Back calculation pavement design pdf

Engineers must always determine the requirements of the. Rdgn042 pavement design for carriageway construction page 23 of 42. This is a proprietary aashtoware computer software product. The basic process of road pavement design is illustrated in figure 1. Therefore, the analytical relationship of inpavement responses and modulus can applied for the modulus backcalculation. Esal is the acronym for equivalent single axle load. Calculation of design traffic for new pavement and overlay design. A guide to airfield pavement design and evaluation defence estates ministry of defence. The first was to assess the potential use of traffic speed deflectometer tsd deflection for the design of pavement structural treatments. The term concentration factor in this paper has been defined as a factor, which is used for determination of vertical stress by boussinesqs theory in a two layered system. For jointed concrete pavements, regardless of whether reinforced or nonreinforced, the aashtoodot method of pavement design calculates the same. Pavement design manual september 29, 2017 page 1 1.

This version of the new zealand guide to pavement structural design is to be used for the design of new pavements for rehabilitation refer to the new zealand guide to pavement evaluation and treatment this guide replaces the nz supplement to the 2004 austroads pavement design guide. It is not intended as definitive treatise, and it does not encompass the design of rigid pavements. As a general guide, factors elaborated in section 3. Subbase thickness10 subbase modulus30,000 psi subgrade m r10,000 psi to get k. Abstracta research focusing on the characterisation of representative local material properties was conducted to facilitate the full implementation of the mechanisticempirical pavement design guide for roadway designs in wyoming. It calculates pavement responses stresses, strains, and deflections and combines them with other. Backcalculation of layer parameters for ltpp test sections, volume ii. The pavement design engineer must integrate this information into the materials design package materials design report, pavement design summary and preliminary pavement structure cost estimate that will provide the necessary documentation and communication of this design process. Airport pavement design and evaluation, dated september 30, 2009. The faa recommends the guidance and standards in this ac for airport pavement design and evaluation. Monitoring the structural capacity of airfield pavement.

The second component included formalising the pavement layer moduli backcalculation algorithm for use in mechanistic empirical pavement treatment design. Daps deflection analysis of pavement structures is a rapid, accurate and reliable method for performing backcalculation of deflection results. This is an introduction to rigid pavement design for engineers. These analysis methods referred to as backcalculation programs provide the elastic layer modulus typically used for pavement evaluation and rehabilitation design. Chapter 25 presents the numerical procedure required for the backcalculation method for flexible pavements. Falling weight deflectometer fwd mndot pavement design. As part of the test program, falling weight deflectometer deflection data were collected from 25 test sites in wyoming for backcalculation of subgrade resilient. Taking advantage of this stress distribution characteristic, flexible pavements normally has many layers. Calback is a sophisticated backcalculation program that contains specific features pertinent to california and. Main wheel gear the undercarriage leg used in acn calculation. Layered elastic analysis for flexible and rigid pavements. Determining effective structural number of existing pavement, sneff from fwd 3 sn ef 0. Index backcalculation of layer parameters for ltpp test. Pavement calculator pavement design calculator software.

Introduction to rigid pavement design ced engineering. Provide material properties of insitu pavement and subgrade layers for the design of pavement rehabilitation alternatives that include extensive maintenance and repair work restoration, functional and structural overlays, partial reconstruction for example, runway keel, and complete reconstruction. Aashtoware pavement me design is the next generation of pavement design software. At present, interpretation of deflection basin test results usually is performed with staticlinear analyses, and there are numerous computer programs that can be used to calculate these elastic modulus values youngs modulus. Although the fwd approach is considered a preferred nondestructive testing method that offers many advantages over laboratory m r testing, especially with its lower cost and higher testing efficiency, its key limitation lies in the backcalculation process. Interpretation of falling weight deflectometer data. In most cases, it is our preference to conduct in situ deflection testing coupled with backcalculation analysis, but we also offer laboratory testing and other forms of in situ testing. The book also includes the latest methodstechniques on pavement materials testing, design and evaluation and uses the latest code provisions and design methods of pavements recommended by the. The mepdg is designed to update the 1993 aashto guide for design of pavement structures, which is primarily based on empirical observations from the aasho road test that began in the 1950s. The purpose of backcalculation is primarily to find out the insitu elastic moduli e of. Calme is a me design program for flexible pavements that parallels the nchrp 7a mepdg and is calibrated for california conditions. The last traffic count was taken 1 year back and the project would be completed in 2 years from now. In the design analysis, it is assumed that the reactive pressure provided by the subbasesubgrade material under a concrete slab is proportional to the deformation below the point of loading. Cut across the e sb cut across m r to the tl vertically meet other line read kvalue k600pci topic 10 aashto rigid pavement design figure 12.

