Jacking Box Culvert 2

[blmsoccer]

For a number of reasons, I would like to replace a number of existing box culverts 8X8 and 10X10 box culverts. I would like to replace them by jacking or other methods instead of open cutting them. Does anyone have experience with this sort of effort?

Thanks

Blmsoccer

 

[dicksewerrat]

Where is this locaed? i may know someone you can call.

 

[bltseattle]

Sounds interesting, please keep us posted. Why the replacement, anyways?

Seems too big to jack, my experience with 8-ft diameter pipes was a microtunneling operation, with a cutter head and narrow gage track inside the pipe to remove the spoils on carts. I don't how that would be adapted to a non-circular section, maybe dicksewerrat's contact has more info. I would try to make a round section work for jacking or microtunneling to be more feasible....


Old school approach at this link....

http://clerk.ci.seattle.wa.us/~scri...URON&d=PHOT&p=2&u=/~public/phot1.htm&r=39&f=G

 

[cvg]

a square section can be jacked and the large size just requires larger hydraulic jacks. you will need a shield and jacking frame to fit the box section. These may have to be custom fabricated for your job. Most contractors have limited experience with boxes since pipes are more common. You can use an auger to assist with mining and removing the dirt but it will likely be a hand mined job.

 

[LHA]

Shows how little I know. I can't imagine jacking a 10'x10' concrete box without either disrupting the roadway above or damaging the new box.

 

[cvg]

I observed the process near Los Angeles about 10 years ago. Caltrans was jacking a large box culvert under Interstate 10 near Ontario. The freeway had 10 lanes and of course is one of the busiest in the world. Surveyors were on site full time to monitor any movement of the pavement.

 

[blmsoccer]

Okay after further research on the topic, it is possible to jack a box culvert. However, most contractor's prefer a round pipe to a box culvert, because... as the pipes are jacked they have a tendancy to roll. Obviously a square box culvert which rotates is rather a big deal, so extreme care must be taken to prevent this roll.

CNA Engineering Inc. provided me this free insight.

Rough costs associated with this operation can be upwards to $1000 per foot. It is an interesting opertation, and if your roadways cannot be shut down, it is a reasonable approach.

Thanks for all of your insight.

Sincerely

BLMSOCCER

 

[DRC1]

I was an engineer for GC on a project where we jacked either 7x7 or 8x8 twins box culverts under the railroad. Operation was not much different than jacking round pipe. We had a specialty sub do the work. I assited with design. Shield was built to fit the culvert. Had two levels (upper & lower) for spoil removal. Had ports for bentonite and post grout. The jacks were large. Biggest challenge was to develop suffient backstop for jacks. The culverts were going through an embakment. As I recall there were at least jacks in all 4 corners and at the mid point of each vertcal wall. This gave enough control to prvent rolling. Biggest concerns are controlling water and obstructions. Removing obstructions is a slow and costly process in any jacking operation. Besure you have a good subsurface profile before you start.

 

[blmsoccer]

I imagine the mining engineers in the audience will know the solution to this problem, how do you analyze the feasibility of jacking? If you have the earth profile, how do you determine whether the solution is feasible and what is the jacking pressure required?

 

[cvg]

start with your geotechnical investigation - this may be the most important data you will need. You are looking for uniform, dense deposits of cohesive material without any boulders. You should be above the water table. I would then start talking to some experienced jacking contractors in your area and ask for an estimate.

 

[DRC1]

Talk to a Pipe Jacking contractor. It is as much of an art as it is a science. Lots of practcal considerations.

 

[boxjacker]

My company does box jacking and pipe jacking. Pipe jacking is done by adding individual lengths of pipe sequentially and pushing the ever-lengthening column of pipe into the ground. Our preferred method of box jacking is to cast the entire box full length on a "launch slab" and then jack the entire box as a single unit. This assures that the box projects most accurately and also provides the strongest structure. We prefer the box jacking method on any conduits larger than 8 feet.