A numerical meshless method is proposed to investigate shallow water equations. Because of The numerical solution of the pure convection equations represents a very important issue in many problems, an Element Free Galerkin (EFG) method is used for solving these equations, and its implementation is described. In this method there is no need to nodal connectivity and just uses nodal data which may be the same as those used in the Finite Element Methods (FEMs) and a description of the domain boundary geometry are necessary. The essential boundary condition is enforced by the penalty method, and the Moving Least Squares (MLS) approximation is used for the interpolation scheme. The numerical efficiency of the proposed method is demonstrated by solving several benchmark examples. Sensitivity analysis on parameters of the EFG method is carried out and results are presented.

Concrete filled steel tube is constructed using various tube shapes to obtain most efficient properties of concrete core and steel tube. The compressive strength of concrete is considerably increased by the lateral confined steel tube in circular concrete filled steel tube (CCFT). The aim of this study was to present an integrated approach for predicting the steel-confined compressive strength of concrete in CCFT columns under axial loading based on large number of experimental data using artificial neural networks. Neural networks process information in a similar way the human brain does. Neural networks learn by example. The main parameters investigated in this study include the compressive strength of unconfined concrete (f'c), outer diameter (D) and length (L) of column, wall thickness (t) and tensile yield stress (fy) of steel tube. Subsequently, using the reliable network, empirical equations are developed for the confinement effect. The results of proposed model are compared with recently existing model on the basis of the experimental results. The findings demonstrate the precision and applicability of the empirical approach to determine capacity of CCFT columns.

Air-water flow is a complex and challenging subject in many engineering fields as well as hydraulic engineering and discovery of its characteristics can help the engineers to predict and analyze a probable phenomenon. In the present paper, development of a device capable of measuring the flow velocity, air concentration, diameter and counts of bubbles in air-water flows is described. The heart of the present device is two resistive probes with a novel configuration. Being pressure and corrosion resistant and also having negligible resistivity in the flow are some of the unique features of the employed needles. Moreover, sampling frequency and time can be set for the intended application by the user. In the present electronic board, maximum available sampling frequency is in the order of KHz, while the time of sampling is not limited. The circuit is designed with ability for avoiding the polarization of the probe tip. Increasing the number of probes up to four which can operate together and suitable for more complex flows with no change in the electronic board is another advantage of the proposed device. Different tests for verification of the device accuracy have been performed and good results were reported for measurements.

In this study, the effects of high temperatures on the mechanical and microstructural properties of high strength concretes (HSCs) made with metakaolin (MK) are investigated. For this purpose, the concrete mixtures made with MK were produced with water-binder ratio of 0.2. The mechanical properties of these concretes at 25, 250, 500 and 750 oC temperatures were determined. Besides, the effect of high temperature on the microstructural changes of cementitious matrix, interfaces between aggregate particles-cementitious materials and aggregates of these concretes were inspected by X-ray diffraction, scanning electron microscope and plane polarized transmitted light (PPTL) analyses. The results indicate that the ultrasound pulse velocity, compressive strength, flexural strength and splitting tensile strength values of these concretes decrease especially depending on the increase of the high temperature after 250 oC. The heated concrete specimens were also examined at both macro and micro scales to determine the discoloration, alteration and cracks of HSC at different temperatures. PPTL analyses show that increasing temperature cause impairing of interfaces between aggregate particles and cementitious materials. The results also show that the partial replacement of MK with cement has the best performance on the mechanical properties of HSC.

Microtremor measurement is a precise and applicable technique for evaluating structural dynamic characteristics and vulnerability index of historical buildings. In this research a historical citadel in Iran has been considered. Karim Khan Citadel (Arg-e Karim Khan) is a huge masonry structure which has been built in the 17th century in Shiraz, Iran. The plan of this building has a rectangular shape and has a circular tower in each corner. The height of each three story circular tower is 14 m and the height of walls between each two towers is 12 m. One of these towers has been swerved and for preventing its collapse, concrete was injected to the foundation of this tower. To study seismic behavior and vulnerability of the swerved tower and compare it with other straight tower, microtremor measurements were performed. Measurements were done on the center of each tower and its basement simultaneously. For determining natural frequency and damping ratio of each tower, Floor Spectral Ratio (FSR) and Random Decrement Method (RDM) were used, respectively. Results show that the natural frequency and damping ratio of the swerved tower are 1.9 Hz and 1.55 % while dynamic parameters of the straight tower are 2.12 Hz and 3.86 %, respectively. Also the towers frequencies are very different to the site frequency (4.18 Hz), therefore the resonance phenomenon isn’t probable. In addition, the vulnerability indexes of the swerved and straight towers were calculated 131.31 and 76.9, respectively, which shows that the swerved tower is more vulnerable.

