• Effect of Steel Plate Jacketing of Columns in Seismic Behavior of[taliem.ir]

    Effect of Steel Plate Jacketing of Columns in Seismic Behavior of Concrete Beam-Column Connections

    تومان

    Design philosophy of having weak beam – strong column is recommended almost in all design codes. But in some  ases, in prior buildings, this philosophy is ignored. In these structures, during major earthquakes, failure  mechanism would begin from columns leading to sever damages. To avoid this event, column in the connection  zone must be strengthened to conduct the plastic zone to the beams. There is several ways for strengthening  concrete columns and one of the efficient ways is using steel plates surrounding column in the critical zone. In  this paper, using steel plates for seismic upgrading of Concrete Beam-Column connections has been investigated  numerically. Effect of plate thickness, length and beam-column dimensions is taken into account. Some empirical  results are used to verify the finite element approach. Analyses are conducted with the use of some modeling  methods including various geometrical models and material behaviors. The results from various methods are  compared and the suitable model is proposed

  • Effects of Circular Opening Dimensions on the Behavior of[taliem.ir]

    Effects of Circular Opening Dimensions on the Behavior of Steel Plate Shear Walls (SPSWs)

    تومان

    In recent years there is a developing attention to steel plate shear walls (SPSWs) thanks to their proper function exposing to lateral wind and earthquake loads. Furthermore, their application in steel and concrete structures in order to strengthening them has raised a lot of focus  upon. In some cases existence of opening is unavoidable due to architectural reasons or installed heating and cooling systems on the walls.  That leads to a decrease in capacity and improper functioning of these systems that also results in an intense variation in inplane stress   distribution. In this paper impact of circular opening dimensions on behavior of steel plate shear walls has been closely studied. On this purpose using ABAQUS finite element method a nonlinear analysis has been conducted considering geometrical and material nonlinearity in the models. Analyzed models indicate that the reduction factor (1-D/H)S and (1-D/H) respectively for resistance value and stiffness value predict lower  error versus the increases in opening diameter

  • EFFECTS OF SOIL-STRUCTURE INTERACTION[taliem.ir]

    EFFECTS OF SOIL-STRUCTURE INTERACTION AND BASE ISOLATION ON SEISMIC PERFORMANCE OF FOUNDATION SOILS

    تومان

    This study primarily focuses on structural induced liquefaction potential. Moreover, the effect of base isolation systems on both structural performance and liquefaction potential was studied including the soil-structure interaction effects. Four different types of structures and three different types of local sites were analyzed under two different input ground motions. It was mainly found that, depending on the structural type and for a certain depth, the liquefaction potential could be higher under the structure than the one in the free field. Besides decreasing the story drifts and shear forces in the structure, base isolation systems were very effective for decreasing liquefaction potential in the soil. It was also observed that soil-structure interaction leads to very significant changes in the response spectra.

  • Efficient exact optimization of multi-objective redundancy allocation[taliem.ir]

    Efficient exact optimization of multi-objective redundancy allocation problems in series-parallel systems

    تومان

    This paper proposes a decomposition-based approach to exactly solve the multi-objective Redundancy Allocation Problem for series-parallel systems. Redundancy allocation problem is a form of reliability optimization and has been the subject of many prior studies. The majority of these earlier studies treat redundancy allocation problem as a single objective problem maximizing the system reliability or minimizing the cost given certain constraints. The few studies that treated redundancy allocation problem as a multi- objective optimization problem relied on meta-heuristic solution approaches. However, meta-heuristic  approaches have significant limitations: they do not guarantee that Pareto points are optimal and, more importantly, they may not identify all the Pareto-optimal points. In this paper, we treat redundancy allocation problem as a multi-objective problem, as is typical in practice. We decompose the original problem into several multi-objective sub-problems, efficiently and exactly solve sub-problems, and then systematically  combine the solutions. The decomposition-based approach can efficiently generate all the Pareto-optimal  solutions for redundancy allocation problems. Experimental results demonstrate the effectiveness and  efficiency of the proposed method over metaheuristic methods on a numerical example taken from the  literature.

  • Energy evolution-taliem-ir

    Energy evolution and blast response of segmented circular tunnels; Considering depth and different soils

    تومان

    Energy assessment of deep tunnels depends on the depth and what kind of ground they surrounded by  .The numerical results showed that high static compressive stress concentration around the underground tunnel results in the accumulation of substantial strain energy at the same location. The roof and floor of the tunnel are more prone to dynamic failures during the blasting loading process. In addition, the analysis of energy dissipation indicated that the strain energy reduction and the residual kinetic energy are positively related to the lateral pressure coefficient and the burial depth of the tunnel, and the residual kinetic energy is much larger than the strain energy reduction under the same condition. Furthermore, for an underground tunnel subjected to high in situ stress, the blasting stress wave with lower amplitude is sufficient to trigger severe dynamic failures. Results indicate that a tunnel in saturated soil is more vulnerable to severe damage than that buried in either partially saturated soil or dry soil. The tunnel is also more vulnerable to surface explosions that occur directly above the centre of the tunnel than those that occur at any equivalent  distance in the ground away from the tunnel centre.

