bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Rail Defects on Track Impact Factors
Authors: Fesharaki Mohammad , Wang Ton-Lo
Published: September 2019

This paper investigates the effect of rail surface flaws on track impact factors for different track and vehicle conditions. For this purpose, a three dimensional vehicle and track as an integrated system modelled. The vehicle, consists car body, bogie frames and wheelsets, is able to model displacements in vertical and lateral directions. Hertz nonlinear springs utilized to connect vehicle to track structure and simulate the interaction between vehicle and track subsystems. Track comprises rail, rail pads, sleepers and ballast materials. For each subsystem, matrices of mass, stiffness and damping were formed and then matrices of total vehicle-track system considering their interaction were solved. Using FRA spectral density functions for rail irregularities, response of track with different qualities to train dynamic forces obtained. Rail random irregularities, rail corrugation and rail joint defects as three common rail defects have been considered in this paper. For each defects the influence of different track and train parameters on impact factor has been studied. The results of study indicate substantial effect of the depth and frequency of the rail flaws on impact factors. This paper has also considered the impact of vehicle speed on dynamic forces and found the critical speed for each case.
Numerical Detection of Cavitation Damage on Dam Spillway
Authors: Fadaei-Kermani E , Barani G. A , Ghaeini-Hessaroeyeh M.
Published: September 2019

The present paper deals with the numerical detection of cavitation damage level and location on dam spillways. At first, flow over a spillway was simulated using the computational fluid dynamics method. The flow characteristics such as pressure, velocity and depth through the spillway have been calculated for five different flow rates. Since the actual flow is turbulent, the RNG turbulence model has been used for simulation. The numerical results of flow characteristics including flow depth, velocity and pressure were compared with the available results of the hydraulic model tests. The numerical results agreed well with the experimental data, and reasonable values for the normalized root mean square error (NRMSE= 0.0476) and coefficient of determination (r2=0.8354) indicated that the numerical model is accurate. Finally occurrence of cavitation damage to the Doosti dam spillway was investigated. Based on cavitation index, five different damage levels from no damage to major damage have been considered. Results showed that the spillway may be at the risk of cavitation damage, and the serious damage can occur at ending parts of the structure.
Numerical Simulation of Impulsive Water Waves Generated by Subaerial and Submerged Landslides Incidents in Dam Reservoirs
Authors: Khoolosi Vafa , Kabdaşli Sedat
Published: September 2019

The water wave generation by a freely falling rigid body is examined in this paper. Landslides on the margins of dam reservoirs may generate large waves that can produce flooding over the banks or overtopping the dam crest. In the present investigation, landslide generated waves are studied using a numerical model based on Navier-Stokes equations. Impulse wave amplitude, period, energy is studied in this work. The effects of bed slope angle on energy conversion from slide into wave are also investigated, and the numerical model we used in this study is the full three dimensional commercial code Flow-3D. Results of the Navier-Stokes model show that waves generated are highly dependent upon the details of slide mechanism and kinematics. Numerical solutions for the velocity fields, pressure distributions, and turbulence intensities in the vicinity of the falling rigid body are also presented. Results show that the general pattern of wave in all cases is the same but the amplitude and period are different. Data analysis shows that the maximum wave crest amplitude in subaerial induced waves is strongly affected by bed slope angle, landslide impact velocity, thickness, kinematics and deformation and by landslide shape.
Effects of Hybridization of Carbon and Polypropylene Short Fibers as Reinforcement on Flexural Properties of Fine Aggregate Concretes
Authors: Halvaei Mana , Jamshidi Masoud , Latifi Masoud
Published: September 2019

Nowadays, the advantages of short fibers as reinforcement in cement based materials are well known. In this paper, the effect of hybridization of short polypropylene (PP) and carbon fibers on flexural properties of a fine aggregate concrete has been investigated. Samples with dimensions of  containing 2 vol% of the polypropylene and carbon fibers with 6 and 8mm length were made. The PP to carbon fiber proportion in the samples were selected as 100:0, 75:25, 50:50, 25:75 and 0:100. A four-point bending test was carried out on all the samples to investigate the flexural behaviour. It was found that the addition of carbon fibers significantly increases the flexural load (i.e. 260%). The application of PP fibers leads to a 2590% increase in the toughness compared to the control sample. It was also found that the sample with carbon to PP ratio of 75/25 shows the optimum results and it leads to 190% and 2070% increment in the flexural load and toughness, respectively, in comparison to the control sample.
Geotechnical Properties of Lateritic Soil Stabilized with Ground-Nut Husk Ash
Authors: Nnochiri Emeka Segun , Ogundipe Olumide Moses
Published: September 2019