Concrete flat roof defects such as water leakage present a significant and common problem in large building, particularly in tropical countries, where rainfall is high. To monitor this condition, effective non-destructive test methods are required to detect problems at an early stage, especially hidden defect within the concrete roof, which are critical. This paper presents the potential use of electromagnetic (EM) waves for determining possible leakage of the concrete flat roof as a result of failure of the waterproof membrane layer. This study was assessed, experimentally by investigation of the propagation of EM waves through the roof and their interaction with water. Novel Microwave sensors described in the paper operates in the 6 GHz to 12 GHz frequency range using a Marconi 6200A microwave test set. A range of existing current methods were overviewed and analysed. Results of experimental tests confirmed that microwaves could be used as an alternative non-destructive method for identifying water ingress caused by membrane failure into the concrete roof.

The construction temporary facilities layout planning (CTFLP) requires an identification of necessary construction temporary facilities (CTFs), an identification of candidate locations and a layout of CTFs at candidate locations. The CTFLP is particularly difficult and complex in large-scale construction projects as it affects the overall operation safety and effectiveness. This study proposes a decision making system to decide on an appropriate CTFLP in large-scale construction projects (e.g. dams and power plants) in a comprehensive way. The system is composed of the input, CTF identification, candidate location identification, layout optimization, evaluation and selection, as well as output stages. The fuzzy logic is employed to address the uncertain factors in real-world situations. In the input stage, the knowledge bases for identifying CTFs and candidate locations are determined. Then, CTFs and candidate locations are identified in the following two stages. In the mathematical optimization stage, a multiobjective mathematical optimization model with fuzzy parameters is established and fuzzy simulation-based Genetic Algorithm is proposed to obtain alternative CTFLPs. The intuitionistic fuzzy TOPSIS method is used to evaluate and select the most satisfactory CTFLP, which is output in the last stage. To demonstrate the effectiveness and efficacy of the proposed method, the CTFLP for the construction of a large-scale hydropower dam project is used as a practical application. The results show that the proposed system can assist the contractor to obtain an appropriate CTFLP in a more efficient and effective manner.

This study evaluated the effects of Warm Mix Asphalt (WMA) additives on the compaction temperature and properties of Crumb Rubber Modified (CRM) asphalt binder and mixture. Two different WMA additives (named as Sas and Evm) were used to prepare warm-mix CRM asphalt binder and mixture. The viscosity of different warm-mix CRM asphalt binders and mastics were measured at different temperatures. The rheological and mechanical properties of different warm-mix CRM asphalt binders were tested. At the mixture level, the volumetric properties of different warm-mix CRM asphalt mixtures were experimented by Gyratory compactor at different temperatures and the performance of different warm-mix CRM asphalt mixtures were evaluated. It was found that, both of the two WMA additives could lower the compaction temperatures of CRM asphalt mixtures by 10°C~20°C. However, they have different influences on rheological properties of CRM binder and performance of CRM mixture. The Sas warm-mix additive can improve the anti-rutting performance of CRM mixture but may degrade its low-temperature performance and moisture stability. The Evm warm-mix additive has no adverse effects on the high-temperature and low-temperature performance of CRM asphalt mixtures and can improve its moisture stability.

This paper has applied operation research to solid waste disposal by which two objective functions are optimized to minimize the expected operational costs (maximize revenues) and the expected net carbon dioxide equivalent (CDE) emissions. Types and uncertain amounts of solid wastes as well as costs of electricity were factored into the selection decision of solid waste disposal, i.e. landfill, incineration, composting and recycling. An optimization model was applied to the solid waste disposal of Bangkok, Thailand. In addition, a multi-objective optimization technique was proposed for a tradeoff decision-making between minimum operational costs and CDE emissions. Composting and landfill are effective alternatives for Bangkok’s solid waste disposal system. The operational costs and net CDE emissions are highly correlated with the quantity of solid waste. Policy-makers and plant operators could adopt the proposed optimization model under uncertainty in the selection of an optimal solid waste disposal.

