SEISMIC FRAGILITY ASSESSMENT AND RETROFIT OF A GOVERNMENT HOSPITAL BUILDING IN CHITTAGONG, BANGLADESH
DOI:
https://doi.org/10.11113/mjce.v30.15718Keywords:
Seismic Fragility, Fragility Curve, Retrofit, Inter-story-drift, Seismic vulnerability and Bangladesh National Building CodeAbstract
Chittagong Medical College Hospital (CMCH) is one of the most important government hospitals in Bangladesh. It is located in the heart of Chittagong city, the only port city of Bangladesh. Bangladesh National Building Code (BNBC) is the only official document, which has been used since 1993 as guidelines for seismic design of buildings. As per the guidelines of BNBC, the CMCH building was designed for an earthquake ground motion having a return period of 200 years. However, the revised version of BNBC has suggested that the building structures shall be designed for an earthquake ground motion having a return period of 2475 years. It is mentioned that a single seismic performance objective, the life safety, of the building is considered in both versions of BNBC. Considering the significant importance of CMCH building in providing the emergency facilities during and after the earthquake, it is indispensable to evaluate its seismic vulnerability for the two types of earthquake ground motion records having return period of 200 (Type-I) and 2475 (Type-II) years. In this regard, this paper deals with the seismic vulnerability assessment of the existing ancillary building (AB) of CMCH. The seismic vulnerability of building is usually expressed in the form of fragility curves, which display the conditional probability that the structural demand (structural response) caused by various levels of ground shaking exceeds the structural capacity defined by a damage state. The analytical method based on elastic response spectrum analyses results is used in evaluating the seismic fragility curves of the building. To the end, 3-D finite element model of the building subjected to 18 ground motion records having PGA of 0.325g to 0.785g has been used in the
response spectrum analysis in order to evaluate its inter-story-drift ratio (IDR), an engineering
demand parameter (EDP) for developing fragility curves. The analytical results have shown that
structural deficiencies exist in the existing ancillary building (AB) for the Type-II earthquake
ground motion record, which requires the building to be retrofitted to ensure that the existing
ancillary building (AB) becomes functional during and after the Type-II earthquake ground
motion record.
References
AS11704, (1993). Australian Building Code,1993.
Billah, A. H. M. M., ASCE1, S. M., M. Alam, M. S., ASCE2, M. S. and Bhuiyan,
M. A. R (2013). “Fragility Analysis of Retrofitted Multicolumn Bridge Bent Subjected to Near-
Fault and Far-Field Ground Motionâ€. Journal of BridgeEngineering, Vol. 18.No.10, ISSN
-0702/12013/10-992-10041. Dx.doi.org/10.1061/(ASCE)BE. 1943-5592.0000452.
BNBC, (1993). Bangladesh National Building Code: Housing and BuildingResearch Institute.
Bolt, B. A. (2005). Earthquakes, W. H. Freeman and Company, New York, NY.
Choi, E., DesRoches, R., and Nielson, B. (2004). “Seismic Fragility of TypicalBridges in
Moderate Seismic Zonesâ€. Engineering Structures, 26(2), 187–199.Doi:
1016/j.engstruct.2003.09.006.
DPF, (2003). Bangladesh Disaster Report 2002, Disaster Preparedness Forum,Dhaka.
Ellingwood B., Galambos T. (1980). Probability Based Load Criteria for American National
Standard, Washington, National Bureau of Standards.Dx.doi.org/10.6028/NBS.SP.577.
FEMA -273. Federal Emergency Management Agency.
Hasan, M. A. (2015). Assessment of Seismic Fragility and Retrofit of Hospital Building using
Base-isolation Devices, M.Sc. thesis, Chittagong University of Engineering and
Technology, Bangladesh.
https://en.wikipedia.org./wiki/Chittagong_Medical_College, 25/10/2016.
Hwang, H., Liu, J.B., and Chiu, Y.H., (2001) Seismic fragility analysis of highwaybridges. Rep.
Project MAEC RR-4, Mid-America Earthquake Center, Urban, IL.
JRA, (2002). Specification for highway bridges - part V: Seismic design, 2002;Tokyo, Japan.
Nagarajaiah S., Reinhorn A.M., Constantinou M.C. (1991). Nonlinear dynamicanalysis of 3–D
base isolated structures, Journal of Structural Engineering, ASCE,Vol. 117, pp. 2035–
NZS 4203, (1992). New Zealand Building Code.
Park Y.J., Wen Y.K., Ang A.H.S. (1986). Random vibration of hysteretic systems under bidirectional
ground motions, Earthquake Engineering and Structural Dynamics, vol. 14, pp.
-557. Doi: 10.1002/eqe.4290140405.
Paul B.K. and Bhuiyan R.H. (2009). Urban earthquake hazard: perceived seismic
Risk and preparedness in Dhaka city, Bangladesh, Journal of Disasters, 34(2):
-59.
Shinozuka, M., Feng, M., Uzava, T. (2000). Statistical Analysis of Fragility Curves,Technical
Report MCEER, State University of New York at Buffalo, NY.
Stafford S. B. (1966).Behavior of square In-Filled Frames. Journal of the structuralDivision,
ASCE, vol.92.
Stratta, J.L., and Wyllie, L. A., (1979). Friuli, Italy, Earthquake of 1976,Earthquake Engineering
Research Institute, El Cerrito, California.
Towashiraporn P., Goodno B., Craig J., (2004). Building Seismic Fragilities Using Response
Surface Meta-models, Ph.D. dissertation, Georgia Institute ofTechnology.