A numerical study on the application of the sub-structure method for retrofitting : a case study of a school building in Dhaka, Bangladesh | |
| Author | May Chue Nyeint |
| Call Number | AIT Thesis no.ST-24-27 |
| Subject(s) | School buildings--Retrofitting--Bangladesh School buildings--Earthquake effects--Bangladesh Building repair--Bangkadesh |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Structural Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | This thesis presents a numerical analysis aimed at assessing the effectiveness of external sub-structure retrofitting methods for enhancing the seismic performance of a school building in Dhaka, Bangladesh. Due to the region’s geological conditions and history of seismic events, improving the resilience of existing structures, particularly in densely populated and economically vital areas, is crucial. The study focuses on the Kobbad Sardar Government Primary School, a two-story reinforced concrete (RC) structure constructed under outdated seismic codes.The research employs the Applied Element Method (AEM) to evaluate three external sub-structure retrofitting techniques: the Master Frame Construction Method, the Portal Grid (PG) Method, and the External PT-PBSPC Frame Sub-Structure Method. Numerical models of both the existing building and retrofitted configurations were analyzed under static monotonic and incremental dynamic loads. Comparative assessments were performed to evaluate seismic performance improvements in terms of base shear capacity, drift ratio, ductility, crack pattern and deformation.Results from static analyses reveal significant enhancements in base shear capacity for all retrofitted cases. While the un-retrofitted building achieves a base shear of 998 kN, Retrofit-1 demonstrates the highest improvement at 2349 kN (a 135% increase), followed by Retrofit-2 at 2157 kN and Retrofit-3 at 2311 kN. Incremental dynamic analysis further confirms the effectiveness of retrofitting. For instance, under Imperial Valley ground motions, the un-retrofitted structure suffers extensive damage, while all retrofitted cases reduce this to slight damage with minimized deformation across all PGA levels. Similarly, under Parkfield and Tottori ground motions, retrofitting mitigates damage significantly, with Retrofit-3 exhibiting the best performance.Additionally, retrofitting slightly reduces the natural frequency of the structure, signifying increased stiffness and improved resistance to seismic forces. These findings highlight the importance of adopting external sub-structure retrofitting techniques for similar buildings in Dhaka, ensuring enhanced safety, cost-effectiveness, and minimal disruption. The proposed methods contribute to sustainable and resilient urban infrastructure development in earthquake-prone regions. |
| Year | 2024 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Krishna, Chaitanya |
| Examination Committee(s) | Pennung Warnitchai;Anwar, Naveed |
| Scholarship Donor(s) | Loom Nam Khong Pijai (Greater Mekong Subregion) Scholarships |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2024 |