Most of the proposed methods for obtaining the free vibration natural frequency of the retaining wall have been presented, assuming the behavior of the wall in two-dimensional domain, and they are not able to express the three-dimensional behavior of these structures in a satisfying manner. In this paper, the plate theory is employed to analyze the free vibration of wall-soil system in three-dimensional domain. So the retaining wall is modeled as a clamped-free plate and the stiffness of the soil existing behind the wall is modeled as a set of springs. Using the approximate Rayleigh method, new analytical expression for obtaining the free vibration natural frequencies for the three first modes of the wall is represented. The results of the proposed model are compared with both the results of the other researchers and the ones from finite element method (FEM). They are also compared with the results of a full-scale experiment and it shows a good agreement. The comparison shows that modeling the wall in two-dimensional form is not accurate enough to calculate all the natural frequencies of the wall. The results of this paper show that there is a considerable difference between two- and three-dimensional behavior of the walls. The proposed method also gives the free vibration natural frequencies of the wall extensional modes with an acceptable accuracy. Finally, the effect of tensile and compressive behavior of the soil on the fundamental frequency is studied. This research can be considered as a new field in three-dimensional calculation of the retaining walls.

To study and predict the behavior of flexible pavement over expansive soils, a pavement structure was subjected to different laboratory and fieldwork experiments. The existing pavement was replaced and designed based on California Bearing Ratio (CBR) method, with a new one, and subjected to the traffic from various number of load cycles from 12.1 up to 155.52 kcycles of standard axle load (80 kN) through dual wheel assembly over a 6-month period. As the preliminary step, the deflection measurements were taken at the asphalt surface layer, using a Total station at different distances as function of truckload applications. The numerical analysis is carried out with the Finite Element software package PLAXIS version 2012. In the new model, the calculation of the transferred pressure to the pavement through contact area of tires is 3D it was turned into a 2D problem, and the pavement was subjected to a static loading using a ratio factor of dynamic additional charge. The materials’ behavior was simulated with nonlinear models: Mohr–Coulomb (MC) for pavement layers and soft-soil model (SSM) for the expansive subgrade, in saturated drained and undrained conditions. The results indicate that displacements under static loading in saturated drained conditions and when non-linear materials are present are the closest to field measured deflections.

The effects of effective stress and void ratio on the secondary compressibility of the sandy and clayey soils were investigated in this study. The coefficient of secondary compression of Ottawa sand in single stage and stepwise loading tests increases with effective vertical stress while that of saturated kaolinite decreases with effective vertical stress. Multi-staged loading tests showed that at a given effective stress, the higher the void ratios of the soils, the higher the coefficients of secondary compression of the soils are. It was concluded that the secondary compressibility of a soil depends on not only the effective stress, but also the void ratio of the soil. A general relationship between the coefficient of secondary compression, and effective stress and void ratio was proposed for soil. The discrepancy of the dependency of secondary compressibility on effective stress for different soils was well explained using this relationship, moreover, the quasi-overconsolidated state of clayed soil induced by time effect and the effect of surcharge preloading on the secondary compressibility of soft ground were discussed in light of the general relationship.

The correlations and relationships between electrical resistivity and geotechnical parameters of soils have become very important for site investigation. However, there is a lack of understanding about the relationships between electrical resistivity and geotechnical parameter values. The resistivity piezocone penetration tests and laboratory tests have been conducted for geotechnical investigations of marine clay in Jiangsu province of China to establish quantitative relationships between electrical and geotechnical data. The geotechnical investigation reveals that electrical resistivity values are very low for marine clay in Jiangsu, ranging from 5 to 10 Ω m. The correlations between electrical resistivity and geotechnical parameters are examined using Spearman’s rank correlation test that is a rank-based test for correlation between two variables without any assumption about the data distribution. It was shown that the electrical resistivity has strong bonds with the moisture content, void ratio, salt content and plasticity index. In terms of quantitative relationships, good fitting relationships between electrical resistivity and selected geotechnical parameters are observed. The statistical analysis indicates that the electrical resistivity is a good indirect predictor of selected geotechnical parameters. The data studied demonstrates the usefulness of the in situ resistivity method in geotechnical investigations, which have an advantage over other geotechnical methods in cost performance.

Present work is devoted to a better insight into the identification of carbonation versus efflorescence formation in alkali-activated blast-furnace slag and investigates the relation between the chemical composition of the alkali-activator and the extent of the occurrence of these two phenomena. Obtained results showed that mixes of relatively lower alkali contents suffers not only from weak compressive strength due microstructural defects, but also from carbonation during the first few days. On the other hand, mixes containing relatively higher alkali contents strongly suffers from efflorescence formation in spite of their interestingly high compressive strengths. Carbonation during the first few days can partially neutralize the alkali content of the surface layers of the material which in turn significantly affects the activation mechanism leading to the formation of binding compounds of lower degree of Si substitution with Al in the molecular structure.

