@article{ author = {Kaveh, A. and ShakouriMahmudAbadi, A.}, title = {Harmony search based algorithms for the optimum cost design of reinforced concrete cantilever retaining walls}, abstract ={Cost optimization of the reinforced concrete cantilever soil retaining wall of a given height satisfying some structural and geotechnical design constraints is performed utilizing harmony search and improved harmony search algorithms. The objective function considered is the cost of the structure, and design is based on ACI 318-05. This function is minimized subjected to design constraints. A numerical example of the cost optimization of a reinforced concrete cantilever retaining wall is presented to illustrate the performance of the presented algorithms and the necessary sensitivity analysis is performed.}, Keywords = { Structural optimization, Reinforced concrete, Cantilever retaining walls, Harmony search algorithm, Modified harmony search}, volume = {9}, Number = {1}, pages = {1-8}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-292-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-292-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {An, Sung-hoon and Cho, Hunhee and Lee, Ung-Kyu}, title = {Reliabilty assessment of conceptual cost estimates for building construction projects}, abstract ={In the early stages of a construction project, the reliability and accuracy of conceptual cost estimates are major concerns for clients and cost engineers. Previous studies applied scoring methods and established common rules or mathematical methods to assess the quality of cost estimates. However, those approaches have some limitations in adapting to real-world projects or require understanding of sophisticated statistical techniques. We propose a Conceptual Cost Estimate Reliability Index (CCERI), a simple, easy-to-use, and easy-to-understand tool that incorporates weights for 20 factors influencing the quality of conceptual cost estimates. The weights were obtained by eliciting experts’ experience and knowledge. Cost data from 71 building projects were used in the analysis and validation of the CCERI. The analysis reveals that a conceptual cost estimate with a CCERI score of less than 3000 has a high probability of exceeding 10% error, and such conceptual cost estimates are unlikely to be reliable. With the CCERI score, a decision maker or a client can recognize the reliability of the conceptual cost estimates and the score can thus support decision making using conceptual cost estimates. In addition, with the CCERI and the relative importance weights of factors affecting the conceptual cost estimates, the estimator can find ways to modify a conceptual cost estimate and reestimate it. These alternatives can decrease the risk in the conceptual estimated cost and assist in the successful management of a construction project.}, Keywords = { Cost estimation, Reliability assessment, Reliability index, Decision making}, volume = {9}, Number = {1}, pages = {9-16}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-463-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-463-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Malaikrisanachalee, S. and Vathananukij, H.}, title = {Integration of Java-based BIM with spatial database}, abstract ={Java is an object-oriented program that has abundant open-source libraries for application development and 3D model rendering. Spatial database is the database that can efficiently store and manage geographic information data though various spatial data management techniques. This paper explores the rationale of coupling java with spatial database to develop an effective platform for future Building Information Modeling (BIM) application. The paper methodically presents the prototype system integration design to demonstrate how the system can be developed. The paper also meticulously presents the logical and physical data models in designing optimum BIM database for a reinforced concrete building. An 8-storey reinforced concrete building was used as an implementation case study to validate the proposed prototype system design and investigates the implementation issues. The outcome shows that not only the proposed prototype system offers technological advantages over the traditional BIM applications, its open-source solution can also overcome the financial constraint that currently inhibits the implementation of BIM especially for medium and small enterprises.}, Keywords = { BIM, spatial database, project management, construction database, 3D model}, volume = {9}, Number = {1}, pages = {17-22}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-439-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-439-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Sebt, M.H. and Yousefzadeh, A. and Tehranizadeh, M.}, title = {The optimal TADAS damper placement in moment resisting steel structures based on a cost-benefit analysis}, abstract ={In this paper, the optimal location and characteristics of TADAS dampers in moment resisting steel structures, considering the application of minimum number of TADAS dampers in a building as an objective function and the restriction for destruction of main members is studied. Genetic algorithm in first generation randomly produces different chromosomes representing unique TADAS dampers distributions in structure and the structure corresponding to each chromosome is time history analyzed. Then the damage index for each member and the average weighted damage index for all members are determined. Genetic algorithm evaluates the fitness of each chromosome then selection and crossover as logical operators and mutation as random operator effect the current generation;#39s chromosomes according to their fitness and new chromosomes are generated. Accordingly, successive generations are reproduced in the same way until the convergence condition is fulfilled in final generation and four distributions are suggested as better options. Since these proposed distributions are selected under the one earthquake, therefore, it is better that the four new structures are cost-benefit analyzed in different earthquakes. Finally, the optimal placement for dampers is compared and selected based on a benefit to cost ratio, drift stories and the number of different TADAS types of such structures. The increase in amount of energy dissipated via dampers located in different floors as well as the status of plastic hinges in main members of the structure strengthened with optimum option are the proof of the optimal placement and suitable characteristics for dampers.}, Keywords = {Optimal location, TADAS dampers, Destruction of main members, Genetic Algorithm, Cost-benefit analyze, Dissipation energy}, volume = {9}, Number = {1}, pages = {23-32}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-433-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-433-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Afandizadeh, Sh. and Yadak, M. and Kalantar, N.