Airfield matting systems are used for the expedient construction of temporary airfields and rapid expansion of existing airfields to provide maneuvering support for military aircraft. They protect the subgrade by distributing the load exerted by aircraft over a larger area. Six airfield matting systems of varying materials and designs were evaluated through the construction of full-scale test sections to determine their effectiveness at reducing the accumulation of subgrade deformation and decreasing the pressure experienced by the subgrade. The matting systems were tested on a California Bearing Ratio (CBR) of 6 and subjected to simulated F-15E aircraft traffic while monitoring mat breakage, deformation, and subgrade earth pressure. The systems were compared in terms of the rate of subgrade permanent deformation. Based on test results, a simplified expression was developed to predict subgrade deformation on a CBR of 6 as a function of F 15E aircraft passes and airfield mat properties.

The AM2 aluminum airfield matting system is currently deployed by the United States military for the creation of temporary, rapidly constructed airfields. The ability to predict the number of allowable aircraft passes across an AM2 installation is challenging because of the complex design of the joining system and the fatigue behavior of critical stress elements in the joints. Prior to the writing of this dissertation, the prevailing methods used to predict the performance of AM2 were based on the CBR design procedure for flexible pavements using a small number of full-scale test sections over CBRs ranging from 4 to 10% and simulated aircraft that are no longer in service. The primary objectives of this dissertation are to present the results from nine full-scale experiments conducted on sections of AM2 matting installed on unstabilized soil and gravel subgrades with CBRs of 6, 10, 15, 25, and 100%, and to provide improved relationships that can be used to predict subgrade deformation underneath an AM2 mat installation and the associated fatigue damage when subjected to F-15E and C-17 traffic. Additionally, a laboratory fixture and procedure is described that can be used to evaluate an AM2 style joint in fatigue and directly relate its performance to in-situ field CBR conditions without requiring the expense of full-scale testing. These relationships are suitable to be implemented into design and evaluation frameworks currently used for airfield pavements and matting systems. The main body of this dissertation is a compilation of three complementary articles that describe different components of the main objectives and results from the full-scale experiments on AM2 mat surfaced airfields. The subgrade deformation relationships developed for the F-15E aircraft are presented in Chapter 2, the fatigue damage relationships and the development of the laboratory procedure for the F-15E aircraft are presented in Chapter 3, and the subgrade deformation relationships, fatigue relationships, and laboratory experiments for the C-17 are included in Chapter 4. Chapter 5 presents conclusions and recommendations.

The objective of this study is to estimate the airport capacity in the National Airspace System (NAS). Previous studies have focused on the airport capacity of large commercial airports. This research study estimates the runway capacity for more than two thousand airports in the NAS in order to understand future tradeoffs between air transportation demand and supply. The study presented in this report includes capacity estimates for general aviation and commercial airports. To estimate airport runway capacity, the Federal Aviation Administration (FAA) Airfield Capacity Model (ACM) is used to assess the capacity at all candidate airports in a target airport set. This set includes all airports with potential Very Light Jet (VLJ) operations. The result of the study provides a broad view about the airport capacity in the future air transportation system, and could help decision makers with a modeling framework to identify congestion patterns in the system. Moreover, airport capacity is an important limiting factor in the growth of air transportation demand. The main motivation in our analyis is to include airport capacity constraints in forecasts of air transportation demand. The framework described in this report has been integrated into the Transportation Systems Analysis Model (TSAM). TSAM is a comprehensive intercity and multimode transportation planning tool to predict future air transportation demand. / Master of Science

