Areas

For some standards, the Surfaces tab of the 'Ultimate Configuration' or 'Strength Configuration' dialog is available. Here, you can make basic settings for the design of surfaces made of solid timber, glued-laminated timber, or mass timber.

The 'Design Parameters' are divided into several categories, which differ depending on the design standard. The parameters of these standards are described in the following sections:

1. EN 1995
2. NDS
3. CSA O86

EN 1995

Tab 'Surfaces' for Timber Design According to EN 1995

Limit Values for Ignoring Internal Forces and Stresses

This category manages user-defined limit values concerning very small stresses: If the ratio η of the existing stress to the design value of the strength is smaller than the limit value, the stress is not considered in the design. The background for this option is described in more detail in the chapter Members | Basis.

System Strength

If the continuous load distribution system is capable of transferring loads from one surface to adjacent surfaces for similar structural components with equal spacing (for example, floor beams all placed next to each other in the same way), the strength of the structural components may be increased by the factor k_sys according to [1] 6.6. In this case, check the check box.

Combination of Compression and Bending in Fiber Direction

If no stability analysis is performed, according to [1] 6.2.4(1), for combined actions of bending and compression, the compression component may be considered quadratically. This option can be activated for solid timber, but not for cross-laminated timber.

Combination of Shear and Stress Perpendicular to Grain

If the interaction of shear in the xy-plane and tension or compression perpendicular to the grain is to be considered in the design, check the check box.

NDS

'Surfaces' Tab for Timber Design According to NDS

Limit Values for Ignoring Internal Forces and Stresses

This category manages user-defined limit values concerning very small stresses: If the ratio η of the existing stress to the design value of the strength is smaller than the limit value, the stress is not considered in the design. The background for this option is described in more detail in the chapter Members | Basis.

Conservatism Factor

When designing cross-laminated timber panels according to ANSI/APA PRG 320, the calculated moment capacities in the strong strength direction (β = 0°) should be multiplied by the coefficient 0.85 for conservative reasons. This coefficient for out-of-plane bending is called 'Conservatism Factor' C_con in the program and is activated by default. You can check the coefficients for the directions of the layers and adjust them if necessary.

CSA

Register 'Surfaces' for Timber Design According to CSA

Limit Values for Ignoring Internal Forces and Stresses

This category manages user-defined limit values concerning very small internal forces: If the ratio η of the existing stress to the design value of the cross-section resistance is smaller than the limit value, the stress is not considered in the design. The background for this option is described in more detail in the chapter Members | Basis.

Adjustment Factor for Bending Capacity of Cross-Laminated Timber Panels

When designing cross-laminated timber panels according to ANSI/APA PRG 320, the calculated moment capacities in the strong strength direction (β = 0°) should be multiplied by the coefficient 0.85 for conservative reasons. This adjustment factor for out-of-plane bending is activated by default. You can check the coefficients K_rb for the directions of the layers and adjust them if necessary.