}, title = {Simultaneous determination of optimal toll locations and toll levels in cordon-based congestion pricing problem (case study of Mashhad city)}, abstract ={The congestion pricing has been discussed as a practical tool for traffic management on urban transport networks. The traffic congestion is defined as an external diseconomy on the network in transport economics. It has been proposed that the congestion pricing would be used to reduce the traffic on the network. This paper investigates the cordon-based second-best congestion-pricing problems on road networks, including optimal selection of both toll levels and toll locations. A road network is viewed as a directed graph and the cutest concept in graph theory is used to describe the mathematical properties of a toll cordon by examining the incidence matrix of the network. Maximization of social welfare is sought subject to the elastic-demand traffic equilibrium constraint. A mathematical programming model with mixed (integer and continuous) variables is formulated and solved by use of two genetic algorithms for simultaneous determination of the toll levels and cordon location on the networks. The model and algorithm are demonstrated in the road network of Mashhad CBD.}, Keywords = { Congestion pricing, Genetic algorithm, Network, Cutset, Cordon, Optimization}, volume = {9}, Number = {1}, pages = {33-40}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-256-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-256-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {RezaieMoghaddam, F. and Afandizadeh, Sh. and Ziyadi, M.}, title = {Prediction of accident severity using artificial neural networks}, abstract ={In spite of significant advances in highways safety, a lot of crashes in high severities still occur in highways. Investigation of influential factors on crashes enables engineers to carry out calculations in order to reduce crash severity. Therefore, this paper deals with the models to illustrate the simultaneous influence of human factors, road, vehicle, weather conditions and traffic features including traffic volume and flow speed on the crash severity in urban highways. This study uses a series of artificial neural networks to model and estimate crash severity and to identify significant crash-related factors in urban highways. Applying artificial neural networks in engineering science has been proved in recent years. It is capable to predict and present desired results in spite of limited data sets, which is the remarkable feature of the artificial neural networks models. Obtained results illustrate that the variables such as highway width, head-on collision, type of vehicle at fault, ignoring lateral clearance, following distance, inability to control the vehicle, violating the permissible velocity and deviation to left by drivers are most significant factors that increase crash severity in urban highways.}, Keywords = { Crash Severity, Human Factors, Highway, Traffic Volume, Artificial Neural Networks}, volume = {9}, Number = {1}, pages = {41-48}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-544-en.html}, eprint = {}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Vafaie, J. and Taghikhany, T. and Tehranizadeh, M.}, title = {Near field effect on horizontal equal-hazard spectrum of Tabriz city in north-west of Iran}, abstract ={The near field ground motions have a high amplitude pulse like at the beginning of the seismogram which are significantly influenced by the rupture mechanism and direction of rupture propagation. This type of ground motion cause higher demands for engineering structures and its response spectrum is dramatically different than far field spectra. Tabriz is one of the ancient cities in Azerbaijan province with many industrial factories, financial centers and historical monuments in North-West of Iran. In this region, North Tabriz Fault which has a well known history of intense seismic activity is passing through in close distance of urban area. In this regard investigation of near field ground motion effect on current practice seismic design spectrum in this region is necessary. Hence, probabilistic seismic hazard analysis is carried out using appropriate attenuation relationship to consider near field effect. The peak ground acceleration (PGA) and several spectral accelerations (SA) over bedrock are estimated for different return periods and maps of iso acceleration contour lines are provided to indicate the earthquake hazard in different points of Tabriz city. Afterward, the generated horizontal equal-hazard spectrums considering near field effect are compared with different spectrums developed base on simple pulses model for near field motion. Both types spectrum used to verify current practice seismic design spectrum of Iranian code (2005) and International Building Code (IBC 2000). The results reveal the long-period structures which are seismically designed based on current practice seismic codes are in high risk to be damaged during near fault ground motion.}, Keywords = { Equal-Hazard Spectrum, Near Field Effect, Tabriz City}, volume = {9}, Number = {1}, pages = {49-56}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-251-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-251-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Mahmoudi, M. and Zaree, M.}, title = {Evaluating the overstrength of concentrically braced steel frame systems considering members post-buckling strength}, abstract ={Inelastic deformation of structural components is generally acceptable in seismic design. In such behavior, the strength of structures increases while plastic hinges are formed in members frequently. The strength revealed during the formation of plastic hinges is called "overstrength". Overstrength is one of the important parameters in the seismic design of structures. The present study tries to evaluate the overstrength of the concentrically steel braced frames (CBFs), considering reserved strength, because of members post-buckling. As such, a static nonlinear (pushover) analysis has been performed on the model buildings with single and double bracing bays, different stories and brace configurations (chevron V, invert Vand X-bracing). It has been realized that the number of bracing bays and the height of buildings have a low effect on reserve strength due to brace post-buckling. However, these parameters have a profound effect on the overstrength factor. These results indicate that the overstrength values for CBFs, proposed in seismic design codes, need to be modified.}, Keywords = { Concentrically steel braced frames, Overstrength factor, Post-buckling strength, Response modification factor}, volume = {9}, Number = {1}, pages = {57-62}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-301-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-301-en.pdf}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Poorazizi, M.E. and Alesheikh, A.A.}, title = {Monitoring real-time environmental information using Web 2.0 and GIServices technology}, abstract ={Air pollution is a serious challenge in densely populated cities. It poses a significant threat to human health, property and the environment throughout the developed and developing parts of the world. Real-time air quality monitoring and public access to related information are the key components of a successful environmental management. Mashups can be customized to adequately address the monitoring of such geographically oriented challenges. The growth of mashups has been accelerated by Web 2.0 technologies. The integration of Web 2.0 and GIS (Geographic Information System) has been highlighted by the second generation of Internet-based services that emphasizes on online information collaboration and sharing among users. The main objective of this paper is to assess, design and develop a Web 2.0 thin client application called Tehran Air Quality Reporter. The application uses Google Maps API (Application Programming Interface), Web GIServices (Geographic Information Services), and AJAX (Asynchronous JavaScript and XML) to disseminate real-time air quality information through internet. Such information can improve the decisions of the pertinent environmental organizations as well as urban settlers. The software also utilized DOM (Document Object Model) and JavaScript functionalities for handling the response events and providing flexibility and more interactivity. The developed Geo Mashup includes geospatial maps and features, standard business charts, node and link displays, as well as custom visual displays. All visualization components run in any web browsers and provide a user friendly environment.