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Structural Engineering and Geotechnics - Volume:8 Issue: 1, Winter and Spring 2018

Journal of the Structural Engineering and Geotechnics
Volume:8 Issue: 1, Winter and Spring 2018

  • تاریخ انتشار: 1396/12/20
  • تعداد عناوین: 8
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  • Hamoon Abroon Shahrbijary, Ali Delnavaz * Pages 1-10
    Using of CFRP carbon sheets because of their high strength, lightness and ease of use have been very expanded in retrofitting concrete members. Including shear walls systems FRP can be used in order to rebuild or maintain the strength of an aged structural member. Repairing, or retrofitting of the intact structural member is conducted to enhance the structural resistance that was deteriorated due to the overloading, construction ignorance and so on. In this study, a model of coupled reinforced shear walls with changing the shape of CFRP fibers arrangement under lateral loading is considered. Then, the effect of coupled concrete compression shear wall resistance vary is investigated on the retrofitting. In all stages, the comparison among the proposed arrangement shape of CFRP fibers are accomplished in terms of lateral load carrying capacity of the specimens. Accordingly, the best form of fiber formation is recommended. Finally, it was concluded that the most optimistic fiber arrangement is fully covered and the next choice is vertically covered FRP arraignment.
    Keywords: Lateral loading, Coupling shear wall, CFRP, Nonlinear, Carbon fiber
  • Adel Asakereh *, Abdol Hamid Kamali Pages 11-18
    Suction caisson is a type of floor foundation for the offshore structures that is also called suction pile, bucket foundation, suction anchor, or sometimes ridge foundation depending on its application. In two past decades, this type of foundation has been widely used around the world as the fixed offshore foundation, anchor of the floating platforms, as well as the foundation of other marine structures such as the offshore wind turbines. Suction caisson is a metal (or sometimes concrete) hollow cylinder that is open from its bellow while it is top is being closed by flat or dome plates. This type of caisson is called suction caisson mainly because its installation is done by suctioning their water outside after drainage. In this research, numerically study the effective factors on the pullout behavior of the suction caissons. The analyses conducted in two-dimensional form on the drainage condition on clay soil. The results of the analysis show that the strength parameters of the soil are significantly effective on the pullout capacity of the suction caisson.
    Keywords: Caisson, Pull, Out Capacity, Drain condition, clay, offshore structures
  • Reza Sallakh Niknejad, Rouzbeh Dabiri * Pages 19-39

    As one of the significant phenomena in earthquake geotechnical engineering, liquefaction can cause severe damages. A number of factors play a role in the occurrence of liquefaction such as magnitude of earthquake, void ratio, relative density, and fines content percentage. The impact of building construction overburdens on liquefaction is of paramount importance. The present study was aimed at evaluating the effects of overburden resulting from building construction on liquefaction potential of saturating soil layers along Tabriz Metro Line 2. Fifty-four boreholes and geotechnical information were collected from the research site. Overburden values were considered to be 100 kPa, 200 kPa, 300 KPa, and 400 KPa equivalents to 5-, 10-, 15-, and 30-story building, respectively. The assessment of liquefaction potential of soil layers was carried out using the standard penetration test (SPT) method. Furthermore, liquefaction potential index (LPI) of soil layers was evaluated. The findings demonstrated that overburden can affect liquefaction resistance of soil layers. With increasing overburden, safety factor against liquefaction became less than one in nearly 80% of soil layers. The rate of growth in LPI of boreholes in the research site was found to be roughly 70%. Hence, an increase in overburden elevated liquefaction hazards in the research site.

