Bill,

 

Just an FYI, the contractor for Exechangar was going to pour 5” concrete with no subgrade in some areas.  David Wilde red tagged it and brought it to my attention.  I pulled the plans
and they call for a 6” concrete on a 4” subgrade, which meets the FAA circulars.  They called their geotech engineer to issue a report saying that they could pour 6” concrete over no
subgrade.  The original report dated Sept 23, 2009 had 6” concrete on a 4” base in accordance with FAA Circulars.  They issued a revised report on January 22, 2010 that called for 5”
concrete on 4” base.  I have informed them that the paving design must be in accordance with the FAA Circulars.

 

If you have any questions, please let me know.

 

Thanks,

Clay Barnett, P.E.

Town Engineer

Town of Addison

16801 Westgrove Drive

Addison, TX 75001-2818

Office: (972) 450-2857

 <http://www.addisongreen.info/> 

 

From: Clay Barnett 
Sent: Friday, April 30, 2010 9:13 AM
To: 'John Johnston'
Cc: David Wilde; cvantrease@vantreasedevelopment.com
Subject: RE: Subgrade Preparation

 

John,

 

According to Mr. Helmberger’s letter dated 2/19/10, “per the Owner, the largest typical aircraft anticipated to utilize the hangar is a medium size corporate jet such as a Cessna Citation
having a gross weight of 22,000 pounds.” FAA Advisory Circular 150/5320-6D, Section 504 (b) requires a minimum subbase thickness of 4 inches for concrete pavements serving aircraft between
12,500lbs and 30,000lbs.  Please incorporate this information in the pavement design for the apron and revise the geotechnical report as required.

 

If you have any questions, please feel free to contact me.

 

Thanks,

Clay Barnett, P.E.

Town Engineer

Town of Addison

16801 Westgrove Drive

Addison, TX 75001-2818

Office: (972) 450-2857

 <http://www.addisongreen.info/> 

 

From: John Johnston [mailto:jjohnston@hja-eng.com] 
Sent: Wednesday, April 28, 2010 9:33 AM
To: Clay Barnett
Cc: David Wilde; cvantrease@vantreasedevelopment.com
Subject: Re: Subgrade Preparation

 

Clay -

 

We used information from A/C No. 150-5320-6D.

 

Thanks,

 

John

	----- Original Message ----- 

	From: Clay Barnett <mailto:cbarnett@addisontx.gov>  

	To: 'jjohnston@hja-eng.com' 

	Cc: David Wilde <mailto:dwilde@addisontx.gov>  ; 'cvantrease@vantreasedevelopment.com' 

	Sent: Tuesday, April 27, 2010 4:50 PM

	Subject: RE: Subgrade Preparation

	 

	John,

	 

	What FAA Advisory Circular was used for the pavement design?

	 

	Thanks,

	Clay Barnett, P.E.

	Town Engineer

	Town of Addison

	16801 Westgrove Drive

	Addison, TX 75001-2818

	Office: (972) 450-2857

	 <http://www.addisongreen.info/> 

	 

	From: cvantrease@vantreasedevelopment.com [mailto:cvantrease@vantreasedevelopment.com] 
	Sent: Tuesday, April 27, 2010 4:18 PM
	To: Clay Barnett
	Cc: David Wilde
	Subject: Fw: Subgrade Preparation

	 

	Clay,
	
	Attached is the soils engineer's latest recommendations for the paving for our project.
	
	I realize you will need to forward this on to your third party consultant for their review. Any expedition you can offer in that regard would be most appreciated.
	
	We have Terracon conducting density testing on the paving and tomorrow I'll be scheduling an inspection with Dave Wilde to verify the concrete encasement of the 2 culverts in the north
approach as well as grade point checks on the same approach.
	
	Please let me know if there's anything further you may require.
	
	Regards,

	Corey Van Trease
	Principal
	Van Trease Development, Inc.
	611 S. Main Street, Suite 400
	Grapevine, TX 76051
	Office (866) 304-7676
	Fax (866) 304-7878

________________________________

	From: John Johnston <jwjohnston-hja@sbcglobal.net> 

	Date: Tue, 27 Apr 2010 13:36:36 -0700 (PDT)

	To: Dan Claassen<dan@exechangar.com>

	Cc: Jim Albertson<jimalbertson@cox.net>; <cvantrease@vantreasedevelopment.com>

	Subject: Subgrade Preparation

	 

		Dan -

	 

	Attached is a letter about subgrade preparation. I trust this approach will be acceptable to the City and to the FAA.  We feel comfortable with it.

	 

	Thanks,

	 

	John
	
	John W. Johnston, P.E.
	
	Henley-Johnston & Associates, Inc.
	235 Morgan Avenue
	Dallas, Texas 75203-1025
	Texas Firm Registration No. F-1238
	Phone: 214-941-3808
	Fax: 214-943-7645
	e-mail: jwjohnston-hja@sbcglobal.net

		

	 

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