JOURNAL OF NEW APPROACHES IN CIVIL ENGINEERING
Year:2019 | Volume:2 | Issue:4 |Papers Count:6

Trusses is one of most usable structures in engineering. Truss is combination of bar elements created. Triangle shape is most stable possible are formed by bar elements in truss. In this research, effects of variations in internal angles, elastic modulus, diameters and loading on truss members and displacement in joints were evaluated. For this purpose, 45 models in Sigma/w analyzed. Results of present study showed that with decreasing elastic modulus in members, vertical and horizontal displacement in joints increase. Also, horizontal displacement in supports with two freedom degree is more than supports including one freedom degree.

Necessity of the human to the safe and permanent water sources is one of the important problems today, especially in Iran that is a buried region. One of the permanent water sources is groundwater. In the last decades, soft rock aquifers of country mainly are used; therefore, this causes to exploration the groundwater in the hard rocks. Tectonics and faults one of the important factors to crush the rocks and formations and make and develop the faulted aquifers. Therefore in this study the role of the structures is researched in development of the water sources in Kelvanaq city area. This city is in the South of Heris city that located in the North of the Ajichai River and its main subdivisions are middle part sources of this river that itself sourced from Ghare-Dagh Mountains. In this study, first field studies, geological maps and search in remote sensing and photo maps help to select area have active tectonics in relation by active faults. Study the hydrologic specifications of the basin, in connection by high potential regions of groundwater are guided. After, geophysical methods helps exploration, and geoelectrical sections and pseudo-sections are shown the fault related aquifers and their developments. Research and compare the resistivity maps and sections in this study, shown the extent of aquifers and shown that in the eastern and north-eastern part of the study area, resistivity are mainly very low and are in 10-15 Ὡ m range, that are in relation by impermeable clay and marl stones of Red-Formation. Geophysical exploration results have shown that the northern part of the study area mainly formed by impermeable or low-permeable hard rocks, and faults of the study area mainly are impermeable or low-permeable fault zones. But study and compare the results have shown that high potential regions are in the southern parts of the region. Finally in relation by the explored aquifers, location of the number 26 and 30 geoelectric wells, respectively proposed for drilling. Large thickness of the explored faulted aquifer and its specifications, promising good Q for the proposed wells.

In high-rise buildings, by increasing the number of floors, designers are forced to use the tubular system or to combine it with other systems. The “ shear lag” phenomenon and also architectural problems due to the low distance between the columns are disadvantages of this system. Concentrically bracings due to their high shear-stiffness combining with tubular system improve the behavior of this system due to the disadvantages mentioned. But the main disadvantage of this system is the sudden change of lateral deformation against wind and earthquake forces. In this paper, a new idea is introduced that uses a steel shear wall at the two ends of the frame and a general bracing between them. These two walls act as a strong moment anchor against overturning moment of building, and due to their high stiffness, absorb the major shear forces. So, the shear lag decreases. The results show that lateral deformation is reduced in the proposed system, and the axial forces and bending moment also have a significant reduction, which indicates the high efficiency of this system.

This research investigated LULC changes and its effect on outlet runoff by detecting LULC changes location and severity via an inverse method for the Little River Watershed, USA. In this research, the artificial intelligence and soft computing capabilities such as wavelet-entropy were employed for this aim, as extraction of sub-watershed delineation and watershed information was done in geographic information system. Thereafter, a conceptual rainfall-runoff model (Clark method) was simulated via HEC-HMS. Different watershed outflow hydrographs were generated by variation of storage coefficient parameters of sub-watersheds in the conceptual Clark model. Then the relationship between storage coefficients (as the representative of land use/cover)-watershed outflow was also modeled by artificial intelligence models (artificial neural network and support vector machine). Whereas wavelet-entropy was utilized to avoid importing noise-full information and reducing huge volume of information to the model. Finally, the obtained model detected watershed land use/cover changes in the future years with dynamic watershed assumption. For the validation, the results were compared with recorded changes via normalized difference vegetation index extracted from landsat images. For instance, the comparison approved the ability of the proposed method for LULC change detection of the LRW in a way that deforestation and cropland increasing of the sub-watersheds from 1990 to 2013 were aligned with the SC reduction e. g., 26% decrease of SC for downstream sub-watershed versus 53% decrease and 21% increase of forest and crop lands, respectively.

One of the important problems in earthquake geotechnical engineering is liquefaction phenomenon that happens in loose saturated granular soils. Liquefaction resistance of soils can be evaluated with using laboratory tests such as cyclic simple shear test, cyclic triaxial tests and cyclic torsional test or field tests for example standard penetration test (SPT), cone penetration test (CPT) and shear wave velocity (Vs). Main aim in this study, comparison results of soils liquefaction potential evaluation in the Barandouz Dam in Urumieh between SPT and CPT tests. In continue, liquefaction potential index (LPI) for both method assessed. In this study, 13 boreholes from Barandouz Dam collected and evaluated. Results of research showed that there is no good agreement between two methods. Also, value of LPI based on CPT is more than SPT.

Nowadays new materials for improving bearing capacity of soils are widely used. Kind of new materials used in this regard are geosynthetics. Geofoam panel type of geosyntethic materials is useful and alternative for backfill in retaining wall or pavement layers. Main idea in this research is study geofoam particles effects on improvement bearing capacity of sand. Geofoam particles effects on sand in 0. 05, 0. 1 and 0. 15% percent were considered and sand was considered in granular and angular conditions. In order to evaluating geofoam particles influence in geotechnical properties of sandy soils some laboratory tests such as compaction, direct shear (in vertical stresses 1, 2 and 3 kG/cm2) and permeability tests were performed. Results of this study showed that with increasing 0. 15% percent geofoam in sandy soils maximum dry density went up, permeability decreased and shear strength of specimens increased. Although, geofoam particles is more effective in angular sandy soil than granular sand.