Ahmed Khalil, Ph.D., P.E. will be presenting a paper entitled, ” Nonlinear Dynamic Alternative Load Path Analysis of 10-story Concrete Shear Wall Flat Plate Building”, at Structures Congress 2019, Saturday, April 27th from 8:00 – 9:30 AM in the Celebration 1-2 Room.

Abstract: This paper demonstrates the use nonlinear dynamic Alternative Load path Analysis (ALPA) based on the ASCE Disproportionate Collapse (DC) Standards to design a 10-story flat plate structure to resist progressive collapse. The Applied Element Method was used to perform the analysis; nonlinear material models that take into consideration cracking of concrete and yielding of reinforcement bars were used. All the reinforcement details were explicitly included in the model which was developed using the Extreme Loading for Structures software. The flat plate structure with no interior beams was modeled as a whole system composed of edge beams, shear walls, columns, and flat-plate slabs.

This case is one of the examples included in the guidelines for modeling of structures to resist disproportionate collapse developed by the ASCE DC Technical committee. Three column removal scenarios were studied. The loading procedure involved applying statical loads followed by instantaneous removal of the column. For every column removal case, the application of the ASCE standard criteria to evaluate the performance of the structure was demonstrated. The most critical column removal scenario based on the structural performance was identified. Guidelines are given for proper use of AEM to achieve reliable results with practical computational requirements.