BALLOON + JET ENGINE = QUALITATIVELY NEW TRANSPORTATION MEAN ??????? NO !

PARTIAL FACTORS METHOD + COMPUTERS = QUALITATIVELY NEW STRUCTURAL RELIABILITY ASSESSMENT CONCEPT ????? NO ! such as EC or LRFD COMPUTERS

PROBABILISTIC METHOD (such as SBRA) + COMPUTERS = QUALITATIVELY NEW STRUCTURAL RELIABILITY ASSESSMENT CONCEPT ??? YES!

4 SBRA Input variables are expressed by bounded non-parametric histograms. Reliability function is analyzed by the designer using Monte Carlo method. Reliability is expressed by P f < P d, where P f is the probability of failure and P d is the target probability given in codes. P f = Σ / Σ < P d R – S = 0

5 Computer Program AntHill  for Windows

6 What is the Load Duration Curve (LDC)? Loading History ‚Sorted‘ History LDC

7 Load Duration Curves, LDC, and corresponding Histograms Dead Short Long Wind

8 Two - and More -Component Load Duration Curves Wind Rosette Wind Directon and Wind Velocity

9 One-component Load Effect Combination Analysis using Monte Carlo technique and ResCom computer program

10

11

12

Probability of Failure P f LRFD SBRA EC estimate

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15

16 SBRA Dead + Long-Lasting Dead +Short-Lasting

17 (a) N (b) N, M x (c) N, M x, M y

18 Combination of multi- component load effects Each Load Effect is expressed, for example, by N, M x and M y x - x N, M x, M y

19 S Load Effect Combination S R - S = 0 Resistance R R

20 Definition of the Resistance P  „Reference Level“ ??? USEABILITY

21 Reference levels a) Onset of yielding b) Tolerable permanent deflection Non-tolerable permanent deflection d) Formation of the full plastic hinge USEFULLNESS c) Limited Damage

22 Probability of Failure CASE Reference level defined by Steel beamProbability of Failure (a) Onset of yieldingElastic range < P d (b) Tolerable permanent deformation Acceptable permanent deformation < P d (c )Tolerable DamageTo be repaired or replaced < P perf (d)CollapseDisposal < ????

Variabilities of yield stress, cross-section area, initial eccentricity and effect of residual stresses are expressed by bounded histograms: Cross-section area  A var Initial eccentricity  e o Effect of residual stresses  Res var Yield stress  f y Column Resistance: Variables

24 Slenderness ratio Stress (N.mm -2 ) Variables: f y, e o, A,..

25 Target Probability P d according to CSN

26 Safety Assessment Using the Probabilistic Simulation-Based Reliability Assessment Concept 1

27 Target Probability P d according to CSN

28 Steel beam exposed to a combination of loads Load Duration Curves and corresponding Histograms

29 Dimensioning of a Beam

30 Safety check of the steel beam (P f,saf = 0,00003 < P d,saf = 0,00007)

31 Bar exposed to Tension and Compression

32 Frame containing leaning columns

33 Serviceability Assessment Using the Probabilistic Simulation-Based Reliability Assessment Concept 1

34

35 Basic alternatives of serviceability reliability conditions (Cases 1 to 25)

36 Target Probability P d according to CSN

37 Steel beam exposed to a combination of loads Load Duration Curves and corresponding Histograms

38 Serviceability Assessment of a steel beam Application of a ‘blurred’ serviceability limiting value

39 Frame containing leaning columns SF= DEL tol - DEL ( DEL tol = 30 mm ) Serviceability assessment P f = < P d = O.K. DEL EXAMPLE 2

40 Durability Assessment Using the Probabilistic Simulation-Based Reliability Assessment Concept 1

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42 1 MIPS 5  10 2 MIPS > 10 GIPS PC XT PENTIUM Hypercomputers and more

43 How will look like the new generation of specifications and design tools?

44 Impact of computer technology Reengineering of the design procedure Application of powerful simulation techniques in designer‘s work From Components to Systems New generation of specifications, application of databases and information technology Education of designers: From deterministic to probabilistic ‘way of thinking‘ SUMMARY AND CONCLUSIONS