Mean E perpendicular	E_90,mean	0.64	0.69	0.75	0.93	1.13	1.33
Mean G	E_mean	0.60	0.65	0.70	0.88	1.06	1.25
Density [kg/m³]
Density	ρ_k	530	560	590	650	700	900
Mean density	ρ_mean	640	670	700	780	840	1080

These properties relate to timber at a temaperature 20°C and a relative humidity of 65%.

Load duration class

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	Approximate duration	Examples of loading
Permanent	More than 10 years	Self-weight
Long-term	6 months to 10 years	Storage loading, water tanks
Medium-term	1 week to 6 months	Imposed floor load
Short-term	Less than 1 week	Snow, maintenance loading on roofs, residual structure after accidental event
Instantaneous		Wind, impact loading, explosion

Load service class

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Service class	Definition	Examples
1	Temperature of 20°C, relative humidity of surrounding air only exceeding 65% for a few weeks per year. Moisture content of timber generally not more than 16%	Warm roofs, intermediate floors, internal and party walls
2	Temperature of 20°C, relative humidity of surrounding air only exceeding 85% for a few weeks per year. Moisture content of timber generally not more than 20%	Cold roofs, ground floors, external walls and external uses where timber is protected from direct wetting
3	Conditions leading to higher moisture contents than in service class 2	External uses, fully exposed

Forces

Parameter	Unit	Description
N_c,Ed	kN	Compression axial force
N_t,Ed	kN	Tension axial force
V_y,Ed	kN	Shear force along local y’-y’ axis
V_z,Ed	kN	Shear force along local z’-z’ axis
M_x,Ed	kNm	Bending moment on the x-axis
M_y,Ed	kNm	Bending moment on the y-axis
M_z,Ed	kNm	Bending moment on the z-axis (only for rectangular cross section)