Composite columns are frequently used in constructing high-rise structures because they can minimize the size of the building's columns while increasing the floor plan's usable space. This study aims to create a nonlinear 3D finite element model for square composite columns designed for solid and hollow columns with various multi-skin tubes subjected to loads at eccentricities of (30 and 60) mm, compressive strength, and mesh size using the ABAQUS software. The comparison was based on the experimental data of six references of composite columns. While the compressive strength of concrete increases, the stiffness of the composite column rise. The ratio of concrete compressive strength values for composite column increased by (0, 12.3, 17.8, and 26.7 percent) for (fc'=25, 31.96, 35, and 40) MPa, respectively. The results of the different mesh sizes (20, 40, and 60) mm are showing; The experimental results and the finite element solution developed using the (20 X20) mm element correspond well. The nonlinear finite element analysis method was used, and the finite element outputs results were confirmed to be in favorable agreement with the experimental data
This paper investigates the results of finite element analysis for three proposed full-scale two-way slabs. The aim of this study is to use finite element method (FEM) by using ANSYS-v15 program to analyze the proposed slabs and study the flexural behavior , especially load-deflection relationship and ultimate strength. Some parametric studies on these works are also done to cover the effect of some important parameters on the ultimate load capacity and deflection. Proposed slabs are divided into three groups with different dimensions to study the effect of using continuous large spans on the structural behavior of two-way ribbed (waffle) slabs as compared to solid slabs. In all three groups, each slab consists of three by three panels supported by concrete columns at corners. For the first group, when the void ratio (the ratio of volume of voids between ribs to total volume of ribbed slab) increases, the stiffness of waffle slab also increases. Increasing stiffness for waffle slab is continued up to some limit, and then will decrease with increasing void ratio. The best case in this example occurs when the void ratio equal to (0.667) which gives increase in stiffness of (0.347) as compared to solid slab with the same thickness. The results of ANSYS analysis shows that the best percentage of increase in deflection is (51%) with decreasing in concrete volume of (59%) for long to short span ratio of (1.5) and (300)mm thickness. For the third group of proposed models, the stiffness of two-way ribbed (waffle) slab is higher than the solid slab which has the same volume of concrete. The displacement of two-way ribbed (waffle) slab in the elastic range (at first crack ) is lower than the solid slab. In this manner, it will give the maximum reduction in concrete weight with higher thickness.
ABSTRACT:The gypseous soils are distributed in many regions in Iraq and other countries. Therefore, it is necessary to study the behavior of such soils due to the large damages that affects the structures founded and constructed in or on it.This research is concerned with studying the effect of leaching soil process on the stability of an embankment erected on foundation gypseous soil. The finite element method is adopted in this research. The analyses carried out using a nonlinear, increment, and stress-dependent finite element computer program. The hyperbolic stress-strain parameters used in the finite element analyses are estimated by the data collected from triaxial compression tests of some researchers. The analysis of the embankment problem carried out, shows that the leaching process for foundation gypseous soil increases the displacements and deformations of the embankment and its foundation. Finally, this research necessitate the success using of the finite element method in design and analyses of the important structures and buildings erected on gypseous soils that may expose to the effect of leaching process. This means that there is possibility to predicate the behavior of structure by a powerful means to establish the suitable solutions for any problems that may be occurred as a result of the present gypseous soil.
This paper presents the numerical study to simulate the flexural behavior of normal strength, high strength and hybrid reinforced concrete beams, under two points load with two different reinforcement ratio. The hybrid beam consists of two layers: the compressive layer is made of high strength concrete, and the tension layer is made of normal strength concrete. The simulation was done with a finite element model using the commercial finite element code, ANSYS (v.9.0). The concrete component material is modeled, the internal steel reinforcement modeled using ''LINK'' elements. The modeled behavior shown a good agreement with the experimental data. The maximum percentage difference in ultimate load-carrying capacity is 8% at the ultimate load level.Analytical study also included the effect of increasing the depth of the normal strength concrete for the hybrid reinforced concrete beam and the effect of increasing the compressive strength for high strength concrete and normal strength concrete respectively on the behavior and the load carrying capacity of the hybrid reinforced concrete beams.