  • Environmental, Economic, and Social Implications of[taliem.ir]

    Environmental, Economic, and Social Implications of Highway Concrete Rehabilitation Alternatives

    تومان

    Currently, there is no comprehensive benchmark of life-cycle assessment for the rigid pavement alternatives for highway rehabilitation. To fill this gap, the major objective of this study is to investigate the  environmental, economic, and social impacts of the three most widely adopted rigid pavement choices  through a life-cycle assessment approach with custom-built economic input-output life-cycle assessment (EIO-LCA) models. Quantity takeoffs were performed for each alternative assuming a 1-lane-km highway  rehabilitation. Subsequently, the construction costs of each alternative were computed in order to determine the present values for a life span of 50 years, while at the same time accounting for a different life expectancy for each pavement rehabilitation strategy. The present values were then incorporated into a corresponding EIO-LCA model. The results clearly indicate that continuously reinforced concrete pavement (CRCP) is the  most sustainable choice and much preferable to the other alternatives for minimizing negative environmental, economic and social impacts from the life-cycle perspective. This finding champions a wider adoption of CRCP for future sustainable transportation infrastructure development projects, as CRCPs relatively high initial  construction cost can be recouped by long-term sustained benefits. The results and findings of this study can serve as a solid foundation for industry practitioners and decision-makers to make better-informed project decisions when choosing the most sustainable pavement alternatives from a life-cycle perspective. DOI: 10.1061/(ASCE)CO.1943-7862.0001063. © 2015 American Society of Civil Engineers.

  • Evaluation of Base Shear Absorption of Combined System; RC[taliem.ir]

    Evaluation of Base Shear Absorption of Combined System; RC Frame & Precast 3d Panels with Irregularities in Vertical

    تومان

    The current study investigates the base shear absorption of combined systems, RC frame pre-cast 3D wall sandwich panels in both linear and non-linear material properties. The seismic behavior of building constructed by 3D panels is studied using numerical approach finite element  method. The obtained results are compared with regular bending RC frames, complete box type sandwich wall panels system, and present the  differences of behavior and absorbance in each system and also the variation of vertical stiffness on structural response is examined. The  material nonlinearities simulated with drucker-prager and von-misses failure criteria. The validation of FEM analysis is test with those obtained  through experimental

  • Evaluation of Horizontal Seismic Hazard of ABADE, Iran[taliem.ir]

    Evaluation of Horizontal Seismic Hazard of ABADE, Iran

    تومان

    This paper presents probabilistic horizontal seismic hazard assessment of Abade, Iran. It displays the probabilistic estimate of Peak  Ground Horizontal Acceleration (PGHA) for the return period of 475 and 2475 years. The output of the probabilistic seismic hazard  analysis is based on peak ground acceleration (PGA), which is the most common criterion in designing of buildings. A catalogue of  seismic events that includes both historical and instrumental events was developed and covering the period from 840 to 2007 is used.  he seismic sources that affect the hazard in Abade were identified within the radius of 150 km and the recurrence relationships  of these sources were generated by Kijko and Sellevoll [2000]. Finally four maps have been prepared to indicate the earthquake  hazard of Abade in the form of iso-acceleration contour lines for different hazard levels by using SEISRISK III

  • Experimental Investigation of Time-Dependent Effect on Shear[taliem.ir]

    Experimental Investigation of Time-Dependent Effect on Shear Strength Parameters of Sand–Geotextile Interface

    تومان

    The time-dependent behavior of soils has been investigated extensively using one-dimensional and triaxial tests. The phenomena  associated with time effects in soils are creep, relaxation, strain rate and rearrangement effects. The engineering properties of soil are  often improved significantly with the time elapse. The objective of this paper is to investigate the time-dependent effect on the shear  strength parameters of sand–geosynthetic interface using large direct shear test apparatus. For this purpose, the geotextile layer has  been adhered gently on a piece of wood with a thickness such that a half of the shear test box has been occupied. The other half of  the box has been filled with the sand and the test has been performed. Three normal stresses of 30, 45, and 60 kPa have been   applied in all tests. The shear stress has subsequently been applied in different times to the failure stage. In all tests, the shearing  velocity has been kept the same. The results of these experiments show that the stiffness and friction angle of the dry sand– geotextile interface increases up to 12.6% and 3.9% at 720 minutes after the sample is poured in the mold

  • Exploiting Home Automation Protocols[taliem.ir]

    Exploiting Home Automation Protocols for Load Monitoring in Smart Buildings

    تومان

    Monitoring and controlling electrical loads is crucial for demand-side energy management in smart grids. Home automation (HA) protocols, such as X10 and Insteon, have provided programmatic load control for  many years, and are being widely deployed in early smart grid field trials. While HA protocols include basic monitoring functions, extreme bandwidth limitations (<180bps) have prevented their use in load monitoring. In this paper, we highlight challenges in designing AutoMeter, a system for exploiting HA for accurate load monitoring at scale. We quantify Insteon’s limitations to query device status—once every 10 seconds to achieve less than 5% loss rate—and then evaluate techniques to disaggregate coarse HA data from fine- grained building-wide power data. In particular, our techniques learn switched load power using on-off-dim events, and tag fine-grained building-wide power data using readings from plug meters every 5 minutes.

