The Second International Conference on Civil Engineering Energy and Environment. a Flexible pavements is the surfacing and road base materials bound with bitumen binder overlay granular. unbound or cement bound material, b Rigid pavements Pavement quality concrete used for the combined surfacing and road base overlays granular. cement bound material The concrete may be reinforced with steel. Stresses are developed in rigid pavements as a result of several factors including the action of traffic wheel. loads the expansion and contraction of the concrete due to temperature changes yielding of the sub base or. subgrade supporting the concrete pavement and volumetric changes For example traffic wheel loads will induce. flexural stresses that are dependent on the location of the vehicle wheels relative to the edge of the pavement. whereas expansion and contraction may induce tensile and compressive stresses which are dependent on the range. of temperature changes in the concrete pavement These different factors that can induce stress in concrete. pavement have made the theoretical determination of stresses rather complex requiring the following simplifying. assumptions, A study at University of Minnesota 10 was reported The goal is to develop an analysis method combined. with a non destructive testing procedure for the evaluation of load transfer for joints in concrete pavements The. basic analysis involved a frequency response analysis by dynamically loading the joints A three dimensional finite. element method was used to analyze various joint conditions for load transfer ranging from full to partial load. Stoner reported on research plans to develop a3Dfiniteelement program to study concrete pavements and to. simulate truck actions The objectives were to develop a truck simulation model to develop a model for doweled. concrete pavement and to implement these two models in an interactive fashion The analysis was intended to. obtain performance relationships based on damages predicted by the program Actual damages recorded on. Interstate 80 were used to verify the predictions 9. Barksdale reported a study of compressive stress pulse at different depths in a flexible pavement Loadings. for variable vehicle speed were considered A series of pseudo dynamic linear and nonlinear elastic analyses were. conducted It was concluded that linear elastic finite element was adequate for the analysis Dynamic effects. including damping and inertial forces were neglected in the study and hence a correction factor was introduced in. order to match the results of AASHTO road tests 12. Paterson reported on the finite element analysis of an asphalt overlay of a cracked airport concrete pavement. in combination with a thin interlayer of elastomeric asphalt Predictions were obtained in terms of an equivalent. thickness of asphalt overlay which yields the same performance of the inter layer system 14. Measured pavement deflections in combination with a three dimensional finite element analysis were used to. evaluate overlay requirement and pavement performance in a study reported by Bala and Kennedy 1986 11 The. response predictions of the finite element analysis were calibrated against surface deflections measured by a. deflector graph The calibration process included adjustments determined through a parametric study The. properties assumed for the materials in the analysis were compared with laboratory determined dynamic test results. for in situ samples, Zaghloul and White 1993 a reported results of a three dimensional dynamic finite element analysis of flexible. pavements The analysis simulated actual truck loads moving at different speeds Linear and non linear material. properties were used to model different paving materials and subgrades An extended Drucker Prager model was. used to model granular materials and an extended Cam Clay model was used for the clayey soils Asphalt mixtures. were modeled as viscoelastic materials Including these material models lead to the capability to obtain accurate. elastic and plastic pavement responses With this capability they are able to predict or to interpret pavement. performances under a variety of loading conditions and for different material characteristics 13. The 3D finite element analysis was verified by comparing the predictions with a multi layer elastic system. assuming linear elastic properties and static loads A linear correlation was found between the results obtained by. the finite element predictions and the multi layer elastic analysis To verify the dynamic nonlinear finite element. analysis the results were compared with actual measurements of pavement deflection Agreementat95 confidence. level was obtained between the deflection predictions and the measurements. A sensitivity study was performed by using the 3D finite elements for the effect of cross section and load. parameters on pavement responses It was found that the speed of moving vehicle load has a significant effect on. elastic and plastic pavement responses