- Preliminary analysis of instrumented Wellington building responses in the July/August 2013 Seddon/Lake Grassmere earthquakes
- E.M. Thomson ; B.A. Bradley
- Book Title / Journal: New Zealand Society for Earthquake Engineering (NZSEE) Annual Technical Conference
- Year: 2014 , Volume: , Series:
- Earthquake engineering
- Keywords: building response ; Earthquake
- Description
- This paper investigates the dynamic response of five instrumented structures in the greater Wellington region during the July/August 2013 Seddon/Lake Grassmere earthquakes. Six events ranging from Mw 5.6 - 6.6 were considered in the
analysis of five different structures: GNS Science at Avalon, BNZ Centre Port, Majestic Centre, Victoria University Te Puni Village Tower, and Wellington Hospital. This preliminary investigation firstly involved determination of the fundamental period of each structure in the principal horizontal directions, and comparison with the simplified method proposed in NZS1170.5:2004. Secondly, the peak floor level acceleration distributions over the height of the structures were analysed and compared with the
design provisions in NZS1170.5:2004 and ASCE/SEI7:2010., The results illustrate that the simplified equation for fundamental period in NZS1170.5:2004 often underestimated the fundamental period and could result with unconservative design forces when using forced based design, and that both NZS1170.5:2004 and ASCE/SEI7:2010 provisions for floor acceleration contain significant deficiencies due to the omission of the dependence of peak floor acceleration variation with height on vibration period.
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- Rehabilitation of earthquake damaged external RC beam-column joints
- J. Shafaei ; A. Hosseini ; M.S. Marefat ; J.M. Ingham
- Book Title / Journal: New Zealand Society for Earthquake Engineering (NZSEE) Annual Technical Conference
- Year: 2014 , Volume: , Series:
- Repair and Retrofit of Structures
- Keywords: RC buildings ; Earthquake ; beam-column joints ; Seismic performance
- Description
- Post-earthquake inspections of damaged RC buildings have demonstrated that poorly detailed beam-column joints can suffer serious damage. The effectiveness of a rehabilitation method based on joint enlargement using prestressed steel angles to
enhance the seismic behaviour of damaged external reinforced concrete beam-column joints was experimentally investigated. Three half scale external RC beam-column joints with seismic and non-seismic reinforcement details were tested before and after rehabilitation by applying lateral cyclic loading of increasing amplitudes. Tested
specimens were comprised of one unit having seismic reinforcement detailing and two units having non-seismic reinforcement detailing. Two defects were considered for the non-seismic units, being the absence of transverse steel hoops and insufficient bond capacity of beam bottom steel reinforcing bars in the joint panel zone. The damaged specimens were rehabilitated by injecting epoxy grout into existing cracks and installing stiffened steel angles at the re-entrant corners of the beam-column joint, both above and below the beam, that were mounted and held in place using prestressed high tensile strength bars. The test results indicated that the seismic performance of the rehabilitated
specimens, in terms of strength, stiffness and ductility were fully recovered with respect to the performance of the seismically detailed specimen in the initial loading.
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