Comparative study of concrete pavement for wheel load stress and warping stress shows that the stresses in the concrete pavement are caused by sub grade condition, pavement size, and moving loads. Figure 1 presents a cross section of a basic modern pavement system, showing the major. Significant amount of work has been presented on temperature distributions and thermal stresses in bridge decks. The effect of compressive axle pressure, axial and peak stresses on asphalt and concretecement pavement structures due to repeated traffic loading conditions on our major highways over the year have recently become research concern. Like highway pavements, city streets and local roads have higher deflections and stresses from loads applied near the edges than from loads imposed at the interior of the slab. They are 3 normal stresses s z, s r, s t and 6 shearing stresses t rz t zr, t rt t tr, and t tz t zt. Vertical stresses in subgrades beneath statically loaded flexible. If the principal stress exceeds the tensile strength of the material. Guide for design of jointed concrete pavements for streets and local roads aci 325. Notice the effect of nonlinearity in shear stresses for very thin surface layers higher values of ah 1.
Theoretical stress distribution in an elastic multilayered. Prediction of the preerosion stage of faulting in jointed. Vertical stresses in subgrades beneath statically loaded flexible pavements george f. Holewinski, seechew soon, andrew drescher, and henryk k.
In this method the tensile stresses computed in the elements of the granular material. Conventional flexible pavements are layered systems with high quality expensive materials are placed in the top where stresses are high, and low quality cheap materials are placed in lower layers. Topic 3 flexible pavement stress analysis purpose of the pavement structure. Stresses in homogeneous mass boussinesq formulated models for the stresses inside an elastic halfspace due to a concentrated load applied on the surface. When pavement compresses, then material in a pavement gets crushed and as a result rutting become visible on the top horizontal pavement. Chapter 5 discusses the design of pavements serving lighter. However, in practice, the slab size is seen to be different than the one recommended by most of the guidelines such as pca thickness design for concrete highway and street pavements, portland cement assosiation, skokie, 1984 and irc 58 guidelines for the. Onelayer theory can be applied as an approximation for a conventional flexible pavement with granular basesubbase with a thin asphaltic layer on. Vertical stresses shear stress radial stress vertical stress effects the pavement by compressing the pavement material. Development of mechanistic empirical design methods 25 5. Scribd is the worlds largest social reading and publishing site.
Stress and strain in asphalt pavements stress mechanics. Most roads found in ethiopia are flexible pavements. In the present investigation, an experimental study was conducted to evaluate the thermal stresses in rigid pavement. Stresses due to environment warping or curling stresses stresses due to temperature differential or change in humidity temperature or moisture gradient location. The equations for stresses in a semiinfinite media under infinite line load is obtained by integration of boussinesqs stress equations. For critical design, a combination of load stress, frictional stress and warping stress is considered. Maximum deviator shear stresses can be deduced easily from principal stresses. Comparison of concrete pavement load stresses at aasho road test with previous work by we r hudson s y n 0 psi s existing rigid pavement design equations spring primarily from the theories developed by mr. Lecture 2 stresses in pavements stress mechanics elasticity. The rigid pavements are made of portland cement concrete either plain, reinforced or prestressed concrete. Bending of the slab due to wheel load on temperature variation and the resulting tensile and flexural stresses. Stresses in rigid pavements principles of pavement.
Faulting is the primary distress in jointed concrete pavement jcp, which is defined as a vertical difference across a pavement joint or crack, due to the combination of the effects of ambient temperature variations, soft foundation, moisture infiltration, nonuniform base support and repeated traffic loads. In roads however the moving traffic load causes a more complex dynamic loading phenomenon and this is normally considered as 3 effects. With respect to asphalt concrete pavements, the current failure criteria used are the horizontal tensile strain at the bottom of the asphalt concrete layer and the vertical strain at the top of the subgrade layer. Various elastic theories have also been proposed for evaluating subgrade stresses beneath pavements. Analysis of rigid pavement stresses by finite element method. Introduction to stresses in flexible pavement vehicular wheel loads induce stresses in. The stresses are not transferred from grain to grain to the lower layers as in the ease of flexible pavement. The stresses as given by the analytical methods are, in general, of smaller magnitude than the observed ones in the unbonded overlay. First, twodimensional layered elastic programs offered desktop computers the ability to calculate these. Evaluation of nonuniform tyre contact stresses on thin. This chapter provides pavement design guidance for airfield pavements intended to serve airplanes with gross weights in excess of 30,000 pounds 608 kg.
Pavement analysis and design pdf download free ebooks. Pdf effect of compressive stresses on asphalt and concrete. Nonlinear temperature gradient effect on maximum warping. Full depth asphalt pavements are constructed by placing bituminous layers directly on the soil sub grade. This is why very thin asphalt pavements are prone to develop shear deformations.
Mechanistic approach requires the accurate evaluation of. Pdf analysis of stressstrain and deflection of flexible. The effects of warping stress are equal in importance to wheel load stress and. If excessive, stresses may cause pavement fatigue cracking andor surface rutting.