}, Keywords = { GIS, Data interoperability, Mashups, Google maps, Web service, Geospatial data interchange format}, volume = {9}, Number = {1}, pages = {63-70}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-274-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-274-en.docx}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Hajivalie, F. and YeganehBakhtiary, A.}, title = {Numerical simulation of the interaction of a broken wave and a vertical breakwater}, abstract ={In this paper, a two-dimensional Reynolds Averaged Navier-Stokes (RANS) model is developed to simulate the shoaling, breaking and overtopping of a solitary wave over a vertical breakwater. Turbulence intensity is described by using a k turbulence closure model and the free surface configuration is tracked by Volume Of Fluid (VOF) technique. To validate the numerical model the simulation results is compared with the Xie (1981) experimental data and a very good agreement between them is observed. The results revealed that wave height and wave energy decrease considerably during the reflection from vertical wall, which illustrates a considerable energy lost during the impaction and wave overtopping process. The turbulence production during the broken wave interaction with vertical breakwater is very significant consequently the vertical breakwater undergoes sever turbulent and dynamic drag force.}, Keywords = { RANS model, shoaling, wave breaking, wave overtopping, k-ε turbulence closure model, VOF technique, solitary wave}, volume = {9}, Number = {1}, pages = {71-79}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-239-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-239-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Abdi, Mahmoud Rez}, title = {Effects of basic Oxygen steel slag (BOS) on strength and durability of kaolinite}, abstract ={The use of various slags as by-products of steel industry is well established in civil engineering applications. However, the use of BOS slag in the area of soil stabilization has not been fully researched and developed despite having similar chemical composition and mineralogy to that of Portland cement. This paper reports on efforts to extend the use of BOS slag to soil stabilization by determining possible beneficial effects it may have on compressive strength and durability. Results of laboratory tests conducted on kaolinite samples stabilized with lime and treated with various percentages of BOS slag are presented. Tests determined strength development of compacted cylinders, moist cured in a humid environment at 35° C and durability by freezing and thawing method. Results showed that additions of BOS slag to kaolinite samples singularly or in combination with lime increased unconfined compressive strength and durability. These characteristics were significantly enhanced by the concurrent use of lime and BOS slag for stabilization of kaolinite.}, Keywords = {BOS slag, Kaolinite, Lime, Durability, Strength, Freezing, Thawing}, volume = {9}, Number = {2}, pages = {81-89}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-234-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-234-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Harichane, Khelifa and Ghrici, Mohamed and Kenai, Sai}, title = {Effect of curing time on shear strength of cohesive soils stabilized with combination of lime and natural pozzolana}, abstract ={When geotechnical engineers are faced with cohesive clayey soils, the engineering properties of those soils may need to be improved to make them suitable for construction. The aim of this paper is to study the effect of using lime, natural pozzolana or a combination of both on the geotechnical characteristics of two cohesive soils. Lime or natural pozzolana were added to these soils at ranges of 0-8% and 0-20%, respectively. In addition, combinations of lime-natural pozzolana were added at the same ranges. Test specimens were subjected to compaction tests and shear tests. Specimens were cured for 1, 7, 28 and 90 days after which they were tested for shear strength tests. Based on the experimental results, it was concluded that the combination limenatural pozzolana showed an appreciable improvement of the cohesion and internal friction angle with curing period and particularly at later ages for both soils.}, Keywords = {Cohesive soil, Lime, Natural pozzolana, Compaction, Shear strength, Curing}, volume = {9}, Number = {2}, pages = {90-96}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-368-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-368-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Pak, Ali and Zahmatkesh, Zahr}, title = {Experimental study of geotextile\'s drainage and filteration propertis under different hydraulic gradients and confining pressures}, abstract ={Geotextiles are one of the most widely used synthetic materials in filtration and drainage applications. Since in real applications, geotextiles are subjected to various hydraulic gradients and confining stresses, hydraulic behavior of geotextiles under different circumstances is of great practical importance. In this study filtration and drainage properties of several nonwoven needle-punched geotextiles with different properties and unit mass per area of 200g/m2, 400g/m2, 500g/m2 and 800g/m2, under various confining stresses and hydraulic gradients, were studied using standard permittivity and transmissivity equipments. Prepared samples were subjected to hydraulic heads in the range of 10cm to 60cm and confining stresses up to 1000kPa and their hydraulic behavior was investigated accordingly. In this study the flow regime through the geotextile fibers and also the anisotropic behavior of geotextile permeability were investigated. The results show that transmissivity will decrease exponentially with increasing the normal stress until a residual value is reached, and permittivity and transmissivity coefficients were seen to decrease with increasing the hydraulic gradient. The flow regime has found to be non-turbulent in all cases.The Geotextile hydraulic behavior is of great usage in the design of landfill covers, design of embankments and irrigation structures drainage systems, and in the design of protection systems in river engineering.