Moving Loads with OpenSTAAD

Being a general purpose analytical solution, there are many occasions when ideas get posted that might not get raised to the top of the priority list, but STAAD.Pro's powerful accomplice can come to the rescue. Take for example the moving load generator. This routine was implemented in the early days of the STAAD story to provide engineers who needed to determine the patterns of forces and displacement resulting from placing a multi wheeled vehicle at specified locations on their structure by following a specified path. This proved to be a satisfactory solution and like the vehicles we all moved on. Since then, STAAD.Pro and its user base has grown immensely. There are many new exciting developments that have been released and more on the way that will continue to add value to the large family of engineers who use STAAD.Pro daily. So what of the engineers who would like to see this moving load functionality change, recognising that it is a niche facility?

This is where we can leverage the power of OpenSTAAD and the Macro Editor provided in STAAD.Pro. 

Here we have defined the inputs in a basic dialog, including the forces to be applied at a given location that begins at a given origin, with a given number of steps each with a given offset in the three global directions:-

The macro then runs using OpenSTAAD to check at each location, where it will create a new load case, is there a node, in which case create a node load. If not, then check if lands on a member, in which case, create a concentrated load. This means that there are chances that the load does not land on a structural node or member, then a warning is displayed. There is no logic to load the structure if the point of application is not on a node or member.

The beauty of this system though is that it is open and free for you to modify the macro so that it can be changed to suit your specific situation, such as the logic used in creating the loads or the dialog used to enter the input values.

This can also be added as a Macro tool in your STAAD.Pro environment :-

Note, this can be added to your environment by providing a suitable name such as 'Moving Load' and using the import button to locate the VBS file on your workstation:-



The macro has been added here for you to download, try and modify. 

Moving load.vbs