<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <body text="#000000" bgcolor="#FFFFFF" link="#0000EE" vlink="#551A8B" alink="#FF0000"> Help,         Now I'm really confused about the tensions/compressions in an arched beam or panel!  Working with model train track,  known as flex track which is designed to bend around turns, I've noticed the following:   When bent around a curve, the outer rail of the turn which has the larger radius (similar to the top of an arched beam) becomes too short to connect to the next section of track.  One must cut off the inner rail at both ends so that both rails can connect to the next piece.   So if a beam is bent into an arch, the top either gets longer  and is therefore stretched or under greater tension then the bottom or it doesn't.  If it doesn't , that means that the angles at the butt ends of the beam must go out of square to accommodate that. (like the track that won't match up).  Doesn't that take a quite a force to pull the butt end of a beam out of square and wouldn't that be from the tension in the top of the arched beam? So doesn't that prove there is much tension in the top of the beam?   Please forgive my idiocy here, -Mike Jorgensen           Delwin D Fandrich wrote: <blockquote TYPE=CITE> <blockquote style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">----------------------------------------------- Good grief, man, the top piece did not "stretch," you wrapped it around a larger circle!</blockquote> </blockquote>   </body> </html>