    Keywords: Fines content, Liquefaction, Liquefaction Potential Index, Overburden, Tabriz Metro Line 2
  • Sahand Mardi, Morteza Bastami * Pages 41-54
    Despite the numerous advantages of using concrete with high strength capacity, the brittle behavior of high strength concrete (HSC) and higher production cost has limited its use in the construction industry. This research aims to develop a cost-effective approach for production of high strength self-compacting concrete with desirable performance in either compressive or tensile loading condition. To reach this purpose, 18 mixtures were cast initially with different w/c, binder, and silica-fume percentages. The results show that it is possible to produce high strength self-compacting concrete economically without using any additives such as silica-fume. Afterward, an innovative reinforcing technique using hexagonal wire mesh (HWM) were introduced for enhancing the HSC performance. The results show that HWM is able to enhance HSC behavior in both tensile and compressive loading condition. Finally, an economic analysis was conducted and the optimum HWM properties are selected according to the analysis results.
    Keywords: High Strength Concrete, Self, Compacting Concrete, Economic Analysis, Silica, Fume
  • Amirmohammad Soleimani, Seyed Amir Hossein Hashemi * Pages 55-67
    In this research, the effect of the cement, sand, and pumice mixture on the durability of lightweight concrete is investigated. The intention of this paper is to replace a certain amount of the pumice percentage as an alternative option of the cement and pumice sand aggregate with conventional sand components. The experimental results include compressive strength, ion-chloride emission factor (RCPT and RCMT). The experiments are carried out at the concrete age of 28 and 90 days. The results indicate that pumice composition improves the durability of lightweight concrete. Furthermore, it was observed that the proposed mixing design have proper permeability resistance against the chloride ion attack. For 90 days aged concrete, it was notified that the samples had a chlorine ion penetration coefficient of 10% which is less than the concrete specimens of 28 days. Finally, the compressive strength of the new mixing design samples can be increased by 1.5 to 2.5 Mpa after 90 days.
    Keywords: Lightweight concrete, Pumice, Chlorine ion, Compressive Strength, RCPT, RCMT
  • Arash Totonchi, Allah Dad Ahmadi * Pages 69-83
    In this paper, a new roofing system is introduced, which is constructued using the precast composite sandwich panels. This roofing sandwich panels system consists of three kinds of precast concrete sandwich panels including capital panels, beam or between columns panels, and slab or middle panels. The panels are composed of three layers; A high strength reinforced concrete top layer. A thick layer of light-weight concrete as the intermediate layer or core. And a tensile resistant reinforced concrete bottom layer. The panels are connected together by special connectors at the edges. In this research, the influence of shear connector stiffness is studied which is measured according to their diameter on ultimate resistant and combined performance of the panels. The results of finite element analysis by ABAQUS software show a logical behavior of load-deflection curves in shear connectors. Based on the economic and weight comparisons the dead and live loads, the proposed sandwich panel roofing is approximately 44 percent lighter than the conventional steel joist and concrete blocks. This comparison shows the superiority of this roofing system to joists and concrete blocks system and seems to be a good alternative for it. Due to the possibility of prefabrication and industrial production of the panels under factory conditions, and various other technical, economic, and constructional advantages of this roofing system, it is concluded that it can be viable substitute for current roofing systems in low to high-rise buildings and can save a considerable amount of material, labor, time, and cost in building construction.
    Keywords: Precast Sandwich Panels, light concrete Core, Resisting facings, Shear connectors, Composite
  • Farhad Cheraghi, Abdolreza S. Moghadam * Pages 85-90
    In this study, an existing hospital structure has been evaluated with incremental dynamic analysis (IDA). This building is accommodated in Karaj with soil type II. At first, two 2-D frames along X, Y direction are selected. Then, five performance levels are determined according to “Rehabilitation Code for Existing Buildings (Publication No. 360) including Immediate Operational (IO), Limited Damage (LD), Life Safety (LS), Limited Life Safety (LLS), and Collapse Prevention (CP). The Peak Ground Acceleration (PGA) as earthquake intensity and relative displacement (Drift) as the failure index has been used for incremental dynamic analysis method via seismo-struct software. In the next step, the probability of reaching or exceeding of the structure to a limit state was determined. Results of incremental dynamic analysis for fragility curves show that the probability of reaching or exceeding from IO level is approximately . This probability is almost for LD, for LS, for LLS, and for CP. It has been signified that the probability of fragility is raised with increasing in PGA.
    Keywords: Fragility curve, Incremental dynamic analysis, Vulnerability, SeismoStruct
  • Mohamadreza Khanban, Mahdi Mahdikhani * Pages 91-106
    Nowadays, waste production is increased due to the growth of technology and excessive use of natural resources as well as production of new chemicals, among which the hazardous wastes are no exception of that stabilization and solidification method is one of the hazardous waste management methods through which the waste materials are stabilized and confined. High flexibility for various pollutant compounds, ease of use, and being economical for large volumes of waste has led researchers to use this method to treat various wastes. In this research, sludge ash from sewage treatment plantsuses as waste in order to perform the stabilization and solidification process. Nine mix designs with a water to cement ratio of 0.46; and 0, 6, and 10 percent dried sludge residue of the Alborz Industrial City in Qazvin as the replacement of fine aggregate; 0, 2, and 4 percent of silica fume; and cement content of 600 kg/m3are produced. The mini slump flow, mini V-funnel, compressive strength, electrical resistancetests were carried out on the solidified samples to investigate the effect of waste on the performance of the mortar.The results show that the use of this waste as a substitute for fine aggregate could be taken into consideration.
    Keywords: Self, Consolidating Mortar, Stabilization, Solidification, Waste, Durability, Fresh Properties, Silica fume, Compressive Strength