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. Everseries for short contains three independent programs. In this study, a twodimensional finite element model was developed, using abaqus software, in order to investigate the impact of static repeated. 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. The program calculates stresses, strains, and displacements in a layered elastic halfspace. Multilayer elastic program for backcalculating layer moduli in.
Oct 19, 2017 first introductory video of the ellea1 worksheet. 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. 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 calculations were carried out using typical loading configurations, layer thicknesses and material moduli found in. Layered elastic models assume that each pavement structural layer is homogeneous, isotropic, and linearly elastic. Linear elastic response assumptions are valid when there is no discontinuity, for example at joints in rigid pavements, or cracks. Scholars research library layered elastic analysis and. The layered elastic analysis software eversress sivaneswaran et al, 2001 was employed in the analysis. Your whole company is connected in one place, knowing status of every project thats open, won, lost, cancelled, and onhold. Slab on elastic solid and slab on denseliquid foundation analysis of rigid pavements, publication no. Backcalculation procedures and user guide for software programs and. For the single layer rigid pavement, a software platform streetpave 12. 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. Calculation of the elastic moduli of a two layer pavement system from measured surface deflections by frank h. Use of hwd deflection, backcalculation, and multilayer. Evaluation of poissons ratio for use in the mechanistic.
Winjulea this is a demo version of the software, which is under development for the aashto 2002 design guide. This function finds the stresses,strains and deflections of pavement or soil layers subjected to circular loading. In that model, the huetsayegh behaviour is taken into account with its equivalent elastic modulus at the 15c french average temperature and a 10 hz frequency. 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. Several different test methods have been developed to determine the elastic modulus of pavement layers. In other words, it is the same everywhere and will rebound to its original form once the load is removed. 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. Fatigue and rutting lives in flexible pavement sciencedirect. The materials used in each layer are defined by elastic parameters i. Burmister 8 laid much of the groundwork for solution of elastic layers on a semi infinite elastic 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.
Modeling analysis of games and kenlayer for highway. Daps deflection analysis of pavement structures is a backcalculation software that also provides layered elastic analysis for pavement. Index determination of inplace elastic layer modulus. A new technique for the estimation of the elastic moduli of. Elastic layer analysis chevronx is used to compute pavement responses. Modeling analysis of games and kenlayer for highway pavement.
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. National pavement performance data base, and will ultimately be available to all researchers to use as they see fit. The copy posted here is the one available on the nhi course 1064 cd fhwa, april 2002. Viscoelastic modelling for asphalt pavements software. Elastic modulus of asphalt layer e1 could be determined as a function of pavement temperature according to the following equation. It implements advanced design procedures based on layered elastic theory developed under the sponsorship of the federal aviation administration faa. The performance models used to predict rut depth and fatigue life were developed using field data in michigan. 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. Scholars research library layered elastic analysis and design.
Moore research report number 1236 a system analysis of pavement design and research implementation research study number 1869123 conducted in cooperation with the. Calculation of the elastic moduli by research report. The calculations were carried out using typical loading configurations, layer thicknesses and material moduli found in the northern periphery. However, most elastic layer computer software applications have been developed for mainframe computers.
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. 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. The washington state dot has developed a layered elastic based software package called the everseries pavement analysis programs sivaneswaran, pierce and mahoney, 2001 1. Fhward00086, federal highway administration, washington, dc, december 2001. Classical pavementsubgrade system analysis is based on multilayer linear elastic analysis, infinite pavement layer dimensions and a semiinfinite subgrade. 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. A toolbox that allows me to analyse various forms of pavement data, run pavement designs, and present all findings on a single stripmap. A new elastic response analysis program has been developed based on the burmister mlet theory to calculate the response of flexible pavement structures. The pavement temperature in egypt ranges from 10 c and 50 c. Stresses and strains in road structures roadex network. The french pavement design method consists in a pavement mechanistic analysis based on the burmister multilayer elastic model 1943 lcpc software alize 1982. Measurements of the stiffness and thickness of the pavement. 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. Multilayer elastic analysis file exchange matlab central.
