A member of the New Zealand Urban Search and Rescue (USAR) team clearing a piece of steel at the site of the CTV building.
Members of the New Zealand and Chinese Urban Search and Rescue (USAR) teams cutting through the steel at the site of the CTV building.
Bracing made of steel beams and concrete blocks that has been applied to the wall of St John the Baptist Church in Latimer Square.
A member of the Chinese Urban Search and Rescue team using wire cutters to cut through steel at the site of the CTV building.
Volunteers in hard hats and high-visibility vests, lifting a pallet up to place on steel rods during the construction of the Pallet Pavilion.
Volunteers in hard hats and high-visibility vests, lifting a pallet up to place on steel rods during the construction of the Pallet Pavilion.
Volunteers in hard hats and high-visibility vests, lifting a pallet up to place on steel rods during the construction of the Pallet Pavilion.
Capacity design and hierarchy of strength philosophies at the base of modern seismic codes allow inelastic response in case of severe earthquakes and thus, in most traditional systems, damage develops at well-defined locations of reinforced concrete (RC) structures, known as plastic hinges. The 2010 and 2011 Christchurch earthquakes have demonstrated that this philosophy worked as expected. Plastic hinges formed in beams, in coupling beams and at the base of columns and walls. Structures were damaged permanently, but did not collapse. The 2010 and 2011 Christchurch earthquakes also highlighted a critical issue: the reparability of damaged buildings. No methodologies or techniques were available to estimate the level of subsequent earthquakes that RC buildings could still sustain before collapse. No repair techniques capable of restoring the initial condition of buildings were known. Finally, the cost-effectiveness of an eventual repair intervention, when compared with a new building, was unknown. These aspects, added to nuances of New Zealand building owners’ insurance coverage, encouraged the demolition of many buildings. Moreover, there was a perceived strong demand from government and industry to develop techniques for assessing damage to steel reinforcement bars embedded in cracked structural concrete elements. The most common questions were: “Have the steel bars been damaged in correspondence to the concrete cracks?”, “How much plastic deformation have the steel bars undergone?”, and “What is the residual strain capacity of the damaged bars?” Minimally invasive techniques capable of quantifying the level and extent of plastic deformation and residual strain capacity are not yet available. Although some studies had been recently conducted, a validated method is yet to be widely accepted. In this thesis, a least-invasive method for the damage-assessment of steel reinforcement is developed. Based on the information obtained from hardness testing and a single tensile test, it is possible to estimate the mechanical properties of earthquake-damaged rebars. The reduction in the low-cycle fatigue life due to strain ageing is also quantified. The proposed damage assessment methodology is based on empirical relationships between hardness and strain and residual strain capacity. If damage is suspected from in situ measurements, visual inspection or computer analysis, a bar may be removed and more accurate hardness measurements can be obtained using the lab-based Vickers hardness methodology. The Vickers hardness profile of damaged bars is then compared with calibration curves (Vickers hardness versus strain and residual strain capacity) previously developed for similar steel reinforcement bars extracted from undamaged locations. Experimental tests demonstrated that the time- and temperature-dependent strain-ageing phenomenon causes changes in the mechanical properties of plastically deformed steels. In particular, yield strength and hardness increases, whereas ductility decreases. The changes in mechanical properties are quantified and their implications on the hardness method are highlighted. Low-cycle fatigue (LCF) failures of steel reinforcing bars have been observed in laboratory testing and post-earthquake damage inspections. Often, failure might not occur during a first seismic event. However, damage is accumulated and the remaining fatigue life is reduced. Failure might therefore occur in a subsequent seismic event. Although numerous studies exist on the LCF behaviour of steel rebars, no studies had been conducted on the strain-ageing effects on the remaining fatigue life. In this thesis, the reduction in fatigue life due to this phenomenon is determined through a number of experimental tests.
