• Suntanu Biswas Dipto
• Wesam Abdullah Kayd
• Elyas Hossain
• Alam Md Shah
• Muhammad Asif

Engineers frequently design single column pier bridges without a specific pier cap due to limited construction space, economical design and some other factors. For this, a single column pier, single support bridge tends to turn over its supports in the same direction as a moving vehicle when it travels along the lane close to the edge of the deck. This problem is ignored most of the time; in fact, during the investigations of some accidents, the overturning issue was underestimated, but later, in some cases, it was proved that the particular accident was caused by the overturning instability. The bridge, studied in this research is a simply supported box girder bridge. The section consists of three spans with a total length of (24m+30m+20m) 74m, where at the middle, two single column piers with single bearing support have been adopted. The main objective of the research is to analyze the structure to evaluate whether there is any overturning instability present in the bridge. In cases of instability some countermeasures should be taken. Some schemes should be developed to make the bridge safe enough to continue the operation. The selected scheme should be analyzed to visualize the substantial evidence to prove the effectiveness of the developed scheme. For evaluating the actual condition of the bridge, finite element analysis has been done using computer software. The bridge was found to have overturning instability after analyzing the original bridge and calculating the overturning coefficient. Where the overturning coefficient was much less than the standard value. To make the bridge safe, three initial strengthening schemes have been proposed: to enlarge the pier cap; to install steel tie plate and stringers and the last one was to install additional CFST piers. The third one was selected and analyzed in the finite element analysis software, and then according to the analysis report, the overturning coefficient has been calculated, which shows significant increments in the value of the coefficient (84.65% and 39.08% increments in support 4L and 7L, respectively) and the results come closer to the standard value. For more increments, it is suggested to increase the distance between additional piers. However, according to the analysis and evaluation of the bridge before and after applying the strengthening scheme, it can be concluded that the bridge has achieved a significant amount of resistance against overturning instability by applying the scheme, and the amount of resistance can be increased more by taking some countermeasures.

Overturning instability; Schemes, Single-column pier; CFST pier; Box girder; Overturning coefficient

"Strengthening Design of Beigao Interchange Bridge Against Overturning Instability", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.11, Issue 8, page no.h1-h140, August-2024, Available :http://www.jetir.org/papers/JETIRTHE2150.pdf

"Strengthening Design of Beigao Interchange Bridge Against Overturning Instability", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.11, Issue 8, page no. pph1-h140, August-2024, Available at : http://www.jetir.org/papers/JETIRTHE2150.pdf