For the elastic analysis of the pavement structure shown in figure 1, the different layers are assumed to be homogeneous and isotropic. A mechanistic computer program pavement interactive. Backcalculation of layer parameters for ltpp test sections. Pavement structural capacity is often indicated by the elastic modulus of the pavement layers, e, for the bound materials e. 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. 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 solutions that calculate stresses, strains, and displacements in pavement structures caused by surface loading have been in existence for several years. Two sets of equations have been found best relate the elastic moduli of the upper pavement layers to the surface deflections. Example on how to use the function is also provided. Layered elastic pavement analysis code ellea1 part 1. Weslea waterways engineering station elastic layer analysis pavement suite. 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. Flexible pavement mechanistic models pavement interactive.
Multilayer elastic theory mlet is often preferred over other methods such as the finite. Leaf a new layered elastic computational program for faa. Pavement design models for roads vti, statens vag och. In place elastic layer moduli from deflection basins for forensic investigations or rehabilitation design.
Multilayer elastic program for backcalculating layer moduli. Longterm pavement performance program determination of inplace elastic layer. The performance and usable life of an asphalt pavement mainly depend on the interlayer bonding state. Introduction to the michigan flexible pavement design system. Comparison of static and dynamic backcalculation of flexible. 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. 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. Multilayer pavement design approach for effective utilization of off. 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.
Layered elastic theory let has been used successfully for many years in the design and analysis of asphalt pavements. Calculation of the elastic moduli by research report number 1236. Pavement designanalysis software university of idaho. In contrast to plate theory, layered theory permits the complete state of stress to be determined at any point in the pavement structure. The basic principle for the elastic layered design procedure is to limit the tensile. 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. An attractive feature of this approach is its ability to represent the layeredpavement structure with variable interface conditions between consecutive layers. 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. Techbrief determination of inplace elastic layer modulus. Pavement layers built specifically for the pavement industry. Trb conducted a webinar on tuesday, october 25, 2016 from 2. It is based on elastic multilayer theory and can be applied in multilayer pavements under single or dual wheel.
Fast layered elastic response program for the analysis of. An attractive feature of this approach is its ability to represent the layered pavement structure with variable interface conditions between consecutive layers. Pavement thickness design evolves with latest software. In other words, it is the same everywhere and will rebound to its original.
However, most elastic layer computer software applications have been developed for mainframe. 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. 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. Several computer programs bisar, weslea, and julea for the analysis of pavement systems were developed on the basis of let. 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 resilient modulus is obtained through correlation with cbr. The program calculates the response of road structures to traffic loading. The most wonderful thing about rubicon toolbox, as the name suggests, is the holistic approach to pavement engineering. Each layer is homogeneous, isotropic, and linearly elastic with an elastic modulus e and a poisson ratio, 2. It reports the layer of failure and residual life by utilizing the lcca module which allows the user to select the optimum rehabilitation alternatives. The software allows structures to be analyzed as linear elastic layer or nonlinear elastic unbound layer. 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. Elmod analyzes the pavement response from the fwd and hwd by determining the modulus, stress and strain of each significant layer.
Simulation dual load fwd systems for determination of. 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. The roadex pavement stress and strain calculation demo. Mechanisticallybased pavement thickness design methods are even more complicated to use and have, to date, required sophisticated computer software and more specialized training. The software is simply a dream for a pavement engineer. Classical pavement subgrade system analysis is based on multi layer linear elastic analysis, infinite pavement layer dimensions and a semiinfinite subgrade. The origin of layered elastic theory is credited to v. Multilayer design requires an integrated assessment of each layers elastic. 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. 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. Tm 5822 pavement design for roads, streets, and open. The layered elastic analysis software eversress sivaneswaran et al.
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