Shaking table testing of a full-scale three storey resilient and reparable complete composite steel framed building system is being conducted. The building incorporates a number of interchangeable seismic resisting systems of New Zealand and Chinese origin. The building has a steel frame and cold formed steel-concrete composite deck. Energy is dissipated by means of friction connections. These connections are arranged in a number of structural configurations. Typical building non-skeletal elements (NSEs) are also included. Testing is performed on the Jiading Campus shaking table at Tongji University, Shanghai, China. This RObust BUilding SysTem (ROBUST) project is a collaborative China-New Zealand project sponsored by the International Joint Research Laboratory of Earthquake Engineering (ILEE), Tongji University, and a number of agencies and universities within New Zealand including the BRANZ, Comflor, Earthquake Commission, HERA, QuakeCoRE, QuakeCentre, University of Auckland, and the University of Canterbury. This paper provides a general overview of the project describing a number of issues encountered in the planning of this programme including issues related to international collaboration, the test plan, and technical issues.
A photograph of the earthquake damage to the former NZ Trust and Loan building on Hereford Street. The front has been supported by steel bracing.
Members of the public take photographs of the damage to the north side of the cathedral. Steel bracing supports the front wall of the cathedral.
Photograph captioned by Fairfax, "Workers apply steel framing to protect the historic building now the 'Octagon' restaurant on corner of Manchester Street and Worcester Street".
Photograph captioned by Fairfax, "Workers apply steel framing to protect the historic building now the 'Octagon' restaurant on corner of Manchester Street and Worcester Street".
A photograph captioned by BeckerFraserPhotos, "Hotel Grand Chancellor car park with steel casing to stabilise a collapsed column. The window was originally rectangular".
Photograph captioned by BeckerFraserPhotos, "Office of MP Brendon Burns. The steel girders in the foreground are from the deconstruction of Avonmore House opposite".
Photograph captioned by Fairfax, "Workers apply steel framing to protect the historic building now the 'Octagon' restaurant on corner of Manchester Street and Worcester Street".
Photograph captioned by Fairfax, "Workers apply steel framing to protect the historic building now the 'Octagon' restaurant on corner of Manchester Street and Worcester Street".
Photograph captioned by Fairfax, "Workers apply steel framing to protect the historic building now the 'Octagon' restaurant on corner of Manchester Street and Worcester Street".
Photograph captioned by Fairfax, "Workers apply steel framing to protect the historic building now the 'Octagon' restaurant on corner of Manchester Street and Worcester Street".
Photograph captioned by Fairfax, "Workers apply steel framing to protect the historic building now the 'Octagon' restaurant on corner of Manchester Street and Worcester Street".
Photograph captioned by Fairfax, "Workers apply steel framing to protect the historic building now the 'Octagon' restaurant on corner of Manchester Street and Worcester Street".
Photograph captioned by Fairfax, "Workers apply steel framing to protect the historic building now the 'Octagon' restaurant on corner of Manchester Street and Worcester Street".
Photograph captioned by Fairfax, "Workers apply steel framing to protect the historic building now the 'Octagon' restaurant on corner of Manchester Street and Worcester Street".
Photograph captioned by BeckerFraserPhotos, "The staircases removed from the Forsyth Barr Building - Armagh Street".
Photograph captioned by BeckerFraserPhotos, "The staircases removed from the Forsyth Barr Building - Armagh Street".
Members of the New Zealand Urban Search and Rescue (USAR) team using a circular saw to cut through steel at the site of the CTV Building.
A close up of cracks running through the stonework of Christ Church Cathedral. Steel bracing has been placed against the front wall to limit further damage.
Reinforcement steel protrudes from a bank which is supporting a walkway on Sumner Road. The area has been cordoned off with road cones and security fencing.
A view down New Regent Street. Several of the buildings have had their verandahs propped with steel poles, and scaffolding has been constructed on their facades.
Photograph captioned by BeckerFraserPhotos, "About the largest piece of the roof beams with its steel brace, lying on the footpath - Durham Street Methodist Church".