Determine insitu structural capacity of the pavement structure and subgrade soil conditions backcalculation procedure to determine youngs modulus of elasticity for pavement materials, using measured surface deflections by working elastic layer theory backwards elastic layer analysis. To design an asphalt pavement, tensile fatigue stress of the asphalt layer and permanent. In the current release of usaces pavement transportation computer assisted structural engineering pcase software, windows version of julea winjulea has been used for the multi layer elastic. Pavement designanalysis software university of idaho. The program calculates the response of road structures to traffic loading.
Multilayer elastic theory mlet is often preferred over other methods such as the finite element method, due to its computational performance for repeated applications. Army engineer waterways experiment station has been developing methodology by which airportairfield pavements can be designed based on elastic layered analysis for the federal aviation administration, the u. Measurements of the stiffness and thickness of the pavement. Pavement design engineers in state and federal agencies have the necessary training and resources, but often city, county and private consulting engineers and. Chevpc this is a pc version of the fortran program of the chevron elastic layer analysis program. One of the key components in analysing pavement structural behaviour is the response model which is used to estimate the stresses, strains and displacements of the pavement structure subjected to the existing traffic, taking into account the material properties and prevailing environmental conditions. Multilayer elastic program for backcalculating layer moduli. The roadex pavement stress and strain calculation demo. Burmister 8 laid much of the groundwork for solution of elastic layers on a semi infinite elastic subgrade.
Elastic layer moduli that are basinspecific from the evercalc or modcomp software packages for all test sections rigid, flexible, and composite included in the ltpp program. Slab on elastic solid and slab on denseliquid foundation analysis of rigid pavements, publication no. It is based on elastic multilayer theory and can be applied in multilayer pavements under single or dual wheel. The basic principle for the elastic layered design procedure is to limit the tensile.
Flexible pavement mechanistic models pavement interactive. During the past two decades, finite element fe techniques were successfully used to simulate different pavement problems that could not be modelled using the simpler multi layer elastic theory. Burmister first developed solutions for a twolayer system and then extended them to a threelayer system with the following basic assumptions. It implements advanced design procedures based on layered elastic theory developed under the sponsorship of the federal aviation administration faa. Design is the next generation of aashtoware pavement design software. Two sets of equations have been found best relate the elastic moduli of the upper pavement layers to the surface deflections. An attractive feature of this approach is its ability to represent the layeredpavement structure with variable interface conditions between consecutive layers. Stresses and strains in road structures roadex network. Layered elastic pavement analysis code ellea1 part 1. Techbrief determination of inplace elastic layer modulus.
Average and standard deviation of the elastic layer moduli for a test day all rigid, flexible, and composite test sections, lane number, and drop height. This procedure incorporates the use of pavement deflections measured using a falling weight deflectometer, layered elastic theory stress and strains, seasonal variations in the base and subgrade materials due to temperature, and truck loading esal to determine overlay thickness. Use of hwd deflection, backcalculation, and multilayer. Fatigue and rutting lives in flexible pavement sciencedirect. The origin of layered elastic theory is credited to v. Elmod analyzes the pavement response from the fwd and hwd by determining the modulus, stress and strain of each significant layer. Layered elastic theory let has been used successfully for many years in the design and analysis of asphalt pavements. In the near term, shrp will apply a backcalculation procedure to these deflection data in order to estimate the in situ elastic moduli of the pavement layer materials. The most wonderful thing about rubicon toolbox, as the name suggests, is the holistic approach to pavement engineering.
May 01, 2002 the development environment for leaf was a computer program for backcalculating the layer modulus values of pavement structures represented by linear elastic layers of infinite horizontal extent. Oct 19, 2017 first introductory video of the ellea1 worksheet. In contrast to plate theory, layered theory permits the complete state of stress to be determined at any point in the pavement structure. Modeling analysis of games and kenlayer for highway pavement. In the current release of usaces pavementtransportation computer assisted structural engineering pcase software, windows version of julea winjulea has been used for the multilayer elastic. Jan 21, 20 multilayer elastic theory mlet is often preferred over other methods such as the finite element method, due to its computational performance for repeated applications. The layered elastic analysis software eversress sivaneswaran et al. Scholars research library layered elastic analysis and design.