This study assesses the geotechnical properties of lateritic soil stabilized with Ground-nut Husk Ash. Preliminary tests were carried out on the natural soil sample for identification and classification purposes, while consistency limits tests were thereafter carried out as well. Engineering property tests such as California Bearing Ratio (CBR), Unconfined Compressive Strength (UCS) and compaction tests were performed on both the natural soil sample and the stabilized lateritic soil, which was stabilized by adding Ground-nut Husk Ash, GHA, in percentages of 2, 4, 6, 8 and 10 by weight of the soil.  The results showed that the addition of GHA enhanced the strength of the soil sample. The Maximum Dry Density (MDD) reduced from 1960 kg/m3 to 1760 kg/m3 at 10% GHA by weight of soil. The Optimum Moisture Content (OMC) increased from 12.70% to 14.95%, also at 10% GHA by weight of soil. The unsoaked CBR values increased from 24.42% to 72.88% finally, the UCS values increased from 510.25 kN/m2 to 1186.46 kN/m2, for both CBR and UCS, the values were at 10% GHA by weight of soil. It was therefore concluded that GHA performs satisfactorily as a cheap stabilizing agent for stabilizing lateritic soil especially for subgrade and sub base purposes in road construction.
Analytical and Laboratory Evaluation of the Solubility of Gypsiferous Soils
Authors: Afsharian Aliabbas , Abbasi Nader , Khoserowjerdi Amir , Sedghi Hossein
Published: September 2019

Gypsum soil is one of the problematic soils because of considerable solubility for Gypsum particles in contact with water. In this research the effects of three factors including; gypsum percent, hydraulic gradient and soil texture were studied on solubility of gypsum soils. To do this, samples of gypsum soils were provided artificially by adding various rates of natural gypsum rock including 0, 5, 10, 20 and 30 percent weight of 3 kinds of soil textures including clay, silty clay and sand. Totally, 15 types of gypsum soils were prepared. Then each of gypsum soils were leached under five hydraulic gradients levels 0.5, 1, 2, 5 and 10. The results of the test indicated that the rate of Gypsum in the soil had direct effect on the rate of soluble and by increasing the percent of Gypsum, the rate of solubility was increased. In addition, by increasing hydraulic gradient, the speed of water existing soil media in a specified time was increased and also higher rate of Gypsum was derived. Also the soil texture has a considerable effect on the rate of solubility of soil. In this study, rate of solubility of gypsum soils with sandy soils was determined as 1.5 to 2 times more than the rate of clay soils. The   statistical   results show the highest impact of gypsum percentage and lowest impact of hydraulic gradient soil on solubility of particles in different types of soils and it has no significant effect on the overall equation of the soil texture.
Thermal-Mechanical Coupled Manufacturing Simulation in Heterogeneous Materials
Authors: El Amri Abdelouahid , El Yakhloufi Haddou M. , Khamlichi A.
Published: September 2019

This work is aimed to investigate on thermal and thermo-mechanical behaviour of 6061 Aluminium alloy. The main target of the present investigation is to apply a numerical procedure to assess the thermo-mechanical damage. Finite element analyses of the notched tensile specimens at high temperature have been carried out using ABAQUS Software. The objective was to study the combined effects of thermal and mechanical loads on the strength and ductility of the material. The performance of the proposed model is in general good and it is believed that the presented results and experimental–numerical calibration procedure can be used in practical finite-element simulation.
Reviewing of the Simulation Models in Cost Management of the Construction Projects
Authors: Al-Zwainy Faiq Mohammed Sarhan , Amer Reem , Khaleel Tareq
Published: September 2019

Simulation and computational techniques cover a variety of aspects also had proved its feasibility in construction management as whole, so it had adopted by a lot of researches during the last decades with rapid progress. The current study presents a focused review about construction cost simulation using, and provides an overview of such advancements achieved between 1990 and 2016 in construction management sector. This paper focuses specifically on many different topics including construction cost simulation, simulation modelling concept, steps of simulation conducting, simulation purposes, simulation advantages and disadvantages, etc.  Major advances in construction cost simulation area are highlighted, as well as the trends for development and application. Over the selected study period, there has been a substantial increase in the use of high-fidelity simulation in construction cost management.
A Study on the Contributing Factors of Major Landslides in Malaysia
Authors: Kazmi Danish , Qasim Sadaf , Harahap I.S.H , Baharom Syed , Imran Muhammad , Moin Sadia
Published: September 2019

Landslide is one of the most prominent geo-hazard that accounts for colossal losses every year. The contributing factors of landslides in Malaysia are reasonably different from rest of the world. According to a study, the most dominant factor that catalysis the slope failure in many countries of the world is geological conditions. However, in case of Malaysia; most of the landslides occur as a consequence of flawed design, improper construction and non-maintenance of slopes which correlates with the human errors. The statistics of Malaysia shows that highest number of landslides took place in 1996 with 71 cases which is followed by 68 cases in 1995. According to the findings of Highland Towers (1993) landslide, the main causes of failure were inaccuracies in design, poor supervision during the construction and inadequate drainage system. Similarly, in case of Taman Hillview and Bukit Antarabangsa landslide, it has been revealed that improper design practices and poor drainage system supplemented with prolonged rain were the significant causes of the cataclysm. Therefore, based on the investigations on retrospective landslides, this study proposes to incorporate Human Reliability Assessment technique as a part of working strategy for slopes along with strong adherence to the design guidelines in order to minimize the likelihood of landslides.
BIM for Facility Management: Challenges and Research Gaps
Authors: Naghshbandi S. Neda
Published: September 2019