}, Keywords = {Nonwoven geotextile, Normal stress, Hydraulic gradient,Transmissivity, Permittivity}, volume = {9}, Number = {2}, pages = {97-102}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-462-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-462-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Shariatmadari, Nader and Salami, Marzieh and KarimpourFard, Mehr}, title = {Effect of inorganic salt solutions on some geotechnical properties of soil-bentonite mixtures as barriers}, abstract ={The main task in the design and construction of impermeable liners in landfills is to block the migration of pollutants to the groundwater systems or to reduce its rate to a reasonable amount. That is why environmental regulations force governments to construct engineered waste dumps for waste management purposes. These liners are exposed to various types of chemical, biological, and physical processes and are affected by the leachate which is produced from decomposition of waste materials accompanying methane gas. The leachate includes a lot of components such as water and different types of salts. For this reason, the geotechnical characteristics of clay liners which are evaluated in laboratories using distilled water or tap water might be far different from the representative sample of the in-situ conditions. There are some evidences regarding the effect of these salts on the physical and mechanical properties of clay barriers which could affect the long-term performance of these liners. Since the main criterion for impermeable bottom liners in landfills is their hydraulics conductivity, the increase of this parameter could have a considerable environmental impact. This paper embraces the results of a recent study on the effect of three inorganic salts, NaCl, CaCl2 and MgCl2 on some geotechnical properties of a common used clay soil in impermeable bottom barrier in Kahrizak landfill, the main waste disposal center of the Tehran Metropolitan. Also the effect of bentonite content by adding different percentage of this special clay mineral, 10 and 20 percent, on these properties was investigated. Laboratory tests like liquid limit, compaction, 1D consolidation and free swell tests were performed for this purpose. Results indicated that all of these salts could have a considerable effect on the geotechnical properties of the mixtures. The main reason of such effects is the changes which occur in diffuse double layer of clay particles.}, Keywords = {Landfill liners, Inorganic salts, Swelling and consolidation, Hydraulic conductivity, Liquid limit, Compaction characteristics}, volume = {9}, Number = {2}, pages = {103-110}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-570-en.html}, eprint = {}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Sadrnejad, Seyed Amirodin and Karimpour, Hami}, title = {Drained and undrained sand behaviour by multilaminate bounding surface model}, abstract ={The present paper is devoted to a new critical state based plasticity model able to predict drained and undrained behaviour of granular material. It incorporates a bounding surface plasticity model describing in multilaminate framework to capitalize on advantages of this mathematical framework. Most of the models developed using stress/strain invariants are not capable of identifying the parameters depending on directional effects such as principal stress rotation and fabric this is mainly because stress/strain invariants are scalar quantities. The principal features of this model can be postulated as considering both inherent and induced anisotropy, principal stress rotation. Since the local instability of saturated sand within post-liquefaction is highly dependent on the residual inherent/induced anisotropy, bedding plane effects and also the stress/strain path the new mode is competent to be employed in this regard. The constitutive equations of the model are derived within the context of non-linear elastic behaviour for the whole medium and plastic sliding of interfaces of predefined planes. As follows, the constitutive equations are described in detail and then the experimental results and sensitive analysis of key material constants are shown which all imply the power of the model in predicting of soil behaviour under any condition in soil structures.}, Keywords = {Multilaminate, Elastic-plastic, Bounding surface, Drained, Undrained}, volume = {9}, Number = {2}, pages = {111-125}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-366-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-366-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Baziar, Mohammad Hassan and Shahnazari, Habib and Sharafi, Hass}, title = {A laboratory study on the pore pressure generation model for Firouzkooh silty sands using hollow torsional test}, abstract ={This paper discusses the applicability of a simple model to predict pore water pressure generation in non-plastic silty soil during cyclic loading. Several Stress-controlled cyclic hollow torsional tests were conducted to directly measure excess pore water pressure generation at different levels of cyclic stress ratios (CSR) for the specimens prepared with different silt contents (SC=0% to 100%). The soil specimens were tested under three different confining pressures (;sigma;#393= 60, 120, 240 kPa) at a constant relative density (Dr=60%), with different silt contents. Results of these tests were used to investigate the behavior of silty sands under undrained cyclic hollow torsional loading conditions. In general, beneficial effects of the silt were observed in the form of a decrease in excess pore water pressure and an increase in the volumetric strain. Modified model for pore water pressure generation model based on the test results are also presented in this paper. Comparison of the proposed pore pressure build up model with seed’s model indicates the advantage of proposed model for soil with large amount of silt.}, Keywords = {Liquefaction, Hollow torsional cylinder test, Firouzkooh silty sand, Cyclic stress ratio, Pore water pressure}, volume = {9}, Number = {2}, pages = {126-134}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-489-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-489-en.docx}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Dabiri, Rouzbeh and Askari, Faradjollah and Shafiee, Ali and Jafari, Mohammad Kazem}, title = {Liquefaction resistance of sand-silt mixtures using laboratory based shear wave velocity}, abstract ={Laboratory data, which relate the liquefaction resistance of Firoozkooh sand and non-plastic silt mixtures to shear wave velocity are presented and compared to liquefaction criteria derived from seismic field measurements by Andrus and Stokoe [1]. In the work described herein, cyclic triaxial and resonant column tests were conducted on specimens of clean sand and sand-silt mixtures with silt content up to 60%, prepared at different densities. Cyclic undrained strength and small strain shear wave velocity were determined for identical specimens formed by undercompaction method. It was found that silt content affects cyclic resistance and shear wave velocity. In addition, the laboratory results indicated that using the existing field-based correlations will overestimate the cyclic resistance of the Firoozkooh sand-silt mixtures when silt content is 60%. For clean sand and the specimens containing up to 30% fines, results of this study on cyclic resistance are fairly consistent with Andrus and Stokoe correlations. These findings suggest the need for further evaluation of the effects of non-plastic fines content upon liquefaction criteria derived from seismic field measurements.