Ledfaa handles new and overlay design of both flexible and rigid pavements. The performance models used to predict rut depth and fatigue life were developed using field data in michigan. Introduction to the michigan flexible pavement design system. In other words, it is the same everywhere and will rebound to its original form once the load is removed. The software is simply a dream for a pavement engineer. A new elastic response analysis program has been developed based on the burmister mlet theory to calculate the response of flexible pavement structures.
Multilayer elastic analysis file exchange matlab central. The calculations were carried out using typical loading configurations, layer thicknesses and material moduli found in. However, most elastic layer computer software applications have been developed for mainframe computers. Pavement design models for roads vti, statens vag och. Evaluation of poissons ratio for use in the mechanistic. Pavement thickness design evolves with latest software. Fast layered elastic response program for the analysis of. The french pavement design method consists in a pavement mechanistic analysis based on the burmister multilayer elastic model 1943 lcpc software alize 1982. Weslea waterways engineering station elastic layer analysis pavement suite.
Rigid pavements are constructed by portland cement concrete pcc and should be analyzed by plate theory instead of layer theory, assuming an elastic plate resting on viscous foundation. Winjulea this is a demo version of the software, which is under development for the aashto 2002 design guide. A new technique for the estimation of the elastic moduli of. Your whole company is connected in one place, knowing status of every project thats open, won, lost, cancelled, and onhold. The materials used in each layer are defined by elastic parameters i. Designs the thickness of the ac layer in a new pavement, or designs the overlay thickness for an existing pavement, to meet userspecified rut and fatigue limits. Classical pavement subgrade system analysis is based on multi layer linear elastic analysis, infinite pavement layer dimensions and a semiinfinite subgrade. During the past two decades, finite element fe techniques were successfully used to simulate different pavement problems that could not be modelled using the simpler multilayer elastic theory. Everseries for short contains three independent programs. Each layer is homogeneous, isotropic, and linearly elastic with an elastic modulus e and a poisson ratio, 2. An attractive feature of this approach is its ability to represent the layered pavement structure with variable interface conditions between consecutive layers. A mechanistic computer program the washington state dot has developed a layered elastic based software package called the everseries pavement analysis programs sivaneswaran, pierce and mahoney, 2001 1. The requirements for calling the dll from an application are illustrated by code excerpts from the backcalculation program. In this study, a twodimensional finite element model was developed, using abaqus software, in order to investigate the impact of static repeated.
The stresses and strains for the demo were precalculated using bisar software based on linear elastic theory. In other words, it is the same everywhere and will rebound to its original. Scholars research library layered elastic analysis and. Backcalculation of layer parameters for ltpp test sections. The pavement temperature in egypt ranges from 10 c and 50 c. Backcalculation procedures and user guide for software programs and. Multilayer elastic theory mlet is often preferred over other methods such as the finite. Layered elastic models assume that each pavement structural layer is homogeneous, isotropic, and linearly elastic. National pavement performance data base, and will ultimately be available to all researchers to use as they see fit. Tm 5822 pavement design for roads, streets, and open. Several computer programs bisar, weslea, and julea for the analysis of pavement systems were developed on the basis of let.
Example on how to use the function is also provided. A toolbox that allows me to analyse various forms of pavement data, run pavement designs, and present all findings on a single stripmap. Highperformance layered elastic analysis program layered elastic theory let has been used successfully for many years in the design and analysis of asphalt pavements. The resilient modulus is obtained through correlation with cbr. Simulation dual load fwd systems for determination of. The washington state dot has developed a layered elastic based software package called the everseries pavement analysis programs sivaneswaran, pierce and mahoney, 2001 1. Due to the inadequacy of measuring the pavement layer thickness by sasw, a resonance search of the pavement layer is used to ensure that the thickness of the pavement layer is determined accurately. Calculation of the elastic moduli of a two layer pavement system from measured surface deflections by frank h. This function finds the stresses,strains and deflections of pavement or soil layers subjected to circular loading. Dec 08, 2010 figure 1 illustrates a typical pavement structure. Mechanisticallybased pavement thickness design methods are even more complicated to use and have, to date, required sophisticated computer software and more specialized training.