This writing presents research gaps in the area of Building Information Modelling (BIM) in Facility Management (FM) industry, and identifies practical challenges that facility management professionals are facing in utilizing BIM. Although this issue, BIM for Facility Management, has gained attention both in literature and practice, and it is highly demanded in FM industry, still it is far away from effective implementation. It is not clear for facility manager whether BIM is helpful to accelerate the process or it is a cost effective solution, and what skills are required for them. The key for effective BIM implementation in FM industry is to enhance collaboration among different parties in project lifecycle. However, still there is a doubt about the importance of FM in Construction industry. In other words, construction does not understand FM. Furthermore, there are issues over interoperability and data exchange. Thus, to assist BIM implementation, it is required to prove the correctness of benefits, uses, and challenges identified in the literature. This paper uses an intensive literature review and highlights the potential research issues in terms of BIM for FM to assist effective implementation of BIM in facility management phase of projects.
Response of Steel Moment and Braced Frames Subjected to Near-Source Pulse-Like Ground Motions by Including Soil-Structure Interaction Effects
Authors: Ayough Pooriya , Mohamadi Sara , Seiyed Taghia Seyed Ali Haj
Published: September 2019

Most seismic regulations are usually associated with fixed-base structures, assuming that elimination of this phenomenon leads to conservative results and engineers are not obliged to use near-fault earthquakes. This study investigates the effect of soil–structure interaction on the inelastic response of MDOF steel structures by using well known Cone method. In order to achieve this, three dimensional multi-storey steel structures with moment and braced frame are analysed using non-linear time history method under the action of 40 near-fault records. Seismic response parameters, such as base shear, performance of structures, ductility demand and displacement demand ratios of structures subjected to different frequency-contents of near-fault records including pulse type and high-frequency components are investigated. The results elucidate that the flexibility of soil strongly affects the seismic response of steel frames. Soil–structure interaction can increase seismic demands of structures. Also, soil has approximately increasing and mitigating effects on structural responses subjected to the pulse type and high frequency components. A threshold period exists below which can highly change the ductility demand for short period structures subjected to near-fault records.
Development of a PSO-ANN Model for Rainfall-Runoff Response in Basins, Case Study: Karaj Basin
Authors: Motahari Meysam , Mazandaranizadeh Hamed
Published: September 2019

Successful daily river flow forecasting is necessary in water resources planning and management. A reliable rainfall-runoff model can provide useful information for water resources planning and management. In this study, particle swarm optimization algorithm (PSO) as a metaheuristic approach is employed to train artificial neural network (ANN). The proposed PSO-ANN model is applied to simulate the rainfall runoff process in Karaj River for one and two days ahead. In this regard, different combinations of the input variables including flow and rainfall time series in previous days have been taken under consideration in order to obtain the best model's performances. To evaluate efficiency of the PSO algorithm in training ANNs, separate ANN models are developed using Levenberg-Marquardt (LM) training algorithm and the results are compared with those of the PSO-ANN models. The comparison reveals superiority of the PSO algorithm than the LM algorithm in training the ANN models. The best model for 1 and 2 days ahead runoff forecasting has R2 of 0.88 and 0.78. Results of this study shows that a reliable prediction of runoff in 1 and 2 days ahead can be achieved using PSO-ANN model. Overall, results of this study revealed that an acceptable prediction of the runoff up to two days ahead can be achieved by applying the PSO-ANN model.
Investigation of Soil Structure Interaction and Wall Flexibility Effects on Natural Sloshing Frequency of Vessels
Authors: Abbasi Maedeh Pouyan , Ghanbari Ali , Wu Wei
Published: September 2019

The main purpose of this study is to establish the effects of vessel walls flexibility on its natural sloshing frequency considering soil-structure-fluid interaction theory. Furthermore, two new efficiently relations to find both of wall flexibility and soil-structure interaction effects on natural frequency are developed. Regarding the aim of current study three different conditions of elevated tanks are applied. Fixed base condition with an emphasis on recommendations of international code ACI-350, analytical FSSI regarding equivalent mass spring method, and the numerical direct method regarding theory of finite element are taken into consideration. Results indicate that there is no significant effect of walls flexibility on natural sloshing frequency regarding fixed base assumptions of vessels. On the contrary, significant effects of wall flexibility are achieved considering SSI theory. Results of international code ACI-350 show that, the international codes assumptions have imprecise estimations of natural sloshing frequency in the range of hard to very soft soil categories.  On the other hand, it is observed that the wall flexibility has a more highlighted effect on natural frequency in soft soils rather than soil-structure interaction. The significance of wall flexibility effect on natural frequency is more than that of SSI considering soil softening.
Evaluation of Load-Bearing Performance of Existing Cast Steel Node
Authors: Su Yusheng , Li Xinkui , Wu Xiaoping
Published: September 2019

