Christchurch couple reflects on quake's seventh anniversary
Audio, Radio New Zealand
Javier and Jackie Garcia Knight look back on the earthquake that changed Christchurch and New Zealand forever.
Javier and Jackie Garcia Knight look back on the earthquake that changed Christchurch and New Zealand forever.
Following the 2010/2011 Canterbury (New Zealand) earthquakes the seismic design of buildings with precast concrete panels has received significant attention. Although this form of construction generally performed adequately in Christchurch, there were a considerable number of precast concrete panel connection failures. This observation prompted a review of more than 4700 panel details to establish representative details used in both existing and new multi-storey and low rise industrial precast concrete buildings. The detailing and quantity of each reviewed connection type in the sampled data is reported, and advantages and potential deficiencies of each connection type are discussed. Following the Canterbury earthquakes, it was observed that brittle failure had occurred in some grouted metal duct connections used for precast concrete wall panels, resulting in recommendations for more robust detailing of this connection type. A set of experimental tests was subsequently performed to investigate the in-plane seismic behaviour of precast concrete wall panel connections. This testing comprised of seven reversed cyclic in-plane tests of fullscale precast concrete wall panels having wall-to-foundation grouted metal duct connections. Walls with existing connection detailing were found to perform adequately when carrying low axial loads, but performance was found to be less satisfactory as the axial load and wall panel length increased. The use of new recommended detailing was observed to prevent brittle connection response and to improve the robustness of the reinforcement splice. A parametric investigation was conducted using the finite element method to predict the failure mode of metal duct connections. From the results of the parametric study on metal duct connections it was identified that there were three possible failure modes, being reinforcement fracture, concrete spalling without metal duct pull out, and concrete spalling with metal duct pull-out. An alternative simple analytical method was proposed in order to determine the type of connection failure without using a time-consuming finite element method. Grouted sleeves inserts are an alternative connector that is widely used to connect wall panels to the foundations. The two full-scale wall panels were subjected to reversed cyclic in-plane demands until failure of either the connection or the wall panel. Wall panel failure was due to a combination of connection reinforcement pulling-out from the coupler and reinforcement fracture. In addition, non-embedded grouted sleeve tests filled with different quality of grout were conducted by subjecting these coupler assemblages to cyclic and monotonic forces.
So what's the Prime Minister Jacinda Ardern got to look forward to when she's back at work? Construction firms falling over, business confidence at a nine-year low, unemployment rising and New Zealand is desperate need of infrastructure to cope with its 10 percent population shock in the last five years. Welcome back Ms Ardern! Ebert Construction is the latest construction company to go belly-up. The Panelists consider why, when the country needs new buildings the most, construction companies aren't making the grade? Peter Silcock of Civil Contractors talks bout the failing of processes and business models used by building firms. Christchurch central seems to have a business micro-climate. And right now it's chilly. The CBD is nothing like it used to be before the 2011 earthquake and those businesses that re-opened say they really had no choice because of the demands of insurance companies. The Kingsland Business Society in Auckland is offering free child minding for couples who go out for the evening in the suburb. United States federal air marshals now follow seemingly ordinary citizens not suspected of a crime, nor on any terrorist watch list. It's a new surveillance programme called "Quiet Skies" and it collects extensive information on travellers based on their behaviour on flights and especailly in airports.