Comments on: Science Olympiad Bridge

By: Garrett Boon

Garrett Boon — Thu, 02 Feb 2012 02:56:58 +0000

Can you explain a little more about what you mean? What holes are you talking about?

By: bondraya

bondraya — Wed, 01 Feb 2012 15:57:35 +0000

Im doing a science project am i have to build a bridge out of this thin wood. The nicer looking designs dont leave big enough spaces for the weights. the holes are too small and it is impossible to shove the metal stick through. we need to put those metals in to see how much the brigde can handle. i can not enlarge my scale. Help piease? ideas?

By: Rob Deis

Rob Deis — Tue, 15 Feb 2011 14:51:06 +0000

The trick with bending balsa is to use thin strips laminated together to make a curved beam, rather than trying to bend a thicker beam.

My arch bridge used an inverted arch under the load bed for the main beam (smile instead of frown), with warren-like truss members from each load point on the road bed to the beam. This puts the longer arch member in tension and the shorter, straight loadbed member in compression.

I tested 2 to failure and found weak points in the design that surprised me. The final version scored 1834 without breaking, which was good enough to win the CO state 1987.

The following year I used a *very* simple, *very* light simple beam design that scored 2150 even though it always broke under a light load.

My favorite glue is a rubberized cyanoacrylate (CA) that you can find in hobby shops. You do need to be careful with it, though, because it will bond skin like superglue and has the same sort of fumes as superglue.

By: Garrett Boon

Garrett Boon — Sun, 31 Oct 2010 15:06:02 +0000

Phoebe, thanks for your question. To clarify, the I define the span of a bridge as the distance between supports. In this case, the bridge spanned 35cm. However, the total length of the bridge was longer, 14.5 inches. This allowed the edges of the bridge to rest on the supports, with a little less than 1cm of overlap on each side.

This bridge was 2.5 inches tall. It was about 2 inches wide. The previous comment asked about the 1:6 ratio, which refers to height:length. Thus, I assumed that they meant length and not width.

By: Phoebe

Phoebe — Sun, 31 Oct 2010 00:57:56 +0000

I’m new to bridge building, but I noticed that you said the bridge pictured spanned 35 cm. Then you said that it was 14.5 in long. These values don’t match, and I was wondering if the span and length of a bridge were different things. Also, when you say that the bridge is 2.5 in tall, is that vertical height? The previous comment was addressing width, so I’m a little confused. Thanks.

By: Daniel W

Daniel W — Fri, 22 Jan 2010 17:23:43 +0000

I have always used a rectangle bridge they weigh alot less

By: Alec Walter

Alec Walter — Thu, 22 Oct 2009 19:23:18 +0000

how did oyu make the bride I am in science olypiad in the bridge competition any pointers or helpful tips?

By: Ryan Prestungen

Ryan Prestungen — Sat, 14 Mar 2009 01:18:25 +0000

I was wondering if you thought a arched bridge like this was better than a rectangle like shape with a lot of equilateral triangles? i was wondering because i was interested i making a arched bridge. I’ve never made one before but they seem good. go ahead and reply at any time

By: Garrett Boon

Garrett Boon — Mon, 19 Jan 2009 15:18:47 +0000

The loading point was on the inside of the bridge.

By: Geoff

Geoff — Sun, 18 Jan 2009 18:21:15 +0000

out of curiosity, where was the loading point on this bridge. Was it on top of the bridge or “inside” of it?