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Steel Reinforcement

north star

north star

Sawhorse
Joined
Oct 19, 2009
Messages
4,596
& ~ & ~ &

Greetings to all !

I am reviewing a Proposal to replace some deteriorated & broken
concrete areas on a Helicopter Taxiway.

My question(s) have to do with the steel reinforcement to replace
what will be removed from the damaged areas.

I do not know the size of the steel reinforcement, of what is
currently in the damaged concreted areas.

QUESTION # 1: I am proposing to replace with 5/8" diameter
steel bars......What is the recommend minimum Grade of the steel
bars I plan to use ?

QUESTION # 2: I plan to propose a grid of 8" - 10", fully tied
and fully supported steel, and with 4,000 psi concrete mix.

Thoughts, questions, observations


& ~ & ~ &
 
Grade 60 for the rebar. I would add air entrainment to the concrete if you were in an area subject to freeze-thaw cycles.
 
Please don't specify 5/8" bar - in place, use the lingo and specify grade 60 #5 bar at 8-in on-center each-way.

Make sure the concrete is air entrained. If the potential for use of salts or other oxidizers is high, may want to specify epoxy coated rebar; if you do, make sure to follow the adjustment factors for development length.
 
On what basis are you evaluating the proposal if you do not have the necessary expertise? Retain a civil engineer who is experienced in designing roads or better yet airport runways..

Find out why the damage occurred. If you do not you might have the same problem with the repaired taxiway.

There are non destructive ways to determine the existing reinforcement and while you are at it determine the thickness of the concrete..
 
# ~ #

Thanks all for your replies !

**ICE**, ...sorry, no train wheels available ! :D

**Mark K**, ...hiring an RDP to design something or to
perform some onsite forensics, while a very good
recommendation, ...simply put, it is not an option that is
available to me........I am trying to make a Silk Purse out
of this Sow's Ear.......Also, I do not know why the concreted
TaxiWay has deteriorated \ sunken......It is what it is sir ! ;)

# ~ #
 
You are buying "trouble" by ignoring our recommendations. What are the choppers hauling, pure "Columbian"?
 
sometimes concrete slabs fail because the subase was the problem. Are your patches wide spread or minimal locations? If the existing slab is not reinforced then the amount of bar or type of bar you use for the patch might need to be just enough to keep the slabs together. I would also apply bonding agent to the edges
 
north star said:
& ~ & ~ &

Greetings to all !

I am reviewing a Proposal to replace some deteriorated & broken
concrete areas on a Helicopter Taxiway.

My question(s) have to do with the steel reinforcement to replace
what will be removed from the damaged areas.

I do not know the size of the steel reinforcement, of what is
currently in the damaged concreted areas.

QUESTION # 1: I am proposing to replace with 5/8" diameter
steel bars......What is the recommend minimum Grade of the steel
bars I plan to use ?

QUESTION # 2: I plan to propose a grid of 8" - 10", fully tied
and fully supported steel, and with 4,000 psi concrete mix.

Thoughts, questions, observations


& ~ & ~ &
Click to expand...
What is it you are reviewing; plans for permit, a bid proposal, etc.?
I take it you are a Contractor, in which state?
 
# ~ #

Thanks again for the additional responses !

**ADAguy**, the choppers are military and haul gear, troops,
supplies, etc.......Like these:

CH-47.jpg


No, I am not a contractor.........The project is for removing the damaged
concrete and to restore the areas to match the surrounding TaxiWay.
For security reasons, I cannot provide my location.


**linnrg**, the damaged concrete areas are currently on a helicopter
TaxiWay, and are sporadic......As I understand it, there IS steel
reinforcement present in the other, entire TaxiWay.

# ~ #
 
north star said:
QUESTION # 1: I am proposing to replace with 5/8" diameter
steel bars......What is the recommend minimum Grade of the steel
bars I plan to use ?

QUESTION # 2: I plan to propose a grid of 8" - 10", fully tied
and fully supported steel, and with 4,000 psi concrete mix.
Click to expand...

north star said:
The project is for removing the damaged
concrete and to restore the areas to match the surrounding TaxiWay.
Click to expand...

north star said:
concrete areas are currently on a helicopter
TaxiWay
Click to expand...
You couldn't pay me enough to touch that review without some specific engineering that considers loading of slab, bearing capacity of soils, etc. You're not dealing with Cessna personal aircraft, this is a military installation where performance of the taxiway could impact national security, and no one is thinking to investigate why the existing slab is failing?

My suggestion, find a way to get un-involved yesterday.
 
FYI, a CH-47 has a maximum gross weight of aprox. 33,000lbs. Spread that over 4 sets of landing gear and say each has an bearing area of 1-sqft, that equates to 8250lbs.

Slab reinforcement is critical to taxiway performance, as the total load exceeds the soil bearing capacity.
 
Last edited:
Who is submitting the proposal you are reviewing and what sort of supporting documentation have they provided?
Did the base officer create a scope of work by which the proposer complied his proposal?
 
Given the limitations you've been given, I question whether the repair of this facility is a priority for the base commander. Perhaps a further discussion is prudent to ensure this facility remains operational.
 
@ - @ - @

Thanks again for the continuing input.......I VERY MUCH
appreciate your input ! ;)

**ADAguy**, ...no "As Builts" available......Also, no Proposal
submitted.......Only an awareness that there are some failed
concreted areas on a TaxiWay that need to be repaired.

**TyJ**, ...I will be involved from start to finish.....No opting
out on this........No Base Officer \ Commander involved, ...lower
echelon personnel only.

**tmurray**, ...the facility is already remaining operational.
There are other TaxiWays & Ramps being used.......Concreted
areas that need repairing will not stop the operational readiness
of the facility. :)

@ - @ - @
 
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