The objectives of this project include:
- creating a model of a WTC tower
- identifying scenarios for analysis
- running analysis codes with the scenarios
- validating the model and verifying results
It is expected that each of these items will have to be repeatedly visited throughout the project.
Model creation will require:
- selecting a building for study
- identifying the major components and their spatial relationships (columns, beams, trusses, floor slabs, etc.)
- determining the geometry of each of the components
- identifying element and section types
- identifying materials and material properties of each of the components
- identifying boundary and initial conditions
- identifying loads
There are a variety of issues involved in identifying the scenarios for analysis. The initial scenario will be for an intact building under normal loading conditions (initially gravity only) to help validate the basic model. Careful consideration must be given to all the factors involved in of the scenarios considered. It is also possible that some scenarios could be investigated that do not require a full building model.
There are several factors to consider in setting up the analysis codes. This first issues is creation of a mesh of the appropriate granularity for the scenario under consideration. It is likely that several meshes with varying granularities will be required for each scenario. Issues of problem size and complexity may need to be addressed which may require re-evaluation of the chosen scenario. The specific FEA code used and platforms to be run on used will require other considerations (for instance, parallel code on a parallel machine vs serial code and serial machine) and will impact the size of the problem that can be handled.
Validation of the model will be an ongoing process that will occur at each stage of the project and covers every facet of the work: model creation, identification of scenarios to consider, and the running of analyses to insure that correct results are obtained. Expert assistance by engineers will be required to validate the model and verify that the results are a reliable indication of processes that lead to the collapse of the buildings.
A further objective of this project is that it be "open". All of the data associated with the models and analysis results will be available for public review and criticism. Additionally, anyone with applicable skills may become involved
