Widening an existing roadway 3

[evett]

I have to widen an existing interstate facility in a rock cut section where we have to maintain traffic on the existing facility. Can the new rock cut be accomplished safely while traffic is maintained within 300’? Are there alternatives to blasting?

 

[BigH]

Yes, there are alternatives. I've not used it before but there are chemicals that you can inject into a hole that will expand - and by expansion set up tensile stresses thereby splitting the rock. Likely more expensive and time consuming.
and HAPPY '04

 

[isaacsdad]

It is possible to Rip rock with a large dozer or Dig it with a large excavator if the rock is soft enough. Caterpillar publishes a book Cate performance Handbook that will give you ripabillity of different rock based on the seismic velocity of the material. Of course you may not have room for big machines. In ca Osha permits drilling and loading of explosives behind a protective Concrete barrier (K-Rail) with a variance from the county where the work will beperformed. The blasting company usually obtains these. I work up and down the state and in some cases the blaster has such great relationships it takes only days to obtain. The road will need to be closed for a period of 20 -30 minutes to allow for the final connection of explosives proper warning and finally cleaning up after the blast. Plan for the worst fly rock is always going to happen. Chemical expansive agents work well but are roughly double the cost for the material. Drilling remains the same.

 

[RDK]

There are some techniques that are used in concrete demolition that may have some use here.

These are large diameter circular saws and diamond cutters on long wire ropes.

They will allow precision demolition of concrete and may also work in hard rock.

For a listing of some companies offering this service see

http://www.consource.com/communities/2358

One of these should be in your area and can advise.

Costs will be higher than traditional blasting but you can work in tight areas with little or no over excavation. I have demolished concrete right next to large operating industrial machinery.





Rick Kitson MBA P.Eng

Construction Project Management
From conception to completion

http://www.kitsonengineering.com

 

[exploengineer]

Just shoot it. Its done everyday. Just make sure you hire a contractor that uses the latest technology such as laser profiling and brehole tracking.

Frank Lucca M.I.Exp.E.

http://www.terradinamica.com

 

[RDK]

Blasting within 300' of the public?

I don't think so.


Rick Kitson MBA P.Eng

Construction Project Management
From conception to completion

http://www.kitsonengineering.com

 

[Focht3]

Blasting can be done with the roadway in service - but it requires a lot of work to protect against fly rock, etc. Personally, I would push hard for temporary road closures. Surely your state DOT will allow the roadway to be closed for 30 to 45 minutes at a time in the middle of the night to accommodate this technique...



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[exploengineer]

We blast in the middle of Manhattan, Boston, other cities, and along roadways daily. This is not a big deal.

Controlled blasting can be done anywhere in any environment if you have the expertize. Not a job for the low bidder.


Frank Lucca M.I.Exp.E.

http://www.terradinamica.com

 

[BigH]

Yes - you can blast anywhere and when properly done, it is okay - but I believe that when you blast in Boston, etc., you clear a zone around the blast site to ensure that the public is not within this zone. This is the main point asked previously. Can I blast within 300 ft of the existing road. Certainly, but with the provision that the traffice is stopped momentarily (say 1/2 hour or so), proper safety provisions are carried out to ensure "walkers" or others near the site are cleared and warned - then blast - but you don't want the blasting done with the traffic moving so close. On one of our jobs in a SE Asian country, the countractor blasted and he had a bulldozer operator about 50m away - sitting in his bulldozer having a roof - anyway, he died; a stone fragment went right through the roof - so take no chances, blast but follow proper safety procedures, temporary closures as Focht3 suggested.

 

[exploengineer]

I wasn't saying to just go and throw rock everywhere. He was asking about using other means besides blasting. Why? Its more costly and this type of blasting is done everyday. 300 feet in the construction blasting world is a long way away.

Actually, I wish we had a three hundred foot zone in the cities. We may get 25 - 50 feet if we're lucky (especially in NYC).

Also, on heavily traveled roads, you'll get maybe a 1-3 minute window to fire the blast. Usually, a rolling roadblock is used.

If you are 300 feet away, matted, and properly loaded, a 1-3 minute window is more then enough. If its a sidehill cut that cannot be matted, then you must use different pattern geometries, timing, and explosives to keep the rock from moving, but still fractured enough to muck. Then, you may actually get a 10 minute window to clean up the road, but they usually want 1 lane open in 5 minutes. If you are 300 feet away and hit the road with enough rock to shut it down, you should get out of explosives engineering.

If you want to talk about blasting in other countries, I've seen it all (28 countries). Except for Europe, Australia, and Japan, I wouldn't trust anybody loading holes that I didn't personnally train.



Frank Lucca M.I.Exp.E.

http://www.terradinamica.com

 

[LHA]

I have no opinion on this matter, because it is not what I do. I would just like to say that I find it incredibly odd that everyone seems to be arguing that "you can not do something" which Exploengineer says he does often. He appears to be more than qualified, so I would tend to believe him. If he cites actually doing it downtown NYC w/ 25' clear, then I would guess 300' is indeed no big deal...this is hard for me to fathom, but I believe someone who says they do it. If he says state road closure for half an hour is not practical (and I DO believe that here in PA, USA the max. PennDOT allows is 5 minutes), then I would have to believe him. Just my unsolicited two-cents...I tend to do that a lot.

 

[Focht3]

Let me clarify my position.

Shorter road closures and closer distances can be done quite successfully. But these require real experts - like [blue]exploengineer[/blue]. (There are quite a few "experts" in this area I wouldn't trust to tie my shoes.) Having said that, I'm sure that [blue]exploengineer[/blue] would agree that a 300 foot clear distance is always preferable to 25 feet, all other things being equal -



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[BigH]

I, too, have no doubt what Exploengineer says; there is no doubt he is the expert on this topic. We (maybe just I?) am only pointing out that if such blasting is done, an expert should do it and all possible safety measures to be employed. I know that imploding buildings in big cities is done - but, I don't think I would be 25ft away (or even 50).
to all and to exploengineer - points well taken!

 

[Focht3]

I've been around a few implosions - they're awesome! But I like to keep at least a city block away, just in case something unexpected happens...



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