The confinement of shoulders has the effect of reducing pavement. deflections A crack along the pavement shoulder joint results in an increase in pavement deflection Temperature. affects the asphalt layer and hence the overall pavement responses The loading time and the rate of loading were. found to have significant effect also When a subgrade is subjected to a high stress level higher than its yield stress. rutting increases significantly, The Second International Conference on Civil Engineering Energy and Environment. The primary objective is to develop a three dimensional finite element program for the analysis of general. pavement problems The program considers conventional static and dynamic loading conditions including. harmonic excitations pulse loadings ramp loadings and multiple step loadings Provisions are made for the. convenience of handling non conventional loadings such as falling weights and general time dependent load. histories generated from non destructive testing used for pavement structural evaluation One particular important. aspect of the programs to develop a general material library Common soil and asphalt material models in the form. of linear and nonlinear elastic materials elastic plastic materials with hardening and viscoelastic materials are. included in the material library,2 Materials and Methods. 2 1 Finite element method, The finite element method is a very world leading structural tool but several factors should be kept in mind. when performing analysis First the method is an approximate analytical procedure whose accuracy will usually. depend on the level of discretization of the mesh Second the accuracy of the results will depend on whether or. not the major influences of the problem behavior are included in the analytical idealization Finally considerable. skill and knowledge is still required to interpret the finite element simulations properly and make significant and. APDL stands for ANSYS Parametric Design Language a scripting language that you can use to automate. common tasks or even build your model in terms of parameters variables APDL also encompasses a wide range. of other features such as repeating a command macros if then else branching do loops and scalar vector and. matrix operations particularly worth mentioning of which is macro You can record a frequently used sequence. of ANSYS commands in a macro file these are sometimes called command files Creating a macro enables to in. effect create your own custom ANSYS command In addition to executing a series of ANSYS commands a macro. is called GUI graphical user interface functions, The modelling of the structure involved the creation of the geometrical model the assignment of the materials. properties mesh contacts the appropriate boundaries and the loadings is done using ANSYS The finite element. model is presented in Figure 1 and was meshed with 4560 of solid elements and 5440 nodes in ANSYS Pre. Fig 1 Model of road pavement,2 2 Material properties. Material properties used for performing ANSYS analysis of the road pavement and each layers model were. obtained from the literature PALSTIC KINEMATIC material type16 was used to represent the surface and. subsurface of superstructure of the road pavement i e Reinforced Cement Concrete material model Finally. modelling and representing the foundation soil subgrade and formation soil was modelled using VISCOELASTIC. MATERIALS material type 24 The vehicle load is applied as concentrated load 7Mpa for each of two vehicles. 3 Finite element analysis result and discussion,3 1 Pavement deformation. The Second International Conference on Civil Engineering Energy and Environment. The total deformation of road pavement was calculated by ANSYS along successive structures including. surface subsurface capping and subgrade respectively The maximum deformation of the vehicle load is. equivalent to 6 mm From the calculated result the analysis of deformation is very high and leads to deterioration. of the road The modelling result is depicted in the following Fig 2. Fig 2 Road pavement deformation,3 2 Road pavement stress and strain state. Contour stress and plastic strain were also presented as the result of the analysis of finite element simulation. The study gives information about the behavior of the road pavement stress strain state The maximum stress from. model analysis is 0 4MPa and similarly the maximum strain is 2mm These result indicate that the impact of the. vehicle load under the road pavement structure Therefore the result is a good input for maintenance plan and. materials selection Figure 3a and 3b is depicted the stress and strain state. 