This paper presents a preliminary evaluation of the load-bearing performance of an existing cast steel node in a constructed tennis stadium using numerical simulations and non-destructive field tests. Given the absolute stress values of the existing cast steel node were immeasurable, the accuracy of the numerical simulations were verified by comparing the stress increments derived from numerical simulations and non-destructive field tests. During the experiment, the existing cast steel node was loaded indirectly by moving the retractable roof to three different positions (i.e. closed, semi-opened and fully-opened configurations); thus, only the stress increments were recorded. Three simplified truss models and one solid finite-element model were developed to simulate the stress distributions with the corresponding roof positions. A comparison suggests that the stress increments simulated with the developed finite-element models were in good agreement with experimental results. Therefore, the simulated stress distributions can be used to judge the load-bearing performance of the existing cast steel node.
Comparing Seismic Performance of Steel Structures Equipped with Viscous Dampers and Lead Rubber Bearing Base Isolation under Near-Field Earthquake
Authors: Ganji Mohammad , Kazem Hossein
Published: September 2019

In the present research, seismic behaviours of a steel frame equipped with either viscous damper or lead-core rubber bearings (LRB) isolator were evaluated and compared under the effect of near-fault earthquake records. For this purpose, three buildings of 5, 10, and 15 stories equipped with lateral bearing systems composed of steel moment-resisting frames were subjected to 7 near-fault earthquake accelerogram pairs at earthquake hazard levels 1 and 2, so as to evaluate their responses under three scenarios, namely without any energy dissipation system, with viscous damper, and with LRB isolator, using dynamic analysis of time history utilizing PERFORM 3D v5 software. The results were indicative of enhancement in seismic performance of the viscous damper-equipped structures at earthquake hazard level 1, as the corresponding performance level was enhanced from life safety to uninterrupted usability, while no significant seismic performance level enhancement was determined at seismic level 2. Seismic isolator-equipped structures were also associated with seismic performance level enhancement from life safety to uninterrupted usability at both earthquake hazard levels. Relative lateral displacement at floor levels in damper-equipped structures and seismic isolator-installed buildings were found to be about 29% and 68% improved over that of the structure with no energy dissipation system. Results of distribution of shear forces within structures equipped with viscous damper and seismic isolator, as compared against that of the structures with no energy dissipation system, indicted increased and decreased shear forces, respectively..
Evaluation of the Performance of Rainwater Harvesting Systems for Domestic Use in Tlalpan, Mexico City
Authors: Nolan Niall Patrick , Lartigue Cecilia
Published: September 2019

Rainwater harvesting (RWH) as an alternative means of providing water in domestic contexts, is viewed as an effective supply option worldwide. In Mexico City, the water situation is critical and the provision of water services to the population represents a formidable challenge for the city’s water utilities. The main objective of this study is to evaluate the potential for RWH to supply domestic properties in Tlalpan, 1 of 16 delegations in the city with one of the highest percentages of homes unconnected to the distribution network. Results show RWH can meet 88% of household water demand during the 6 month wet season, with an annual saving of 55%. Modelling a World Health Organisation minimum demand of 20 l/p/d as a means of resilience management in the event of a water crisis, 6-month and annual savings were 99% and 80% respectively. The minimum tank size to achieve wet season savings of 90% was 6m3 in two precipitation bands and tank sizes of 13,000 – 17,000L were sufficient in 3 out of 4 to prevent overspill. The report concludes RWH is a viable method of providing water in the south of the city and should be part of an integrated water management solution.
Development Behavior for Post-Tensioned Self-Centering Steel Connection under Cyclic Loading
Authors: Torabipour Ahmadreza , Shiravand M. R.
Published: September 2019

One of the newest steel beam-column joints to replace conventional welded connections, post-tensioned connection steel is with the upper and lower angles. In this connection are high-strength steel strands that parallel beam web and angles between beams and column. Actually high resistance strands and upper and lower angles respectively are provider centralization properties and energy dissipation capacity of the connection. The benefits of post-tensioned steel can be used in connection with the centralization and lack of relative displacement (drift) persistent, stay elastic core components such as connecting beams, columns and fountains connection, appropriate initial stiffness and joint manufacture with materials and traditional skills. . In this study, numerical modelling in Abaqus software, the results of the analysis were compared with the results of laboratory samples and the results showed that the two together are a perfect match. After validation, parameters influential centrist connection then pulled the thick angles in three numerical models were evaluated.  The results show that by increasing the thickness of the angles, increase energy dissipation capacity and ductility connection and the β₁ value does not experience tangible changes with changes in angle thickness.
Slope Remediation Techniques and Overview of Landslide Risk Management
Authors: Kazmi Danish , Qasim Sadaf , Harahap I.S.H , Baharom Syed , Mehmood Mudassir , Siddiqui Fahad Irfan , Imran Muhammad
Published: September 2019

