PSI - Issue 52

Rakesh Katam et al. / Procedia Structural Integrity 52 (2024) 72–88 Rakesh Katam/ Structural Integrity Procedia 00 (2019) 000 – 000

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There is a likelihood that the present condition of the structure is identical to case three. From visual observation and numerical analysis, in which almost every column in in-situ condition has a cracked bottom third to a half resembles the case three numerical model. This demonstrates the significant likelihood of material strength degradation and the effect of increased dead loads in the structure over the period of 30 years. Therefore, the results show that the building is unsafe even for the current loads because the columns' cracks are actively spreading. If the ground floor's columns are damaged, the entire structure could be in danger if it is not strengthened for the current loads. Considering all the parameters from visual inspection, NDT, and numerical modelling the following recommendations are suggested. 5. Recommendations and Retrofitting A numerical model helped in predicting the overall behavior of the structure by considering the actual load conditions that are present on site. After considering the scenario, the numerical results, and the client’s requirements, recommendations are provided. A type one solution is suggested for the columns adjacent to the next building, while a type two solution is suggested for the remaining columns. While L-sections are advised in locations where all sides of the columns are inaccessible. Steel encasement and I-sections to existing RCC columns can increase their load carrying capacity and structural integrity by, providing increased stiffness and strength for columns that are not located in the tightest spaces or are difficult to reach. This method is frequently employed to reinforce pre-existing structures that may not have been built to sustain the loads they are currently caring for. A composite section is produced when an RCC column is close to a steel encasement and an I-section. Together, the RCC column and the steel encasement work to withstand the applied loads. The added steel parts give the column more stiffness and strength, which may boost its ability to support more loads. Accessing the area where the necessary strengthening must occur is one of the main obstacles when adding two different types of steel encasements to RCC columns. This is especially true for columns that are situated in constrained or challenging-to-reach locations. Fig. 10 shows the type-1 recommendations to withstand the additional loads coming from the above floors.