}, Keywords = {Non-plastic fines, Liquefaction resistance, Shear wave velocity, Field performance data, Cyclic triaxial test, Resonant column test}, volume = {9}, Number = {2}, pages = {135-144}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-400-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-400-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {MahdaviAdeli, Mehdi and Banazadeh, Mehdi and Deylami, Ardeshir}, title = {Bayesian approach for determination of drift hazard curves for generic steel moment-resisting frames in territory of Tehran}, abstract ={The objective of this paper is to determine the drift demand hazard curves of steel moment-resisting frames with different number of stories in territory of Tehran this is done through the combination of the results obtained from probabilistic seismic hazard analysis and the demand estimated through the best probabilistic seismic demand models. To select the best demand model, in this paper, a Bayesian regression has been used for the statistical analysis of the results obtained from incremental dynamic analysis in order to estimate the unknown parameters of model and to select the best Intensity Measure (IM) parameter also the probability of overall collapse of structures has been computed. Considering the efficiency and sufficiency of the models, the results indicate that the accuracy of models with one single IM is a function of the number of stories, consequently the current widely used model with spectral acceleration in first period as IM is not suitable for all structural heights. Furthermore, regarding the fact that it is difficult to prepare a seismic hazard curve for a combined IM, it seems that the best model can be found among models with two single IMs. In other words, the best model to cover all structural heights is the one with linear combination of spectral acceleration of the first and the second period. Furthermore, using different models to calculate the curves shows that regardless of the number of IMs, estimated demands strongly depend on the standard deviation of model.  }, Keywords = {Drift hazard curves, Steel moment-resisting frame, Bayesian, Tehran}, volume = {9}, Number = {3}, pages = {145-154}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-401-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-401-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Sadeghi, Kabir}, title = {Energy based structural damage index based on nonlinear numerical simulation of structures subjected to oriented lateral cyclic loading}, abstract ={An energy based damage index based on a new nonlinear Finite element (FE) approach applicable to RC structures subjected to cyclic, earthquake or monotonic loading is proposed. The proposed method is based on the evaluation of nonlinear local degradation of materials and taking into account of the pseudo-plastic hinge produced in the critical sections of the structure. A computer program is developed, considering local behavior of confined and unconfined concretes and steel elements and also global behavior and damage of reinforced concrete structures under cyclic loading. The segments located between the pseudoplastic hinges at critical sections and the inflection points are selected as base-models through simulation by the proposed FE method. The proposed damage index is based on an energy analysis method considering the primary half-cycles energy absorbed by the structure during loading. The total primary half-cycles absorbed energy to failure is used as normalizing factor. By using the proposed nonlinear analytical approach, the structure;#39s force-displacement data are determined. The damage index is then calculated and is compared with the allowable value. This damage index is an efficient means for deciding whether to repair or demolish structures after an earthquake. It is also useful in the design of new structures as a design parameter for an acceptable limit of damage defined by building codes.  The proposed approach and damage index are validated by results of tests carried out on reinforced concrete columns subjected to cyclic biaxial bending with axial force.}, Keywords = { Numerical simulation, Reinforced concrete, Earthquake, Cyclic loading, Damage index}, volume = {9}, Number = {3}, pages = {155-164}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-563-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-563-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Khanzadi, Mostafa and Tavakkoli, Seyed Mehdi}, title = {Optimal plastic design of frames using evolutionary structural optimization}, abstract ={An evolutionary structural optimization (ESO) method is used for plastic design of frames. Based on safe theorems some criteria are derived and made an effort to satisfy them during the optimization process. In this regard, equilibrium is checked and yield condition is gradually satisfied during the optimization process. In this method, the amount of used material and the stiffness for each element are improved, simultaneously, to impose upper bound of moment in the element. Frame analysis and optimization algorithm are implemented as PLADOF (PLAstic Design of Frames) computer code. Four examples are presented to illustrate the performance of the algorithm}, Keywords = { Optimization, Plastic design, Evolutionary methods, Safe theorem, Plastic moments}, volume = {9}, Number = {3}, pages = {165-170}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-411-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-411-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {SabbaghYazdi1, Saeed Reza and AmiriSaadatAbadi, Tayebeh}, title = {Sequential computations of two-dimensional temperature profiles and thermal stresses on an unstructured triangular mesh byGFVM method}, abstract ={In this research, a novel numerical algorithm is introduced for computation of temperature-induced before crack steady strainstress field in plane-stress problem. For this purpose, two dimensional heat transfer equation and force equilibrium equations are sequentially solved using Galerkin Finite Volume method on identical unstructured triangular meshes when proper convergence for each field is achieved. In this model, a proper thermal boundary condition that is suitable for unstructured triangular meshes is introduced for analysis. Two test cases are used to assess accuracy of thermal and structural modules of the developed solver and the computed results are compared with theirs analytical solution.First, thermal analysis is performed for a rectangular plate which is connected to a supporting body with constant temperature and expose to surrounding liquid at three edges.Second, structural analysis is performed for a plate under distributed loads in two directions. Having obtained acceptable results from thermal and structural modules, thermal stress analysis is performed for a plate with fixed-end condition at one of edges,due to a uniform temperature field and the computational principle stress contours are compared with the Finite Element method results which have been reported in the literatures.}, Keywords = { Plane stress, Thermal stress, Galerkin finite volume method, Unstructured triangular mesh, Explicit solution.