JOURNAL OF CIVIL ENGINEERING ISLAMIC AZAD UNIVERSITY
Year:2009 | Volume:1 | Issue:3|Papers Count:8

In this work, Impulsive wave generation and propagation caused by landslides are studied numerically for a real case. Maku Dam reservoir, in the northwestern of Iran is considered as the case study. Generated wave heights, wave run-up and probable overtopping volume have been evaluated for two scenarios using a twodimensional numerical model (LS3D). Based on the results, the generated wave height for first and second scenarios is 12m and 18m respectively. The wave height of 8m is observed close to dam body. The dam freeboard is 9m, so no overtopping happens in normal condition. However in rainy seasons that water level is close to spillway level, maximum wave height above dam crest is 4m and dam overtopping volume is about 20000m3.

Significant compressive forces can develop in the offshore pipeline due to restricted expansion caused by high temperature and high pressure conditions. As a consequence, the pipeline tends to release the compressive forces by buckling. This uncontrolled buckling results in significant failure in the pipelines.This paper, first, Summarizes lateral buckling mitigation methods and then, evaluates Snaked-Lay as the most economical and useful method to control lateral buckling of HP-HT pipelines. Numerical models in this paper present the optimized pattern for snaked configuration.

Mathematical models have an important role in water resources systems management and analysis. System operators can use models to determine optimum operation including release and/or storage decisions in the system.Dynamic Programming (DP) is among the most used methods in multi-reservoir systems optimization. However, DP based models suffer from dimensionality or as Bellman called “curse of dimensionality” in large systems. Dimensionality limits the model applicability by tremendous increase in problem dimension and therefore execution time required to reach the solution. Discrete Differential Dynamic Programming (DDDP) is among the methods, and probably the best, proposed to tackle the dimensionality problem in deterministic DP based models. On the other hand, a Corridor based Stochastic DP (CSDP) is suggested for handling probabilistic systems. In this paper, DDDP and CSDP are applied in a six-reservoir system in Karun River Basin, located southwestern Iran. Results indicate a substantial improvement when these models are applied in the system, as compared to the usual DP and SDP. Evaluations are based on several factor, in which, similar improvement trend was observed.

From the numerical viewpoint in the simulation of wave run-up, most of the problems arise in the determination of the shoreline position since the shoreline moves up and down the sloping beach during the run-up and run-down processes. In other words, investigation of long wave run-up can be categorized as a moving boundary problem, and consequently, the main question to be answered is how to track this boundary. Therefore, a special treatment is necessary in the numerical model to define the shoreline position. In the present study, by recourse to a Lagrangian-Eulerian transformation, the time-varying physical domain is converted to a fixed-length time-invariant computational domain. However, this computational mapping introduces additional non-linear terms into the governing equations. By imposing appropriate boundary conditions on the shoreline, the mapped equations are solved using the two-step Richtmyer-Lax-Wenderoff numerical scheme. All of the computations are carried out by employing a program code developed by authors in FORTRAN 90. The simulated surface profiles show very satisfactory agreement with available analytical solution as well as experimental data.

In this study filtration and drainage behavior of some nonwoven geotextiles were studied after assembling permittivity and transmissivity equipments. Prepared samples was subjected to hydraulic head in the rang 10cm to 60cm and confined stress up to 1000kPa and their hydraulic behavior was investigated. In this study Effect of increasing the layers of geotextiles in permeability was investigated too.The results show that transmissivity will decrease exponentially with increasing normal stress until a residual value is reached, and permittivity and transmissivity response in each case was seen to decrease with increasing hydyaulic gradient.

In this study filtration and drainage behavior of some nonwoven geotextiles were studied after assembling permittivity and transmissivity equipments. Prepared samples was subjected to hydraulic head in the rang 10cm to 60cm and confined stress up to 1000kPa and their hydraulic behavior was investigated. In this study Effect of increasing the layers of geotextiles in permeability was investigated too.The results show that transmissivity will decrease exponentially with increasing normal stress until a residual value is reached, and permittivity and transmissivity response in each case was seen to decrease with increasing hydyaulic gradient.

Construction projects typically generate a large volume of information from various and widely varying sources at different levels of detail. From this quantitative data, project managers need correct (precise, factual), timely and quality (efficient) information for decision making. Any lag or lack of information, or its quality and level of detail can potentially cause project delays, cost overruns, loss of quality and the spearheading of claims and conflicts. In spite of this, what may appear to be a well known fact, most construction companies in Iran do not have any clear or standard framework for organization of seamless information management systems for the documentation, archiving, evaluation and reporting (transfer?) of construction project related information.This study addresses project information handling from widely different sources in the form of reports and documents, and its systemization. It does not claim to evaluate and analyses information for the purpose of project planning or cost estimation.

It is so important to know the behavior of traffic at intersections. In this research has been tried to give recognition of some intersections with stops by understanding of square information. The research has compared Iranian driver's behavior at intersection which has a stop with the behavior of drivers which are shown in AASHTO1994 and AASHTO2001.There is information about decelerating in the main street, form of movement, distance-time curve in AASHTO1994 and we have information about decelerating in the main street and the time of gap in AASHTO2001. It is essential to know time and place position of vehicles in order to compute mentioned cases. For this purpose, some intersections of Tehran city are marked and ruled. Then, they are filmed in the morning and evening. Finally, primary information such as time and place position of vehicles, type of movement, brand of vehicles, sex of drivers and the time of gap are recorded. After having organized and analyzed data banks, comparable cases are compared with AASHTO.