توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱PERFORMANCE INVESTIGATION OF RC SHORT COLUMNS RETROFITTED WITH FRP COMPOSITES IN PASSIVE & ACTIVE STATES
نویسنده(ها): ، ، ،
اطلاعات انتشار: سومین کنفرانس بین المللی بتن و توسعه، سال
تعداد صفحات: ۸
Short columns and columns having weakness in transverse reinforcement have shown inappropriate behaviour in confronting with shear forces during different earthquakes and the shear failure mode of these columns is the main failure mode. One of the most conventional methods for improving the behaviour of these columns is the application of wrapped FRP jacket. These FRP jackets are lightweight, high strength and have a convenient installation process. These jackets can be utilized both in active and passive states. In this study, weak and retrofitted columns have been modelled using “Seismostruct” software and have been compared with experimental conclusions as well. In passive retrofitted specimens, the improvement in value of energy dissipation observed was about 1.7 to 4 times greater than control specimens. Furthermore, drift angle was increased about 1.4 to 2.5 times greater. Moreover, active retrofitted specimens have emonstrated a better behaviour than passive ones. In most of the specimens the growth was about 20% and 30 to 40 percent in shear strength and quantity of energy dissipation, respectively. Finally, AFRP composites have demonstrated higher ductility than CFRP composites, despite the fact that the shear strength of CFRP was higher than AFRP type.<\div>

۲NONLINEAR FINITE ELEMENT ANALYSIS OF FLANGED RC SHEAR WALLS BASED ON MULTI–LAYER SHELL ELEMENT
نویسنده(ها): ، ،
اطلاعات انتشار: سومین کنفرانس بین المللی بتن و توسعه، سال
تعداد صفحات: ۱۰
Nonlinear simulations for structures under earthquakes have been widely focused on in recent years. However, precise modeling for the nonlinear behavior of reinforced concrete shear walls, which are the major lateral–force–resistant structural member in high–rise R.C. buildings, still has many items to be investigated. In this paper, based on the principles of composite material mechanics, a multi–layer shell element model is proposed to simulate the in–plane bending and the coupled in–plane bending–shear nonlinear behaviors of RC shear wall. The multi–layer shell element is made up of many layers with different layers of thickness, and different material models (concrete or rebar) are assigned to various layers so that the structural performance of the shear wall can be directly connected with the material constitutive law. Besides the traditional elasto–plasticfracture constitutive model for concrete, which is efficient but does not give satisfying performance for concrete under complicated stress condition, a novel concrete constitutive model, referred as microplane model, which is originally proposed by Bazant et al., is developed to provide a better simulation for concrete in shear wall under complicated stress conditions and stress histories. Three flanged shear walls under static push–over load were analyzed with the proposed
shear wall model for demonstration. The simulation results show that the multilayer shell elements can correctly simulate the in–plane bending failure for tall flanged walls and the coupled in–plane bending–shear failure for short flanged walls. In addition, with microplane concrete constitutive law, the behavior and the damage accumulation of flanged shear wall can be appropriately modeled, which is
very important for the performance–based design of structures under disaster loads.<\div>

۳SEISMIC HAZARD ASSESSMENT OF METROPOLITAN TEHRAN,IRAN
نویسنده(ها): ، ،
اطلاعات انتشار: سومین همایش مقاوم سازی و مدیریت شهری، سال
تعداد صفحات: ۲۶
This paper presents a probabilistic seismic hazard assessment of Tehran , the capital of Iran Two maps have been prepared to indicate the earthquake hazard of tehran and its vicinity in the form of iso –acceleration contour lines. They display the probabilistic estimate of Pead Ground Acceleration(PGA) over bedrock for the return periods of 475 and 950 years . tehran is a densely populated metropolotan in which more than 10 milion people live. many destructive earthquakes happened in Iran in the last centuries. It comes from historical references that at least 6 times, tehran has been destroyed by catastrophic earthquakes. the oldest one happened in the 4th century BC. A collected catalogue containing both historical and instrumental events and covering the period from the 4th century BC to 1999 is then used.<\div>

۴Ground–Motion Prediction Equations of Spectral Ordinates and Arias Intensity for Iran
اطلاعات انتشار: سومین همایش مقاوم سازی و مدیریت شهری، سال
تعداد صفحات: ۲۹
the purpose of this study is to complete the previus research publication of the first author on the subject of ground – motion prediction equations (GMPEs) for Iran [Ghodrati amiri et al. 2007}. Several studies are being conducted to systematically assess the seismic hazards of areas within the seismic zones of Iran . Therefore there is an inevitable need for appropriate GMPEs of spectral ordinates. similarly suitable relations of Arias intensity (AI) for this region are are useful to capture the potential destructiveness of an earthquake. this article derives new relations using the strong motion database for two seismic zones of Zagros and Alborz – Central Iran according to tectonic conditions following a new processing of all of the records .<\div>

۵simulation method of near –field pulse typeground motion
نویسنده(ها): ، ،
اطلاعات انتشار: اولین کنفرانس بین المللی ساخت و ساز شهری در مجاورت گسلهای فعال، سال
تعداد صفحات: ۹
this paper is aimed at combining genetic algorithm and non–stationary clugh and penzien model for the simulation of earthquake accelerograms. A genetic based non stationary clough and penzien GB–CP model has been employed to effectively capture the frequency content of a particular acceleration record . the genetic algorithm GA optimizer has been implemented to determine five unknown parameters of clough and penzien CP spectral form. the proposed model is able to accurately capture the non–stationary features and high and low frequency components of near field earthquake accelerograms. the artificial near –field accelerogram is achieved via a random acceleration record corresponding to a clough and penzien power spectral model and multiplied by a time modulating envelope function.<\div>

۶uniform seismic hazard spectra for guilan a northern province of Iran
نویسنده(ها): ، ،
اطلاعات انتشار: اولین کنفرانس بین المللی ساخت و ساز شهری در مجاورت گسلهای فعال، سال
تعداد صفحات: ۱۰
Guilan is a northern province of iran which its important capital city , rasht is located in southern side of caspian sea . The result of this analysis is preparation of vertical and horizontal spectral acceleration maps with exceeding probability of 2 and 10 percents in a 50 year life cycle and 5 percents of damping for 16 different periods which can support gilan from east to west and south . utilizing these maps vertical and horizontal components of uniform seismic hazard spectra for cities of rasht anzali fooman , lahijan , roodbar and manjil for exceeding probability of 2 and 10 percents in a 50 year life cycle is presented.<\div>

۷Application of Aeroelasticity in Civil Engineering
اطلاعات انتشار: نهمین کنگره بین المللی مهندسی عمران، سال
تعداد صفحات: ۸
The Tacoma Bridge disaster, in the 40s, has opened a new interesting chapter in Civil Engineering. Besides, development of Science caused to use other sciences in Civil Engineering. Certain types of civilengineering structures can be subjected to aero–Dynamic forces generated by structural motions. These motions, called self–excited, are in turn affected by the aerodynamic forces they generate. Behavior associated with self–excited motions is called aeroelastic. Aeroelastically is divided in tow group: Staticaeroelasticity and dynamic aeroelasticity. Tall chimneys, buildings structures, Cable bridges,Communication masts, Electricity transmission lines, Lighting columns and Marine structures May also respond aeroelastically and need to be designed accordingly. In this research we tried to discuss whether the seismic design is sufficient for aeroelastic forces. Finally tried to explain Aeroelasticity application’s in Civil Engineering<\div>
نمایش نتایج ۱ تا ۷ از میان ۷ نتیجه