}, volume = {9}, Number = {3}, pages = {171-182}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-519-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-519-en.docx}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Firouzi, Afshin and Rahai, Ali Rez}, title = {Prediction of extent and liklihood of corrosion-induced cracking in reinforced concrete bridge decks}, abstract ={Corrosion of reinforcement due to frequently applied deicing salts is the major source of deterioration of concrete bridge decks, e.g. severe cracking and spalling of the concrete cover. Since crack width is easily recordable in routine visual inspections there is a motivation to use it as an appropriate indicator of condition of RC bridge elements in decision making process of bridge management. While few existing research in literature dealing with spatial variation of corrosion-induced cracking of RC structures is based on empirical models, in this paper the extent and likelihood of severe cracking of a hypothetical bridge deck during its lifetime is calculated based on a recently proposed analytical model for corrosion-induced crack width. Random field theory has been utilized to account for spatial variations of surface chloride concentration, as environmental parameter, and concrete compressive strength and cover depth as design parameters. This analysis enables to track evolution of cracking process, spatially and temporally, and predict the time for the first repair of bridge deck based on acceptable extent of cracked area. Furthermore based on a sensitivity analysis it is concluded that increasing cover depth has a very promising effect in delaying corrosion phenomenon and extension of the service life of bridge decks.}, Keywords = { Bridge, Corrosion, Crack Width, Random Field}, volume = {9}, Number = {3}, pages = {183-192}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-491-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-491-en.docx}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Kaveh, Ali and Sabzi, Omi}, title = {A comparative study of two meta-heuristic algorithms for optimum design of reinforced concrete frames}, abstract ={This article presents the application of two algorithms: heuristic big bang-big crunch (HBB-BC) and a heuristic particle swarm ant colony optimization (HPSACO) to discrete optimization of reinforced concrete planar frames subject to combinations of gravity and lateral loads based on ACI 318-08 code. The objective function is the total cost of the frame which includes the cost of concrete, formwork and reinforcing steel for all members of the frame. The heuristic big bang-big crunch (HBB-BC) is based on BB-BC and a harmony search (HS) scheme to deal with the variable constraints. The HPSACO algorithm is a combination of particle swarm with passive congregation (PSOPC), ant colony optimization (ACO), and harmony search scheme (HS) algorithms. In this paper, by using the capacity of BB-BC in ACO stage of HPSACO, its performance is improved. Some design examples are tested using these methods and the results are compared.}, Keywords = {Structural optimization, Reinforced concrete plane frames, Big Bang-Big Crunch algorithm, Particle swarm, Ant colony optimization}, volume = {9}, Number = {3}, pages = {193-206}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-477-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-477-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Arabzadeh, Abolfazl and Aghayari, Reza and Rahai, Ali Rez}, title = {Investigation of experimental and analytical shear strength of reinforced concrete deep beams}, abstract ={An experimental-analytical investigation was conducted to study the behavior of high-strength RC deep beams a total of sixteen reinforced concrete deep beams with compressive strength in range of 59 MPaOf;#39c O65 MPa were tested under two-point top loading. The shear span-to-effective depth ratio a/d was 1.10 all the specimens were simply supported and reinforced by vertical, horizontal and orthogonal steel bars in various arrangements. The test specimens were composed of five series based on their arrangement of shear reinforcing. The general behavior of tested beams was investigated. Observations were made on mid-span and loading point deflections, cracks form, failure modes and shear strengths. The test results indicated that both vertical and horizontal web reinforcement are efficient in shear capacity of deep beams, also the orthogonal shear reinforcement was the most efficient when placed perpendicular to major axis of diagonal crack. Concentrating of shear reinforcement within middle region of shear span can improve the ultimate shear strength of deep beam. The test results were then compared with the predicted ultimate strengths using the ACI 318-08 provisions ACI code tended to either unsafe or scattered results. The performed investigations deduced that the ACI code provisions need to be revised.}, Keywords = {Deep beams, Strut-and-tie, Shear strength, Shear reinforcement}, volume = {9}, Number = {3}, pages = {207-214}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-478-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-478-en.docx}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Bakhtiyari, S. and Allahverdi, A. and Rais-Ghasemi, M. and Ramezanianpour, A. A. and Parhizkar, T. and Zarrabi, B. A.}, title = {Mix design, compressive strength and resistance to elevated temperature (500°C) of self-compacting concretes containing limestone and quartz fillers}, abstract ={Self Compacting Concrete (SCC) specimens with limestone (L) and quartz (Q) powders were formulated. The influence of the type of the powder on the properties of fresh and hardened concrete was evaluated. Dense packing theories were used for mix design of samples. The equation of Fuller and Thompson for particle size distribution (PSD) of aggregates was modified with considering fine particles and a proper PSD curve was obtained for SCC. Experimental results showed that this method needs use of less powder content and results in higher strength/cement ratio compared to traditional mixing methods. No significant difference was observed between the compressive strengths of specimens containing limestone (L-specimens) and quartz (Q-specimens) powders, with similar proportions of materials. The residual compressive strength of specimens was examined at 500°C and contradictory behaviors were observed. One Q-specimen suffered from explosive spalling, while no spalling was occurred for L-specimens. On the other hand, the residual strength of remained Q-specimens showed considerable increase compared to L-specimens. The results show the necessity for more detailed investigations considering different effective parameters.}, Keywords = {Concrete, Self-compacting, Mix design, Packing density, Fire resistance}, volume = {9}, Number = {3}, pages = {215-222}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-403-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-403-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Ghasemzadeh, Hasan and AkbariJalalabad, Esmat}, title = {Computing the compressive strength of carbon nanotube/cement composite}, abstract ={In this study compressive strength of carbon nanotube (CNT)/cement composite is computed by analytical method. For this purpose representative elementary volume (REV) as an indicator element of composite is chosen and analyzed by elasticity relationships and Von mises;#39 criterion applied to it. It is assumed that carbon nanotubes are distributed uniformly in the cement and there is perfect bonding in the interface of cement and nanotube. At first for simplicity of computations, carbon nanotubes ( CNTs) are assumed to have unidirectional orientation in the cement matrix. In following, the relations are generalized to consider random distribution of nanotubes in cement, and a new factor suggested for random orientation of fibers in the CNT/cement composite. The results of analytical method are compared with experimental results.