This page includes a few of the tools that we have found helpful in our research.
This Page Includes The Following Tools:
Excel tools for computing calibrated model parameters for reinforced concrete elements.
Dynamic solution algorithm for use with OpenSees analyses.
Collapse animation videos showing selected results of nonlinear dynamic collapse simulations.
A packaged single-degree-of-freedom model in OpenSees (including MATLAB pre- and post-processors).
The following simple Excel tool can be used to compute the predicted component parameter for a reinforced concrete column failing in flexure or flexure-shear (inelastic deformation capacity, etc.). [Download Excel File]
The following simple Excel tool can be used to compute the yield moment, based on the ACI publication by Panagiotakos and Fardis (2001). [Download Excel File]
Throughout our collapse work using OpenSees, numerical stability was a huge problem, and we developed these algorithms over the course of a couple of years, in order to get past the numerical issues. Hopefully your use of this algorithm can help you to avoid similar frustrations!
The full algorithm has some complications that are not too easy to follow in the code (it checks the nodal displacement output to search for singularity, etc.), so included are two sets of files to try and make things easier to follow.
1.) The first set of files is a simplified solution algorithm that does not include all of the complication. This can be used to get a general idea of how the algorithm is structured. [Download Zip File]
2.) The second set of files is the full solution algorithm, as well as the procedure that calls the algorithm. [Download Zip File]
The following files include packaged videos, which are animations of the analytical collapse predictions completed as part of this research. Please feel free to use these videos for educational purposes, but please do so with proper reference to this research.
Structural response animation videos are available in .wmv file format for the following two ground motions at three intensity levels. Note that the PowerPoint file package below includes these six .wmv files, as well as summary information.
Superstition Hills (M=6.7) – El Centro Station:
Loma Prieta (M=6.9) – Gilroy Array #3 Station:
Spectral acceleration: 40% of collapse level (near MCE on average) [Download Video]
Spectral acceleration: 102% of collapse level [Download Video]
Spectral acceleration: 200% of collapse level (note some numerical instability at end of record, but this is after dynamic instability and large displacements have already occurred.) [Download Video]
Full Packaged Set of Videos (PowerPoint):
The full package of collapse animation files (both PowerPoint and .wmv) is available [Download Zip File]
The collapse videos show the progression of plastic hinging through the nonlinear dynamic analyses. The following figure (from Goulet and Haselton et al. 2007) shows the final collapse mechanisms for a 4-story RC SMF subjected to many ground motions.
Figure 6 above shows the final damage mechanisms at collapse, while the videos show the progression of plastic hinging. The legend below explains the meaning of the blue and red circles in the videos. As the circle grows, this indicates the progression of plastic hinging; when the circle turns red, this indicates that the plastic hinge has reached the “capping point” where strain softening (rebar buckling) occurs.
The link below contains a single-degree of freedom model that uses a deteriorating component model in the OpenSees structural modeling platform. The pre- and post-processing can be completed using MATLAB. The MATLAB files are also included in this file link for your convenience.
To use the model, please start with the file RunCollapseAnaMatlab->SDOF.m, and then follow the progression of the file structure.
The set of files for this SDOF model is available here. [Download Zip File]