Seismic load tests on two concrete interior beam-column joints reinforced
by plain round bars designed to pre-1970s codes

  • Aizhen Liu University of Canterbury, Christchurch, New Zealand
  • R. Park University of Canterbury, Christchurch, New Zealand

Abstract

Two identical reinforced concrete interior beam-column joint assemblies were tested under simulated seismic loading as part of an investigation of the behaviour of existing reinforced concrete structures designed to pre-1970s codes when subjected to severe earthquake forces. The test units were full-scale in size, and were replicas of part of the moment resisting frame of an existing building in Christchurch that was constructed in the 1950s. The longitudinal and transverse reinforcement were from plain round bars, the beams and columns had low quantities of transverse reinforcement and the joints had no shear reinforcement at all, as was typical of pre-1970s construction in New Zealand. One unit was tested with zero axial column load, and the other unit with a constant axial column load of 0.12 f’c Ag, where f’c = concrete cylinder compressive strength and Ag = the gross column section area. The units displayed very low structural stiffness, flexural strength less than conventionally calculated, and significant degradation of stiffness and strength during testing. The low structural stiffness and flexural strength could be attributed to the slip of the plain round longitudinal bars through the joint. However, the utilisation of plain round bars although leading to bond slip was found to improve the joint shear strength and to result in reduced shear distortion of the joint. Buckling of longitudinal column bars was found to initiate failure, due to inadequate ties.

References

Park, R. and Paulay, T. (1975), Reinforced Concrete Structures, John Wiley and Sons, New York. DOI: https://doi.org/10.1002/9780470172834

Standards New Zealand (1995), The Design of Concrete Structures, NZS 3101: 1995, Standards NZ., Wellington.

Aoyama, H. (1981), A Method for the Evaluation of the Seismic Capacity o f Existing Reinforced Concrete Buildings in Japan, Bulletin of the New Zealand National Society for Earthquake Engineering, Vol.14, No. 3, September, pp 105-130.

Brunsdon, D. R. and Priestley, M.J.N. (1984), Assessment of Seismic Performance Characteristics of Reinforced Concrete Buildings Constructed Between 1936 and 1975, Bulletin of the New Zealand National Society for Earthquake Engineering, Vol. 17, No. 3, September, pp 163-181.

ATC (1989), A Handbook for Seismic Evaluation of Existing Buildings ATC-22, Applied Technology Council, Redwood City, California, 169 p.

Rodriguez, M. and Park, R. (1991), Repair and Strengthening of Reinforced Concrete Buildings for Earthquake Resistance, Earthquake Spectra, Vol. 7, No. 3, pp 439-459.

Priestley, M.J.N. and Calvi, G.M. (1991), Towards a Capacity Design Assessment Procedure for Reinforced Concrete Frames, Earthquake Spectra, Vol.7, No.3, pp 413-437.

Park, R. (1992), Seismic Assessment and Retrofit of Concrete Structures - United States and New Zealand Developments, Proceedings of Technical Conference of New Zealand Concrete Society, Wairakei, pp 18-25.

Rodriguez, M. and Park, R. (1994), Seismic Load Tests of Reinforced Concrete Columns Strengthened by Jacketing, Structural Journal of the American Concrete Institute, Vol. 91, No.2, pp 150-159.

Priestley, M.J.N. (1995), Displacement Based Seismic Assessment of Existing Reinforced Concrete Buildings, Proceedings of Pacific Conference on Earthquake Engineering, Vol.2, Melbourne, pp 225-244.

Hakuto, S., Park, R. and Tanaka, H. (1995), Retrofitting of Reinforced Concrete Moment Resisting Frames, Research Report 95-4, Department of Civil Engineering, University of Canterbury, August.

Park, R. (1997), A Static Force-Based Procedure for the Seismic Assessment of Existing Reinforced Concrete Moment Resisting Frames, Bulletin of the New Zealand National Society for Earthquake Engineering, Vol. 30, No. 3, pp 213-226.

Park, R., Billings, I. J., Clifton, G. C., Cousins, J., Filiatrault, A., Jennings, D.N., Jones, L.C.P., Perin, N.D., Rooney, S.L., Sinclair, J., Spurr, D.D., Tanaka, H. and Walker, G. (1995), The Hyogo-ken Nanbu Earthquake (The Great Hanshin Earthquake) of 17 January 1995. Report of the NZNSEE Reconnaissance Team, Bulletin of the New Zealand National Society for Earthquake Engineering, Vol. 28, No.1, pp 1-98. DOI: https://doi.org/10.5459/bnzsee.28.1.1-98

Published
1998-09-30
How to Cite
Liu, A., & Park, R. (1998). Seismic load tests on two concrete interior beam-column joints reinforced
by plain round bars designed to pre-1970s codes . Bulletin of the New Zealand Society for Earthquake Engineering, 31(3), 164-176. https://doi.org/10.5459/bnzsee.31.3.164-176
Section
Articles

Most read articles by the same author(s)

1 2 3 4 > >>