}, Keywords = {Compressive strength, Carbon nanotube (CNT), Cement matrix, Random orientation of fibers, Analytical solution}, volume = {9}, Number = {3}, pages = {223-229}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-490-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-490-en.docx}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Maghsoudi, A.A. and aMohamadpour, Sh. and Maghsoudi, M.}, title = {Mix design and mechanical properties of self compacting light weight concrete}, abstract ={Considering normal concrete (NC) the type of concrete need to be vibrated after placing in the formwork, Lightweight concretes have been successfully applied in the building constructions for decades because of their low specific weight in connection with a high strength, a high capacity of thermal insulation and a high durability. The development leading to a self compacting light weight concrete (SCLWC) represents an important innovative step in the recent years. This concrete combines the favorable properties of a lightweight concrete with those of a self compacting concrete (i.e., the type of concrete need no vibration after placing in the formwork). Research work is aimed on development of (SCLWC) with the use of light weight aggregates " Light expand clay aggregate (Leca)". In this investigation, by trial and error procedure, different mix design of SCLWC were caste and tested to reach a so called standard self compacting concrete in fresh matrix phase such as values of slump flow, L-box, V-funnel and in hardened phase, the 28 day compressive strength. Based on the results obtained, for two best so-called standard mix design of SCLWC the stress-strain diagrams are drawn and discussed. Also by three different methods, the modulus of elasticity of SCLWC are obtained and discussed here. It was found that a brittle mode of failure is governed in SCLWC.}, Keywords = {Mix design, Fresh properties Leca, SCLWC}, volume = {9}, Number = {3}, pages = {230-236}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-376-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-376-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Abbasnia, Reza and Mirzadeh, Neda and Kildashti, Kamyar}, title = {Assessment of axial force effect on improved damage index of confined RC beam-column members}, abstract ={In recent years, different damage indexes have been introduced in engineering literature. The most prominent one among other counterparts is the 1985 Park and Ang;#39s damage index (DIPA), which demonstrates well calibration against experimental results. Hence, it has traditionally had broad application in the field of structural engineering. Commonly, in DIPA relevant parameters are assessed based on plastic-hinge approach, which is not well suited to consider the coupled response between stress resultants (axial force and flexural moment) especially in grossly nonlinear domain. The reason is that named approach is utilized constant shape plastic moment-curvature curve, which is not capable of varying the shape throughout loading history. Another drawback of plastic-hinge method is the difficulty of representing precisely partial yielding of the cross-section. To remedy the situation, the fiber discretization technique is used in this paper. Based on the fiber discretization strategy, not only have the stiffness and strength degradation been characterized more accurately, but also the distribution of plasticity along the plastic zone has been considered. Besides, the multi-directional effect of axial force and flexural moment is considered to assess DI parameters. Additionally, this strategy directly incorporates the effect of transverse confinement into cross sectional constitutive behaviour.}, Keywords = {Damage index, Fiber discretization, Multi-directional effect, Transverse confinement}, volume = {9}, Number = {3}, pages = {237-246}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-237-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-237-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Miraboutalebi, M. and Askari, F. and Farzaneh, O.}, title = {Effect of bedrock inclination on seismic slope stability according to Iran seismically data}, abstract ={In this paper, the effect of bedrock inclination on seismic performance of slopes is investigated. The study was conducted based on dynamic analysis of different slopes, evaluation of the earthquake acceleration in sliding mass, and calculating the permanent displacement of the slope, using Newmark sliding block. The investigation indicates that variation of the bedrock inclination may cause the acceleration magnitude and the displacement in the sliding mass to reach to their maximum level. This may happen in conditions that the mean period of the acceleration time history on failure surface (Tmt) and the predominant period of the slope (Ts ) are close to each other. Typical results are presented and discussed. A two dimensional model of a typical slope was considered and conducting dynamic analyses, the slope performance was studied for different geometries, strength parameters and shear wave velocities. Such a performance has been studied by assessing the record of acceleration in sliding mass (the mass above the critical sliding surface) and calculating the slope displacement using Newmark method. It is shown that neglecting the effect of bedrock inclination, would lead to non-real results in assessing the seismic slope performance.}, Keywords = {Permanent displacement, Seismic slope performance, Acceleration of the sliding mass}, volume = {9}, Number = {4}, pages = {247-254}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-264-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-264-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Hassanipour, A. and Shafiee, A. and Jafari, M.K.}, title = {Low-amplitude dynamic properties for compacted sand-clay mixtures}, abstract ={Shear modulus and damping ratio are important input parameters in dynamic analysis. A series of resonant column tests was carried out on pure clays and sand-clay mixtures prepared at different densities to investigate the effects of aggregate content, confining stress, void ratio and clay plasticity on the maximum shear modulus and minimum damping ratio. Test results revealed an increase in the maximum shear modulus of the mixture with the increase in sand content up to 60%, followed by a decrease beyond this value. It was also found that the maximum shear modulus increases with confining stress, and decreases with void ratio. In addition, minimum damping ratio increases with sand content and clay plasticity and decreases with confining stress. Finally, on the basis of the test results, a mathematical model was developed for the maximum shear modulus.}, Keywords = {Maximum shear modulus, Minimum damping ratio, Sand-clay mixture, Mathematical model}, volume = {9}, Number = {4}, pages = {255-264}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-302-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-302-en.pdf}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {MoghaddasTafreshi, S. N. and TavakoliMehrjardi, Gh. and Ahmadi, M.