For the single layer rigid pavement, a software platform streetpave 12. In place elastic layer moduli from deflection basins for forensic investigations or rehabilitation design. A mechanistic computer program the washington state dot has developed a layered elasticbased software package called the everseries pavement analysis programs sivaneswaran, pierce and mahoney, 2001 1. 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. A layered elastic model can compute stresses, strains and deflections at any point in a pavement structure resulting from the application of a surface load. The calculations were carried out using typical loading configurations, layer thicknesses and material moduli found in the northern periphery.
The software allows structures to be analyzed as linear elastic layer or nonlinear elastic unbound layer. Modeling analysis of games and kenlayer for highway. Recently, a deflection analysis of pavement structures daps software has been developed, which enables the rapid calculation of layer stiffness moduli using a singular decomposition technique. The copy posted here is the one available on the nhi course 1064 cd fhwa, april 2002. Multilayer pavement design approach for effective utilization of off. Multilayer elastic program for backcalculating layer moduli in.
Pavement layers built specifically for the pavement industry. Ltpp computed parameter tables the backcalculated elastic layer modulus values, simulated pavement structures for each ltpp test section, and other related parameters were integrated into the cpts of the ltpp database and are now available for use. Figure 2 elastic layer model diagram for a typical pavement section figure 3 screenshot of the poissons ratio input screen for asphalt materials figure 4 original dataset used to develop poissons ratio prediction equation constants figure 5 screenshot of material data input for unbound materials. Classical pavementsubgrade system analysis is based on multilayer linear elastic analysis, infinite pavement layer dimensions and a semiinfinite subgrade. Vti has developed the calculation program erapave elastic response analysis of pavement based on the mlet multilayer elastic theory. Comparison of static and dynamic backcalculation of flexible. The program calculates stresses, strains, and displacements in a layered elastic halfspace. In rigid pavement, load is distributed by the slab action, and the pavement behaves like an elastic plate resting on a viscous medium figure 4. A mechanistic computer program pavement interactive. Trb conducted a webinar on tuesday, october 25, 2016 from 2. Multilayer design requires an integrated assessment of each layers elastic. The performance and usable life of an asphalt pavement mainly depend on the interlayer bonding state.
The back analysis algorithm solves for both a two layer elastic system and the thickness of subgrade, or a three layer elastic system and the thickness. Moore research report number 1236 a system analysis of pavement design and research implementation research study number 1869123 conducted in cooperation with the. Viscoelastic modelling for asphalt pavements software. It reports the layer of failure and residual life by utilizing the lcca module which allows the user to select the optimum rehabilitation alternatives. However, most elastic layer computer software applications have been developed for mainframe. Linear elastic response assumptions are valid when there is no discontinuity, for example at joints in rigid pavements, or cracks. For the elastic analysis of the pavement structure shown in figure 1, the different layers are assumed to be homogeneous and isotropic. Calculation of the elastic moduli by research report. Longterm pavement performance program determination of inplace elastic layer.
Index determination of inplace elastic layer modulus. The development environment for leaf was a computer program for backcalculating the layer modulus values of pavement structures represented by linear elastic layers of infinite horizontal extent. Fhward00086, federal highway administration, washington, dc, december 2001. Elastic modulus of asphalt layer e1 could be determined as a function of pavement temperature according to the following equation. Use of linearelastic layered theory for the design of. Sasw is used to evaluate the strength of the pavement system and concrete structure using surface wave velocity to determine the elastic properties. The layered elastic analysis software eversress sivaneswaran et al, 2001 was employed in the analysis. Leaf a new layered elastic computational program for faa. Calculation of the elastic moduli by research report number 1236.
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