how do you create solid arches?

just got sketchup . . need to create a model of something similar to the "Gateway Arch" in St. Louis, MO . . then make rotated copies to form an open-frame dome . .

most of the topics related to this in the "tips and shortcuts" forum seem to have been deleted (or inaccessible on my computer) . . anybody got any helpful suggestions? . .

thanks in advance

Nightshore

Here's an arch making technique that utilizes Ruby script plugins to speed things up. You can build up the model without the scripts too by following the same steps.

Edit: The use of the Scale tool was used in the skippies to mirror some geometry. The script Mirror3.0.rb has since been written and can be used instead of the steps with the Scale tool.

The downloadable video tutorials for both versions 4 and 5 are very helpful. They can be found under Training in the toolbar at the top of the webpage.

[Edit: the plugin Mirror is now found at SketchUcation.]