# Steel  Reinforcement



## north star (Feb 14, 2019)

*& ~ & ~ &*

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 


*& ~ & ~ &*


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## ICE (Feb 14, 2019)

recycled train wheels


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## jeffc (Feb 14, 2019)

Grade 60 for the rebar. I would add air entrainment to the concrete if you were in an area subject to freeze-thaw cycles.


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## classicT (Feb 14, 2019)

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.


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## Mark K (Feb 14, 2019)

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..


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## north star (Feb 15, 2019)

*# ~ #*

Thanks all for your replies !

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

***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 !  

*# ~ #*


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## ADAguy (Feb 21, 2019)

You are buying "trouble" by ignoring our recommendations. What are the choppers hauling, pure "Columbian"?


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## linnrg (Feb 21, 2019)

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


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## ADAguy (Feb 22, 2019)

north star said:


> *& ~ & ~ &*
> 
> Greetings to all !
> 
> ...


What is it you are reviewing; plans for permit, a bid proposal, etc.?
I take it you are a Contractor, in which state?


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## north star (Feb 23, 2019)

*# ~ #*

Thanks again for the additional responses !

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








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.

*# ~ #*


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## ADAguy (Feb 25, 2019)

Understood but there should be as-builts available from the base.


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## classicT (Feb 25, 2019)

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 ?
> 
> ...





north star said:


> The project is for removing the damaged
> concrete and to restore the areas to match the surrounding TaxiWay.





north star said:


> concrete areas are currently on a helicopter
> TaxiWay


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.


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## classicT (Feb 25, 2019)

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.


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## jeffc (Feb 25, 2019)

"that equates to 8250kips". Given that a kip is 1000 lb, I think it would be 8.2 kips per loading point.


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## ADAguy (Feb 26, 2019)

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?


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## tmurray (Feb 27, 2019)

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.


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## north star (Mar 2, 2019)

*@ - @ - @*

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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