1 Tarbiat Modares University 2420 Investigation of Seismic Behavior of Frame-Panel Systems Gerami M. Kaboli S.A.R 1 9 2011 11 2 0 0 07 07 2007 19 05 2010 Abstract: Implementation of 3D panels in buildings is increasing due to the importance of lightening, optimizing and reduction of fuel consumption. These panels are used as interior, outer, load bearing and partitioning walls beside the structural frame without considering the frame-panel interaction. Steel frames act in shear mode and panel frames act in flexure; hence, combining the two systems will change the structural behavior of each system. So, investigation of the seismic behavior of combined systems using nonlinear dynamic methods seems to be mandatory. In this article, frames with 3, 5 and 10 stories (filled in different bays by panel) were modeled in ANSYS. These frames were then analyzed under Elcentro, Tabas and Naghan seismic records. The results illustrated that using panel not only results in more acceptable drifts, but also it lets the system to have a better seismic behavior and more energy dissipation. For example, the displacements of the structures in the highest level decrease more than 35% by using one bay panel for filling steel frames. This amount of filling also leads to more than 100% increase in the area under the base shear-displacement diagram of a steel frame.
9322 A Study on the Effect of Section Shape of RC Columns on the Loss of Load-Carrying Capacity in Fire Lotfollahi Yaghin1 M.A Najafi P. 1 9 2011 11 2 0 0 04 04 2010 29 07 2010 Abstract: In the present article, the effect of fire on the axial compressive strength of reinforced concrete (RC) columns was studied. Method of research was laboratory investigation. The axial compressive strength of RC columns was measured by applying variable heat in different time intervals in the process of experiment. Thirty two samples of fine-scale RC columns with square and circular cross sections, the gross cross section area of 225 cm² (for both sections), longitudinal reinforcement area of 3.1 cm², general height of 30 cm for all samples and other uniform structural characteristics ( 25 c f   MPa , 300 y f  MPa ) were exposed to fire and different temperatures (300°C to 700°C) were applied in the time intervals of 30, 60 and 90 minutes. Then they were exposed to axial loading by hydraulic jack with 200 ton capacity, and their strengths were measured. It is worth noting that, in the heating stage of samples, caps with thermal insulation were used in order to prevent instantaneous strain at the two ends of the samples. By carrying out the experiments, it became clear that at the time of fire, two factors, i.e., the "period of fire" and "temperature of fire" resulted in the loss of strength in RC columns. Of course, the "period of fire" factor was more effective than temperature of fire. It also became clear that RC columns with circular cross section fail faster in comparison with the columns with square cross sections at the time of fire. In order to evaluate and measure the results obtained, a relative factor called "Fire Factor" was utilized. The results indicated that the amount of axial compressive strength loss resulting from fire is approximately 3-5% greater in circular RC columns in comparison with square columns. 7876 Considering the Effect of Six Component of Near-Fault Earthquake Ground Motions on the Three Dimensional Systems Shakib H. Alirezaie M. 1 9 2011 11 2 0 0 18 07 2009 29 09 2010 Abstract: The rotational components of seismic strong-motion are attracting attention since it is becoming evident that it may contribute considerably to the overall response of structures to earthquake motions. Also, it is clear that the effects of near-fault ground motions with large velocity pulses, large amplitude, long period, and pulse type of excitation can create critical working conditions. In the near-field of an earthquake the effects of the rotational components of ground motion may not be negligible specially for important structures. In this paper, an improved method for calculating the time histories of torsional and rocking components of ground motion corresponding to a set of three recorded orthogonal translational components is presented. The current processing of earthquake records provide information only about the three translational (two horizontal and one vertical) components of the ground motion, primarily because these are the only components that can be directly instrumentally measured. However, the translational components during a seismic event are always accompanied by rotational components because of the traveling wave effects. Several studies have shown the importance of rotational components in the seismic analysis and design of structures. The seismic design codes also prescribe “accidental eccentricity” in the design force calculations to account for the unknown torsional inputs and unintended eccentricity in the design of a building. One of the reasons why this input is not explicitly taken into account in the seismic design codes is the lack of reliable information on torsional ground spectra. In this study the three rotational components of earthquakes records is generated artificial by