Slope failures are common in many parts of the world which occur due to manifold reasons and they result in huge losses to the respective locals. This study evaluates the initiatives that can enhance the safety of slope by considering the remedial measures to deal with the factors causing slope instability and discusses the application of risk management strategies to address the problems that can cause the slope to fail. The methods for the remediation of slope include modification in slope geometry, drainage, use of retaining structures and internal slope reinforcement. This study also discusses the risk management process which is a hierarchical procedure that includes assessment and control of risk through different techniques in order to manage the uncertainties associated with the slope. It has been observed that the implementation of risk management strategy aids in the proper identification of risk and its severity which dictates the selection of appropriate remedial measure for the rectification of slope. For reducing the number of landslides, this study suggests the use of risk based strategies to curtail the chances of slope failure.
State of the Art: Mechanical Properties of Ultra-High Performance Concrete
Authors: Baqersad Mohamadtaqi , Sayyafi Ehsan Amir , Mortazavi Bak Hamid
Published: September 2019

During the past decades, there has been an extensive attention in using Ultra-High Performance Concrete (UHPC) in the buildings and infrastructures construction. Due to that, defining comprehensive mechanical properties of UHPC required to design structural members is worthwhile. The main difference of UHPC with the conventional concrete is the very high strength of UHPC, resulting designing elements with less weight and smaller sizes.  However, there have been no globally accepted UHPC properties to be implemented in the designing process. Therefore, in the current study, the UHPC mechanical properties such as compressive and tensile strength, modulus of elasticity and development length for designing purposes are provided based on the reviewed literature. According to that, the best-recommended properties of UHPC that can be used in designing of UHPC members are summarized. Finally, different topics for future works and researches on UHPC’s mechanical properties are suggested.
Experimental Investigation of RC Exterior Beam Column Connection with Eccentric Beam Subjected to Reversible Quasi Static Loads
Authors: Asran Ahmed G. , EL-Esnawi Hassan H. , Fayed Sabry Elmorsy
Published: September 2019

Insufficiency of the Beam Column Joint (BCJ) caused structures failures particularly in case of the earthquakes. In most of the buildings, the beam center line was not aligned with the column center line. So, the effect of the eccentricity of the beam was studied in this article. Behaviour of reinforced concrete (RC) eccentric beam-column joint under reversible cyclic loading was investigated experimentally. The experimental program is one specimen. The specimen consisted of column and beam. The column divided into symmetry two parts (upper and lower parts). The beam fixed in middle of the column and it was free end. The main parameter was the effect of the eccentricity of the beam center line about the column center on behaviour of RC BCJ. The specimen was tested under reversible ten cycles. The horizontal displacement for the column and the vertical deflection at free end of the beam were recorded at each cycle. The crack pattern of the tested specimen was studied at every cycle in details. It was noticed that the eccentricity of the beam has concentrated more stresses on the joint side close to the eccentricity. The failure took place at the joint due to its weakness.
Forecasting by Stochastic Models to Inflow of Karkheh Dam at Iran
Authors: Hamidi Machekposhti Karim , Sedghi Hossein , Telvari Abdolrasoul , Babazadeh Hossein
Published: September 2019

Forecasting the inflow of rivers to reservoirs of dams has high importance and complexity. Design and optimal operation of the dams is essential. Mathematical and analytical methods use for understanding estimating and prediction of inflow to reservoirs in the future. Various methods including stochastic models can be used as a management tool to predict future values of these systems. In this study stochastic models (ARIMA) are applied to records of mean annual flow Karkheh river entrance to Karkheh dam in the west of Iran. For this purpose we collected annual flow during the period from 1958/1959 to 2005/2006 in Jelogir Majin hydrometric station. The available data consists of 48 years of mean Annual discharge. Three types of ARIMA (p, d, q) models (0, 1, 1), (1, 1, 1) and (4, 1, 1) suggested, and the selected model is the one which give minimum Akaike Information Criterion (AIC). The Maximum Likelihood (ML), Conditional Least Square (CLS) and Unconditional Least Square (ULS) methods are used to estimate the model parameters. It is found that the model which corresponds to the minimum AIC is the (4, 1, 1) model in CLS estimation method. Port Manteau Lack of fit test and Residual Autocorrelation Function (RACF) test are applied as diagnostic checking. Forecasting of annual inflow for the period from 2006 to 2015 are compared with observed inflow for the same period and since agreement is very good adequacy of the selected model is confirmed.
Numerical Modeling of Soil-Pile-Interaction with Near and Far Field Earthquake's Effects
Authors: Shahmohammadi Mehrjerdi Mohammad , Fallah Ahmad Ali , Tabatabaei Aghda S.T.
Published: September 2019

This paper studies Near and Far Field effects of the response of a column-pile to earthquakes considering Dynamic-Soil-Structure-Interaction (DSSI) effects in soft clay (Vs<180 m/s ) and stiff clay (180<Vs<375 m/s). Opensees software that can simulate the dynamic time history analysis is used. Both kinematic and inertial interactions are considered and Finite Element Method (FEM) is used to solve DSSI. The direct method applies to 3D modeling of the layered soil and column-pile. A Pressure Independ Multi Yield Surface Plasticity Model is used to simulate different kinds of clay behavior.  Time history seismic analyses provide for the mass and stiffness matrices to evaluate dynamic structural response with and without directivity effects for Near and Far Field earthquakes. Results show that the Multi-Yield-Surface-Kinematic-Plasticity-Model can be used instead of bilinear springs between piles and clay soil, for both Near Field and Far Field earthquakes. In addition, comparing Near and Far Field analyses, acceleration response spectrum at the top of the structure in the Far Field increases with the softness of the soil more than that in the Near field.
Fuzzy and Classical MCDM Techniques to Rank the Slope Stabilization Methods in a Rock-Fill Reservoir Dam
Authors: Shafiee Haghshenas Sina , Mikaeil Reza , Shaffiee Haghshenas Sami , Zare Naghadehi Masoud , Sirati Moghadam Pedram
Published: September 2019