Stresses and strains calculated in unbound materials can be unreasonable such as unrealistically high tensile stresses at the bottom of uab due to stress sensitivity and anisotropy of the materials. Stolarski university of minnesota department of civil engineering 122 cive building 500 pillsbury dr. Joints are the discontinuities in the concrete pavement slab, and help to release stresses due to temperature variation, subgrade moisture variation, shrinkage of concrete etc. This may result in both structural and functional failure, thus causing a safety.
The warping stress results were more significant than traffic load stress. Stresses in rigid pavement and westergaards analysis stresses in rigid pavement and westergaards equations for analysis of stress at different. Nowadays, the failure of the surface of flexible pavement roads is common before the. The stresses that occur in a flexible pavement under load are quite complex. The plain cement concrete slabs are expected to take up about 45kgcm2 flexural stress. In rigid pavement the stresses are not transferred from the grain to grain to the lower layers. Kenlyer software tool is utilized to calculated accurately stresses and strains in asphaltic pavement that are ultimately used in calculating allowance for rutting and fatigue failure utilizing. Y subjects the bottom zone to tension and thus cracking. For plain concrete pavements, the spacing between contraction joints is so chosen that the stresses due to friction will not cause the concrete to crack. An experimental study and evaluation of thermal stresses. Stresses in pavements elastic halfspace solutions 1.
Considerations for sustainable longlife concrete pavements. Pavement stresses free download as powerpoint presentation. In the case of flexible pavement, the design is based on overall performance of flexible pavement, and the stresses produced should be kept well below the allowable stresses of each pavement. Cerrasco, soheil nazarian, nancy aguirre caitutc065 9.
Finite element analysis of rigid concrete pavements using everfe software. Modeling of interaction between steel and concrete in continuously reinforced concrete pavements 6. Investigation of factors related to surfaceinitiated cracks in flexible pavements final report prepared by jill m. Effect of k and h on warping stresses thickness design criteria. Stresses in fulldepth granular pavements transportation. Sudhakar reddy, department of civil engineering, iit kharagpur.
Specific chapter topics include stresses and strains in flexible pavements, stresses and deflections in rigid pavements, traffic loading and volume, material characterization, drainage design, pavement performance, reliability, flexible pavement design, rigid pavement design, design of overlays, theory of viscoelasticity, theory of elastic layer systems, superpave, pavement management systems. Minneapolis, mn 554550220 january 2003 published by. Stress based, lte faa criteria stress based, lt free edge loaded slab free edge free edge loaded slab stress stress stress stress stress lt 1 loadedslab unloadedslab deflection deflection lted loadedslab unloadedslab stress stress lte lte lte lt load transfer efficiency lte 1 in rigid pavements 2 2 3 1 689 370 154 1206 377 393 d lte l a l a. Finite element method fem is a numerical analysis technique to obtain the stress, strain and deflection of pavement layers. Effect of panel size and radius of relative stiffness on. The fwd generates a load pulse by dropping a weight. Stresses in layered systems at any point, 9 stresses exist. The difference in the magnitude of stresses is considered attributable to the manner in which the stresses are distributed in the slab through the contact area with the load. Assessment of thermal stresses in asphalt pavements due.
Analytical method usually uses layers thickness, loads, elastic modulus and. Temperature differential between the top and bottom of the slab causes curling warping stress in the pavement. Saxena and khazanovich 2 1 determination of critical bending stresses in the pcc layer with 2 asphalt overlay 3 4 5 abstract 6 7 an asphalt concrete ac overlay of a jointed plain concrete pavement jpcp is intended to. Flexible pavement deflectionsmethods of analysis and. Lecture notes ct 4860 structural pavement design design of.
The theory can be used to determine the stresses, strains, and deflections in the subgrade if the modulus ratio between the pavement an d the subgrade is close. Pdf toward using tireroad contact stresses in pavement. Pdf fatigue and rutting analysis of asphaltic pavement. Lowertrafficvolume pavements are usually not subjected to the load stresses or the pumping action associated with heavily loaded pavements. Analytical and experimental stresses in concrete pavements. There are various types of stresses yields in flexible and rigid pavements under the applied live load. Thermal stress analysis of jointed plane in concrete pavements. Due to axis symmetry, there are only three normal stresses. Nonlinear temperature gradient effect on maximum warping stresses in rigid pavements bouz1d choubane and mang tia the. Rigid pavementrigid pavement 21 rigid pavements, though costly in initial investment, are cheap in long run because of low maintenance costs, the cost of construction of single lane rigid pavement varies from 35 to 50 lakhs per km in plain area, rigid pavement have deformation in the sub grade is not transferred to subsequent layers. A halfspace has an infinitely large area and an infinite depth with a top plane on which the loads are applied. Stresses and strains in flexible pavements civil iitb. Wheel load stresses at critical points on the pavements i.