3 3 Road pavement shear stress, The finite element analysis of ANSYS Element code could analyze the shear stress of the road pavement under. the impact of the vehicle load The shear stress has significant influence in road pavement deterioration and failures. of the subgrade to carry the stress of superstructures The study analysis result showed the shear stress that about. Fig 3a Stress state, The Second International Conference on Civil Engineering Energy and Environment. Fig 3b Strain state,Figure 4 Shear stress,4 Conclusion and Recommendation. All of the effort made in this research is to develop the applicable procedures for evaluating pavement layer. conditions from the geometry and material properties of road pavement The characteristics of the road pavement. under vehicle load are acquired through numerical simulation when vehicles pass through the pavement under. axial load with different layers This research can provide reference for the improvement of road pavement and. materials design, The analysis result showed that the vertical deformation of the road pavement and stress strain state the shear. stress to the vehicle load response of the structures The result can be used as pavement vehicle road design. response with finite element model using ANSYS finite element code Therefore the method can be considered as. one of the methods to calculate the vehicle load response of road pavement. References, 1 K P Biligiri Effect of pavement materials damping properties on tire road noise characteristics Journal of. Construction and Building Materials 2013 PP 222 232. The Second International Conference on Civil Engineering Energy and Environment. 2 P Selvi Fatigue and rutting strain analysis on lime stabilized subgrades to develop a pavement design chart. Journal of Transportation Geotechnics 2015 PP 86 98. 3 M A P Taylor M L Philp Investigating the impact of maintenance regimes on the design life of Road. Pavements in a Changing Climate and The Implications Journal of Transport policy 2015 PP 117 135. 4 A Adel A Azzawi Finite element Analysis of Flexible Pavements Strengthened with Geogrid ARPN Journal. of Engineering and Applied Sciences 2012, 5 H Behbahani S A Sahaf Designing a Mathematical Model for Predicting the Mechanical Characteristics of. Asphalt Pavements Using Dynamic Loading, 6 M I Khan M A Qadeer A B Harwalkar Mechanistic Analysis of Rigid Pavement for Temperature Stresses. Using Ansys IOSR Journal of Mechanical and Civil Engineering IOSR JMCE 2014 PP 90 107. 7 J A Boateng J Maina Permanent Deformation Testing for a new South African Mechanistic Pavement Design. Method Journal of Construction and Building Materials 2012 PP 541 546. 8 P Mackiewicz Thermal Stress analysis of Jointed Plane in Concrete pavements Journal of Applied Thermal. Engineering 2013 PP 169 1176, 9 Stoner T W Bhatti M A Kim S S Kou J K Milinas Vega I and Amhof B Dynamic Simulation Methods. for Evaluating Motor Vehicle and Roadway Design and Resolving Policy Issues Iowa University Public Policy. Center Iowa City Iowa January 1990, 10 Koubaa A Krauthammer T Numerical Assessment of Three Dimensional Rigid Pavement Joints Under. Impact Loads MN RD 91 03 Minnesota Department of Transportation Maplewood Minnesota August 1990. 11 Bala K V and Kennedy C K the Structural Evaluation of Flexible Highway Pavements Using the. Deflectograph Proceedings 2nd International Conference on the Bearing Capacity of Roads and Airfields. Plymouth England September 16 18 1986, 12 Barksdale R D Compressive Stress Pluse Tunes in Flexible Pavement for Use in Dynamic Testing Highway. Research Record No 345 Highway Research Board Washington D C and January 1971 PP 32 44. 13 Paterson W D O Design Study of Asphalt Membrane Overlay for Concrete Runway Pavement. Transportation Research Record No 930 Transportation Research Board Washington D C January 1983 PP. 14 Zaghloul S and White T D Use of a Three Dimensional Dynamic Finite Element Program for Analysis of. Flexible Pavements Submitted to Transportation Research Board National Academy of Sciences Washington.
The role of microRNA in regulation of lineage-specific gene expression through the cell cycle by Bryony Jane Graham A thesis submitted to Imperial College London for the degree of Doctor of Philosophy MRC Clinical Sciences Centre Imperial College School of Medicine May 2012 . 2 I, Bryony Jane Graham, declare that the work presented in this thesis is my own, and that any work carried out by ...
and pencil, or on a computer using a spreadsheet program like Excel, or with a financial application like Quicken or QuickBooks. Many times churches with small annual incomes feel it is not necessary to have an annual budget. But neither the size of the church nor the size of the income should be the determining factor. In
ELSA 7 Unit 4 Interpersonal & Group Dynamics 3 POSSIBLE TOPICS Topic In this unit, learners explore interpersonal communication and group dynamics in various contexts relevant to their needs and lifestyles. These contexts and topics could include any of the following:
Interpersonal and Group Process Approaches 1- Understand the diagnostic issues associated with interpersonal relations and group dynamics interventions. 2- Illustrate the principles of the process consultation intervention. 3- Describe the process of third-party conflict resolution.
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