This paper deals with the nonlinear finite element analysis of two shear-critical concrete dapped-end beams. Reinforced concrete dapped-end beams having nominal shear span to depth ratio values of 0.56 and 0.59, concrete strength 32MPa and 34MPa, and reinforcement ratio via yield strength 2.83MPa and 7.39MPa, that failed in shear have been analyzed using the ‘ANSYS’ program. The ‘ANSYS’ model accounts for the nonlinearity, such as, post cracking tensile stiffness of the concrete, stress transfer across the cracked blocks of concrete. The concrete is modeled using ‘SOLID65’- eight-node brick element, which is capable of simulating the cracking and crushing behavior of brittle materials. The internal reinforcements have been modeled discretely using ‘LINK8’ – 3D spar element. A parametric study is also made to explain the effects of variation of some main parameters such as shear span to depth ratio, concrete compressive strength, and the parameter of main dapped-end reinforcement on the behavior of the beams. From the present modality the capability of the model to capture the critical crack regions, loads and deflections for various types of shear failures in reinforced concrete dapped-end beams have been illustrated. The parametric study shows that the beams shear strength is affected by the shear span to depth ratio, concrete compressive strength and the amount of main reinforcement.
The mechanical behaviour of partially saturated soils can be very different from that of fully saturated soils. It has long been established that for such soils, changes in suction do not have the same effect as changes in the applied stresses, and consequently the effective stress principle is not applicable. A procedure was proposed to define the soil water characteristic curve. Then this relation is converted to relation correlating the void ratio and matric suction. The slope of the latter relation can be used to define the H-modulus function. This procedure is utilized in the finite element analysis of a footing on unsaturated coarse grained soil to investigate its bearing capacity. The finite element results demonstrated that there is a significant increase in the bearing capacity of the footing due to the contribution of matric suction in the range 0 to 6 kPa for the tested compacted, coarse-grained soil. The ultimate pressure increases from about 120 kPa when the soil is fully saturated to about 570 kPa when the degree of saturation becomes 90%. This means that an increase in the bearing capacity of about 375% may be obtained when the soil is changed from fully saturated to partially saturated at a degree of saturation of 90%. This development in the bearing capacity may exceed 600% when the degree of saturation decreases to 58%.
The structural behavior of steel plate girders with web opening is investigated in this study. An experimental and theoretical investigation of plate girders with different types of openings in the web was conducted. Two types of web opening is investigated (square & circular) opening. The experimental work included testing of seven plate girder specimens under two point loads. Three specimens were tested to observe the influence of the circular web opening. The influence of the presence of square web openings was studied by testing other three specimens. While the last one was tested without opening as a reference (control) specimen. These specimens had the same dimensions. From experimental results the ultimate load of girders decreases with increasing opening size, and the position of plastic hinge depends on the size of hole A nonlinear 3D finite element model was deveioped using FE program ANSYS to validate the experimental results Four- nodes shell element (SHELL 181) was used to represent the steel plate. The proposed finite element model was used to study the effect of web slenderness on shear resistance of plate girder with web opening. Equation was suggested to predict the shear resistance. The analysis study give good agreement with experimental work.
The finite element method capable of simulating the behavior of deep foundations subjected to negative skin friction in Basrah soil is investigated. Single piles under drag forces are analyzed using the PLAXIS program with an axisymmetric model. Linear elastic, Soft Soil and Mohr-Coulomb constitutive relations are adopted, where higher order triangular element is chosen for pile and soil clusters. Both pile and soil are modeled using (15)-node triangular elements. Three sites in Basrah province (Umm Qasr Port, Khor Al-Zubair, and Shatt AlArab Hotel) were selected to perform this study. The soil profile and layer characteristics are obtained from the soil investigation reports. Where the negative skin friction is evaluated due to filling loads. It is Conclusion thatSmall relative displacements are necessary to activate the negative skin friction. The elastic shorting for pile effect negative skin friction, due to increase relative displacement. The elastic shorting of the driven pile is more than that of the bored pile due to the less cross-sectional area of the driven pile. The results revealed proportional relation between the developed drag forces and pile section dimensions, interface friction factor, and fill height, with a maximum effect on the section dimension and minimum effect on the interface factor. The locations of neutral points are not sensitive to the above-mentioned factors.
