Timber

Cross calculation

Timber cross calculation taking into account bending moments, shear and axial forces.

 

General options:

Option

Unit

Description

Section

-

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

-

Strength classes: characteristic values for softwoods

 

C14

C16

C18

C20

C22

C24

C27

C30

C35

C40

C45

C50

Strength properties [N/mm²]

Bending

fm;0;k

14

16

18

20

22

24

27

30

35

40

45

50

Tension parallel

ft;0;k

8

10

11

12

13

14

16

18

21

24

27

30

Tension perpendicular

ft;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

fc;0;k

16

17

18

19

20

21

22

23

25

26

27

29

Compression perpendicular

ft;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

fv;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

E0;mean

7

8

9

9.5

10

11

11.5

12

13

14

15

16

5% E parallel

E0;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

E90;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

Emean

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

ρk

290

310

320

330

340

350

370

380

400

420

440

460

Mean density

ρmean

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

fm;0;k

30

35

40

50

60

70

Tension parallel

ft;0;k

18

21

24

30

36

42

Tension perpendicular

ft;90;k

0.6

0.6

0.6

0.6

0.6

0.6

Compression parallel

fc;0;k

23

25

26

26

32

34

Compression perpendicular

ft;90;k

8.0

8.4

8.8

9.7

10.5

13.5

Shear

fv;0;k

3.0

3.4

3.8

4.6

5.3

6.0

Stiffness properties [kN/mm²]

Mean E parallel

E0;mean

10

10

11

14

17

20

5% E parallel

E0;0.05

8.0

8.7

9.4

11.8

14.3

16.8

Mean E perpendicular

E90;mean

0.64

0.69

0.75

0.93

1.13

1.33

Mean G

Emean

0.60

0.65

0.70

0.88

1.06

1.25

Density [kg/m³]

Density

ρk

530

560

590

650

700

900

Mean density

ρmean

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

-

 

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

-

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

Nc;Ed

kN

Compression axial force

Nt;Ed

kN

Tension axial force

Vy;Ed

kN

Shear force along local y’-y’ axis

Vz;Ed

kN

Shear force along local z’-z’ axis

Mx;Ed

kNm

Bending moment on the x-axis

My;Ed

kNm

Bending moment on the y-axis

Mz;Ed

kNm

Bending moment on the z-axis (only for rectangular cross section)