بررسي عددي اثر فاصله ي شيار بر رفتار خمشي تير بتني تقويت شده به روش EBROG

Numerical Investigation of Flexural Behavior of Concrete Beams with effect from the Distance between the Grooves on the EBROG Method

در سال‌هاي اخير مسئله‌ي تقويت و ترميم سازه‌هاي ضعيف و آسيب‌ديده در سطح وسيعي مطرح گرديده است. در اين راستا روش تسليح خارجي با نصب بر روي شيارهاي طولي EBROG در سال‌هاي اخير ايجاد شده است. نتايج حاصل از تحقيقات صورت گرفته بر اين روش نشان داده كه با انتخاب عرض و عمق شيار معين مي‌توان جداشدگي را به تعويق انداخت و يا آن را به‌طور كامل حذف نمود. در اين مطالعه به‌منظور ارزيابي عوامل مؤثر بر روش EBROG، رفتار اين روش به‌صورت مدل اجزاي محدود با استفاده از نرم‌افزار Abaqus موردبررسي قرارگرفته است. نتايج حاصله نشان‌دهنده‌ي دقت بالاي مدل‌سازي عددي نسبت به نمونه‌ي آزمايشگاهي مي‌باشد. نتايج نشان داده است كه افزايش فاصله‌ي شيار در روش EBROG؛ ميزان افزايش باربري نهايي نمونه‌ها نسبت به نمونه‌ي تقويت نشده را تا 30 درصد كاهش مي‌دهد. همچنين با افزايش تعداد شيار در اين روش باربري نهايي و جذب انرژي در نمونه‌ها افزايش مي‌يابد.

By aging of steel and concrete structures in the world, structural retrofitting and strengthening has become among the major issues of engineering. several methods of strengthening have been developed by researchers for bonding the FRP sheet to the concrete surface until now, including the Externally Bonded Reinforcement , Near Surface Mounted for non-prestressed or prestressed FRP rebars or strips, and also the new developed grooving method with two techniques of Externally Bonded Reinforcement on Grooves (EBROG) and Externally Bonded Reinforcement in Grooves (EBRIG). The results of the researchs on EBROG method showed that by choosing specified width and height for grooves, this method can considerably postpone the debonding and in some cases may completely eliminate it. This study has tried, to evaluate the factors affecting EBROG method, function of this method has been examined by using finite element model in Abaqus software. The results show the high accuracy of numerical modeling compared with the experimental specimens. Moreover, it examins the effect of the distance between the grooves on the function of specimens reinforced by EBROG method. The results show that the rate of increasing ultimate load in specimens compared to unreinforced specimen, reduces up to 30 percent with increasing the distance between the grooves. So that in each group, specimen with the largest distance between the grooves, has the lowest increase its ultimate load. Also, it is observed that the ultimate load and energy absorption in the samples have been raised by increasing the number of grooves in this method.