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 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".
The Arts Centre on Worcester Boulevard with damage to the gables. Steel bracing has been placed against the front of the building to hold the walls together.
The site of a demolished building on the corner of Bealey Avenue and Victoria Street where steel has been laid for the foundations of a new building.
The site of a demolished building on the corner of Bealey Avenue and Victoria Street where steel has been laid for the foundations of a new building.
The clock tower at the Arts Centre supported by steel and wooden bracing to prevent further damage. The photographer comments, "A bike ride around the CBD. Arts Centre".
A photograph captioned by BeckerFraserPhotos, "The Colombo Street bridge, badly damaged in the 22 February 2011 earthquake. The large steel beams supporting the bridge are distorted".
A view down London Street in Lyttelton, cordoned off by wire fencing. On the right, the Harbourlight Theatre can be seen with steel bracing holding up the front.
A sculpture of a rock climber that has been installed on the steel bracing that has been placed on the tower of the Octagon Live Restaurant (formerly Trinity Church).
Damage to a car parking building on Lichfield Street. Part of the concrete wall has crumbled, exposing steel reinforcing rods within, and damaging an artwork painted on the wall.
Steel bracing on the Moorhouse Avenue overpass. The photographer comments, "Standing underneath I did hear a clump as if a part of the road overhead was pivoting as a car passed over it".
Bunting on wire fencing at the end of London Street. In the distance, the Harbour Light Theatre can be seen with steel bracing holding the building together and limiting damage from further aftershocks.
A view down New Regent Street. Several of the buildings have had their verandahs propped with steel poles, and scaffolding has been constructed on the facade of one of the buildings.
A view down Worcester Boulevard. Steel bracing against Our City O-Tautahi can be seen. The Cathedral can be seen at the end of the street and the Clarendon Tower on the right.
This paper presents preliminary field observations on the performance of selected steel structures in Christchurch during the earthquake series of 2010 to 2011. This comprises 6 damaging earthquakes, on 4 September and 26 December 2010, February 22, June 6 and two on June 13, 2011. Most notable of these was the 4 September event, at Ms7.1 and MM7 (MM as observed in the Christchurch CBD) and most intense was the 22 February event at Ms6.3 and MM9-10 within the CBD. Focus is on performance of concentrically braced frames, eccentrically braced frames, moment resisting frames and industrial storage racks. With a few notable exceptions, steel structures performed well during this earthquake series, to the extent that inelastic deformations were less than what would have been expected given the severity of the recorded strong motions. Some hypotheses are formulated to explain this satisfactory performance. http://db.nzsee.org.nz/SpecialIssue/44%284%290297.pdf
Extended Direct Analysis (EDA), developed at the University of Canterbury, is an advance on the AISC Direct Analysis method for the analysis of frames subjected to static forces. EDA provides a faster, simple and more rational way to properly consider the second-order effects, initial residual stresses (IRS) and the initial imperfections or steel structures under one directional loading than conventional analysis methods. This research applied the EDA method to quantify the effect of member overstrength on frame behaviour for a single storey frame. Also, the effects of IRS, which were included in the EDA static analysis, but which are not considered explicitly in non-linear seismic analysis, were evaluated in two ways. Firstly, they were considered for simple structures subject to increasing cyclic displacement in different directions. Secondly, incremental dynamic analysis with realistic ground motion was used to quantify the likely effect of IRS in earthquakes. It was found that, contrary to traditional wisdom and practice, greater member strengths can result in lower frame strengths for frames under monotonic lateral loading. The structural lateral capacity of the overstrength case was reduced by 6% compared to the case using the dependable member strengths. Also, it resulted significantly different in member demands. Therefore, it is recommended that when either plastic analysis or EDA is used, that both upper and lower bounds on the likely member strength should be considered to determine the total frame strength and the member demands. Results of push-pull analysis under displacement control showed that for IRS ratio, gamma < 0.5 and axial compressive force ratio, N*/Ns, up to 0.5, IRS did affect the structural behaviour in the first half cycle. However, the behavior in the later cycles was not significantly affected. It also showed that the effect of initial residual stresses in the frame was less significant than for the column alone when the column was subjected to similar axial compressive force. The incremental dynamic analysis results from both cantilever column and the three-storey steel frame showed that by increasing gamma = 0 to 0.5, the effect of IRS on seismic responses, based on the 50% confidence level, was less than 3% for N*/Ns, up to 0.5.
Heavy steel bracing holding up the clock tower on the Worcester Street side of the Arts Centre. Wire fencing has been placed along the road in order to cordon off the building.
A photograph of a flight of concrete stairs salvaged from a building and placed in a car park in the Christchurch central city. Steel reinforcement can be seen sticking out of the concrete.
The Empire Hotel on London Street in Lyttelton with heavy steel bracing holding up the facade. Bricks from the side wall have collapsed on to the footpath and wire fencing encloses the site.
Damage to St John the Baptist Church in Latimer Square. Behind steel bracing, the gable end of the building has partly collapsed. The photographer comments, "The bracing did help hold the church up".
A tent on Worcester Street set up for the soldiers stationed around the cordon. In the background, the damaged Our City O-Tautahi Building can be seen with steel bracing holding up the front.
A photograph captioned by BeckerFraserPhotos, "The base of a pillar on the site of the PGC building on Cambridge Terrace".
The wall of the Carlton Hotel has crumbled, exposing the interior of the upstair rooms. Scaffolding and steel bracing has been put up on the side, and a pile of building rubble can be seen on the footpath.
The wall of the Carlton Hotel has crumbled, exposing the interior of the upstair rooms. Scaffolding and steel bracing has been put up on the side, and a pile of building rubble can be seen on the footpath.
A photograph of the earthquake damage to Kenton Chambers on Hereford Street. Large cracks have formed between the windows, the brick crumbling onto the footpath below. Steel fences have been placed around the building as a cordon.
The front entrance of the Durham Street Methodist Church. The door is blocked by a safety fence and large concrete blocks, which have been used to secure the steel bracing supporting the front wall of the building.
A photograph of a badly-damaged shop on Colombo Street. The front wall of the top storey of the building has crumbled into the street, exposing the inside of the building. Steel and wooden bracing is keeping the ceiling up.
Sculptures of a kayaker, cyclist and bungee jumper decorating the steel bracing that has been placed on the front of the Worcester Street face of the Octagon Live Restaurant (formerly Trinity Church). Two of the figures are wearing santa hats.