اثر زاویه اعمال زلزله و تحریک غیرهمزمان تکیه گاهی بر روی پل های قوسی بتن آرمه

نوع مقاله : پژوهشی اصیل (کامل)

نویسندگان
ادهم قلی پور
محمد رضا داودی
حسین یوسف پور
دانشگاه صنعتی نوشیروانی بابل
10.22034.24.3.71
چکیده
با وجود رواج کاربرد پل ­های قوسی در مناطق لرزه ­خیز دنیا، رفتار لرزه ­ای این پل­ ها تاکنون مورد مطالعات محدودی قرار گرفته ­است. مطالعه ­ی حاضر به بررسی اثرات تغییر زاویه ­ی اعمال زلزله و تحریک غیرهمزمان تکیه­ گاهی بر پل ­های قوسی بتن مسلح می ­پردازد. چهار پل قوسی بتن آرمه ساخته شده در ایران به صورت سه بعدی مدلسازی شده و تحت تحلیل تاریخچه زمانی غیرخطی بر اساس 7 شتاب­ نگاشت قرار گرفتند که هریک از آن­ ها با تغییر زاویه در گام ­های 15 درجه اعمال شدند. تحریک غیرهمزمان تکیه ­گاهی نیز از طریق ایجاد تاخیر زمانی برای رکورد ورودی به هر تکیه­ گاه اعمال شد. نتایج نشان داد که افتادگی عرشه بیش از سایر پارامترها به زاویه اعمال زلزله حساس بوده است. افزایش نیروی محوری پای قوس در اثر رخداد زلزله تا 40 درصد مشاهده شد که بیشترین آن در حالت اعمال زلزله عرضی محاسبه گردید. اعمال تاخیر زمانی در تحریک تکیه ­گاه­های سازه نیز منجر به حداکثر 10 درصد افزایش در معیارهای آسیب و حداکثر 5 درصد افزایش در نیروی محوری و لنگر خمشی پای قوس گردید.

کلیدواژه‌ها

موضوعات

عنوان مقاله English

Effects of Earthquake Incidence Angle and Asynchronous Support Excitation on Reinforced Concrete Arch Bridges

نویسندگان English

Adham Gholipour
Mohammad Reza Davoodi
Hossein Yousefpour
Babol Noshirvani University of Technology
چکیده English

Arch bridges have been commonly used in high-seismicity regions of the world, as a result of which notable damage has been documented in several arch bridges during past earthquakes. Certain aspects of seismic behavior of arch bridges are different from those in typical slab-on-girder bridges, including the significance of axial loads, sizable differences between in-plane and out-of-plane stiffness, and the use of piers with different heights. However, limited previous studies have addressed the seismic behavior of concrete arch bridges. In the present study, the effects of earthquake incidence angle and asynchronous support excitation on reinforced concrete arch bridges are investigated. Nonlinear 3-D models of four existing reinforced concrete deck-type arch bridges in Iran were developed. The bridges had arch spans of 23, 35, 45 and 50 meters and were subjected to nonlinear time history analyses using seven acceleration records. The incidence angle was changed in 15 degrees increment between 0 and 90 degrees. Moreover, the effect of asynchronous support excitation was investigated by means of introducing a time delay between excitation input for different supports. The relative displacement (drift) of the piers, the curvature ductility demands within the piers, the curvature ductility demand at different locations of the arch, and the displacement of the deck at the abutments (unseating) were used as damage indicators. The results showed that unseating of the bridge deck from abutments and pier drifts were the most and the least sensitive damage parameter to the change in incidence angle, respectively. The axial force at the end points of the arch was found to change significantly during earthquake, with a maximum of 40 percent in case of 90-degree incidence angle. The effect of asynchronous support excitations was relatively small, with a maximum increase of 10 percent in damage indicators and 5 percent in the axial forces and bending moments.

کلیدواژه‌ها English

Arch bridge
Nonlinear time history analysis
Incidence angle
Asynchronous Support Excitation
Unseating
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مهندسی عمران مدرس
دوره 24، شماره 3
مرداد و شهریور 1403
صفحه 71-84