Seismic Damage to RC Low-rise Building Structures Having Irregularities at the Ground Story During the 15 November 2017 Pohang, Korea, Earthquake

2017.11.15. 포항 흥해지진의 저층 RC 비틀림 비정형 건축물의 피해 및 손상 특성

  • Hwang, Kyung Ran (School of Civil, Environmental, and Architectural Engineering, Korea University) ;
  • Lee, Han Seon (School of Civil, Environmental, and Architectural Engineering, Korea University)
  • 황경란 (고려대학교 건축사회환경공학부) ;
  • 이한선 (고려대학교 건축사회환경공학부)
  • Received : 2018.02.20
  • Accepted : 2018.03.07
  • Published : 2018.04.30


This study examines the seismic failure of RC low-rise building structures having irregularities at the ground story during the 15 November 2017 Pohang, Korea, earthquake, $M_w=5.4$, which is the second strongest since the government began monitoring them in 1978 in South Korea. Some 2,000 private houses were damaged or destroyed in this earthquake. Particularly, serious damage to the piloti story of RC low-rise residential building structures of fewer than five stories was observed within 3 km of the epicenter with brittle shear failure of columns and walls due to severe torsional behavior. Buildings below six stories constructed before 2005 did not have to comply with seismic design requirements, so confinement detailing of columns and walls also led to inadequate performance. However, some buildings constructed after 2005 were damaged at the flexible side of the piloti story due to the high torsional irregularity. Based on these results, this study focuses on the problems of the seismic torsion design approach in current building codes.


Seismic design Seismic damage;Torsion;Irregularity;Pohang earthquake;Reinforced concrete;Low-rise building


Supported by : 한국연구재단


  1. Lee HS, Lee KB, Hwang KR, Cho CS. Shake-table Responses of an RC Low-rise Building Model Strengthened with Buckling Restrained Braces at Ground Story. Earthquakes & Structures. 2013;5(6):703-731.
  2. Lee HS, Hwang KR. Torsion Design Implications from Shake-table Responses of an RC Low-rise Building Model Having Irregularities at the Ground Story. Earthquake Engineering & Structural Dynamics. 2015;44:907-927.
  3. Sezen H, Moehle JP. Seismic Tests of Concrete Columns with Light Transverse Reinforcement. ACI Structural Journal. 2006 Nov 1;103 (6):842.
  4. ACI. Building Code Requirements for Structural Concrete, ACI 318M-14, American Concrete Institute. Farmington Hills, MI. c2014.
  5. Wallace JW, Massone LM, Bonelli P, Dragovich J, Lagos R, Lüders C, Moehle J. Damage and Implications for Seismic Design of RC Structural Wall Buildings. Earthquake Spectra. 2012 Jun;28(S1): S281-99.
  6. Shegay AV, Motter CJ, Henry RS, Elwood KJ. A Database for Investigating NZS3101 Structural Wall Provisions. In 10th Pacific Conference in Earthquake Engineering (10PCEE) 2015 Nov 6.
  7. Federal Emergency Management Agency (FEMA). FEMA 454: Designing for earthquakes - a manual for architects. 2006. Washington, D.C., USA. c2006.
  8. Lee HS, Jung DW, Lee KB, Kim HC, Lee K. Shake-table responses of a low-rise RC building model having irregularities at first story. Structural Engineering & Mechanics. 2011;40(4):517-539.
  9. AIK. Korean Building Code. KBC 2016, Architectural Institute of Korea. c2016.
  10. Ministry of the Interior and Safety. Report of earthquake occurrence and coping situation in Pohang, Gyeongbuk: 2017 Dec 8 [Internet]. Available from:
  11. Cho JH. OhmyNews: 2017 Nov 18 [Internet]. Available from:
  12. Kim SJ. Building Damage Investigation after the November 2017 Pohang, Korea, Earthquake. Concrete and Seismic Engineering Laboratory (CSEL). Department of Architectural Engineering, Keimyung University.
  13. AIK. Korean Building Code. KBC 2009, Architectural Institute of Korea. c2009.
  14. SBS. Columns in the Piloti Story Broken in Three Seconds (News): 2017 Nov 17 [Internet]. Available from:
  15. Chung LL. Policy on Seismic Evaluation and Retrofit of School Buildings and Low-rise Buildings (non-seismic design) in Taiwan. Forum in Improving policies and regulations through lessons learned from the 2017 Pohang Earthquake, Structural Performance Enhancement research Center. 2018 Feb 26; Seoul, Korea. Available from:
  16. AIK. Korean Building Code. KBC 2005, Architectural Institute of Korea. c2005.
  17. Jeong SH. Summary of 2017 Pohang Earthquake (2017.11.15., ML=5.4). 2017 Special Forum of EESK: Pohang earthquake and building damage: 2017 Nov 27; Seoul, Korea. c2017.