2. Safety assesment of a steel frame using current code and SBRA method Petr Konečný, M.S. Structural Mechanics Division Department of Civil Engineering VŠB – TU Ostrava Czech Republic

3. Euro-SiBRAM’2002 Prague June 24 to 26, 2002 Introduction Summary Safety Assessment of a steel frame (a) according to the Eurocode (EC) and (b) according to SBRA method Comparison of results Subject of the discussion

4. Euro-SiBRAM’2002 Prague June 24 to 26, 2002 Steel frame

5. Euro-SiBRAM’2002 Prague June 24 to 26, 2002 Loadings Obr. 6 Mostový jeřáb Dead load Wind (from the right or left) Snow (entire roof, right or left side of the roof) Crane girder (vertical and lateral horizontal forces)

6. Euro-SiBRAM’2002 Prague June 24 to 26, 2002 Eurocode vs. SBRA SBRA All input random variables are represented by bounded histogram Reference value is defined by the onset of yielding The safety function SF = R – S is evaluated using direct Monte Carlo method The safety is expressed by comparing the calculated probability of failure P f and target probability P d, i.e., P f < P d Uses load and resistence factors Reference values correspond to ultimate (plastic) carrying capacity Eurocode (EC)

7. Euro-SiBRAM’2002 Prague June 24 to 26, 2002 Probability of failure P f (R <  ) < P d = 7.10 -5 R - F y yield stress  - Two component load effects combination expressed by stress Assessment N - Axial force M – Bending moment SBRA Probability of failure P f Is calculated using Anthill TM Computer program Eurocode (see criteria contained in the code)

8. Euro-SiBRAM’2002 Prague June 24 to 26, 2002 Inner forces Scatter axial forces N (kN)

9. Euro-SiBRAM’2002 Prague June 24 to 26, 2002 Inner forces Scatter bending moments M (kNm)

10. Euro-SiBRAM’2002 Prague June 24 to 26, 2002 Comparison of results In this study the shapes designed according to EC [2] are larger compared to cross-sections resulting from SBRA design. For details see M.S. Thesis (Konečný, 2002, VŠB - TU Ostrava) SBRAEC 1100%121% 2100%110% 3100%140% Cross- sections Area

11. Euro-SiBRAM’2002 Prague June 24 to 26, 2002 Summary Transparent analysis of the multi- component load effects combinations Rather complicated transformation model SBRA Eurocode (EC) Planar frame had to be analyzed considering 144 load effects combinations Load effects combination analysis was time consuming and not consequente.

12. Thank you for your attention Petr Konečný, M.S. Structural Mechanics Division Department of Civil Engineering VŠB – TU Ostrava Czech Republic