Abstract    The Behavior of conventional braced frames, are not the same in tension and compression. This problem can be improved by prevention of buckling under compressive loads, which is called buckling restrained brace(BRB). In this field TTD metal damper also have much attention due to simplicity in construction and execution. This damper is recommended because of accessing to better performance than BRB brace and also having easier construction technology and consequently cheaper until possibility of making it is feasible in countries without complex technologies. In this research, three steel structures with three, five and eight stories that require to retrofitting, are retrofitted using buckling restrained brace and TTD metal damper separately, and are compared before and after the retrofitting using nonlinear dynamic analysis in Perform 3d software. Finally, the effects of this systems in reduction of structure displacement, reduction of energy dissipation due to nonlinear behavior in main members of structure, and increasing of performance level is inspected. The observation of both of systems results also imply that with increasing of the number of building stories, expressed positive effect, is reduced. Which that, indicates more effect of this energy dissapation systems in short-order structures.

Keywords    Seismic Retrofitting, Buckling Restrained Brace, TTD Metal Damper, Conventional Braces, Energy Dissipation Systems, Nonlinear Dynamic Analysis

چکیده    رفتار قاب‌هاي مهاربندي شده متداول در كشش و فشار یکسان نیست. این مشکل را مي‌توان با جلوگيري از كمانش مهاربند تحت بارهاي فشاري، بهبود بخشید. چنين مهاربندي، مهاربند مقید در برابر کمانش یا مهاربند کمانش ناپذیر(BRB) ناميده مي‌شود. همچنین در این عرصه میراگر فلزی نوعTTD به دلیل سادگی در ساخت واجرا از توجه زیادی برخوردارند.. این میراگرباهدف دستیابی به عملکرد بهتر از مهاربند BRBوهمچنین داشتن تکنولوژی ساخت ساده تر و در نتیجه ارزان تر، معرفی شده است تا امکان ساخت آن در کشورهای فاقد تکنولوژی های پیچیده امکان پذیر باشد. در اين مقاله سه ساختمان فولادی سه ،پنج و هشت طبقه که نیاز به بهسازی دارند را به صورت جداگانه با مهاربند کمانش ناپذیر و میراگر TTD بهسازی کرده و آنها را در دو حالت قبل و بعد از بهسازی و با استفاده از تحلیل دینامیکی غیر خطی در نرم افزارPERFORM 3D مورد مقایسه قرار می دهیم. در نهایت تاثیر این سیستم ها درکاهش تغییر مکان سازه، کاهش اتلاف انرژی ناشی از رفتار غیرخطی در اعضای اصلی سازه و افزایش سطح عملکرد سازه مورد بررسی قرار می گیرد. همچنین نتایج نشان می دهد که با افزایش تعداد طبقات ساختمان تاثیرات مثبت بیان شده ،کاهش می یابد که این نشان دهنده ی تاثیر مناسب تر این سیستم های اتلاف انرژی در سازه های کوتاه مرتبه می باشد.

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