Slope stabilization is one of the most crucial tasks in rock-fill reservoir dam projects to prevention of erosion and destruction of upstream and downstream slopes. Inappropriate choice and design of the protection can cause irreparable damages imposing additional costs and time to the project. In this paper, the body slope ranking is conducted by using the classical and fuzzy multi-criteria decision making approaches specifically VIKOR and Fuzzy-TOPSIS methods. To this aim, eight important and effective criteria were considered to select the most appropriate cover among five most common ones for protecting and conserving body slope of the rock-fill dams. The study was conducted on a dam in Bijar city located in the province of Guilan, the north of Iran. According to results of a comparative analysis using fuzzy and classical MCDM techniques, the concrete facing cover and the soil-cement cover have placed at the highest and lowest ranks to protect the body of the dam, respectively, suggested by both employed methods.
Influence of Parameters the Wall on Reinforced Soil Segmental Walls
Authors: Salah Eddine Baaziz , Mekki Mellas
Published: September 2019

The behaviour of retaining walls in geosynthetic reinforced soil is complex and requires studies and research to understand the mechanisms of rupture, the behaviour of the reinforcements in the soil and the behaviour of the main elements of the system: reinforcement-wall-soil. Several researches have been done on the use of geosynthetics as backfill massive reinforcement material (experimental studies, numerical analysis, reduced models ...). This parametric study was conducted to investigate the influence of numerical parameters of the wall which confront us in the projects, on the behaviour of walls on reinforced soil segmental walls.  A 3.6m high wall is composed of modular blocks of earth sand reinforced with four geogrids layers was modelled. The properties of materials, the wall geometry, and the boundary conditions will be explained later. The finite difference computer program FLAC3D was used in this study. The results of this numerical study allowed to deduce the importance of each parameter of the wall selected for the behaviour of retaining walls in soil reinforced by geogrid. The inclination of wall "W" is of great importance for the calculation of retaining walls in modular blocks and can provide an important contribution to the horizontal balance of this type walls. The value of lateral displacements of the facing tends to continuously decrease with the increase of "W". More the wall is inclined plus the horizontal stresses behind the wall and values of the tensile stress in the layers of geogrid "T" decrease in an expressive manner. The dimensions of modular blocks (types) and the mechanical characteristics of modular blocks (category) have a remarkable effect on the calculation of retaining walls in modular blocks reinforced with layers of geogrid.
Recycled Aggregate Self-curing High-strength Concrete
Authors: Bashandy Alaa Ali , Soliman Noha M. , Abd Elrahman Mahmoud Hamdy
Published: September 2019

The use of recycled aggregates from demolished constructions as coarse aggregates for concrete becomes a need to reduce the negative effects on the environment. Internal curing is a technique that can be used to provide additional moisture in concrete for more effective hydration of cement to reduce the water evaporation from concrete, increase the water retention capacity of concrete compared to the conventionally cured concrete. High strength concrete as a special concrete type has a high strength with extra properties compared to conventional concrete. In this research, the combination of previous three concrete types to obtain self-curing high-strength concrete cast using coarse recycled aggregates is studied. The effect of varying water reducer admixture and curing agent dosages on both the fresh and hardened concrete properties is studied. The fresh properties are discussed in terms of slump values. The hardened concrete properties are discussed in terms of compressive, splitting tensile, flexure and bond strengths. The obtained results show that, the using of water reducer admixture enhances the main fresh and hardened properties of self-curing high-strength concrete cast using recycled aggregate. Also, using the suggested chemical curing agent increased the strength compared to conventional concrete without curing.
Structure Analysis of Marine Pipes under the Effect of Water Explosion Force (Wave)
Authors: Khalifehei Kamran
Published: September 2019

Underwater explosion is a subject that has been paid attention to by many researchers. In this study the underwater explosion phenomena under shockwave loading is explored by numerical method. For this purpose, by modeling a marine pipe buried in the water by ABAQUS software, the effect of the shock wave and the damages were assessed. Then using the laboratorial results, the fluid-structure interaction and shock wave loading and its results were analysed. Finally, it was concluded from numerical modeling that the highest levels of strain on the pipe buried in the water under underwater explosion and shock wave loading occur in the ending parts of the pipe in both sides and away from explosion field.
Relationship between Texture and Uniaxial Compressive Strength of Rocks
Authors: Esmailzadeh Akbar , Behnam Shekar , Mikaeil Reza , Zare Naghadehi Masoud , Saei Salar
Published: September 2019