three translational components. The torsional motions in terms of time derivative of translational components and shear wave velocity of site are derived. Seven translational earthquake records of far fault and seven translational earthquake records from near-fault have been selected. The rotational components of far fault and near fault are generated the response spectral for translational as well as rotational components are presented and compare to each other in other to verify the characteristic of the near fault response spectral compare to the far fault response spectral. Furthermore, the effect of rotational motion on structural response is investigated. Therefore the six components of earthquakes records of far fault and near fault applied to the idealized system model and the response of the system are determine. 1437 The Use of Dynamic Probing For Investigation of Fine Soils and Evaluation of Undrained Shear Strength Khodaparast M. Fakher A. 1 9 2011 11 2 0 0 10 04 2007 29 12 2010 Abstract: The Dynamic Probe is an effective and efficient tool used in site investigation. It is more economic than the use of boring equipment particularly when the depth of exploration is moderate. The paper covers the design and development of a dynamic probing rig and a new soil sampler to increase the efficiency of conventional dynamic probes. The repeatability of the results are considered and correlations between dynamic probing results and undrained shear strength identified. A new equation relating dynamic resistance to undrained shear strength is proposed. The paper encourages the wider application of dynamic probing for site investigation in fine soils. 1208 Seismic Response and Free Vibration of Rectangular Liquid Storage Tanks Ghods A.S Esfahani M.R 1 9 2011 11 2 0 0 06 12 2009 29 12 2010 Abstract: The experimental study of structural vibration is often performed to determine the modal parameters of a structure or to verify the theoretical models and predictions. The first phase of this research involved the experimental determination of the modal properties of a rectangular steel tank with different levels of water. The natural frequencies obtained from the experiments were compared to those calculated by the analytical models. In the second phase, a procedure for computing hydrodynamic pressures in rectangular tanks is proposed. This procedure considers the effect of tank wall flexibility in determining the hydrodynamic pressures produced by the impulsive response. Based on a two-dimensional model of the tank wall, a dynamic time-history analysis was carried out. The results were compared with other models based on the current design practice codes and standards, which use a lumped mass approach. The comparison shows that, in most cases, the lumped mass approach overestimates the base shear. The effect of wall flexibility on wall displacements and base shears are also discussed. 7445 Effect of Rail Corrugation on the Pressure between Sleeper and Ballast Zakeri J.A Gharouninik M Moazami M. 1 9 2011 11 2 0 0 19 04 2010 27 02 2011 Abstract: Because of the complicated nature of track and train, investigation of interactions between them has been always an complex problem in railway engineering. Perceiving of this interaction is an complex problem only in track with various defects but also in the track without defects. Estimating of the forces exerted on track and train will be much difficult when a defect such as rail corrugation is added to this interaction. If an accurate computer model is available, we can have a good forecast of these forces. However, precise estimating of them is only reached field measurement. In this study, we tried to present a good estimation of passenger and freight wagon forces on track with rail corrugation defect. The pressure between sleeper and ballast was calculated by these forces. Afterwards pressure (on ballast surface)-rail corrugation wavelength diagrams was determined. By using these diagrams, the rail corrugation wavelength where ballast stresses were beyond the permissible limit for each type of operation, was determined (it was named critical corrugation wavelength). A computer model was developed in ADAMS/Rail software for passenger and freight wagons with various speeds to estimate the forces exerted on the ballasted track with corrugation defect. 3712 The Experimental Study of the Effect of FRP Laminates on Shear Strength of RC Fixed Ended Deep Beams Arabzade A Mahanpoor H. 1 9 2011 11 2 0 0 07 07 2010 02 03 2011 Abstract: Very little researches hasbeen performed about strengthening and repairing of deep beams. In this paper, shear strength of Reinforced Concrete (RC) deep beams in two cases of repair and strengthening with Carbon Fiber Reinforced Polymer (CFRP) is evaluated. To achieve the objective of the research, six deep beams were constructed in three coupling groups with constant reinforcement arrangement and concrete strength and clear span-to-depth ratio of 2. In each group, one beam without strengthening was used as reference beam. This beam was loaded up to failure and then reinforced by CFRP and reloaded again. The other one was reinforced before loading, similar to the first one. The results indicated that repair and strengthening the beams would increase the ultimate load. In general, when one directional CFRP strip is attached to the face of the beams perpendicular to crack with the angle of 45o (SS45), the ultimate strength is increased by 7 and 61%, respectively. Therefore it can be conclude that SS45 system because of uniform distribution of CFRP perpendicular to the direction of shear cracks, could be the best method for repair and strengthening of tested fixed ended deep beams and in comparison with reference beam, if it used to repair the damaged beam, the ultimate load would increase up to 7 percent. 