Bridge Design Challenge

[grizz441]

OK i redid mine little bit more to scale i think and the Cables are ran different to spread the load out through out the tower as apposed to my first drawing


(Image removed from quote.)

That is a beautiful suspension bridge idea. 

[68ZooM]

Grizz alot of the Design of the Bridge depends on the area its going to be built in, is the Bridge going to be located in the country a trendy area of town or historical area and so on, i know when designing a home i take that in consideration, unless the person flipping the bill has a set design in mind

[Tupac]

Just wait till all you guys see my "Bridge".

Everyones going to be envious of my talents as a designer.

[Melvin]

The center span of the Mackinac bridge is ~1100 meters. Scale that down, with a tower and anchor at each end.

Since you can't go into a tunnel, just remove the fill.

Sorry I can't draw this up for you, I suck at that stuff.

[grizz441]

Grizz alot of the Design of the Bridge depends on the area its going to be built in, is the Bridge going to be located in the country a trendy area of town or historical area and so on, i know when designing a home i take that in consideration, unless the person flipping the bill has a set design in mind

It's pretty open ended.  Design will be governed purely by economy and the bridge satisfies aashto design.  I don't think aesthetics will come into play much, although I don't think it should be ugly...

Idea 2:

[Dichotomy]

Zoom beat me to it.  I was thinking suspension as well.  Hmmmmmm...  thinking



Okay Grizz this is totally off the top of my head and based on current economies as I understand them (I'd really prefer to run calcs on this stuff but don't have the tools here at the house)

I'd want to elevate the bridge a bit above the extreme range of the water just for safety's sake.  I'm also assuming we're using the most current version of AASHTO with all the LTS's included (ASCE applies in lighting standards but it's my understanding that AASHTO meets or exceeds ASCE requirements). 

Not being able to tell except visually I'd prefer to keep my piers equally spaced although the left side pier will, most likely, be larger od and embed depth.  Primary material would be reinforced concrete as that is less expensive than steel (and oh boy is steel about to take a jump).  I'm assuming decent soil conditions at the point of ingress / egress and haven't considered a foundation below the ramps for this reason.

Pass / Fail?

By the way if you have any interest at all in getting into the light pole business I have several licensed PE contacts and I'd be more than happy to introduce you to them. 

[greens]

2 things possible here grizz
1. we can give you a design for the bridge
2. why dont you use ur 109 n fly ppl across the gap, can make sum good money i bet.

[grizz441]

The center span of the Mackinac bridge is ~1100 meters. Scale that down, with a tower and anchor at each end.

Since you can't go into a tunnel, just remove the fill.

Sorry I can't draw this up for you, I suck at that stuff.

I'll have to run some numbers but I would think that a suspension bridge would be more expensive than a traditional type of bridge at this span.  I could be wrong.

[68ZooM]

Another factor of price thou is the ability to use your Cut from the Hillside as fill, it might not meet the Fed standards for compaction tests as far as your approaches go, then you'll have to factor in the cost of Importing Spec Fill to meet the requirements for that job, the cut either can be used else where on jobsite or trucked off, Dirt work was my living until my Injury

[grizz441]

Another factor of price thou is the ability to use your Cut from the Hillside as fill, it might not meet the Fed standards for compaction tests as far as your approaches go, then you'll have to factor in the cost of Importing Spec Fill to meet the requirements for that job, the cut either can be used else where on jobsite or trucked off, Dirt work was my living until my Injury

For site work, to keep things simple and even for everyone, we are using $51/m^3 for site work.  So I assume that means for cut and fill.  It really simplifies having to worry about that stuff.

[grizz441]

Zoom beat me to it.  I was thinking suspension as well.  Hmmmmmm...  thinking

(Image removed from quote.)

Okay Grizz this is totally off the top of my head and based on current economies as I understand them (I'd really prefer to run calcs on this stuff but don't have the tools here at the house)

I'd want to elevate the bridge a bit above the extreme range of the water just for safety's sake.  I'm also assuming we're using the most current version of AASHTO with all the LTS's included (ASCE applies in lighting standards but it's my understanding that AASHTO meets or exceeds ASCE requirements). 

Not being able to tell except visually I'd prefer to keep my piers equally spaced although the left side pier will, most likely, be larger od and embed depth.  Primary material would be reinforced concrete as that is less expensive than steel (and oh boy is steel about to take a jump).  I'm assuming decent soil conditions at the point of ingress / egress and haven't considered a foundation below the ramps for this reason.

Pass / Fail?

By the way if you have any interest at all in getting into the light pole business I have several licensed PE contacts and I'd be more than happy to introduce you to them. 

Well it would have to be either prestressed precast concrete or post tensioned cast in place concrete.  Reinforced concrete isn't really used much anymore for beams, typically only walls, piers, and foundations now.  The arched girders won't be possible with concrete in that configuration, although that could be done with steel.

As for the equal span lengths, a couple things...
1.  Dropping a pier down into the deepest part of river will require a larger cross section pier, since it will be more slender, and also more concrete.
2.  I'm not sure how each span would connect at the piers.  3 span continuous maybe, I'll have to check if that is feasible.

[fbWldcat]

Can't beat the old Through-truss. With two pillars, it should do fine with minimal girder strength at certain points.

[Dichotomy]

 

Grizz now you have me thinking about this.  You know how much I hate to think and I don't have my code books handy.

Actually thanks bro.. nice intellectual challenge. 

[grizz441]

Grizz now you have me thinking about this.  You know how much I hate to think and I don't have my code books handy.

Actually thanks bro.. nice intellectual challenge. 

I figured it would be fun for a lot of posters on here, there are some smart folks.  We now await patiently for the sunbat p.e. to chime in.   

[grizz441]

Can't beat the old Through-truss. With two pillars, it should do fine with minimal girder strength at certain points.

Yep, although imo steel truss bridges are rather ugly.