  • Exploiting Home Automation Protocols[taliem.ir]

    Exploiting Home Automation Protocols for Load Monitoring in Smart Buildings

    تومان

    Monitoring and controlling electrical loads is crucial for demand-side energy management in smart grids.  Home automation (HA) protocols, such as X10 and Insteon, have provided programmatic load control for many years, and are being widely deployed in early smart grid field trials. While HA protocols include basic  monitoring functions, extreme bandwidth limitations (<180bps) have prevented their use in load monitoring. In this paper, we highlight challenges in designing AutoMeter, a system for exploiting HA for accurate load monitoring at scale. We quantify Insteon’s limitations to query device status—once every 10 seconds to achieve less than 5% loss rate—and then evaluate techniques to disaggregate coarse HA data from fine- grained building-wide power data. In particular, our techniques learn switched load power using on-off-dim events, and tag fine-grained building-wide power data using readings from plug meters every 5 minutes .

  • Fading and color changes in colored asphalt quantified by the image[taliem.ir]

    Fading and color changes in colored asphalt quantified by the image analysis method

    تومان

    Colored asphalt pavement can create better visual setting as well as improve the safety and smoothness of  driving. In this research, colored asphalt samples with various amounts of dye are examined to study the  surface color changes at different aging periods. Distributions of surface colors on the samples are analyzed in both the RGB and HSI color spaces. Two types of dyes, green and red, with five different ratios are mixed with clear asphalt to make colored asphalt samples. The samples are exposed to ultraviolet light in the QUV tester for five different aging spans. Results show that the amount and type of dye added, and the different aging spans affect fading in the colored asphalt. Results also indicate that clear asphalt mixed with 5% or  more of dye is capable of manufacturing better-colored asphalt. Finally, colored asphalt with red dye showed better resistance to ultraviolet light.

  • FFECTS OF SOIL-STRUCTURE INTERACTION[taliem.ir]

    FFECTS OF SOIL-STRUCTURE INTERACTION AND BASE ISOLATION ON SEISMIC PERFORMANCE OF FOUNDATION SOILS

    تومان

    This study primarily focuses on structural induced liquefaction potential. Moreover, the effect of base isolation systems on both structural performance and liquefaction potential was studied including the soil-structure  interaction effects. Four different types of structures and three different types of local sites were analyzed  under two different input ground motions. It was mainly found that, depending on the structural type and for a certain depth, the liquefaction potential could be higher under the structure than the one in the free  field. Besides decreasing the story drifts and shear forces in the structure, base isolation systems were very  effective for decreasing liquefaction potential in the soil. It was also observed that soil-structure interaction  leads to very significant changes in the response spectra.

  • Flexibility based method for the extent of damage in degrading bridge structures after in-service loading[taliem.ir]

    Flexibility based method for the extent of damage in degrading bridge structures after in-service loading

    تومان

    This paper presents a method to identify damage in bridge structures based on the flexibility matrices in the modal strain space. In the  tudy by the Ritz vectors extracted from flexibility matrix, the damage is identified. The localization approach is applied to low  levels of damage on the prestressed concrete girder of simply supported bridge, with a focus on using a small number of sensors and  only the fundamental mode of vibration. The validity of the method is also demonstrated using experimental modal data of a plate  girder from I-40 Bridge over the Rio Grande. The predictions were found to closely match the actual response of the bridges. The  proposed method can detect the damage in bridge structures using a limited number of sensors and vibration modes

  • Foundation size effect on modulus of sub grade reaction on[taliem.ir]

    Foundation size effect on modulus of sub grade reaction on Sandy soils

    تومان

    Winkler model is one of the most popular models in determining the modulus of sub grade reaction. In this model, the sub grade soil is  assumed to behave like infinite number of linear elastic springs. The stiffness of these springs is named as the modulus of sub grade reaction.  This modulus is dependant to some parameters like soil type, size, shape, depth and type of foundation. The direct method for estimating the  modulus of sub grade reaction is plate load test that is done with 30-100 cm diameter circular plate or equivalent rectangular plate. Afterward,  we have to extrapolate the test value for exact foundation. In the practical design procedure, Terzaghi’s equation is usually used to determine  the modulus of sub grade reaction for exact foundation, but there are some uncertainties in utilizing such equation. In this paper the size effect  of foundation on sandy sub grade with use of finite element software (Plaxis 8.2) is proposed to investigate the validation of Terzaghi’s  formula on determination of sub grade reaction modulus. Also the comparison between Vesic’s equation, Terzaghi’s one and obtained results are presented