# Compiling OpenSees

In the early days of G3/OpenSees, I was in change of compiling the Windows version using Visual C++, part of Visual Studio. Frank maintained the Linux version. Pretty soon after arriving in Eastchester, I switched to compiling OpenSees on Linux and periodically compiled in Visual Studio--only when I absolutely had to do so. Visual Studio … Continue reading Compiling OpenSees

For large structural models, the solution to $latex {\bf K}_T\Delta {\bf U}={\bf R}$ can be the computational bottleneck during an analysis. Although computing speed and algorithms to solve $latex {\bf K}_T\Delta {\bf U}={\bf R}$ are very good, you still want to make sure the solution happens as quickly as possible, particularly when inside the double … Continue reading Reduce Your Bandwidth

# Moving and Influential

OpenSees is probably not the first, or second, software you think of when you need to generate influence lines or perform moving load analysis, e.g., across bridge girders. However, Tcl and Python scripting capabilities make OpenSees ideal for this type of analysis. To keep things to the point, I'll show an influence line analysis for … Continue reading Moving and Influential

The OpenSees Twitter bot I created, the one that likes and retweets any tweet with the hashtags #OpenSees or #OpenSeesPy, passed the 200 follower mark recently after just under a year in service. The bot's mission is to share with the Twitterverse all the cool things people do with OpenSees. Some day I'd like to … Continue reading Twitter Bot 200

# Mass and Weight

Many structural analysis software programs will automatically define mass based on the input gravity loads. OpenSees is not one of those programs. You have to define mass and weight separately. Fortunately, using variables for units makes the mass and weight definitions easy. Plus, if using customary units, you won't have to waste time Googling the … Continue reading Mass and Weight

# Rigid Joint Offsets

The geometric coordinate transformation objects handle rigid joint offsets for frame elements in OpenSees. This is nice because the code for the transformations of displacements and forces is not duplicated in the element state determinations. There are three things to keep in mind when using rigid joint offsets. First, the offsets are global with respect … Continue reading Rigid Joint Offsets

# Fibers of Higher Dimensions

When we talk about fiber sections in OpenSees, we often refer to Bernoulli sections where each fiber is in a state of uniaxial stress. This approach captures axial-moment interaction, which is important for reinforced concrete columns, whose cross-sections are defined using patch and layer commands. Those same patch and layer commands can be used for … Continue reading Fibers of Higher Dimensions

# You Know You’ll Have to Write About It

The odds are, if you're running OpenSees analyses, you're going to write about it, whether it's a thesis/dissertation, technical report, funding proposal, conference paper, or journal article. Several writing books are available and some are very good. One book that I've found useful is Becoming an Academic Writer by Patricia Goodson. The title may sound … Continue reading You Know You’ll Have to Write About It