When damaged, military airfields must be repaired quickly so that flying operations can resume. Due to their rapid-setting and high-strength properties, epoxy-based polymer concretes (PC) may provide a good alternative to the portland cement concrete (PCC) rapid repair mixes currently used by the United States Air Force (USAF) for their Rapid Airfield Damage Recovery (RADR) operations. Epoxy-based PCs use epoxy polymers in place of portland cement to bind together aggregate and form the composite concrete. A commercially available epoxy-based PC, referred to as Commercial Product "B" in this thesis, was tested according to the procedures stated in the Tri-Services Pavements Working Group (TSPWG) Manual M 3-270-01.08-2. This manual defines testing protocol to be used for rapidsetting rigid repair materials intended for use on rigid airfield pavement spall repairs. These tests include various ASTM standards for compressive strength, flexural strength, slant-shear bonding strength, modulus of elasticity, coefficient of thermal expansion, and slump. Commercial Product "B" was not able to set and cure within the time limits set by the TSPWG manual, but otherwise surpassed final compressive strength, flexural strength, slant-shear bonding strength, and slump requirements. However, its modulus of elasticity was below the acceptable range, and its coefficient of thermal expansion was several times higher than the maximum allowed value. In addition, a second epoxy-based PC currently under development by Luna Labs and D.S. Brown was tested for compressive strength and, in most mix designs, surpassed the minimum requirements. This PC was also field tested in a series of four (4) 2-feet by 2-feet by 8-inch deep patches placed within an 8-inch thick PCC slab. Three of these patches did not meet minimum compressive strength requirements and none of them exhibited good bonding between the PC repair material and the original PCC slab. Finally, the effect of the surface moisture content of PCC on the bonding strength and chloride ion penetration resistance when PCC is bonded to PC was tested by casting Commercial Product "B" against ordinary PCC under two different moisture conditions: surface saturated dry (SSD) and PCC that had been conditioned at 10% relative humidity (RH) for 48 hours. The bonded samples underwent three- and four-point bond flexural testing and rapid chloride penetration testing (RCPT). The bond flexural testing showed that Commercial Product "B" bonds to PCC better when the PCC has been conditioned at 10% RH rather than being at SSD conditions. No statistically significant difference was detected for RCPT between bonded samples cast under the two surface moisture conditions, but did show that samples of PCC bonded with Commercial Product "B" are less susceptible to chloride ion penetration than samples comprised entirely of PCC. The results of this thesis show that PC may be useful to the USAF for repair airfields as short term repairs, but further work is required to ensure they meet all standards set by TSPWG for rapid repair materials. They also demonstrate that, when possible, a PCC repair surface should be dried completely before PC repair material is cast against it. / Master of Science / When damaged, military airfields must be repaired quickly so that flying operations can resume. Due to their rapid-setting and high-strength properties, epoxy-based polymer concretes (PC) may provide a good alternative to the portland cement concrete (PCC) rapid repair mixes currently used by the United States Air Force (USAF) for their Rapid Airfield Damage Recovery (RADR) operations. Epoxy-based PC use epoxy polymers in place of portland cement to bind together aggregate and form the composite concrete. To test whether epoxy-based PC can be used for RADR or other airfield repair operations, a commercially available epoxy-based PC, titled Commercial Product "B" in this thesis, underwent a battery of tests as specified for potential rapid repair materials in the Tri-Services Pavements Working Group (TSPWG) manual for testing protocol for rapid-setting rigid repair materials. Commercial Product "B" was not able to set and cure within the time limits set by the TSPWG manual but otherwise surpassed final strength, bonding, and workability requirements. However, it is not nearly as stiff as ordinary PCC and it expands and contracts far more than PCC when it undergoes temperature changes. In addition, a second epoxy-based PC currently under development by Luna Labs and D.S. Brown was tested for compressive strength and, in most mix designs, surpassed the minimum requirements. This PC was also field tested in a series of four (4) patches placed within a PCC slab. Three of these patches did not meet minimum compressive strength requirements and none of them exhibited good bonding between the PC repair material and the original PCC slab. Finally, the effect of the surface moisture content of PCC on the bonding strength and resistance to chloride ions, often found in de-icing agents, when PCC is bonded to PC was tested by casting Commercial Product "B" against ordinary PCC under two different moisture conditions: surface saturated dry (SSD) and PCC that had been conditioned at 10% relative humidity (RH). The bonded samples underwent bond flexural testing and rapid chloride penetration testing (RCPT). The bond flexural testing showed that Commercial Product "B" bonds to PCC better when the PCC has been conditioned at 10% RH rather than being at SSD conditions. No statistically significant difference was detected for RCPT between bonded samples cast under the two surface moisture conditions but did show that samples of PCC bonded with Commercial Product "B" are less susceptible to chloride ion penetration than samples comprised entirely of PCC. The results of this thesis show that PC may be useful to the USAF for repair airfields as short term repairs, but further work is required to ensure they meet all standards set by TSPWG for rapid repair materials. They also demonstrate that, when possible, a PCC repair surface should be dried completely before PC repair material is cast against it.

abstract: The structural design of pavements in both highways and airfields becomes complex when one considers environmental effects and ground water table variation. Environmental effects have been incorporated on the new Mechanistic-Empirical Pavement Design Guide (MEPDG) but little has been done to incorporate environmental effects on airfield design. This work presents a developed code produced from this research study called ZAPRAM, which is a mechanistically based pavement model based upon Limiting Strain Criteria in airfield HMA pavement design procedures. ZAPRAM is capable of pavement and airfield design analyses considering environmental effects. The program has been coded in Visual Basic and implemented in an event-driven, user-friendly educational computer program, which runs in Excel environment. Several studies were conducted in order to insure the validity of the analysis as well as the efficiency of the software. The first study yielded the minimum threshold number of computational points the user should use at a specific depth within the pavement system. The second study was completed to verify the correction factor for the Odemark's transformed thickness equation. Default correction factors were included in the code base on a large comparative study between Odemark's and MLET. A third study was conducted to provide a comparison of flexible airfield pavement design thicknesses derived from three widely accepted design procedures used in practice today: the Asphalt Institute, Shell Oil, and the revised Corps of Engineering rutting failure criteria to calculate the thickness requirements necessary for a range of design input variables. The results of the comparative study showed that there is a significant difference between the pavement thicknesses obtained from the three design procedures, with the greatest deviation found between the Shell Oil approach and the other two criteria. Finally, a comprehensive sensitivity study of environmental site factors and the groundwater table depth upon flexible airfield pavement design and performance was completed. The study used the newly revised USACE failure criteria for subgrade shear deformation. The methodology utilized the same analytical methodology to achieve real time environmental effects upon unbound layer modulus, as that used in the new AASHTO MEPDG. The results of this effort showed, for the first time, the quantitative impact of the significant effects of the climatic conditions at the design site, coupled with the importance of the depth of the groundwater table, on the predicted design thicknesses. Significant cost savings appear to be quite reasonable by utilizing principles of unsaturated soil mechanics into the new airfield pavement design procedure found in program ZAPRAM. / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2011

