Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 107
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Book Description
The objective of this research project is to develop an analytical model for rigid pavement joints that can be implemented into advanced pavement design models. This report documents a background investigation including a comprehensive review of rigid pavement joint models with particular emphasis on their joint and foundation modeling capabilities. The major historical developments in airport rigid pavement design are discussed. Closed form solutions akin to those by Westergaard were derived in this study for the maximum responses on the unloaded side of a rigid pavement slab edge capable of a degree of load transfer. When used together with Westergaard's own closed form equations for the free edge problem, the formulae derived in this study constitute a complete solution of the edge load transfer problem, recognized over the years as a critical consideration in rigid pavement design. The newly derived solution is presented in convenient form for routine engineering application and is compared to earlier finite element data. The improvement in ease of application and precision is considerable.
Author: Michael I. Hammons
Publisher:
ISBN:
Category : Pavements, Concrete
Languages : en
Pages : 107
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Book Description
Author: Michael I. Hammons
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Andreas Loizos
Publisher: CRC Press
ISBN: 1351585797
Category : Technology & Engineering
Languages : en
Pages : 364
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Book Description
Bearing Capacity of Roads, Railways and Airfields includes the contributions to the 10th International Conference on the Bearing Capacity of Roads, Railways and Airfields (BCRRA 2017, 28-30 June 2017, Athens, Greece). The papers cover aspects related to materials, laboratory testing, design, construction, maintenance and management systems of transport infrastructure, and focus on roads, railways and airfields. Additional aspects that concern new materials and characterization, alternative rehabilitation techniques, technological advances as well as pavement and railway track substructure sustainability are included. The contributions discuss new concepts and innovative solutions, and are concentrated but not limited on the following topics: · Unbound aggregate materials and soil properties · Bound materials characteritics, mechanical properties and testing · Effect of traffic loading · In-situ measurements techniques and monitoring · Structural evaluation · Pavement serviceability condition · Rehabilitation and maintenance issues · Geophysical assessment · Stabilization and reinforcement · Performance modeling · Environmental challenges · Life cycle assessment and sustainability Bearing Capacity of Roads, Railways and Airfields is essential reading for academics and professionals involved or interested in transport infrastructure systems, in particular roads, railways and airfields.
Author: Thomas Bennert
Publisher:
ISBN:
Category : Asphalt
Languages : en
Pages : 160
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Book Description
Author: William G. Buttlar
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 408
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Book Description
This collection contains 31 papers presented at the 2001 Airfield Pavement Specialty Conference at the 27th International Air Transportation Conference, held in Chicago, Illinois, August 5-8, 2001.
Author: Marshall R. Thompson
Publisher:
ISBN:
Category : Pavements
Languages : en
Pages : 154
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Book Description
Author: K. W. Heinrichs
Publisher:
ISBN:
Category : Pavements, Concrete
Languages : en
Pages : 380
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Evaluation of analysis models and design methods.
Author: Edward H. Guo
Publisher:
ISBN:
Category : Finite element method
Languages : en
Pages : 76
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Book Description
"FEDFAA, Finite Element Design-Federal Aviation Administration, is a computer program for both airport rigid and flexible pavement thickness design. NIKE3D (a general-purpose, three-dimensional finite element method (3D-FEM) computer program) is the selected engine for critical stress calculation for airport rigid pavement design. The calculated edge stresses are used in the FEDFAA failure model to determine the slab thickness. Since FEDFAA is a tool for thickness design rather than for analysis, certain program modifications and selection of available elements in NIKE3D have been made during FEDFAA development; it includes (1) selection of the nonconforming eight-node solid element to model all layers of the pavement except the subgrade, (2) introduction of the infinite element to model the infinitely deep subgrade, (3) mesh densities in vertical and horizontal directions, and (4) slab size and width of subbase extension have been determined to fit the needs of the design. A procedure has also been developed to calculate the critical stress of the pavement from the stresses calculated by NIKE3D at the element Gaussian points. Finally, the modified 3D finite element-based program was evaluated by using three criteria: (1) the model must be theoretically correct; (2) the final stress calculation engine with modifications and simplifications provides critical stress close enough to the precise one; and (3) it should be able to complete this computation under aircraft load within a few minutes. This report provides detailed descriptions for model selections, program modifications, and numerical evaluations. The report concludes that the final tool satisfies all three criteria; therefore, it is a reliable and applicable tool for airport rigid pavement design."--P. [ii].
Author: Shad M. Sargand
Publisher:
ISBN:
Category : Pavements, Concrete
Languages : en
Pages : 109
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Book Description
This work is conducted to provide a complete verification and validation of four different finite element programs (ISLAB2000, JSLAB, EVREFE, and OU3D) for rigid pavement. The experimental data used in this process was collected from the Ohio SHRP Test Road (including four core sections with various geometry and pavement layers) and the Ohio University Accelerated Pavement Load Facility (three different loading conditions). The variety of the pavement sections and loading conditions makes this verification a complete and unique study. The verification outcomes are applied to optimize the joint spacing for least critical stresses within the pavement design life by using three concrete fatigue models (PCA, Huang, and Domenichini). The validation results show that the finite element models follow the general trend of the experimental data in strain, deflection, and vertical pressure. However, two issues are pointed out: stress reversals between the truck axle loads, and slab rocking. Experimental results show that moisture loss that occurred after placing concrete slabs produces a residual negative temperature gradient of -2.2oF/inch ( -0.48C°/cm). This leads to a permanent loss of support (LOS) under the pavement corners. Thus, positive gradient-based curling will only reduce the amount of LOS without eliminating it. When tested under different loading conditions, ISLAB2000 shows some inaccuracy in modeling the joints under combined traffic and environmental loadings. With the presence of built-in negative temperature gradient due to the curing of concrete, the critical tensile stresses are located at the top of the slab, and are maximized when the two truck axle loads are positioned on the two edges of the slab. This fact is confirmed experimentally; the slab cracks are observed to initiate at the top and develop towards the bottom of the pavement. The review of the three fatigue models shows that the level of tensile stress overcomes the frequency of load application. This is due to the tensile stresses resulting from the built-in negative temperature gradient. For the four pavement sections in the study, 13 ft (4.0 m) slabs had the longest design life.
