Quartzite keeps airport projects on schedule
Construction is always challenging, especially when you consider the unpredictability of the weather. Event in a drought year, it's likely that with outdoor construction, rain eventually appears-sometimes in copious amounts. A phased project at the Sioux Falls Regional Airport fortunately had exactly the right material to deal with excess moisture on the jobsite: crushed quartzite aggregate.
HDR Engineering serves as consulting engineer to the Sioux Falls Airport. HDR began planning for a runway expansion and renovation project several years ago, including analyzing the impact a runway extension would have to the existing site. It was determined that the planned expansion of Runway #15/33, and the addition of arresting barrier systems at either end of the runway, would first require rerouting the Sioux River one mile to ensure a "safety area" around the extended runway. Engineers designed a rerouting of the Sioux River, which they completed four years ago in preparation for the runway project. The $7.6 million project was funded jointly by the Sioux Falls Airport and the South Dakota Air National Guard.
The three phased expansion and renovation project includes:
Extension of a 6670' concrete runway to 8000' - a 1300' extension
Reconstruction of a 2200' runway to concrete
Construction of a parallel asphalt taxiway extension
Construction of a 7600 s.y. concrete holding apron
Construction of 9600 s.y. arm/de-arm apron
Construction of an arresting barrier system for the F-16s
(similar to those found on naval aircraft carriers)
Relocation and construction 8300' of a two-lane asphalt perimeter roadway
Upgrading of all lighting
The construction projects at the airport were time-sensitive: airport runways, taxiways and aircraft parking aprons had to remain in use by aircraft to the "maximum extent" possible. The contractor would be held responsible for any failure to complete work or restore the area to a safe condition for air traffic operations within a pre-ordained period of time. Both the engineer and contract had strict schedules to maintain.
Runways utilize Quartzite
The most time-sensitive area of the projects was the runway work. Designed and constructed in compliant with FAA specifications, the new and reconstructed runways were to be of PCC pavement, with a very substantila base capable of accommodating large, commercial jets like the 747, as well as SDANG F-16 fighter planes. The runways include 15" of PCC pavement, 12" of P-209 base course spec, excerpted in the Tech Corner article, calls for "...clean, sound, durable particles of crushed stone, crushed gravel, or crushed slag...Fine aggregate passing the No. 4 sieve shall consist of fines fron the operation crushing the coarse aggregate."
The curshed aggregate also had to undergo sixteen ASTM tests in order to qualify.
The contract was awarded to Terin Corporation who selected crushed quartzite aggregate for the runway base course. Because of its durability, quartzite has been used for years on airport projects, including runways, taxiways, and aircraft aprons, all with positive results. In addition to its inherent strength and durability, an added value of the crushed quartzite base course became apparent when it rained while construction was underway at the airport. "The more rain you get, the harder it (the quarzite base course) gets," according to Terin Corporation Project Supt. Eric Thompson. Because of its incredibly low absorption (0.3%), the rain quickly drained away from the quarzite base, so trucks could continue driving on it, precluding work stoppages. "There are no rain delays with quartzite. It really performed well."
Engineering Project Manager Mark Wiederrich agrees, "The quartzite performed great after rain. With our base section consiting of 19" sand sub-base and 12" of quartzite base course, we were able to pave the next day after overnight thunderstorms. The angular faces of the crushed quartzite provided great stability so that the loaded ready mix trucks never rutted-out, regardless of the condition." Although there were other options, quartzite is "the product that best fits that (P-209) requirement in our area" states Wiederrich.
Tech Corner
Description
209-1.1 This item consists of a base course composed of crushed aggregates constructed on a prepared course in accordance with these specifications and in conformity to the dimensions and typical cross sections shown on the plans.
Materials
209-2.1 Aggregate. Aggregates shall consist of clean, sound, durable particles of crushed stone, crushed gravel, or crushed slag and shall be free from coating of clay, silt, vegetable matter, and other objectionable materials and shall contain no clay balls. Fine aggregate passing the No. 4 (4.75 mm) sieve shall consist of fines from the operation of crushing the coarse aggregate. If necessary, fine aggregate may be added to produce the correct gradation. The fine aggregate shall be produced by crushing stone, gravel, or slag that meet the requirements for wear and soundness specified for coarse aggregate.
The crushed slag shall be an air-cooled, blast furnace slag and shall have a unit weight of not less than 70 pounds per cubic foot (1.12 Mg/cubic meter) when tested in accordance with ASTM C29.
The crushed aggregate portion which is retained on the No. 4 (4.75 mm) sieve shall contain not more than 15 percent, by weight, of flat or elognated pieces as defined in ASTM D 693 and shall have a least 90 percent by weight of particles with at least two fractured faces and 100 percent with at least one fractured face. The area of each face shall be equal to at least 75 percent of the smallest midsectional area of the piece. When two fractured faces are contiguous, the angle between the planes of fractures shall be at least 30 to count as two fractured faces.
