4. THE E M K I N FILES

5. What is the Mystery of Engineers are using software for which limitations have been documented. Engineers are designing structures without fully understanding the limitations of the software analysis tools they are using. THE E M K I N FILES ? WHY ?

6. Many have not listened… For more than 29 years, Dr. Leroy Emkin has been telling the story… WHY ?

7. For more than 29 years the comparisons have been difficult. Until Now…

8. The Emkin Files now brings you two illustrations of some significant differences. We used the Structural Desktop program to translate files and run them through parallel analysis.

9. Original Bracing Layout A Look at Load Distribution and Torsion in the 2 nd, 3 rd & 4 th Stories Double & Single-Story Bracing Results Base Shear Comparison Limitations of RISAFloor & RAM Steel Type Programs Conclusion 14 STORY BUILDING

10. Double-Story Bracing vs. Single-Story Bracing

11. GT STRUDL Base Shear Comparison

13. Load Application Limitations of RISAFloor and RAM Steel –Inability to account for non-rectangular geometry –Assumes that side wall wind loadings are equal and opposite –Applies the Wind Load in orthogonal directions only –Difficult to account for architectural features, or other exterior obstructions Load Application with GT STRUDL and STAAD.Pro –Engineer can apply loads correctly regardless of geometry –Can handle any shape of structure –Can account for architectural features and exterior obstructions and distribute the load along the load path of the structure

14. Conclusions Torsion is a cause of unusual story shears due to the 2 nd floor weak story (atrium), architectural features, non- orthogonal window wall projections, and the non- symmetric locations of brace frames The 2-Story X-Bracing contributed to the unusual loading patterns in the Bracing. The ability of RAM Steel / RISAFloor-like programs to model the correct wind loadings is limited to symmetrical / rectangular structures. GT STRUDL and STAAD.Pro require more time to create a model, but allow the user to correctly apply wind pressures and other loadings.

15. Cable Pavilion Structure – Preliminary Design Base~ 40 meters square Tower Height~ 25 meters Comparisons based on selfweight only

16. Structural Desktop Model

17. GT STRUDL Model

18. STAAD.Pro Model

22. TRUST NO ONE

23. Our first responsibility is to the public safety. The Stamping Engineer is 100% responsible.

24. THE TRUTH IS OUT THERE

25. Good engineering practice is finding the true answer, not just getting an answer. Understanding your software is a requirement, not an option. All software is NOT created equal.

26. I WANT TO BELIEVE

27. …that the structural engineering profession has the integrity that we must have to fulfill our commitment to the public trust.

28. The Emkin Files is one means to assist our fellow structural engineers to accomplish this goal.

29. Special Thanks to: Dr. Leroy EmkinDr. Kenneth (Mac) Will Michael SwangerRobert Abernathy The Ramblin’ Wrecks from Georgia Tech The GT STRUDL Users Group Hamid Zand Ben Deaton

30. And, of course, to: Joan “Joan of Tech” Incrocci