This research presents an efficient strategy to find optimum analysis and shape design for arch dams. Where the design geometry is built using (Solid Work Program), which is considered as one of important programs for analysis and design of complex structures. A finite element method is used to analyze the arch dam body, which is proved to be an important method for analysis and gives accurate results according to previous researches. The design of the basic shape of the dam has been done by using horizontal curve and vertical curve equations. After conducting the analysis and design of the initial model by (SolidWork) program, it was transferred to the second phase. This is the shape optimization process by using (Genetic Algorithm) in (Matlab) program. This method is an efficient method for all optimization problems in different branches. The objective function in this research is the minimum volume of the dam, which leads to minimum weight design. There are many constraint controls the selecting of optimum shape. In this work, geometrical and structural constraints are considered. At this stage, to calculate the volume of the dam body, integration method is used to convert the volume in terms of the design variables (tc1, tc2, and tc3) which represent the thickness of the dam at three levels. Then this equation has been moved to (Genetic Algorithm tools) using (m-file) to complete the optimization process. The results show that the best design shape of the dam is with thicknesses (5.5m, 13.3m, and 19.8m) with a final optimal volume of53.75% less than the initial model and the stress is still less than the allowable limits
This paper includes an analysis to asses the behavior of stone columns using the finite element method and to provide bases and information helping geotechnical engineers to design foundations resting on weak soils reinforced with stone column. The axisymmetric quadrilateral element is adopted in the finite element program to simulate the soft soil and the stone column while the one-dimensional element is used to simulate the soft soil and the stone column-soil interface. The nonlinear inelastic stress-dependent model is used to simulate the behavior of the soil and the interface throughout the incremental loading stages adopting nonlinear parameters obtained from triaxial and direct shear stress. The analysis is carried first on a selected basic problem, to clarify the nonlinear of the column, in which a selected geometry, boundary condition, and material properties for both soil and interface as chosen. The rest of the analysis is grouped into the effect of some of the parameters concerning the geometry of the stone column and the material of column and adjacent soil are investigated. It was found that the increase in stone column length and in relative stiffness of stone column material to soil play an important role in increasing ultimate capacity of the stone column and in reducing settlements.
This paper presents the testing results and numerical results of nine reinforced concrete thick slabs with and without openings. All slab specimens have the same planar dimensions (1000mm×1000mm) with three different thicknesses of (120mm,100mm,and 80mm).The slabs resting on 4 corner steel columns and tested under concentrated static loading up to failure. These slabs were also analyzed using nonlinear finite element method assuming nonlinear material properties. From the experiments, it was found that, The presence of openings in slabs supported on their four corners decreases the strength and rigidity of slabs to about (12-23) % depending on the slab thicknesses and the shape of these openings. The slabs with (circular opening) recorded a reduction in ultimate strength to about(20) % from those with square openings having an equivalent opening areas. The yielding of main steel reinforcement occurred at load about 85% of the slab ultimate load. The ultimate loads predicted by ANSYS model have showed a good agreement with the experimental results.
