JOURNAL OF HYDRAULIC STRUCTURES ENGINEERING
Year:2011 | Volume:3 | Issue:5 (8)|Papers Count:7

Analysis methods proper to the level of design and the type and configuration of the dam are used for evaluating the concrete dam response under static and dynamic loadings. The amount of tensile stresses that occur inside the dam body has been very important to assess the safety of suchlike structures during earthquake. In this study, two- dimensional finite element model of the tallest monolith of Javeh RCC dam was provided for the purpose of analysis. The hydrodynamic effect of the reservoir was applied by solving the wave equation. The assumptions of water compressibility and structure deformation were used in the analysis. The foundation rock underlying the dam and reservoir bottom was modeled as a homogeneous, isotropic and viscoelastic half- plane. Static analysis results show that the compressive stresses exist in the whole of the dam body. In the dynamic analysis subject to maximum credible earthquakes, principal tensile stresses of some elements at the downstream face of the dam are greater than allowable tensile stress of RCC. Normal tensile stresses are less than the tensile strength of RCC layers.

In this study, thirteen samples of the steel ring in the software ANSYS (V12) modeling and using cod ATC-24 subject to loading and non-linear static analysis are located. Then bearing capacity and diameter variation yield and ultimate rings were calculated. A concentric steel frame one story one span using cod- 2800 third edition of Iran ETABS (V9.5) software to help with Equivalent static method analyzed and designed. Then with calculate the critical buckling load brace, appropriate steel ring was selected. Using the SAP2000 (V12) software frame contain steel ring modeling and using the seven-far field accelerogram was subject to non-linear time history dynamic analysis. Of the analytical study of the rings, it was found that, the increase ring width and thickness, cause of increase bearing capacity and the increase diameter ring, reduction bearing capacity. The using steel ring in concentric braced frame, it cause of reduction of base shear and effective stiffness of the Structure and increase time period and displacement structure.

Different alternatives are usually available to improve the resistance of existing buildings against catastrophic effects of progressive collapse to ensure continuing services and protection of lives. The best retrofitting alternative is the one that through technical and economic considerations reduces the rate of damage to existing buildings and the possible human casualties. This paper presents a procedure to determine the best retrofitting alternative against progressive collapse of buildings using Multiple-criteria hierarchical decision making and TOPSIS methods. Application of developed procedure in retrofitting a group of important concrete buildings identifies the specific technique of "Adding Shear Wall" as the best alternative against progressive collapse of this type of buildings.

One of the problems in earthquake geotechnical engineering for researchers and experts is liquefaction phenomenon in non-dense saturated granular and sand-silt mixtures soils. Liquefaction resistance of soils can be evaluated by various field and laboratory methods. In this study, results of two field methods for assessing soil liquefaction potential i.e. Cone Penetration Test (CPT) according to process proposed by Robertson and Wride (1998) and Shear Wave Velocity (Vs) Test based on Andrus and Stokoe (2004) method with using empirical relationships were compared. Study area is South of Tehran and 67 boreholes were collected and analyzed. Also, soil liquefaction potential index (PL) was calculated for both of them. Results show that, there is no appropriate harmony and complete adaption between two soil liquefaction potential mentioned above with using three empirical equations in assuming cementation and non-cementation states for soils. Also, liquefaction potential index values presented that liquefaction hazard based on CPT test is less than Vs method in study area.

The base flow of permanent rivers which emanate from the mountainous regions of Iran is provided from the snowmelt runoff during the dry seasons. In precipitation-runoff studies, two phenomena occur in high elevations. With the height increase, the temperature is reduced and this results in the precipitation to change from rain to snow beyond the threshold temperature. Moreover, with the logic pyramid mountains resumption the surface to save the snow is reduced in higher positions.This paper studies the elevation change effect on snowmelt runoff in Karun river basin. Satellite snow covered maps in the region during study period were collected. The region was divided into five zones by the GIS. Moreover, snowmelt runoff model (SRM) was calibrated and validated using climatic variables of two periods containing one wet year (1991-92) and one dry year (1992-1993). The results showed that SRM efficiently predicted the total daily runoff of snowy regions without the need for ground data and just relying on the remotely sensed snow covered areas. In the next step, contribution of snowmelt runoff was simulated by inserting the snow covered areas during the study period and artificially eliminating rain form of precipitation.It was further found that the role of snowmelt in runoff is bolder in higher elevations in the study region. Using model results, the specific discharge caused by snowmelt during the wet and dry periods was determined to be 0.70 (mÙ3/kmÙ2) and 0.23, respectively. The snowmelt runoff volume for the wet and dry years was estimated to be 13833.9 and 5492.5 million cubic meters respectively.

Hydraulic engineers have been interested in studying about "The Rate of Erodible Bed Scouring and its Development due to Jet Impacts". In this research it was investigated the changes of a jet down stream bed in two conditions of submerged & falling with applied discharge changes. Calvert outlet in submerged condition is exactly tangency on material bed level and in falling condition has 46 Cm distant from it. Tail water path in all of tests was constant and equal to 15 Cm. The jets in both two conditions make a 10 degree angle by horizon. The results indicated in early minutes of test the changes of scouring were severe but by passing time the changes in both two conditions are reduced. Hence, in submerged condition approximately 80% of final depth appears in early 5 minutes but in falling condition the rate is 70%.

This paper looks at high energy consumption in buildings due to the population growth, and traditional practices in construction in the country. And also outlines the Insulated Concrete Forms (ICFs) construction technology and its impact on reducing energy consumption in buildings due to the insulation and its High heat resistance as a result of the two layers of polystyrene.