JOURNAL OF NEW APPROACHES IN CIVIL ENGINEERING
Year:2019 | Volume:3 | Issue:1 |Papers Count:6

The Tabriz city, as one of the metropolises of Iran, has a special geotechnical condition. In the northeastern part of Tabriz, due to the fine-grained soil layers and high groundwater level, a number of structures have been damaged. The Fereshteh town is one of the areas where in recent years unbalanced settlement of newly constructed buildings has been observed. With considering the importance of using pile-raft foundations, in this research by using the results of two boreholes in the Fereshteh area of Tabriz, the geotechnical characteristics of the soil have been evaluated. Subsequently, direct soil-structure interaction numerical models have been studied by Plaxis software. Based on the obtained results in this study, the minimum required length of piles in the pile-raft foundation system to change the status of the designation of structures from unauthorized to authorized, for 4 and 6-floor buildings is 6 meters and for the 8-story building is 8-meters. Also, in the 4, 6 and 8-floor buildings, respectively using 8, 10 and 12 meters for piles length is an optimal choice.

Nowadays, the Iran country with considering huge reserves of building stone, is one of the important countries in world. But, unfortunately when building stones are processed in factories, significant part of material changed to waste. In final of processing, simultaneous national treasures are spoiled and environment is damaged too. Therefore, propose new methodologies and reuse of waste materials due to building stone is necessary. In this research, main idea is study of mudstone due to travertine and granite on geotechnical properties of dune sand. In present research, some factors such as optimum water content, dry density, bearing capacity, internal friction angle and cohesive by using laboratory tests including compaction, California Bearing Ratio (CBR) and direct shear tests were evaluated.

Nowadays, utilization of pozzolanic materials is one of the usual method for improvement of concrete strength. Pozzolanic reactions cause to voids in concrete materials filled and in continue strength and bearing capacity increased. Zeolite is one of the natural pozzolan is found in Iran and can be extracted and processed simply. In present laboratory research, compressive and tensile strength of self-compacting concrete (SCC) contains zeolite and glass fiber reinforced polymer (GFRP) were evaluated. For this purpose, zeolite content 0, 10 and 20 percentage (in weight) and GFRP value 0, 0. 5 and 1 % (in weight) of cement amount were considered. Therefore, nine mix design for specimens prepared and compressive strength and Brazilian tests performed. Results of present study showed that zeolite in SCC can increase compressive strength. So that, maximum and minimum bearing capacity values in specimens with zeolite respectively 13. 24 and 8. 82 percentage are more than unimproved condition. Also, 10% zeolite in specimens (improved by zeolite and GFRP) with 28 days curing is more effectiveness than 20% in compressive strength. In the other side, Variations of tensile strength in improved SCC specimens from the point of view GFRP effectiveness illustrated 1 % GFRP significantly increase tensile strength in specimens (improved by zeolite and GFRP).

Porous concrete is one of concrete with high voids generally is utilized in pavement. In field of maintenance and repair of this type of concrete there is not sufficient information and methodology. For protection of porous concrete as a best method in flood management, this type of pavement should be extended and blocked porous have to improve. In this research, voids in porous concrete is filled by materials such as soil, sand and volcanic sand. Until, with stable compressive strength permeability protected. Results of present study showed that overall with filling voids in porous concrete permeability decreased. When, voids filled by sand, maximum horizontal permeability with 0. 38 cm/sec value is made. In contrast, while voids filled by volcanic sand, maximum vertical permeability with 0. 33 cm/sec is created. In the other side, maximum compressive strength in specimen with volcanic sand with 5. 71 MPa observed. Therefore, it can be explained that, porous concrete useable in shoulder of road, parking, parks and roads with low traffic volume.

Improvement and optimization of seismic performance of structural systems is one of the principal methods for decreasing probability damages due to earthquakes. Composite shear wall is one of lateral load bearing systems. In this system, compressive strength of concrete and tensile behavior of bars is composited for achievement suitable performance in terms of stabilization and economic performance in usual steel and reinforced concrete structures. In this research, composite shear wall with embedded steel columns in boundary sides is introduced and comprised with normal reinforced shear wall. In present study, seismic behavior of system under gravitational and lateral loading with assuming nonlinear behavior of material by utilization Abaqus software according to finite element theory analyzed. It should be noted, in analysis process pushover method was applied. According to obtained results can be explained that embedded steel column cause increase bearing capacity and ductility in shear wall.

In last decade,decreasing vulnerability of buildings and life lines due to earthquake is one of the main problem and challenge in Iran.Indeed,when a huge disaster as earthquake happens in metropolitan cities,importance of reducing vulnerability and retrofitting subject bolded.Whereas,most of structures and buildings in Iran are vulnerable and have not evaluated versus major earthquakes,it is necessary that retrofit operations to be performed.Also,majority of constructed buildings in Iran in terms of defect in performance,design and changes in loading codes,especially in Code No.2800 are detected vulnerable.In this research,a five-story reinforced concrete structure with flexural frame according to Code No.2800-Ver.2 designed and with applying Code No.2800-Ver.4 evaluated and performance level based on seismic rehabilitation guidelines calculated.Results showed that structure is weak and with using six method retrofitted.Reinforcement methods are:concrete shear wall,steel centrically brace,reinforced masonry infilled frame,steel buckling restrained brace,viscous damper,and mass damper.Obtained outcomes illustrated that in retrofitted models drift value of roof decreased and performance level closed to safety structural reliability.