ی This research aims to highlight the role of risks management in presenting a formalapproach to entry decisions to the markets of construction through the adoption of theanalytical hierarchy techniques, and simulation, as a technique in selecting particularrisk responses.To attain the aim of the research, special data which deal with the topic of risksmanagement, and their techniques, were collected from personal interviews ofspecialists of designers and executives of construction projects.The results of data analysis of samples have shown that risks of fluctuation of supplyand demand on materials, equipment or labor and changes in government policy are the most emerged risks with respect to qualitative assessment and the most highlight risksof relative importance are risks of changes in government policy and the fluctuation ofsupply and demand on materials and internal factors. And risk responses which arerepresented by contingency and specifying a clause in the contract which is concernedwith the changeable circumstances have gained the largest share of importance ascompared with other alternatives.In the light of what have been reached by the surrounded risks of the constructionproject, a management system has been constructed which can be adopted in qualitativeassessment of risks and in simulating this assessment ,so that can be depended on inquantitative assessment of risks through quantifying the influence of risks on projectcost by using simulation technique. To gain from the advantages of computer, acomputer program has been designed that depends on the bases of the managementsystems which have been suggested to be constructed.
This research concerns, with studying the proposed of a simulation program, which is related with the process of movement and handling of construction materials on site. to reduce the handling wastes cost. This research deals with all factors affecting construction materials movement on site. Through a proposed program, weakness points of the mentioned factors can be specified and treated either with an applied program or Administrative procedures. Detailed literature survey was performed, detailed field investigation, analysis of collected data, and interviews with selected and well qualified and experienced management personal representing a wide variety of construction firms and companies. The results obtained from the mentioned actions confirmed the research hypothesis. A computer program was prepared, to simulate all construction materials movement stages affecting the movement and handling of construction materials. The proposed program, includes and perform several functions such as , simulation of construction materials management activities, evaluation of the existing status, finding out management solutions and training aspects, that helps in training engineers, possessing little experience in managing construction materials on site. To examine the capability extent of applying the proposed program at the site, the program function applied on tow construction projects and to be examined by experts. The examination was illustrated the program efficiency to reduce movement and handling costs of construction materials. The research recommended the applications of the proposed program to get its benefits and to achieve the research objectives. Further and future researches were proposed, such as expert system to evaluate and develop the performance of construction management in the field of on site materials management.
Traffic control devices notify road users of regulations and provide warning and guidance needed for safe, uniform, and efficient operation of all elements of the traffic stream. Traffic control devices have been a part of the roadway system. Researches have evaluated various aspects of the design, operation, placement, and maintenance of traffic control devices. The purpose of this research is to develop a simulation model in order to evaluate the effect of overhead sign position on the traffic performance at exit of freeway weaving area. To achieve that subroutine was developed and added to FWASIM program to compute the sign position and compare it with the driver sight distance. Following that a proposed example represents an exit weaving area was examined with different traffic flow configuration (different percentages of link flow and on-ramp flow) with respect to no sign installed and other three sign positions. Results indicate that the average traffic speed is underestimated when there is no sign installed, while no significant effect is shown when the sign position is changed within the driver sight distance. In conclusion Guide signing is a critical element in the effective, efficient and safe operation of motorways and expressways. Signing issues must, therefore, be fully considered at the feasibility stage of any project.
The management of water resources requires adequate information on the quantities of water supplied from the basins that outfall into a river, especially during the flood seasons. The study area located in the western part of Iraq within the administrative boundaries of the Heet district about 70 km from Haditha Dam, 45km from Ramadi in Anbar province. The study aims to evaluate the amount of surface runoff through a long-term period (1981-2019). Soil and Water Assessment Tool (SWAT) related to Geographic Information System (ArcGIS) was used for the simulation. The input data was the Digital Elevation Model (DEM) of SRTM with resolution 30m, land use/land cover map from the European Space Agency (ESA) with resolution 300m and, soil map from the Food and Agriculture Organization (FAO). The weather data used in the study were obtained from the Climate Forecast System Reanalysis (CFSR) combined with the weather data from the Surface meteorology and Solar Energy (SSE) produced by NASA. These weather data prepared using SWAT weather database software to be ready for the simulation processes. Al-Mohammedi valley was calibrated and validated using SWAT-CUP software using the available recorded discharges at Heet, Ramadi, and Al-Warar gauge stations. The calibration is based on the meteorological data for the period January 1, 2002, to December 31, 2006, and the validation was based on the data between January 1, 2007, to December 31, 2009. The model calibration and validation results based on two objective functions “Nash-Sutcliffe (NS) and coefficient of determination(R2)” showed that SWAT was successfully simulated Al-Mohammedi valley with NS = 0.72 and R2 = 0.76 for calibration, and NS = 0.63 and R2 = 0.65 for validation. According to SWAT results, the average runoff volume in the long-term period of simulation from January 1, 1981, to October 31, 2019, was 79.2 million m3 while the average runoff depth was 18.25 mm with about 17 % of rainfall becomes surface runoff.
