Alternative calculation of the effective cross-sectional properties –Consteel's solution

This overview delves into Consteel's solution, offering an alternative approach to calculating effective cross-sectional properties and reshaping conventional methodologies in structural analysis and design.

Determine the strength utilization of a double symmetric welded I cross-section with 384x4 web and 300x8 flanges, if the internal forces on the cross-section are N_Ed=500kN compressive force and M_y,Ed=100kNm bending moment. The material grade of the cross section is S235.

Calculation of cross-sectional properties

First, take the cross-section data (symmetric welded I-section), from which the Consteel software generates the EPS (and GSS) (see Online Manual/10.1.1 The EPS model) cross-section model (Fig. 1).

If the cross-section is class 4, the effective model is determined by the assumed normal stress distribution. According to EC3-1-1, the EPS model of a class 4 cross-section can be defined in two ways :

- method A: based on pure stress conditions,

- method B: based on complex stress condition.

In order to compare the results, the cross-section properties will be calculated by method A at first and then by method B.

Cross-sectional properties by method A

• pure compression N_Ed  (Fig. 2): 

A_eff=4720mm²   

• pure bending M_y,Ed  (Fig. 3): 

W_eff,y,min=864080mm³

e_z=14.5mm 

Cross-sectional properties by method B