The hyperbolic model is a simple stress-strain relationship based on the concept of incrementally nonlinear elastic behavior. The hyperbolic stress-strain relationship was developed for use in finite element analysis of stresses and movements in earth masses. To estimate hyperbolic parameter values required for nonlinear finite element analysis, data used from the triaxial compression tests for the gypseous soils exposed to the effect of drying and wetting cycles carried out by (Mohammed, 1993). From these data, the parameters (C, φ, K, n, Rf), which are required by Duncan-Chang model, 1970 can obtained for analyses of dams, excavations and various types of soil-structure interaction problems. In addition, it can be found that the primary loading modulus, K, the exponent number, n, and the failure ratio, Rf, have random values during rewetting cycles for CU and UU triaxial compression tests
The finite element method is used to simulating the behavior of deep foundations subjected to negative skin friction in Basrah soil. Pile groups are analyzed under dragforces using 3D Plaxis software. Linear elastic and Mohr–Coulomb constitutive relations are adopted for the pile and soil materials. Three sites are selected to perform the study, where the negative skin friction is developed due to fill loads. The dragforces on driven piles, within (3 x 3) square groups with spacing of (3B), are evaluated and compared to their counterparts of single piles. The dragforces are decreased on piles constituting the group, and the reduction depends on pile location within the group. Centeral piles exhibit maximum reductions of (50%). To study the effect of pile spacing, a range of [(3B) to (6B)] was adopted. Apart from pile location, it is concluded that, the dragforce is proportional to pile spacing.
AbstractThe aim of this study is to analyze the slope stability for sections in Al-Furat River where engineering construction build on it, when a sudden decrease in the river water level happens. Two sections were chosen from the river in the area located about 35 km away from Ramadi city called Tel Aswad where undisturbed samples are taken and laboratory tests are done to obtain the soil parameters which are used in Geo-Slope program. The finite element method was applied in this study with elastic-plastic soil model. The analysis results show that the sections slope chosen from the river are stable. The second purpose of this analysis to reduce the risk of using earth structures when engineering construction build on it. Also, it is clear that the values of factor of safety calculated by the FEM are low compared with limit equilibrium methods.
In this study, eight rectangular reinforced concrete beams strengthened by bottom steel plates firmly interconnected to them by headed-stud shear connectors are manufactured using self compacting concrete and tested up to failure under two point loads to demonstrate the effect of steel-plate thicknesses, lengths, and the shear-connector distributions on the behavior, ductility and strength of this type of beams. A trial mix conforming to the EFNARC Constraints had been successfully carried out to satisfy the three fresh tests of SCC, these tests are flowability, passing ability and segregation resistance. The results show that there is a substantial improvement in the flexural resistance, increasing the flexural stiffness and decreasing the ductility ratio due to thickening steel plate, On contrary, increasing the spacing between shear connectors to 50% had slight effect on the flexural resistance, but subsequent increase of their spacing to 100% had seriously lowered that resistance, The spacing between shear connectors has a primary effect on the average flexural stiffness and ductility ratio. In regard to the steel plate length, its shortening has reduced the flexural resistance significantly, decreased the average flexural stiffness and had increased the ductility ratio. The experimentally determined ultimate flexural strength had been compared with its corresponding one computed by the "Strength Method" using ACI requirements where high agreement gained between them due to the nearly perfect interaction provided by SCC. The eight composite beams had also been analyzed by the non-linear three dimensional Finite Element Analysis employing ANSYS program (release 12.1),where high agreement is achieved compared with experimental results.
Abstract: This research is devoted to investigate the behavior of steel fiber reinforced concrete members subjected to blast loading. Material nonlinearity due to nonlinear response of concrete in compression, tensile cracking, strain softening after cracking, crushing of concrete and the yielding of steel reinforcement are considered. Three-dimensional finite element is used with eight and twenty-node are hexahedral isoparametric brick element for the spatial discretization. In the idealization of the reinforced concrete structures, the steel reinforcement is incorporated in the concrete brick element as a smeared layer assuming perfect bond. Concrete is modeled as an elasto-viscoplastic model in compression and as a linear elastic strain softening in tension. The steel reinforcement is assumed to have uniaxial properties in the direction of the bars. A classical elasto-viscoplastic model is used to model the reinforcement. Some numerical problems are solved and compared with other studies to verify the applicability and accuracy. Parametric study to investigate the effect of some important parameters has been carried out. The results showed that the use of steel fibers in members subjected to dynamic loading lead to better performance.
The effect of change of channel width on bed load and transport load of sedimentation for given discharge are studied. The transport load is a mathematical function of change in channel width . The phenomena of transport load of sedimentation in a meandering alluvial channels are significant problems in river engineering and important factor that effects on the works of river control . The finite element model is developed to determine the effect of change of channel width on bed load capacity to ( 2.5 km ) length of the Euphrates river within hit city used value of manning roughness is ( 0.028 ). Calculated the optimum width actualized maximum transport capacity .