The fraction passing the No. 40 (0.42 mm) sieve shall have a liquid limit no greater than 25 and a plasticity index of not more than 4 when tested in accordance with ASTM D 4318. The fine aggregate shall have a minimum sand equivalent value of 35 when tested in accordance with ASTM D 2419.
a. Sampling and Testing. Aggregates for preliminary testing shall be furnished by the Contractor prior to the start of production. All tests for initial aggregate submittals necessary to determine compliance with the specification requirements will be made by the Engineer at no expense to the Contractor.
Samples of aggregates shall be furnished by the Contractor at the start of production and at intervals during production. The sampling points and intervals will be designated by the Engineer. The samples will be the basis of approval of specific lots of aggregates from the standpoint of the quality requirements of this section.
In lieu of testing, the Engineer may accept certified state test results indicating that the aggregate meets specification requirements.
Samples of aggregates to check gradation shall be taken by the Engineer at least once daily. Sampling shall be in accordance with ASTM D 75, and testing shall be in accordance with ASTM C 136 and C 117
b. Gradation Requirements. The gradation (job mix) of the final mixture shall fall within the design range indicated in Table 1, when tested in accordance with ASTM C 117 and C 136. The final gradation shall be continuously well graded from coarse to fine and shall not vary from the low limit on one sieve to the high limit on an adjacent sieve or vice versa.
The job mix tolerances in Table 1 shall be applied to the job mix gradation to establish a job control grading band. The full tolerance still will apply if application of the tolerances result in a job control grading band outside the design range.
The fraction of the final mixture that passes the No. 200 (0.075 mm) sieve shall not exceed 60 percent of the fraction passing the No. 30 (0.60 mm) sieve.
Personal Highlights
|
|
 |
Title:
Transportain Engineering Section Manager,
HDR Engineering, Inc.
Sioux Falls, South Dakota
Education:
BS in Civil Engineering, 1987
SD School of Mines & Technology
Hometown:
Aberdeen, SD
|
|
|
What types of projects have you been
involved in at the Sioux Falls Airport?
I've been involved in a wide variety of projects including:
New Cargo Apron (concrete)
Big Sioux River Channel Relocation for current runway extension
Reconstruction of the South Terminal Apron (concrete)
Short Term parking Lot Expansion (asphalt)
Rental Car Parking Lot Expansion (asphalt)
Taxiway Bravo Asphalt Overlay
Runway 21 Concrete Holding Apron
General Aviation Drainage Study
Taxiway Alpha and General Aviation Ramp Overlays
Runway 321 Lighting Improvements
Numerous Glideslope Studies
Regarding the current project at the Sioux Falls
Airport, what has been most challenging?
The runway extension project is a joint funded project between the Sioux Falls Regional Airport and the SD Air National Guard. One of the biggest challenges is designing a cost effective facility that meets the needs of both parties.
What are the challenges of airport projects?
Has anything changed since 9/11?
One of the biggest challenges in airport work is schedule. It is very typical not to know until the last minute if the federal funding planned for a project will be there. That usually results in a very compressed time frame to complete final plans and get them out for bidding. Phasing work on airfields while maintaining air traffic is also a challenge.
Obviously, the biggest thing that has changed in working at airports since 9/11 is security. We are all familiar how security has changed at airports for the traveling public. Security also has been tightened on the construction side and considerable thought and planning needs to be included when preparing the construction safety plans so that high level of production can be maintained by the contractor when hauling in materials and equipment without jeopardizing safety to the public.
How have engineering specifications/design/materials/etc.
on airport projects changed in the last 10 years?
Just like the highway and roadway industry, specifications and design guidelines are constantly changing as new technologies, materials and products are developed. The FAA maintains an excellent website of all their current specifications that can be easily downloaded. It makes it a lot easier than a few years ago when we would have or order a hardcopy of each specification as it was updated.
As a pilot yourself, what changes in airport
design do you see for the future?
As mentioned, security is the biggest change at airports. As the security issues are sorted out, we expect to see many airport design changes implemented, such as greater parking setbacks, blast proofing building walls, revised terminal layouts to incorporate new security equipment and staging areas, revised perimeter security standards, et. Capacity and delay are big issues. As the country's air traffic increases and the land to expand airports becomes less available, airport design standards will change with emphasis on maximizing air traffic capacity per runway.
Navigational aids for aircraft landing in poor visibility conditions are constantly improving to provide greater positional accuracy and reliability with Global Positioning system (GPS) being one of the latest and greatest technologies. Advances in precision-guided instrument approaches are on the immediate horizon with differential GPS and precision runway monitoring (PRM). These new advances will provide near-term reductions in the delay situation. New cockpit technologies are also being developed to enable planes to operate safely with less separation, thereby increasing runway capacity.
Airport design standards will also change in the future due to environmental concerns. Air quality, noise and energy conservation will all have impacts to future airport design.
