Steel structures according to EN 1993-1



GUI improvements

SCIA Engineer v. 2013.1 provides an improved GUI for settings and execution of steel checks according to 1993-1. The improved steel Setup and input dialogues ensure a fluent workflow and improved user experience. First of all, input variables are rearranged and, where necessary, organized in groups in order to provide a more logical structure to the GUI dialogues. Furthermore, descriptions are provided to individual settings in the steel Setup, as well as references to the clause in the code that was used and how it is interpreted (if any clarification is needed).

Other GUI improvements concern the output of checks and reporting of results. Likewise, items are rearranged to ensure both organized and transparent output and methods of calculation, as well and organized reports. Additional tabs with intermediate values are added, as well as more details related to the derivation of critical elements/load cases. Furthermore, notes and clarifications ensure that the generated reports give all necessary information and avoid misinterpretations.

These improvements concern the menus and output related to steel checks for common heavy gauge members and cold-formed steel elements, for fire-resistance checks, checks for plated elements, etc.

Shear check improvements (plastic vs. elastic)

EN 1993-1-1:2005 provides a list of shear area formulas for commonly used cross-sections in art.6.2.6(3). In older versions of the software, if the code did not explicitly specify a formula for the shear area, the shear check was still performed in the plastic range if the shear areas Ay and Az were defined in the cross-section properties. In this way, unwarranted conservatism was avoided in the check, but the user did not have the possibility to disable the execution of plastic checks.

The issue was addressed during recent improvements. SCIA Engineer v. 2013.1 includes a new setting that allows for elastic shear checks to be executed for cross-sections for which no shear area is listed in EN 1993-1-1:2005 (thus, ignoring the shear area calculated in the Section Library). The option is located in the steel Setup; the default setting results in elastic shear checks. The user can change that by allowing for plastic shear checks to be performed for uncommon cross-sections, for which Ay or Az (depending on the direction of force effect) are available.

Limit value for torsion checks

In the past, torsion moments with low intensity used to result in elastic checks for the combined action of bending moments, shear and normal forces, and torsion moments (Von Mises criterion). In real structures, torsional moments often appear at the juncture of elements, due to the interaction of different elements in the structure and the lack of fully-hinged connections. As joint stiffness is more realistically represented in modern models, it is not justified to ignore the plastic moment capacity of members due to the presence of a very limited amount of torsion.

In SCIA Engineer v. 2013.1, if a member undergoes torsion moments smaller than the limit value set in the steel Setup, the effects of torsion will be deemed insignificant and the interaction checks will not include torsion moments. Plastic checks will be performed for section class 1 and 2, and elastic checks for section class 3 and 4. The value listed in the steel Setup corresponds to the percentage of torsion in the element in relation to the torsion capacity of the cross-section.

Section factors in fire checks

Section factors for fire resistance calculations Am/V and Ap/V and their box values [Am/V]b and [Ap/V]b are updated and accurately calculated even in the case of general cross-sections. Insulated walls are not taken into account in the calculation of Ap/V. This means that any section, including closed sections with hollow parts, and sections from multiple materials will be correctly checked for performance at elevated temperatures.

Read also Steel input/output improvements in SCIA Engineer 2013.1