This paper presents the numerical study to simulate the flexural behavior of normal strength, high strength and hybrid reinforced concrete beams, under two points load with two different reinforcement ratio. The hybrid beam consists of two layers: the compressive layer is made of high strength concrete, and the tension layer is made of normal strength concrete. The simulation was done with a finite element model using the commercial finite element code, ANSYS (v.9.0). The concrete component material is modeled, the internal steel reinforcement modeled using ''LINK'' elements. The modeled behavior shown a good agreement with the experimental data. The maximum percentage difference in ultimate load-carrying capacity is 8% at the ultimate load level.Analytical study also included the effect of increasing the depth of the normal strength concrete for the hybrid reinforced concrete beam and the effect of increasing the compressive strength for high strength concrete and normal strength concrete respectively on the behavior and the load carrying capacity of the hybrid reinforced concrete beams.
The mechanical behaviour of partially saturated soils can be very different from that of fully saturated soils. It has long been established that for such soils, changes in suction do not have the same effect as changes in the applied stresses, and consequently the effective stress principle is not applicable. A procedure was proposed to define the soil water characteristic curve. Then this relation is converted to relation correlating the void ratio and matric suction. The slope of the latter relation can be used to define the H-modulus function. This procedure is utilized in the finite element analysis of a footing on unsaturated coarse grained soil to investigate its bearing capacity. The finite element results demonstrated that there is a significant increase in the bearing capacity of the footing due to the contribution of matric suction in the range 0 to 6 kPa for the tested compacted, coarse-grained soil. The ultimate pressure increases from about 120 kPa when the soil is fully saturated to about 570 kPa when the degree of saturation becomes 90%. This means that an increase in the bearing capacity of about 375% may be obtained when the soil is changed from fully saturated to partially saturated at a degree of saturation of 90%. This development in the bearing capacity may exceed 600% when the degree of saturation decreases to 58%.
Abstract:This paper presents exact probabilistic model as a complementary mathematicalbase for the traditional deterministic approach to quantify the selection of a factorof safety for each term of the load equation of friction piles in clay. The procedureof assigning a partial value of factor of safety for each clay layer using a quantifiedprobabilistic model instead of the use of a single global factor of safety for alllayers that based on arbitrarily judgments seems to introduce an enhancement toboth economical and safety consideration in the design procedure of the frictionpiles. it is suggested in this paper to derive probabilistic equation that describe eachlayer of the problem individually, each term of the pile load equation (clay layers) consists on a certain amount of uncertainty and each request assigning a certainvalue of factor of safety to eliminate this variability and to keep the probability offailure (which is more reliable risk index) at certain level. Exact probabilityequation is mathematically derived on the bases of the variability inherited in soilparameters (average un-drained shear strength and thickness of each clay layerinserted). The equation was verified using Monte carol simulation method andresults indicate excellent agreement in both, probability distribution shape andcalculated failure values. The relationship between factor of safety and probabilityof failure produced from the derived equation was inspected in addition to thesensitivity of the equation to the change of the variability of input parametersthrough a reference example.Keywords: Friction Pile, Load, Probability, factor of safety
ABSTRACT An applied hydrological models were performed to model the rainfall-runoff relationship for Upper Adhaim River Basin. Three lumped integral models (hydrologic models) based upon the concept of the unit hydrograph were applied to analyze the rainfall-runoff relationship on a daily basis. These models are: the Simple Linear Model (SLM), the Linear Variable Gain Factor Model (LVGFM), and the Non-Linear Model (NLM). Five performance evaluation criteria have been used in this study. The application results of the (SLM) model showed a weak rainfall-runoff relationship. It was demonstrated that the linear assumption is valid only for the first four antecedent days. A considerable non-linear rainfall-runoff relationship was clearly observed from the results of (LVGFM) and the (NLM) models. Both models were satisfactorily identified at system memory of (17) antecedent days. However, the (LVGFM) was slightly superior to the (NLM). The (LVGFM) identified at system memory of seventeen antecedent days was used to simulate runoff flows. The simulation results show an acceptable applicability for the (LVGFM) in terms of simulating runoff events in time of its occurrence and volumetric fitness. The water budget for Upper Adhaim River Basin showed that an average of 73.4% from annual rainfall was evapotranspired, 8.0% was infiltrated and 18.6% was observed as direct runoff.
The spillway is an important structure in the dams, used to pass the flood wave to the downstream safely. In the past decades, Computational fluid dynamics (CFD) has evolved. Research findings have shown the CFD models are a great alternative for laboratory models. According to it, the flow pattern over ogee spillways can be studied in a short time and without paying high expenses. Because the flow over the ogee spillway is turbulent and has a free surface, its properties are complex and often difficult to predict. Therefore, the present paper focuses on the study of turbulence closure models including the standard k-ε, RNG k–ε, k–ω, also, the large-eddy simulation (LES) models, to assess their performance to simulate flow over the spillway. The Flow-3d software with the volume-of-fluid (VOF) algorithm is applied to obtain the free surface for each turbulence model. The results of the analysis show that the LES model yielded better results when compared with laboratory results, while the turbulence closure models result of Reynold average Navier Stocks equations (RANS) was more stable, especially standard k-ɛ and RNG models.