No description available.

Master of Landscape Architecture / Department of Landscape Architecture and Regional & Community Planning / Jessica Canfield / Located eight miles from the heart of Dallas, The Dallas Air Naval Station is a 1045-acre decommissioned airfield site. Since its closure in 1998, it has predominantly sat idle, bringing little value to adjacent neighborhoods and the greater community. Due to prolonged site remediation and no formal redevelopment plan, the site’s full potential has yet to come to fruition. Current urban design models tend to primarily focus on achieving a singular, end-result. However, as cities and the environment become more complex and unpredictable, these types of models often lack the ability to respond to change. Adaptive design, on the other hand, allows for more exploration of innovative practices, tools, techniques and methods that are informed by ecological knowledge and research design. As means of illustrating how adaptive design can catalyze and benefit brownfield sites, this project proposes an urban design framework informed by ecosystem services. Ecosystem services are an essential component to human well-being and environmental health, and when used as a guiding principle in site design, can add resiliency and beneficial outcomes to a site. To inform the development of the Ecosystem Services Urban Design Framework, this project uses literature, a site analysis, an applicable ecosystem services analysis, and precedent analyses. The framework is then applied to an urban brownfield site, the Dallas Air Naval Station, to show its applicability for short-term and long-term adaptive design scenarios. Dallas’ current issues and needs are addressed by the short-term plan, whereas informed projections of future issues inform the long-term design scenarios. Collectively, this project illustrates the imperative for incorporating adaptability into urban design, and for the value of using ecosystems services as underlying foundation.

The main objective of the thesis is to design and construct a taxiway and a lifting device for moving a BELL helicopter with slides. Handling equipment is used for transporting helicopters between the airfield and hangars. The thesis is divided into several parts. The first part includes the design of taxiway and lifting equipment. Other parts contain strength calculation of selected parts and design documentation, which includes assembly drawings and important groups drawings.

The main goal this thesis is presenting solution for manipulation with chopper BELL between of hangar and landing zone. The main task is design useful construction solution by required task, also perform a strenght calculations each part of mechanism and drawing documentation. Also included is a 3D visualization of the entire mechanism.

Rutting failures are prominent in expedient airfields constructed with AM2 landing mats over soft existing subgrades. There are many issues that must be addressed when approaching this multiaceted problem. The load transfer mechanism occurring at interlocking mat joints and the mat-soil interface bonding condition affect near surface subgrade response. The repeated loading coupled with lateral aircraft wander causes significant principal stress rotation in the subgrade. This kneading action then causes variations in the excess pore-water pressure and a subsequent softening of the soil. The purpose of this study is to investigate the critical factors that lead to subgrade rutting failures in landing mats constructed over soft subgrades. A three dimensional finite element (3D FE) model of a landing mat system over soft subgrade is implemented under both static and pseudo-dynamic loading conditions with aircraft wander. To capture the complex stress histories induced by the simulated moving gear loads over the unique structural features of the AM2 mat system, an elastoplastic kinematic hardening constitutive model, the Multi-Mechanical Model, is developed, calibrated and used to represent the subgrade response. Under both static and pseudo-dynamic loading, the FE model results match very well with the stress and deformation results from full-scale instrumented testing of the AM2 mat over 6 CBR subgrade. Results show that incorporating the load transfer mechanism occurring at the mat joints and varying the mat-soil interface condition affect the near surface subgrade deformation and stress responses that contribute to rutting failures. Furthermore, rotation of the principal stress axes and changes in excess pore-water pressures occur in the subgrade because of the moving tire load. These phenomena contribute to extension of the field of deformation influence around the trafficked area in the subgrade and upheaval at the edges of the test section. Findings of this study show that although layered elastic analysis procedures are the basis of current airfield design methodologies, critical design features and the corresponding deformation responses can be better modeled using the FE approach. Furthermore, the proposed 3D modeling approach implementing aircraft wander can provide a reliable platform for accurately simulating the subgrade response under pseudo-dynamic loading conditions.