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Posted: 2003-01-21 08:35pm
by Raxmei
Red Knight wrote:Ive got mine down to 151,827.13. Its using all carbon tubes, and I dont think I can get it much cheaper.
Try replacing the glowing blue parts with thinner solid bars. Tube is more expensive but no stronger than bar for equivalent mass in tension.
I've gotten down to $140k.
Posted: 2003-01-21 11:24pm
by Beowulf
Anybody able to beat my score?
Posted: 2003-01-21 11:26pm
by The Dark
Raxmei wrote:Red Knight wrote:Ive got mine down to 151,827.13. Its using all carbon tubes, and I dont think I can get it much cheaper.
Try replacing the glowing blue parts with thinner solid bars. Tube is more expensive but no stronger than bar for equivalent mass in tension.
I've gotten down to $140k.
Hmmm...I found the tubes to be cheaper than the bars if it was just tension. Bars were better for stress (red).
Posted: 2003-01-22 12:16am
by Exonerate
Beowulf wrote:Anybody able to beat my score?
I will when I get the time...
Posted: 2003-01-22 01:22am
by Red Knight
A tip: if you go lower than 100mm for tubes, it gets more expensive for some reason.
Ive got it to 148,322.84 using a railroad truss type bridge. Prety sturdy too.
Posted: 2003-01-22 10:07am
by RedImperator
I suspect $124 is getting close to the bottom. Even the very cheapest site layout (24 meters high, standard truss abutments) costs around $80,000, and that design has to be so long that it winds up more expensive than some arches with a shorter span (and greater excavating and abutment costs in the beginning).
My guess is that the cheapest possible design is an arch. I can get away with only two solid members in the entire design (all carbon steel) with an arch, while every truss design I've tried has needed almost all the deck support members to be solid.
Posted: 2003-01-22 08:32pm
by Exonerate
Hmm... Well, I've gotten 1 126k. The best way seems to be distributing all the weigh as equally as possible.
Posted: 2003-01-22 09:07pm
by Exonerate
WOOT! $125,662.52
Posted: 2003-01-22 09:27pm
by Beowulf
$123,900.62
I think that's pretty close to the lowest possible.
It's using the 20m high, 4m arch supports. It has:
4 180mm tubes
8 170mm tubes
4 140mm tubes
4 130mm tubes
14 110mm tubes
4 30mm tubes
and 5 45mm bars
23 joints
all carbon steel
bridge weight: 4231.4 kg
Posted: 2003-01-22 10:12pm
by Exonerate
Beowulf, submit that. I submitted my 125k one, and got like in the top tenth percentile... I'm willing to bet you will get a lot higher
Posted: 2003-01-22 11:26pm
by Beowulf
#17 out of 210... need to get a better bridge...
Posted: 2003-01-22 11:28pm
by Exonerate
Whoa... You're like 40 places ahead of me
Posted: 2003-01-23 09:28pm
by Beowulf
Try harder then...
Posted: 2003-01-23 10:34pm
by aerius
I've gotten down to $135k with an all tube arch design. It took me the longest time to get something under $160k until I realized the joys of tubes.
Posted: 2003-01-23 10:40pm
by Exonerate
Gah, currently, my design is the cheapest possible with the current configuration... Must find a new design...
Posted: 2003-01-23 11:25pm
by Beowulf
aerius wrote:I've gotten down to $135k with an all tube arch design. It took me the longest time to get something under $160k until I realized the joys of tubes.
you know, in some places bars are cheaper than tubes. When it's under tension, use bars, under compression, use tubes.
Posted: 2003-01-23 11:26pm
by The Dark
Beowulf wrote:aerius wrote:I've gotten down to $135k with an all tube arch design. It took me the longest time to get something under $160k until I realized the joys of tubes.
you know, in some places bars are cheaper than tubes. When it's under tension, use bars, under compression, use tubes.
I thought it was the other way around...merde, no wonder I haven't been doing that good!
Posted: 2003-01-23 11:30pm
by ArmorPierce
Got mines to 143k, after that weird stuff started happening.