AbstractA full three dimensional finite element computational model is constructed for nonlinear analysis of reinforced concrete curved beams. This model was presented utilizing computer program ANSYS (Version 11), which is capable of an efficient analysis of the response at different load levels including ultimate loads.This work deals with the structural analysis of concrete curved beams behaviour subjected to two concentrated loads. Concrete curved beams are widely used in building and bridge constructions. Some of the available experimental tests on reinforced concrete curved beams are theoretically analyzed. This covers load-deflection relationships, crack pattern and propagation of crack at different stages of load and ultimate load capacity. The reliability of the model is demonstrated by comparison with available experimental results and alternative numerical analyses which shows 4 – 8 % difference.
In this study an investigation of castellated beam are presented. The experimental and analytical results of seven simple castellated beams and other one has webbed section are summarized in this study. The target of the search was to study the structural behavior and mode of failure of castellated beams which have different geometric shape of hole and varies lengths span of beams, and attempt to find out the possibility of Biodgett equation and Halleux equation to determine ultimate and limit load respectively. Four angle off cutting were used to achieve the change in the geometry of hole (45, 50, 60 and 90 degree). The specimens were made from IB 203x133x25 and were expanded to 1.5 times the standard depth. Ultimate and limit load, load-deflection relation shapes and mode of failure were presented and discussed. The experimental results showed that the ultimate and limit load of castellated beams decreases with increasing the angle of cutting and Biodgett equation gives acceptable results for estimating ultimate load when the angle of cutting 50° or less. Also it is found that the limit load of castellated beam by Haleux equation is incorrect when the angle of cutting greater than 50°. As well as ANSYS-12 was used to analysis these beams by nonlinear finite element method. Four- nodes shell element (SHELL 181) was used to represent the castellated and webbed beams. This model was validated by comparison of the experimental and numerical results of ultimate load and their corresponding modes of failure.
Composite beams, made up of a concrete slab and steel in the IPE steel section, are commonly used in bridges and buildings. Their main function is to enhance structural efficiency by merging the compressive strength of concrete with the tensile resistance of steel, thereby improving overall stiffness, ductility, and load-bearing capacity. This study offers an extensive review of the flexural behavior of steel-concrete composite beams, focusing on the interplay of concrete strength, shear connector types, and interaction levels in determining structural performance. It integrates experimental and numerical research to analyze critical parameters, including load-deflection behavior, shear transfer efficiency, and crack propagation at the steel-concrete interface. The study emphasizes the effect of concrete compressive strength, particularly in ultra-high-performance concrete (UHPC) and lightweight concrete, on stiffness, ductility, and load-bearing capacity while reducing self-weight and enhancing sustainability. The study revealed that fully bonded shear connectors, using CFRP sheets and welded plates, enhance flexural capacity and stiffness. In contrast, partial bonding or pre-debonding reduces performance due to crack propagation. Indented and hot-rolled U-section connectors enhance interaction and minimize slip, while uniform distribution of shear connectors optimizes load capacity and stiffness. Lightweight concrete decreases slab weight without compromising performance, and high-performance materials such as ECC, SFRC, and UHPFRC improve strength and ductility. Numerical modeling, particularly finite element methods, and higher-order beam theories validate experimental results, providing accurate tools for predicting structural behavior under various loading and environmental conditions.