566 Comparison between Epoxy and Waterproof Sealers in TiO2 Immobilization on Concrete Surface for Treating Phenolic Wastewater by Photocatalytic Process Delnavaz M. Ayati B. Ganjidoust H. Sanjabi S. 1 9 2011 11 2 0 0 17 01 2011 15 06 2011 Abstract: Two kinds of concrete sealers including epoxy and waterproof were used to immobilize TiO2 nano-particles on concrete surfaces for treating 25-500 mg/L synthetic phenolic wastewater using photocatalytic process. The reactor consisted of contaminated tank, photocatalytic and aeration zones. Irradiation of TiO2 was performed by UV-A lamps at different intensity (4.42- 8.9 mW.cm-2) placed 10 cm above the concrete surfaces. SEM and EDX analys is showed a uniform appearance of TiO2 catalyst on the concrete. In influent phenol concentration (100 mg/L), pH=7 and retention time (4 hr), the removal efficiency by epoxy sealer was more than 20% compared to the waterproof sealer because of hydrophobic effects. Reduction of removal efficiency was less than 2% for the epoxy sealer after several iterations of the process. Finally, the effects of intensity and wavelength of UV lamp and system pH in removal efficiency were evaluated. 3319 Numerical Modeling of Confinement Effects on Failure Pattern of Brittle Rocks in Triaxial Tests Golshani A Rajabi H 1 9 2011 11 2 0 0 15 07 2009 06 09 2011 Abstract: One of the most important goals of the experiments is to determine deformation and strength of the rock specimen under applying triaxial load. The status of failure condition is one of the subjects, which can be used in soil mechanic and foundation engineering applications. To investigate the effect of confining pressure on the triaxial test, the rock was considered as bonded-particles method and simulated by PFC3D program. To compare the mechanical behavior and failure pattern of the numerical and experimental results at uniaxial and triaxial tests at the same conditions, the Young's modulus, Poisson's ratio and maximum axial stress were considered. On the other hand, the microcracks growth and change of failure pattern at the modeling of the uniaxial and triaxial tests with different confining pressures up to failure point were reported. According to the experimental work, the number density of microcracks decreases from starting value and remains almost constant up to the failure beyond that point. Comparison of the numerical and experimental results of maximum axial stress and the Poisson's ratio revealed a good accordance. The simulated Young's modulus was smaller in comparison with the experimental ones and the difference was about 36%, which seems to be due to absence of the pre-existing microcracks on the model. The initial number density of microcracks at the model was zero and increased while microcracking. Also the sudden increment around the maximum stress was observed, which is because of unstable growing of microcracks near the maximum stress. In all uniaxial and triaxial tests with different confining stresses, the number density of microcracks during the failure remained almost constant, which can be considered as a proof of failure occurring in the model. The experimental results indicated a similar trend as well. 6549 Proposing an Error Estimator for Collocated Discreet Least Square (CDLS) Meshless Method Afshar M.H Lashckarbolok M. 1 9 2011 11 2 1 15 02 05 2007 06 09 2009 The error estimation should be a main tool in every adaptivity process. This is the reason for the great importance of the estimation. It allows us to know the quality of the solution, and hence, if it is acceptable or not. Moreover, it provides some information about the changes that are necessary to be made in the mathematical model to reach, in an economic way, the desired solution. In this paper, a new error estimator for solving the hyperbolic problems to be used in conjunction with the Collocated Discreet Least Square Meshless (CDLS) method is presented. The error estimator is shown to be naturally related to the least-squares method, providing a suitable measure of the errors in the solution. The estimator is easily calculated by the use of already existing matrices of the least-squares computation, hence, it is very cheap. The proposed error estimator was implemented with CDLS method to solve three benchmark examples from the literature and the effect of collocation points on them was investigated. These examples are nonlinear burgers equation, dam break problem and the problem of shoaling a wave on sloping shallow waters. The results showed that the error estimator works very well in all numerical examples.