# A Case Study on the Rehabilitation of a Fire-Damaged Structure
## 6 Concluding Remarks  
This paper presents a case study on establishing a rehabilitation plan for a fire-damaged reinforced concrete structure. A team of structural and material researchers/engineers in concrete inspected the structure in the earliest possible time after the fire, and carried out both on-site and laboratory tests on the damaged concrete and rebar. A finite element analysis was also performed to estimate the residual capacity of the structure. The following is the conclusion of the study and the recommended rehabilitation methods.  
(1) Through visual inspection of the structure, the mostly damaged structural elements were identified as the slabs, the girders and beams being the second, and the columns, wall, and the floor slab were the least affected elements. The slabs were mostly damaged because they are located at the highest elevation of the room where they are exposed to the highest temperature during the fire.  
(2) The judgment from the visual inspection is supported by the material test using the indicator method, where the concrete beneath the surface proved to retain its alkaline property for the girders, beams, walls, and even for the slabs.  
(3) Strength tests on concrete cores and rebar coupons obtained from the slabs, girders and beams showed that the concrete and the reinforcing bars in the girders and beams were only slightly damaged and still fit for continuous usage, while the reinforcing bars in the slab had considerably degraded in their structural capacity and therefore could not be used any longer.  
(4) A finite element analysis was also performed assuming more severe condition, _i.e._, the strength of concrete structure in both the girders and columns amounting 50 mm from the cover degraded to the level of 60% compared with the original strength. The results of analysis also confirmed that the girders and columns remain strong and stiff enough to perform their original structural intent.  
(5) It is recommended that the slabs be replaced with new ones, and the girders and beams be retrofitted. The columns and walls only needs surface treatment without a structural retrofit.  
(6) Considering the tight construction schedule and complexity of rehabilitating work, including the dismantling and reassembly of HVAC system in upper floors, a more efficient method of work is proposed as an alternative plan: a series of steel beams and deck plates perform the role of temporary slabs during the rehabilitation work and act as permanent supplementary slab when the rehabilitation work is over.  
**Acknowledgments:** The corresponding author of this paper acknowledges support from the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT (Information and Communication Technology) & Future Planning (Grant number: 2013R1A1A1076011).  
**Author Contributions:** In this paper, the overall rehabilitation plan of the fire-damaged structure was prepared by [PERSON] and [PERSON], the material tests were performed by [PERSON], and the finite element analysis was conducted by [PERSON]. The manuscript was written by [PERSON], [PERSON] and [PERSON].  
**Conflicts of Interest:** The authors declare no conflict of interest.