Nonlinear numerical analysis of nine reinforced concrete beams with dimensions (150 x 200 x 1200) width, height and length, respectively, was carried out through the finite element theory using the ANSYS software (version 15) to know the effect of different properties of layers in the one beam on the flexural behavior of reinforced concrete beams. The beams are consisting from two layers for the one cross-section. three beams are similar properties layers and the other six are with different properties layers. The beams differ among them depending on the percentage of Polyethylene terephthalate (PET) fibers added, the location of the fibrous concrete layer as well as the thickness of the layer. PET fibers were added in proportions (0%,0.5%, and 1%) from volume of the one layer, with dimension (50 x 4 x 0.3) mm length, width, and thickness respectively. All beams are reinforced with steel reinforcement (6 mm diameter at the top, 10 mm diameter for reinforcement against shear and 12 mm diameter in the tension area). The mechanical properties of each type of mixture have been studied. It was found that the different properties of the layers significantly affected the flexural behavior of reinforced concrete beams. Also the results of the numerical modeling were very close to the laboratory results obtained from the practical study, where the largest difference between the two studies was 8% and 11% for the load and deflection respectively at the ultimate point
AbstractIn this paper a nonlinear finite element analysis is presented to simulate the fire resistance of reinforced concrete slabs at elevated temperatures. An eight node layered degenerated shell element utilizing Mindlin/Reissner thick plate theory with initial stiffness technique is employed. The proposed model considered cracking, crushing, and yielding of concrete and steel at high temperatures. More complicated phenomena like concrete transient thermal strain and concrete spalling are excluded in the present analysis. The validation of the proposed model is examined against experimental data of previous researches and shows good agreement.Keywords: Fire resistance, Material nonlinearity, Reinforced Concrete Slabs
The buckling analysis of Euler-Bernoulli beam resting on two-parameter elastic foundation (EBBo2PEF) has important applications in the analysis and design of foundation structures, buried gas pipeline systems and other soil-structure interaction systems under compressive loads. This study investigates the buckling analysis of EBBo2PEFs. The governing differential equation of elastic stability (GDiES) is derived in this work using first principles equilibrium method. In general, the GDiES is an inhomogeneous equation with variable parameters for non-prismatic beams under distributed transverse loadings. However, when transverse loads are absent and the beam is prismatic the GDiES becomes a fourth order ordinary differential constant parameter homogeneous equation. General solution to GDiES is obtained in this work using the classical trial exponential function method of solving equations. Two cases of end supports were considered: simply supported ends and clamped ends. Boundary conditions (BCs) were used to obtain the characteristic buckling equations whose eigenvalues were used to determine the critical buckling loads for two cases of BCs considered. It was found that the method gave exact solutions for each of the BCs. The critical elastic buckling load coefficients for dimensionless beam-foundation parameter and ranging from for simply supported EBBo2PEFs were identical with previous results that used Stodola-Vianello iteration methods and finite element method. Similarly, the critical buckling load coefficients for and are identical with previous results that used Ritz variational method.
The present study, the effect of changes that developed in concrete structures with time is presented. Two way slab investigated experimentally by [1]was analyzed using finite element method by ANSYS commercial program. Many parameters studied such as length to thickness ratio, reinforcement ratio and ultimate load ratio. The slab with dimension (2360*2360*63) mm and reinforced with different types of materials such as steel bars ,GFRP and CFRP (fiber reinforced polymer) bars . The results show that the strain increase gradually with time after apply the load. It can see that the strain in steel model increase with ratio of 19.98% when the load increase from 75% to 90%,and decrease with ratio 50% when the load decrease from 75% to 50% .That is, the change by increasing the strain is less and slower than the change by decreasing the strain, since the strain when dropping the load is less than the strain when lifting the load, because the structure has not undergone and its stiffness is still high and it is trying to recover its original shape. It increases significantly at the beginning, and then the difference decreases or stabilizes approximately after 330 days.
AbstractDeflection of partially prestressed concrete beams is investigated using the finite element method taking in to account the plasticity of steel, nonlinearity of concrete in compression and tension softening of concrete. Embedded bar approach is used to represent the steel reinforcement and prestressing tendon in concrete layer. Elastic perfectly-plastic approach has been employed to model the compressive behaviour of the concrete.The yield condition is formulated in terms of the first two-stress invariants. The movement of the subsequent loading surfaces is controlled by the hardening rule, which is extrapolated from the uniaxial stress-strain relationship defined by a parabolic function. Concrete crushing is a strain controlled phenomenon, and can be monitored by a fracture surface similar to the yield surface. A smeared fixed crack approach is used to model the behaviour of the cracked concrete, with a tensile strength criterion to predict crack initiation. The steel is considered as an elastic perfectly plastic material with linear strain hardening, steel reinforcement is assumed to have similar tensile and compressive stress-strain relationship. The calculated and the observed effects have shown a satisfactory agreement compared with experimental results.
