Tim, Yes, “profilograph”, that was it! I’d almost be willing to bet that the troubles we had with our runway project at NEW was at least part of the reason that got added to the spec! That project was completed in September 2000 just a few weeks before we hosted the Static Display for the NBAA Annual Convention, so a very large part of the business aviation community had the opportunity to see just how bad of a job our contractor did right after it was finished. We definitely got comments … I didn’t think we were ever going to hear the end of it. Thanks, & Happy Weekend! Joel ________________________________ From: Siemens, Paul, T [mailto:PTSiemens@GarverUSA.com] Sent: Friday, December 11, 2009 4:55 PM To: Jenkinson, Joel; McIllwain, Frank O. Cc: Joe; david.foster@addisonairport.net; macevedo@addisontx.gov; Nancy Cline; Clay Barnett Subject: RE: Runway Resurfacing Joel, Yes. It’s called a profilo-graph. The FAA added it to the paving spec (as an option) 4-5 years ago. Prior to that, when we wanted to use it, we added it as a modification to the specs. We’ll plan on using the Profilo-graph in our specs, and we can discuss more smoothness tools/ criteria as we move forward. P. Timothy Siemens, PE Garver, LLC From: Jenkinson, Joel [mailto:Joel.Jenkinson@wgint.com] Sent: Friday, December 11, 2009 4:42 PM To: Siemens, Paul, T; McIllwain, Frank O. Cc: Joe; david.foster@addisonairport.net; macevedo@addisontx.gov; Nancy Cline; Clay Barnett Subject: RE: Runway Resurfacing Tim, Thanks for the reassurance. However, I have to say (from personal experience) that the FAA test with the 16-foot straightedge is woefully inadequate. I spent a lot of time on the runway at NEW with a contractor and a 16-foot straightedge, and it was next to useless because of how the testing was specified. Obviously bad areas passed the test; in my view a ¼-inch variation is far too much to allow, and the 15% threshold is too generous. Also, that method of testing is virtually stone-age technology; in addition to being inadequate, it is very time-consuming. I would be willing to bet that test has been around since before there was an FAA (i.e., before 1958). In New Orleans, we eventually made the contractor come out with a big bicycle-wheeled contraption that was about 45 feet long – I can’t recall what it was called – to make about five passes up and down the runway (centerline, 10 feet left/right, 25 feet left/right) to measure the smoothness, and that did a better job of highlighting the problem areas. If you do the math, an aircraft traveling at 100 knots covers almost 17 feet in a tenth of a second, so a quarter-inch vertical variation over that distance can be pretty significant. On the runway at Lakefront, we had a “bumpy” area that had a particularly bad effect on the later-model Lears: on the take-off roll on 36L, the undulations in the runway would cause the airplane to bounce up and down on its nosewheel strut like it was a pogo stick. The pilots quickly learned to hold a little back pressure on the yoke on take-off to reduce the bouncing. A lot of the problem in New Orleans was likely due to the fact that the airport was built on hydraulic fill that was essentially sand and muck sucked up off the bottom of the lake and pumped to fill in behind the seawall. The runway base course was pretty thick, but it was sitting on sand, clay, and muck that did not react well or uniformly to the vibratory rolling. We didn’t have any outright base failures, but we did get some differential settling. Bottom line, I think we need better testing / acceptance criteria than the FAA’s antiquated 16-foot straightedge. I don’t know what that might be, but surely there is something better out there? Regards, Joel Joel Jenkinson Director, Addison Airport main: (972) 392-4850 fax: (972) 788-9334 ________________________________ From: Siemens, Paul, T [mailto:PTSiemens@GarverUSA.com] Sent: Friday, December 11, 2009 2:42 PM To: Jenkinson, Joel; McIllwain, Frank O. Cc: Joe; david.foster@addisonairport.net; macevedo@addisontx.gov; Nancy Cline; Clay Barnett Subject: RE: Runway Resurfacing Joel, Yes, smoothness is a very valid concern. And I know that the Town had something similar years ago on Beltline Road. We’ve seen similar “speed bumps” appear during the rolling process. Commonly the “rebound” of the mat is due to the underlying (& excess) crack sealer from the previous project. When something like that happens, our inspectors will immediately halt production until we’ve figured out the problem. Also, the current FAA paving spec includes smoothness as an acceptance criteria. Specifically, the finished surface may not vary more than ¼” when using a 16’ straightedge. Both longitudinal & transverse smoothness are checked at 50’ intervals. If 15% or more fails, the section is milled & replaced. And, the FAA recently added a “finished grade” survey where the Contractor is required to survey the finished profile. And like smoothness, if 15% or more fails, the section is milled & replaced. Finally, regarding the design, the profile will have very long vertical curves for a smooth ride. All that to say, we understand your concern and the need for smoothness. Have a good weekend. P. Timothy Siemens, PE Garver, LLC From: Jenkinson, Joel [mailto:Joel.Jenkinson@wgint.com] Sent: Friday, December 11, 2009 1:52 PM To: McIllwain, Frank O.; Siemens, Paul, T Cc: Joe; david.foster@addisonairport.net; macevedo@addisontx.gov; Nancy Cline; Clay Barnett Subject: Runway Resurfacing Gentlemen, I know you are wrapping up the PER right now, but there is something I wanted to bring up with you regarding the final design. This is a concern that stems from the bad experience I had with the runway overlay we did when I was at New Orleans Lakefront. On that project, the contractor turned what had been a good smooth runway into something that more closely resembled a waffle. We got pilot complaints about it for years afterwards, so naturally it is something I would very much like to avoid with our upcoming overlay here in Addison. There were some basic problems with that job, not the least of which was the competence (or lack thereof) of the engineer; at least I am confident we will not have that particular issue on this job. In the bid specifications, there was effectively no standard or measure of either longitudinal or lateral smoothness that the contractor had to meet. All of the focus was on obtaining maximum compaction of the asphalt, with the specs written in such a way that the higher the compaction (PWL), the higher the payout. So of course the contractor focused on maximizing his payout with aggressive use of vibratory rolling. The adverse effects of this were apparent when the very first lane of asphalt was put down and they pounded some big dents in the runway. The engineer didn’t stop them and make them revise their methods, so they just filled in the lower spots with more asphalt and kept right on rolling (over the screaming objections of airport staff, which went unheeded). Anyway, the job went poorly and we had an undulating runway when it was all done. So this is probably just my oversensitivity based on a previous bad experience, but given the phasing and the way we will likely have to construct this overlay, the smoothness of the finished product is a major concern for me. I very much want to assure that there are appropriate standards and measures for the smoothness of the finished surface in place, so the contractor has every incentive to insure that the finished product will be at least as smooth as – and hopefully even better than – what we have out there now (which is actually pretty good, in spite of the fact that some low spots have developed here and there). So I just wanted to bring this up now, to make sure we address it in the final design and the bid specs. Thanks, Joel Joel Jenkinson Director, Addison Airport main: (972) 392-4850 fax: (972) 788-9334