How Would You Fix This Bridge?

[Snobdds]

Box culverts are going to be your cheapest option. All prefab. Dig and place.

 

[Engineer42]

We installed the guardrail ourselves. It was state surplus and we got it for cheap.

Yeah, that $50K estimate was a few years ago. Maybe double today.

Dang, was hoping a county or the state had done the guardrail, then you could hang the r&r on them. So much for that.

I think your options are many, and all very costly. Sorry.

 

[jigs_n_fixtures]

Box culverts are going to be your cheapest option. All prefab. Dig and place.

The cost is lower if you cast in place. Longer project time. But could be done half at a time to keep road access.

 

[dodge man]

They just did a box culvert by my house, smaller than the OP likely needs. It’s a township road but the county did the work more or less for no labor cost. I thought just the materials was $60k. I think an old rail car bridge would be cheapest assuming the ground on either side is stable. It would be a matter of putting it in place and a gravel ramp to get up on it.

 

[Snobdds]

The cost is lower if you cast in place. Longer project time. But could be done half at a time to keep road access.

I highly doubt forming it in place is cheaper.

Precast is so cheap these days...

 

[Jstpssng]

I had a precast open bottom 16 foot concrete bridge put in, 1 block high for around $23000. That was preCovid. Now it likely would be twice that, but still a permanent option.
Again; it's dependent on the stream. If there are fish in it, those pesky regulations come into play.
As others have mentioned, adding to whatever is there without disturbing the stream banks likely is the cheapest option... especially for " a couple of 80 YO men."

 

[bdhsfz6]

How wide is the stream, bank to bank upstream and downstream? Also how deep is the channel? Looking at your picture it appears that there is a fair amount of water going through, and the flow has been restricted at the bridge for quite some time. (113 years?)
While others mention regulations, I'd be more concerned with the new bridge blowing out. Paying to do it half assed twice is going to cost more than fixing it right once.
Concrete waste blocks are relatively cheap. Rent an excavator, go two blocks high if necessary and then you likely could go with the RR car. I've also seen them made with the steel from log truck trailers, and we trucked over them with 100,000 lb loads.

The stream (Navajo Creek) averages around 8' wide and 1 - 2' deep. The flow varies with rainfall. During high water events, the 6' pipe runs full.

What you can't see in the picture is, the bridge is sloped upward toward the left of the picture. The right side is only 2' above stream level. When the pipe obstructs the flow, the water backs up and flows over the roadway on the low (right) side. This acts as a "safety valve" and is likely why the bridge has lasted so long.

The most severe event happened during Hurricane Ivan in 2004:

 

[rScotty]

I highly doubt forming it in place is cheaper.

Precast is so cheap these days...

I'd agree with that - and that a precast box with wings is the right engineering solution too.
Maybe because precast is cheaper in the rocky mountain states? - not suire of that, but does it matter/

Because it sounds to me like these good old boys own lots of land and are looking for the cheapest solution rather than the easiest or the best. Best is the easiest - carve a building lot off of a piece of their land and swap that for the work. By his own argument, (in message #16) a decent flood-rated bridge would increase their existing property value enough to make that attractive.

 

[jigs_n_fixtures]

I'd agree with that - and that a precast box with wings is the right engineering solution too.
Maybe because precast is cheaper in the rocky mountain states? - not suire of that, but does it matter/

Because it sounds to me like these good old boys own lots of land and are looking for the cheapest solution rather than the easiest or the best. Best is the easiest - carve a building lot off of a piece of their land and swap that for the work. By his own argument, (in message #16) a decent flood-rated bridge would increase their existing property value enough to make that attractive.

I used to prepare bid packages for highway construction projects, and specified box culverts with the option of either precast or cast in place, unless there was a very specific reason for limiting the choice to just one, such as distance from batch plants, or the need to keep the roadway closure or one way traffic to a minimum. The contractors always bid the cast in place.

The precast has the advantage that it is built offsite, and the contractor doesn't have to pay prevailing rate labor costs. But, it has downsides such as it requiring a well compacted, flat base, with the grade perfectly controlled for the entire length. Sealing the seams between segments can be difficult. And getting the wing walls attached well can also be an issue. And you have to mobilize something to the site with enough lift capacity to move and place the segments. And, I've seen two serious on the job injuries trying to place precast RCB segments. which is more of an issue with inexperienced contractors. The segments are big, heavy, and have a lot of momentum.

On a private job, the cast in place isn't at a disadvantage for labor costs. The base preparation isn't as critical. So long as the base is well compacted, it can have wibbles, and wobbles, and the floor of the box will still cast to grade, and not have any duckponds. You might run over a bit on concrete volume, smoothing out the wibbles and wobbles. But, the structure will work. If piping past the structure, and backfill erosion is a concern, you can cast in cutoff walls. If fish passage is a concern, you can cast a fish ladder into the floor. And, forming concrete is something pretty much any carpenter can handle. Or possibly the owner can handle.

If I was doing a design, I'd also consider steel arch pipe, or a cast in place concrete base with metal arch above. If fish passage is critical, then the concrete base with an integral fish ladder would be the way to go.

I'd also look at a bridge deck of some kind supported on shallow abutments back from the edges of the stream to avoid environmental issues. The shallow abutments are similar to a shallow daylight basement, open on the end away from the stream, with an enlarged footing on the stream side, on which the bridge deck rests, and the interior of the walls filled with gravels to provide a counterweight, and graded as the approach to the deck.

 

[nyone]

Very close. The main problem is, it can be seen from the main highway.

Plant some really fast growing ever greens and fertilize them often. Wait a few years until it gets really bad then fix.

Or you could just make it a water crossing.

 

[ruffdog]

If it is repaired or not, is there a liability issue being that many homeowners use that private bridge? If the bridge is not safe, whose fault is that?

 

[bdhsfz6]

Plant some really fast growing ever greens and fertilize them often. Wait a few years until it gets really bad then fix.

Or you could just make it a water crossing.

I assume you're joking.
I'll be beyond caring about the bridge by the time the trees grow.

We discussed a low water crossing, but the DEP won't permit it. It may turn into one on it's own eventually when the bridge finally washes out. It isn't clear what the DEP would do then.

 

[bdhsfz6]

If it is repaired or not, is there a liability issue being that many homeowners use that private bridge? If the bridge is not safe, whose fault is that?

Good question. There are hundreds if not thousands of private bridges in the state. I've never heard of a liability case in court involving bridge maintenance, or lack there of. Not sure just who would be liable if something should happen.