The design of reinforced concrete structures has traditionally relied on empirical techniques based on experience or experimental research on actual structural members. Although this approach produces a high level of precision, it is usually exceedingly costly and time-consuming. This paper studied the convergence between theoretical analysis (ACI 318-19 Equations) and numerical analysis (FEM) of eleven one way reinforced concrete slab specimens casted by shotcrete contains three types of plastic fibers including waste plastic (PET), polypropylene (PP), and hybrid (PET+PP) fibers with three addition ratios (0.35%, 0.7%, and 1%) for each type. The results concluded that the numerical analysis (ANSYS FE model) showed a good agreement with the theoretical (ACI 318-19) of one-way slab in terms of ultimate load, with a variance, and standard deviation equal to 0.00076, and 0.027 respectively. Hence, ANSYS v15 software can be used for the analysis of reinforced concrete slabs casted by shotcrete contain waste plastic fibers and polypropylene fibers.
In this paper, AlMg3-plates are studied through experimental and numerical using finite element representation under concentrated load at the center point. The plates of (300- × 200 mm) are clamped at the shorter ends and strengthened longitudinally by one rib at the centerline and two at different spans. the stiffened plates were modeled using a 3-D 10-node tetrahedral element with a non dimensional analysis. The models were validated using the results of tests on full-size stiffened plate specimens and were subsequently used to perform the study of the parameters presented in this paper. The parameters investigated are: the maximum stress, deflection of the plate and the position of ribs. Effect of the investigated parameters on the concentrated load strength were studied within elastic range. FEA give closer results with those of experimental and these results show that the use of two parallel ribs with a 40-mm span improves the strength of the plate. Due to these results, further investigation is presented to show the optimum thickness of the ribs at the best span.
Abstracte: The stress-strain behavior of any type of soil depends on a number of different factors including density, water content, structure, drainage conditions, strain conditions (i.e., plane strain, triaxial), duration of loading, stress history, confining pressure, and shear stress. In many cases it may be possible to take account of these factors by selecting soil specimens and testing conditions which simulate the corresponding field condition. Even when this can be done accurately, however, it is commonly found that the soil behavior over a wide range of stresses is nonlinear, in elastic, and dependent upon the magnitude of the confining pressure employed in the tests. In order to perform stress analysis of soils, it is desirable to employ techniques, which account for these important aspects of soil behavior.
In this research the finite element method is used to analyses the effect of groynes on the coefficient of Manning's value in meandering sandy channels is used. A two dimensional model of quadrilateral isoperimetric element is used, two meandering sandy channels were analyzed. The first channel has a central angle of ( 40o) with radius of curvature of (1.7m) , while the second channel has a central angle of ( 60o) with a radius of curvature of (2m) with a trapezoidal cross – section having a lower base of(1m) and side slope of ( 2H : 1V) and with bed slope of channels of ( 0.15% ). The main diameter of the sand used in this research of channels of (0.9mm ) achieved using observed data of Euphrates river at regulator of falluja. Five sections were located on each channels and four different discharges were passed through the two channels, the groynes sloped towards upstream were used in different locations at upstream and down stream of channels.
In the present paper, a one-dimensional finite element model for the analysis of composite beams of partial interaction is constructed. This model was verified against some analytical results available in the literature and achieved very good agreement with the natural frequencies and the time histories it was compared to. Then it was utilised to analyse partial interaction composite beams under the effect of uniform step loads and provided important information about the expected dynamic amplification factors, which turned out to be particularly high, and the effects of the linear stiffness ratio of the interface and the boundary conditions of the lower layer of the beam. The results, in particular, showed that even for extreme cases the orders of magnitude of the slip and the corresponding uplift remain the same. This pointed out an important finding that the uplift in the researched context, at least, is not negligible as it is widely assumed in the literature.