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THE. E M K I N. FILES. 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 ?.
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THE E M K I N FILES
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 NFILES ? WHY ?
For more than 29 years, Dr. Leroy Emkin has been telling the story… • Many have not listened… WHY ?
For more than 29 years the comparisons have been difficult. Until Now…
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.
14 STORY BUILDING • Original Bracing Layout • A Look at Load Distribution and Torsion in the 2nd, 3rd & 4th Stories • Double & Single-Story Bracing Results • Base Shear Comparison • Limitations of RISAFloor & RAM Steel Type Programs • Conclusion
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 obstructionsand distribute the load along the load path of the structure
Conclusions • Torsion is a cause of unusual story shears due to the 2nd 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.
Cable Pavilion Structure – Preliminary Design • Base ~ 40 meters square • Tower Height ~ 25 meters • Comparisons based on selfweight only
TRUST NO ONE • Our first responsibility is to the public safety. • The Stamping Engineer is 100% responsible.
THE TRUTH IS OUT THERE • 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.
I WANT TO BELIEVE …that the structural engineering profession has the integrity that we must have to fulfill our commitment to the public trust.
The Emkin Files is one means to assist our fellow structural engineers to accomplish this goal.
Special Thanks to: The Ramblin’ Wrecks from Georgia Tech Dr. Kenneth (Mac) Will Michael Swanger Robert Abernathy Dr. Leroy Emkin Hamid Zand Ben Deaton The GT STRUDL Users Group
And, of course, to: Joan “Joan of Tech” Incrocci