بررسی آزمایشگاهی رفتار برشی دال‌های یک ‌طرفه مقاوم‌سازی شده با ورق ‌پیش‌ ساخته کامپوزیت‌های سیمانی توانمند الیافی مسلح

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشگاه سمنان

چکیده

به ‌منظور حفظ و نگه‌داری سازه‌ها و نیز افزایش عمر مفید آن‌ها، مقاوم‌سازی سازه‌های آسیب ‌دیده متدوال گردیده است. دال‌های بتنی به عنوان عضو سازه‌ای کلیدی، نقشی تاثیر گذار در توزیع بار و رفتار سازه داشته و از سوی دیگر عدم برطرف سازی آسیب‌های وارد بر دال های بتنی میتواند خسارات جبران ناپذیری را به همراه داشته باشد. در این پژوهش آزمایشگاهی مقاوم‌سازی دال‌های بتن مسلح یک ‌طرفه با کمک ورق‌های پیش ‌ساخته‌ از جنس کامپوزیت سیمانی توانمند الیافی در ناحیه کششی دال انجام شده است. سپس سطوح جانبی آن برای افزایش ظرفیت برشی با ورق‌های پلیمری مسلح شده به الیاف کربن مقاوم‌سازی شده است. این مطالعه به ‌طور خلاصه در سه گام انجام شده است. در گام اول طرح اختلاط و مشخصات مکانیکی مصالح کامپوزیت سیمانی توانمند الیافی بررسی گردید. در گام دوم ظرفیت خمشی ورق‌های پیش‌ ساخته کامپوزیت سیمانی توانمند الیافی به ‌طور جداگانه قبل از اتصال به دال تعیین گردید. در گام نهایی دال‌های بتن مسلح مقاوم‌سازی شده به صورت خمشی و برشی، تحت آزمایش بررسی رفتار برشی قرار گرفتند. نتایج نشان داد که مقاوم‌سازی برشی وجوه جانبی دال باعث بهبود ظرفیت خمشی، الگوی شکست، سختی و جذب انرژی به‌ واسطه آزمایش بررسی رفتار برشی نمونه‌ها شده است. همچنین برای دال‌های یک ‌طرفه مقاوم‌سازی شده با ورق پیش‌ ساخته کامپوزیت سیمانی توانمند الیافی، در صورتی که بار متمرکز به دال اعمال شود به طوری که نسبت دهانه برش به ارتفاع مؤثراز 2/5 کمتر باشد، حتی اگر در سطوح جانبی برای افزایش ظرفیت برشی مقطع مقاوم‌سازی شده باشد، مد شکست دال به طور حتم برشی خواهد بود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental investigation of shear behavior of one-way reinforced slabs with high-performance fiber-reinforced cementitious composite laminates

نویسندگان [English]

  • Mahdieh Sabbaghian
  • Ali kheyroddin
Semnan University
چکیده [English]

It has been used to preserve structures and extend their useful life, retrofit damaged structures. Concrete slabs, as a key structural member, play an important role in the load distribution and structural behavior, and lack of resolving the damage to concrete slabs can lead to irreparable damage. In this experimental study, the one way reinforced concrete slabs were strengthened by using high-performance fiber-reinforced cementitious composite (HPFRCC) laminates in the slab's tensile side. Its lateral surfaces are then strengthened with carbon fiber reinforced polymer laminates to increase shear capacity. This study is summarized in three steps. In the first step, the mixing design and mechanical properties of fiber-reinforced cement composites were investigated. In the second step, the flexural capacity of fiber-reinforced cement composite laminates was determined separately before bonding to the slab. In the final step, shear and shear reinforced concrete slabs were tested for shear behavior investigation. The results showed that the strengthening of the lateral sides of the specimens was improved the flexural capacity, fracture pattern, stiffness, and energy absorption by examining the shear behavior of the specimens. Also, for one-way slabs strengthened with fiber-reinforced cement composite laminates, if the concentrated load is applied to the slab so that the shear Span-to-effective height ratio is less than 2.5, even If it is strengthened at the lateral surfaces to increase the shear capacity of the cross-section, the failure pattern will certainly be shear.

کلیدواژه‌ها [English]

  • One way RC slabs
  • shear strengthening
  • Flexural Strengthening
  • fiber-reinforced cementitious composite
  • HPFRCC
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