Mi is the coefficient of drainage for flexible pavement design used to modify layer coefficients. Rdgn042 pavement design for carriageway construction page 7 of 42 pavement type for different sections andor different lanes on the same road. Esal is a concept developed from data collected at the american association of state highway officials aasho road test to establish a damage relationship for comparing the effects of axles carrying different loads. The software is written using modern windows programming languages with this version being developed for the windows 98 operating system. Pavement designanalysis software university of idaho.

Campus students are required to use it for their design activities. The wheel load acting on the pavement will be distributed to a wider area, and the stress decreases with the depth. Design pamphlet for the backcalculation of pavement layer moduli in support of the 1993 aashto guide for the design of pavement structures. New zealand guide to pavement structural design waka. Chapter 26 presents a practical test of interest with both types of road structures rigid or flexible multilayered structures. Austroads and the nzta have adopted the mechanistic design procedure for pavement rehabilitation treatments. Stand alone software version of the pavement design portion of the ce calc website. Ac 15053206f, airport pavement design and evaluations.

The structural condition of inservice airfield pavements, either remaining life or strength of the pavement is deduced from the fwd response, inducing a test load. Engineers are cautioned that much of pavement design is governed by codes, specifications and practices of public agencies. Engineers are cautioned that much of pavement design is governed by codes, specifications and practices of. One of the widespread use of bitumen is in the pavement design and construction. It is not intended as definitive treatise, and it does not encompass the design of flexible pavements. Aashtoware pavement me design is a productionready software tool to support the daytoday operations of. Collection and interpretation of pavement structural. However, use of the standards in this ac is mandatory for all projects funded under the airport. A preplanned bituminous mix design for pavement construction helps in producing a mix that is workable, durable, strong, and economical in nature. The pavement structure of the taxiway in beijing capital international airport was simplified as two layers, i. Several options are available to analyze fwd data depending on purpose.

This is an introduction to flexible pavement design for engineers. The infor mation and process given in the figure are by no means an exhaustive list of functions and responsibilities, but rather represent a basic approach to the ho listic process of pavement design. Flexible overlay pavement design example 1993 aashto. A guide to airfield pavement design and evaluation dmg27. Coefficient of drainage cd or mi cd is the coefficient of drainage for rigid pavement design used to account for improved or decreased quality of drainage. Since the roadway curves to the left, the pavement transitions from a negative cross slope to a.

Determination of bituminous overlay thickness of flexible. The tonn program may be downloaded from the pavement design software webpage. Calculation of revised thicknesses based on the kgp back software results. In this paper, attempts are made to formulate a methodology for determination of bituminous overlay thickness of flexible pavement by mechanisticempirical approach based on concentration factor. Backcalculating pavement structures fwd deflection survey. Project traffic is indicated in terms of million standard axles. Design a suitable pavement section for a design life of 15 years. Tonn2010 method evaluation of hma pavements elmod backcalculationevaluation of hma and pcc pavement layer moduli load transfer efficiency evaluation of pcc pavement joints. Calback is a sophisticated backcalculation program that contains specific features pertinent to california and is designed to work standalone, or in concert with calme. Although the fwd approach is considered a preferred nondestructive testing method that offers many advantages over laboratory m r testing, especially with its lower cost and higher testing efficiency, its key limitation lies in the back calculation process. Performs civil engineering calculations for trafficroad geometry, surveyingearthwork, pavement, concrete floors and unit c download transportation engineering software pavement calculator 2. One of the more common methods for analysis of deflection data is to backcalculate the elastic properties for each layer and provide the elastic layer modulus that are typically used for pavement evaluation and rehabilitation design.

Geodesign offers several ways to measure or estimate the resilient modulus of pavement materials. It is built upon the nchrp mechanisticempirical pavement design guide. Systematic backcalculation protocol and prediction of. Included in the book are discussions on vehicle pavement interaction, investigations by falling weight deflectometer fwd and heavy vehicle simulator hvs, and design aspects of low volume and. Vehicle damage factor based on axle load survey was 4. In this project for flexible pavement design only commercial.

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