رفتار محوری و خمشی ستون‌های بتن‌‌آرمه‌ی تقویت‌شده با کامپوزیت‌های frp با استفاده از روش نوار گوشه- دورپیچ

مقاوم‌سازی ستون ها به‌عنوان یکی از اعضاء اصلی سازه، اهمیت بسیاری دارد. هدف پژوهش حاضر، بررسی رفتار ستون های بتن‌آرمه ی تقویت‌شده با کامپوزیت های frp با استفاده از روش جدید نوار گوشه- دورپیچ تحت بار محوری با خروج از مرکزیت های مختلف است. برای این منظور، 10 ستون تحت بار محوری با خروج از مرکزیت های صفر، 30، 60، و 90 میلی‌متر قرار گرفته‌اند؛ که 2 ستون با استفاده از دورپیچ و 4 ستون با استفاده از روش نوار گوشه- دورپیچ محصورشده و بقیه به عنوان نمونه ی شاهد در نظر گرفته شده‌اند. نتایج نشان داده است که استفاده از روش نوار گوشه- دورپیچ منجر به توزیع یکنواخت تر تنش در محیط مقطع شده و به‌دنبال آن، عملکرد تقویت در افزایش ظرفیت باربری و شکل‌پذیری ستون بهبود یافته است. به‌عنوان مثال، در نمونه ی تقویت‌شده با روش نوار گوشه- دورپیچ تحت بار محوری خالص، ظرفیت باربری و شکل‌پذیری به ترتیب به میزان 15 و 77 درصد نسبت به نمونه ی محصورشده با دورپیچ افزایش یافته است.

axial and flexural behavior of reinforced concrete columns retrofitted with frp composites through the corner strip-wrap technique

column strengthening is critically important as one of the fundamental elements in structures. the objective of this study is to investigate the behavior of reinforced concrete (rc) columns strengthened with fiber-reinforced polymer (frp) composites using the novel corner strip-wrap technique when subjected to axial loading with varying levels of eccentricity. in order to compare the proposed method with the wrapping technique, ten square reinforced concrete (rc) columns, each with cross-sectional dimensions of 133×133 mm and a height of 500 mm, were subjected to zero, 30, 60, and 90 mm load eccentricities. among these specimens, two columns were confined using the wrapping method, and four columns were confined using the corner strip-wrap technique, while the remaining columns were designated as control specimens. in other words, the test parameters consisted of the technique used for column confinement and the applied load eccentricity. the experimental results revealed that, in comparison to both unconfined and wrapped rc columns, improved performance in terms of increased ductility and load carrying capacity under eccentric loading was demonstrated by square rc columns when confined through the corner strip-batten technique. moreover, it is evident that eccentric loads, in contrast to concentric ones, significantly reduce the load-carrying capacity and ductility of confined rc columns. however, in this experiment, confined columns exhibited a higher load-carrying capacity and greater ductility in comparison to their unconfined counterparts, both in concentric and eccentric testing conditions. for instance, the load carrying capacities of columns confined using the corner strip-wrap technique increased by 15% and 13% when compared to those confined through the conventional wrapping technique when subjected to eccentricities of zero and 90 mm, respectively. additionally, columns confined with the corner strip-wrap technique demonstrated ductility enhancements of 607% and 330% in comparison to the unconfined columns when subjected to zero and 60 mm eccentricities, respectively. finally, axial loading-bending moment (p-m) interaction diagrams were created for both the unconfined and confined columns. a comparison of the experimental results with the values derived from the expressions recommended in various codes showed that the code-based estimates were conservative compared to the experimental measurements.