Uniaxial compressive strength (UCS) is one of the most important parameters of rocks that is routinely used in rock engineering designs. This parameter is influenced greatly by textural properties of rocks; hence it is possible to estimate it from quantified texture coefficient (TC). In this paper, fourteen different types of rocks were experimentally studied to evaluate the effect of texture coefficient on UCS. Thin sections were first prepared, and then some digital photographs were taken from each section and were digitized in computer. Then, the texture coefficient for all samples were calculated. Subsequently, UCS of the samples were measured in laboratory. Finally, relationships between TC and UCS of rock samples were evaluated and related mathematical equations were presented. Results showed that the UCS has a power relationship with TC which can be utilized for future estimation purposes.
Mechanical Behavior of Normal Concrete Reinforced with Kantharo Suter Fiber
Authors: Ahmed Syed Iftikhar , Shaikh Fahad Ali , Jakhrani Sadam Hussain , Mushtaq Muhammad Yousaf , Sidiqy Junaid Ahmad
Published: September 2019

Physical characteristics of concrete can be enhanced by addition of different materials in various proportions. Fibrous substances, such as, steel, synthetic, glass, and natural fibers not only increase the structural and tensile strength but also cohesion of concrete by overcoming micro cracks and deficiencies in concrete. In this study, the effect of Kantharo suter fibers (animal hair) on compressive, flexural and split tensile strength, and workability of plain concrete was determined. For that, experiments were conducted on concrete cubes, beams and cylinders by adding different proportions of Kantharo suter fibers from 0.125 to 1.0 percentage by weight of cement. In each proportion of Kantharo suter fibers, three cubes, three cylinders and one beam were casted and cured for 28 days. The acquired results were compared with the plain cement concrete specimens. It was discovered from the results that 0.375 percentages of Kantharo suter fibers in normal concrete was optimum by weight of cement. The strength parameters and slump of concrete showed better results than control mixes even without using any admixture in the specimens. This study could also be enhanced using combinations of different fibers and other admixtures.
Analyzing Microscopic Behavioral between Two Phases of Follower and Leader in Traffic Oscillation with Developing Artificial Neural Networks
Authors: Mirbaha Babak , Abdi Kordani Ali , Salehikalam Arsalan , Akbarinia Farzad , Zarei Mohammad
Published: September 2019

A Sudden speed drop in the leader vehicle of vehicle platoon results in propagating the deceleration wave from downstream towards the upstream flow. Points of wave propagation of the leader vehicle towards the follower vehicle identification are done based on Newell’s theory in trajectory data. Deceleration wave propagates based on two parameters, time and space, τ- δ. A follower driver performs different behavioural reactions that they result in deviating follower driver from Newell’s trajectory. In this paper, follower driver behaviour was identified based on two theories. The asymmetric microscopic driving behaviour theory and traffic hysteresis were used during the deceleration and acceleration phases, respectively. The data trajectories were classified into different traffic phases. Driver’s parameters were identified at the microscopic level. Since the follower driver had the nonlinear behaviour, artificial neural networks were developed. They were able to analysis and identify effective parameters of dependent variable between deceleration phases leading to congestion phase, based on the behavioural patterns. Analysis results present effective parameters based on any behavioural patterns. Spacing difference of two phases, deceleration and congestion phases, was the most effective parameter of both two behavioural patterns, under reaction – timid and over reaction – timid. Increasing the spacing difference of two phases results in decreasing (increasing) time based on under reaction – timid (over reaction – timid)..
Some New Correlations of Q-Value with Rock Mechanics Parameters in Underground Oil Storage Caverns
Authors: Lin Fang , Luan Hebing , Zeng Yanhua , Zhong Zhibin
Published: September 2019

Q-system is a preferred alternative method of rock mass classification for underground oil storage caverns where stable lithological rocks are widely distributed. In this paper, correspondences between important input rock mechanics parameters (friction angle, cohesion, tensile strength, Poisson’s ratio, deformation modulus) and Q values were investigated, thereby bringing convenient to rapidly obtain available parameters when it’s hard to collect measured field data in underground storage projects basically with similar lithology. The proposed correlations were verified through numerical simulation and on-site monitoring measurement. In addition, comparison of different criteria among Q-system and other codes for rock mass classification has been made to help for making a preliminary evaluation of rock mass quality in the practical engineering. Finally, the behaviours of surrounding rock deformations under different Q values were analysed by using FLAC3D code with the calculating parameters suggested in this paper, and the calculation results match well with measured values in situ. Above results will not only guide the construction but also could be relevant to other underground storage engineering under similar geological conditions.
Transient Behavior of CFRP Tensegrity System in a Suspen dome
Authors: Olofin IfeOlorun , Liu Ronggui
Published: September 2019