One kind of the irregularities in structures, with considerable effect on seismic performance, is setback in elevation that causes large damage especially in the vicinity of the irregularity. The main objective of this research is to propose and develop drift based index to estimate damage to Reinforced Concrete Moment Resisting Frames (RCMRFs) with setback. For this purpose, first, inelastic dynamic time-history analysis is performed on several frames with different types of setbacks subjected to various earthquake records and damage to them is computed by the Park-Ang damage index. Then two relations between the damage and drift are derived by applying irregularity indices to account for setback effects. It is shown that the proposed damage indices are capable to estimate the damage index of setback frames.

The motorcycle is considered as one of the most applicable transportation modes for different types of trips in Iran. According to the report by Iran Police Department in 2011, almost 25% of all crash fatalities are related to the motorcycle riders and their passengers. The objective of this study is to identify the most important factors that contribute to the fault of motorcyclists involved in crashes. This is done by using the Classification And Regression Trees (CART) model to differentiate between at-fault and not-at-fault cases. The results show that the most important factor in determining at-fault probability of motorcyclists is the collision type. According to this fact, the probability of rear-end collision is the highest, while the probability of side collisions is the lowest. The importance of other factors is variable considering the collision type. In the case of rear-end collisions, the passengers characteristics and the age of the rider are the most important factors. However, in the case of side collisions, lighting condition and area type (in both urban and rural roads) are the most important. Finally, it is suggested that, training of riders can reduce rear-end collisions as well as installing systems that warn drivers when they are close enough to motorcycles in side collisions.

This paper investigates the frequency response method for waterhammer phenomenon in piping networks. The unsteady flow governing equations are solved in time domain using the method of characteristics. They are also solved in frequency domain using the transfer matrix method. For the pipe network under consideration, critical transient excitation scenarios are identified. For each scenario, the frequency responses of the system as well as the time history of the transient pressures at the network nodes are calculated. The model is applied against a real pipe network and the results of the transfer matrix method are compared with those of the method of characteristics. It is concluded that the frequency response method not only presents a very fast algorithm for analyzing pipe systems but also, has an acceptable accuracy compared to the method of characteristics. The frequency response method requires linearization in some terms of the governing equations. Instead of that, it needs no computational discretization and interpolation necessary in time-space domains when using the method of characteristics.

In recent years, environmental protection is increasingly becoming a major issue in transportation including asphalt production. Despite the fact that Hot Mix Asphalt (HMA) is widely used around the world some recent studies suggest using Warm Mix Asphalt (WMA) technology that reduces the production and placement temperature of asphalt mixes. Currently, a common way of producing WMA is through the utilization of additives. This paper firstly characterizes the effect of WMA additives (organic, chemical, water containing additives) on base bitumen properties. Following the determination of optimum bitumen content of the mixtures with different WMA additives through Marshall Test, Hamburg Wheel Tracking Device is used to measure the permanent deformation characteristics of WMA mixtures. Based on the findings of this study, the utilization of WMA additives help in the reduction of viscosity values which are in return decreases mixing and compaction temperature leading to the reduction of energy costs as well as emissions. Besides, it can be concluded that all WMA mixtures performed better than HMA mixtures in the matter of rut depth.

Among important issues in progressive collapse behavior of a building is tracking down the type and location of the damaged elements. This paper deals with identifying the distribution of collapse from the first element to the entire building due to earthquake loads. Here, 3D collapse propagations in symmetric and asymmetric reinforced concrete buildings are compared using nonlinear time history analyses. The variables of such analyses are earthquake load intensity and the level of in plan one directional mass eccentricity. Results show that collapse distribution is dependent on the degree of asymmetry in building. Some patterns to predict progressive collapse scenarios in similar symmetric and asymmetric buildings are also determined. One main pattern shows that the propagation of collapse is horizontal through the stories, but not vertical through the height of the buildings. Spread of the collapse is independent of the earthquake records also according to the results, damage concentration is larger in places with larger mass concentration.

Compressive strength is as one of the most important properties of concrete and mortar that its measurement may be necessary at both early and later ages. Prediction of compressive strength by a proper model is a fast and cost-effective way for evaluating cement quality under various curing conditions. In this paper, a logarithmic model based on the results of an experimental work conducted to investigate the effects of curing time and temperature on the compressive strength development of chemically activated high phosphorous slag content cement has been presented. This model is in terms of curing time and temperature as independent variables and compressive strength as dependent variable. For this purpose, mortar specimens were prepared from 80 wt.% phosphorous slag, 14 wt.% Portland cement, and 6 wt.% compound chemical activator at Blaine fineness of 303 m2/kg. The specimens were cured in lime-saturated water under temperatures of 25, 45, 65, 85 and 100 ºC in oven. The model has two adjustable parameters for various curing times and temperatures. Modeling has been done by applying dimensionless insight. The proposed model can efficiently predict the compressive strength of this type of high phosphorous slag cement with an average relative error of less than 4%.