Timber code check (esatd.01)

 

esatd.01

The Timber code check module enables the user to design and check timber structures according to the principles of the European standard EC-EN 1995-1-1 for both ultimate and serviceability limit state. It consists of a stress and stability verification of timber members according to the Eurocode inclusive a wide range of National Annexes. For ultimate limit state optimization design process is also available.

The analysis may be performed in two different ways: a first order analysis without redistribution or a second order analysis with reduced stiffness in order to take into account the nonlinearities of the model.

Timber materials

According with the last version of Eurocode5 the library of timber material includes:

  • Solid timber (EN 338)
  • Glulam timber (EN 1194)
Highlights
The timber structure can be solved within the larger model consisting also of parts made of other materials.
According with EN 1995-1-1 the calculation can be done in different ways, the same as in steel, first and second order calculation. If the second order analysis is executed it takes into account the reduced stiffness and the presence of global and local imperfections.
Linear and non-linear functionalities can be selected.
The “cross-section” library contains standard shapes. Furthermore, the custumer has the possibility to define a cross-section by means of dimensions; besides the integrated drawing tools, cross-sections can also be imported from .dxf and .dwg files.
SLS check including creep can be performed.
Optimal speed of timber code check with multi-threading support.
The solution is valid for straight and curved beams, as well as for beams with a varying section. An automated optimization procedure (AutoDesign) selects suitable cross-section for the ULS timber checks.

Performed checks

  • Slenderness: this functions allows the user to review the buckling-related data determined from a linear calculation or from the second order analysis.
  • Ultimate Limit State check:
    • Unity check: The unity check is the maximum of the section and stability check.
    • Section check: The section check only depends on the section (tension, compression, bending, shear, ...).
    • Stability check: The stability check depends not only on the section but on the whole beam behaviour: buckling and lateral-torsional buckling. In case an imperfection would be inputted and a 2nd order analysis is done then in fact no stability check is needed anymore
  • Serviceability Limit State check:
    • Instant relative deformation.
    • Final relative deflections (including creep)
  • System strength [1995-1-1, 6.6]: in case of several equally spaced member components or assemblies which are laterally connected by a continuous load distribution system (floor system) then SCIA Engineer takes into account ksys coefficient that increases the strength of the beam.
  • Bending checks [1995-1-1, 6.1.6] will be done in case there is any moment present (both direction My,Mz)
  • Detailed checks:the user has access to detailed output of the timber checks, it has the same structure as has been used in steel. Everything is automatically filtered out.

Special considerations for analysis and calculation

Ultimate Limit State check
  • Timber is a natural material so it is also influenced by environmental conditions and this is something that users need to look at. Specific parameters for timber like: kmod(modification factor modifying the strength properties that takes into account the moisture influence on deformation [1995-1-1] ), load duration, kh (deep factor [1995-1-1, 3.2(3) 3.3(3)]) by default are defined according with EC, but all of them could be manually changed by the user.
  • Compression perpendicular to the grain taking into account the contact length can also be checked. From the theoretical background, if there is any point load or any jump in shear force on the beam this specific check must be taken into account (the same as it is performed for "purlin design" in steel). The actual code version being used is in the Theoretical Background.
Serviceability Limit State check
  • Within Scia Engineer the deformation factor kdefis included.
  • It is possible to perform a relative deformation checks for timber that do not include only the initial deformation but also the final deflection with presence of creep. For each structural type the user can define the limit for both the instant deflection and the final deflection. For example, if the user executes the deflection check, including creep, the software will show for each directions that two values need to be checked: the instant check and the final check that takes into account the additional creep effect.

Regulations background

  • EN 1995-1-1, Part 1-1: General – Common rules and rules for buildings.
  • Actual code version used according with the "Timber code check - Theoretical Background".

16/09/2015