In order to establish a conclusive result for the application of carbon fibre reinforced polymer (CFRP) cable as a tensegrity system for a suspen dome, the structural integrity assessment of the system, subjected to transient load, must be considered. This paper gives a preliminary assessment of the dynamic behavior of carbon fibre reinforced polymer cable in a suspen dome in comparison with that of the steel counterpart, using a small model of 4 m span and 0.4 m rise. A commercial finite element software namely ANSYS was used for the structure simulation in respect of the experimental design. The results from the simulation show that the carbon fibre reinforced polymer cable gives a reliable assessment as the steel counterpart. The natural frequencies of CFRP cables are higher than those of steel cables due to the CFRP cables’ high stiffness-to-weight ratio and less curvature under gravity loads. CFRP cables influence the structure with good stiffness which provides good vibration resistance. The results also indicate that from a technical point of view, carbon fibre reinforced polymer cables can perform better than steel cables as tensegrity system for a suspen dome. It is concluded that CFRP cables can be applied to replace steel ones as tensegrity system for a suspen dome.
Integrated Metaheuristic Differential Evolution Optimization Algorithm and Pseudo Static Analysis of Concrete Gravity Dam
Authors: Memarian Taher , Shahbazi Yaser
Published: September 2019

A differential evolution-algorithm-based optimum design method is presented for concrete gravity dams under stability, principal stress, and sliding constraints. A gravity dam is a large scale hydraulic structure providing its stability based on weight of concrete volume. Hence, optimization of dam cross-section leads to an economic and low cost structure. For this aim, a general dam section is reconstructed with seven proper horizontal and vertical geometric parameters which take into account all possible cross section shapes. Weight of dam is considered as goal function and the optimization problem of geometric parameters is solved using DE algorithm. The DE algorithm written as a MATLAB code are applied to Four benchmark gravity dams including Middle Fork, Richard, Pine Flat, and Friant. The comparison of DE optimum solutions with real dimension of dams and another optimization method in literature shows the performance of the DE algorithm. In mentioned benchmark dams, there are 26.82%, 30.11%, 25.31%, and 20.93% of weight reduction Compared to real values, respectively. Also, optimization results of DE algorithm are compared with literatures. The comparison shows 3.55%, 5.1%, 19.13% and 12.14% reduction of weight compared to GA and PSOD algorithms, respectively.
Investigation of to the Effect of Bedrock Stiffness on Seismic Behaviour of Roller Compacted Concrete Dam
Authors: Jalali Mohammad , Pasbani Khiavi Majid , Ghorbani Mortaza Ali
Published: September 2019

In this research, the effect of bedrock stiffness on seismic performance of roller compacted concrete (RCC) dam is evaluated using probabilistic analysis. Due to the geometry and behavior of RCC dams, a two-dimensional modeling was selected for system. Ansys software is used for modeling and analysis of dam-reservoir- foundation system. Newmark implicit time integration scheme is developed to solve the time-discretized equations which are an unconditionally stable method. The Watana dam, due to San Fernando earthquake has been selected as a case study. In order to propagate the parametric sensitivity to the seismic performance of the system, Monte Carlo simulation with Latin hypercube sampling (LHS) method is used as a probabilistic method and uncertainty analysis. The sensitivity of responses under seismic loading is reliably examined utilizing different values of ratio of bedrock stiffness to body concrete stiffness as random inputs. Consider to obtained results, it is revealed that the bedrock stiffness how can effect on seismic behavior of concrete gravity dams due to earthquake. Regarding the safety of dams due to compressive stresses, various ways have been assessed to investigate the induced tensile stress in the heel and the results have been investigated. Finally, appropriate range of the ratio of bedrock stiffness to concrete stiffness of dam body is presented to assess the safety design.
Ngeramut Wareh Sapen : Implementasi Program Konservasi dan Keanekaragaman Hayati (Kehati) Hutan Blok Sapen Berbasis Pemberdayaan Masyarakat di Gunung Arjuno Pasuruan
Authors: Mulyono Wibisono  , Fafit Rahmat Aji  , Diyono Yusuf  , Kasiman  , Amang Fathurrohman
Published: September 2019

Permasalahan lingkungan hidup terus berkembang, isu pemanasan global menjadi perhatian dunia, sehingga program konservasi dan kehati terus digalakkan. Program Ngeramut Wareh Sapenmerupakan salah satu bentuk konservasi dan kehati berbasis pemberdayaan masyarakat sekitar hutan Arjuno ini diinisiasi oleh Yayasan Satu Daun dan PT. Tirta Investama Pabrik Pandaan bekerjasama dengan Perhutani, Pemerintah Desa Jatiarjo, LMDH Bumi Lestari, Universitas Yudharta, serta beberapa stakeholders lainnya. Hasil implementasi program Ngeramut Wareh Sapen diantaranya dilakukan pembibitan, penanaman pohon, inisiasi pendidikan lingkungan hidup berkelanjutan dengan mendirikan laboratorium tanaman langka, kandang sangkar hewan endemik, serta pondok latih. Selain itu, pemantauan dan evaluasi yang holistik terus dikembangkan untuk mengetahui perkembangan program Ngeramut Wareh Sapen ini, diantaranya melakukan data base pohon online, pemantauan hutan berbasis drone, studi lingkungan hidup yang berkelanjutan, serta evaluasi dengan melibatkan multistakholders.