}, title = {Experimental and numerical investigation on circular footing subjected to incremental cyclic loads}, abstract ={The results of laboratory model tests and numerical analysis on circular footings supported on sand bed under incremental cyclic loads are presented. The incremental values of intensity of cyclic loads (loading, unloading and reloading) were applied on the footing to evaluate the response of footing and also to obtain the value of elastic rebound of the footing corresponding to each cycle of load. The effect of sand relative density of 42%, 62%, and 72% and different circular footing area of 25, 50, and 100cm2 were investigated on the value of coefficient of elastic uniform compression of sand (CEUC). The results show that the value of coefficient of elastic uniform compression of sand was increased by increasing the sand relative density while with increase the footing area the value of coefficient of elastic uniform compression of sand was decreases. The responses of footing and the quantitative variations of CEUC with footing area and soil relative density obtained from experimental results show a good consistency with the obtained numerical result using “FLAC-3D”.}, Keywords = {Experimental model, Numerical model, Coefficient of elastic uniform compression, Circular footing, Footing area,Sand relative density}, volume = {9}, Number = {4}, pages = {265-274}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-523-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-523-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {FarshbafAghajani, Hamed and Soroush, Abbas and TabatabaieShourijeh, Pilt}, title = {An improved solution to capillary rise of water in soils}, abstract ={Evaluating the rate and maximum height of capillary rise is of prime interest in unsaturated soil mechanics. Antecedent solutions to this problem have dwelled mostly on determining the maximum capillary rise height, overlooking moisture and suction changes in the capillary region. A comprehensive improved solution for the capillary rise of water in soils is presented. Salient features of the formulation including consideration of initial soil suction (if any) prior to capillary rise, and determination of water content variation in the capillary region are elaborately discussed. Results reveal that suction head variation within the capillary region is non-linear, where the curvature decreases as water rises to higher elevations. The solution is verified and compared with existing solutions, by means of two sets of experimental data available in the literature. The comparison suggests that the improved formulation is more accurate and versatile than previous solutions for capillary rise.}, Keywords = {Unsaturated soils, capillary rising, unsaturated transient seepage, suction}, volume = {9}, Number = {4}, pages = {275-281}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-413-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-413-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Majidi, A. R. and Mirghasemi, A.A. and Arabshahi, M.}, title = {Three dimensional bearing capacity analysis of shallow foundations using discrete element method}, abstract ={In the current study, an effort is made to determine three dimensional bearing capacity of rectangular foundations using Discrete Element Method. The soil mass is modeled as discrete blocks connected with Winkler springs. Different factors affect the geometry of failure surface. Six independent angles are used to define the failure surface. By trial and error, the optimum shape of failure surface beneath the foundation can be found. The paper includes the derivation of the governing equations for this DEM based formulation in three dimensional state as well as parametric sensitivity analyses and comparison with other methods. Moreover, using the current method, bearing capacity coefficients are presented for various friction angles and foundation aspect ratios.}, Keywords = {3 Dimensional, Bearing capacity, Shallow foundations/footings, Discrete element method, Numerical modeling/analysis}, volume = {9}, Number = {4}, pages = {282-292}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-374-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-374-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Jahanandish, M. and Veiskarami, M. and Ghahramani, A.}, title = {Investigation of foundations behavior by implementation of a developed constitutive soil model in the ZEL method}, abstract ={Foundations behavior is affected by soil behavior which can vary from dilative to contractive depending on the stress level, particularly in dense frictional soils. The Zero Extension Lines (ZEL) method has been generally developed to predict the foundations behavior. Knowledge of soil behavior enables the ZEL method to predict the general and local shear failure modes. In this paper, a relatively simple work hardening/softening soil constitutive model is developed to represent dense frictional soils behavior under different stress levels. This model is based on the accumulation of the plastic work during a simple direct shear test and its relationship to stress ratio to establish the hardening law. Verifications have been made for the developed soil model. The model is then implemented into the ZEL method to theoretically investigate the bearing capacity and load-displacement behavior of foundations over dense frictional soils. Utilization of this model enables the ZEL method to capture different modes of failure depending on the foundation size. A numerical study on foundations behavior was performed showing the ability of the presented approach in capturing both failure modes.}, Keywords = {Constitutive soil model, Plasticity, Foundation, Stress level, ZEL}, volume = {9}, Number = {4}, pages = {293-306}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-446-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-446-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} } @article{ author = {Hassanlourad, M. and Salehzadeh, H. and Shahnazari, H.}, title = {Undrained triaxial shear behavior of grouted carbonate sands}, abstract ={The effects of cementation and the physical properties of grains on the shear behavior of grouted sands are investigated in this paper. The consolidated-undrained triaxial shear behavior of three grouted carbonate sands with different physical properties, including particle size distribution, particle shape and void ratio, was studied. Two sands were obtained from the north shores of the Persian Gulf, south of Iran, called Hormoz and Kish islands sands, and one sand was obtained from the south beaches of England and called Rock beach sand. The selected sands were grouted using a chemical grout of sodium silicate and tested after one month of curing. Test results showed that the effect of bonding on the shear behavior and strength depends on the bond strength and confining pressure. In addition, the shear behavior, yield strength and shear strength of grouted sands under constant conditions, including the initial relative density, bonds strength, confining pressure and loading, were affected by the physical properties of the sands. Furthermore, the parameters of the Mohr-Coulomb shear strength failure envelope, including the cohesion and internal friction angle of grouted sands under constant conditions, were affected by the physical properties and structure of the soils.}, Keywords = {Carbonate sands, Triaxial test, Grouting, Sodium silicate}, volume = {9}, Number = {4}, pages = {307-314}, publisher = {}, title_fa = {}, abstract_fa ={}, keywords_fa = {}, url = {http://ijce.iust.ac.ir/article-1-275-en.html}, eprint = {http://ijce.iust.ac.ir/article-1-275-en.doc}, journal = {International Journal of Civil Engineering}, issn = {1735-0522}, eissn = {2283-3874}, year = {2011} }