Stress and strain in asphalt pavements free download as pdf file. Assessment of thermal stresses in asphalt pavements due to. The first detailed study of stresses related with temperature in rigid concrete pavements was published by westergaard. Aci spring 20 convention minneapolis, minnesota april 15, 20 considerations for sustainable longlife concrete pavements shiraz tayabji fugro consultants, inc. The top most paved surface of such type of pavement is flexible, that is extremely dependent on the underlying layers. Chapter 1 introduces the historical development of pavement design, the major road tests, the various design factors, and the differences in design concepts among highway pavements, airport pavements, and railroad trackbeds.
Different types of joints are required like expansion and contraction. Vesic, respectively, professor and asso ciate professor of civil engineering, georgia institute of technology fullscale static load tests have been made of single, dual, and dual tandem truck tire loads on flexible pavements to. The pavement structure is a combination of subbase, base course, and surface course placed on a subgrade to support the traffic load and distribute it to the roadbed. The model is based on the interfacial friction stress transmitted between slab and base when concrete shrinks. A falling weight deflectometer fwd is a device designed to simulate deflection of a pavement surface caused by a fastmoving truck. The simplified stress equation for a uniform contact.
Interior loading edge loading corner loading shrinkageexpansion stresses b. Even more research publications are found in thermal action of pavements. Nov 05, 2016 rigid pavementrigid pavement 21 rigid pavements, though costly in initial investment, are cheap in long run because of low maintenance costs, the cost of construction of single lane rigid pavement varies from 35 to 50 lakhs per km in plain area, rigid pavement have deformation in the sub grade is not transferred to subsequent layers. Statistical analysis of stresses in rigid pavement c international journal of civil and environmental engineering 6 2012 265. In pavements design, temperature differential is having dominant role across the depth at critical locations. In all of these the pavement is represented by a simplified. Stresses in flexible pavement rutting engineering intro. Download pdf of pavement design note civil engineering offline reading, offline notes, free download in app, engineering class handwritten notes, exam notes, previous year questions, pdf free download.
This load pulse is transmitted to the pavement through a 300millimeter mm diameter circular load plate. The first one described stresses and deflections in the pavement caused by wheel loads. Effect of tire pressure, total load, and wheel configuration. Although rigid pavement stresses have been routinely calculated since the 1920s, routine calculation of flexible pavement stresses is a more recent development. Analysis of stress, strain and deflection of pavements using finite element method abstract. Stresses and strains in road structures roadex network. Rigid pavements are those which posses note worthy flexural strength or flexural rigidity. Pavement design note pdf download lecturenotes for free. Material containing subgrade and environment condition are also responsible for stresses in the pavement.
The second paper studied stresses under various temperatures and divided them into two components. Lecture 2 stresses in pavements free download as pdf file. Theoretical stress distribution in an elastic multi. Since this is a problem of plain strain these stresses are independent of poissons. On the basis of these combined effects, the progression of. In the special case of no shear stresses as shown in figure 2, the normal stress become principal stresses.
Stresses in rigid pavements principles of pavement design. Boussinesq equations are developed for computing stresses in a homogeneous, isotropic and elastic media due to a point load at the surface. Romanian journal of transport infrastructure jorge pais, the reflective cracking in flexible pavements article no. Investigation of factors related to surfaceinitiated. Pavement analysis and design transportation research board. May 17, 2018 design of concrete pavements is carried out with the help of available guidelines that are generally based on single size of slab panel. Analysis of shrinkageinduced stresses in concrete pavements. Stresses and strains the common analytical method to model pavement traffic load response is stress strain analysis.
The literature basically subdivides itself into two major areas of research. At each point in the system there exists a certain orientation of the element such that. In this paper, the effect of pavement material properties as well as slabbase interfacial characteristics on the shrinkageinduced stresses in concrete pavements is investigated by application of an analytical shrinkage stress model. The friction between a concrete slab and its foundation causes tensile stress.
Vertical stresses in subgrades beneath statically loaded. Nov 19, 2008 lecture series on introduction to transportation engineering by prof. Seasonal climate changes influences the characteristic of pavement track. Stresses are the response of loading on the pavement. Introduction omplex analysis of pavements is often very difficult for design practice. Analytical method usually uses elastic modulus and poissons ratio of the pavement materials as design parameters. Chapter 2 discusses stresses and strains in flexible pavements. Rheological properties of materials, cracking, joints, contact of concrete slabs in joints, contact of. Inthefinalanalysis,stresses,andthepavementsabilitytoresist thesestresses,determinethepavementsloadcarryingcapacitypavement deflsctionhas a definiterelationtostresses and, foragiven load, gives. Effect of modulus of subgrade reaction on thickness. Analysis of stressstrain and deflection of flexible pavements. Rutting is the depression in the surface of wheel path. Toward using tireroad contact stresses in pavement design and analysis article pdf available in tire science and technology 404. Comparison of concrete pavement load stresses at aasho.
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