ارزیابی آسیب پذیری لرزه ای پل های بتنی عرشه پیوسته بر روی تیپ های مختلف خاک با استفاده از منحنی های شکنندگی

نوع مقاله : علمی - پژوهشی

نویسندگان

1 گروه مهندسی سازه و زلزله، دانشکده مهندسی عمران، آب و محیط زیست، دانشگاه شهید بهشتی، تهران، ایران.

2 استادیار، دانشکده مهندسی عمران، آب و محیط زیست، دانشگاه شهید بهشتی، تهران، ایران

چکیده

یکی از روشهای متداول در برآورد خرابی سازه ها و خسارات ناشی از زلزله بر آنها استفاده از منحنی های شکنندگی با بهره گیری از روشهای احتمالاتی می باشد. در این روشها سازه از جمله پل را می توان در چند تیپ سازه ای از نظر تعداد دهانه، نوع اتصال، جنس اعضا، اثر خاک ساختگاه و نظایر آن طبقه بندی نمود. همچنین نیروی لرزه ای وارد بر پل را با شاخص هایی نظیر بیشینه شتاب سطح زمین (PGA) یا شتاب طیفی (Sa) می توان در نظر گرفت. در این پژوهش، تعداد اثر دهانه و نوع خاک ساختگاه بر منحنی های شکنندگی پل های بتنی با عرشه پیوسته مورد بررسی قرار گرفته است. بدین منظور پل های دو، سه و چهار دهانه در نرم افزار المان محدود مدلسازی گردیدند و سپس منحنی های شکنندگی هر یک از آن ها به روش احتمالاتی و با انجام تحلیل های دینامیکی غیرخطی فزاینده (IDA) برای شتابنگاشت های ثبت شده حوزه دور در چهار نوع خاک مطابق آیین نامه لرزه ای ایران به دست آمد. نتایج نشان دهنده این حقیقت است که نوع خاک ساختگاه پل بر منحنی شکنندگی تاثیر به سزایی دارد و احتمال خرابی پل ها با تغییر نوع خاک از تیپ یک به چهار و همچنین با افزایش تعداد دهانه های پل افزایش میاید.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Seismic vulnerability of continuous concrete bridges on different types of soil using fragility curves

نویسندگان [English]

  • pedram omidian 1
  • Hamid Saffari 2
1 Department of Structural and Earthquake Engineering, Shahid Beheshti University, Tehran, Iran
2 Assistant Professor, Faculty of Civil & Environmental Engineering, Shahid Beheshti University, Tehran, Iran
چکیده [English]

One of the common methods for estimation of structural failures and earthquake damages is using fragility curves with probabilistic methods. In these methods, a structure such as a bridge can be classified into several structural types in terms of number of spans, type of connections, material used for members, even type of soil, and so on. Also, the seismic load on the bridge can be considered with indicators such as peak ground acceleration (PGA) or spectral acceleration (SA). In this research, the number of span and soil type of concrete bridges with continuous deck have been investigated on the fragility curves. For this purpose, the two, three, and four span bridges were modeled in the finite element software. Then, the fragility curves of each condition were determined by probabilistic method and by performing nonlinear incremental dynamic analysis (IDA) for far field accelerograms and for four soil types of seismic design code of Iran. The results show that the soil type of the bridge site has a significant impact on the fragility curve, and the probability that the bridges will collapse will vary with the type of soil from type I to IV and damage increases as the number of bridge spans increases.

کلیدواژه‌ها [English]

  • Reinforced Concrete Bridge
  • Incremental Nonlinear Dynamic Analysis
  • Failure Criteria
  • Fragility curve
  • Impact of Soil Type
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