Search

found 32 results

Images for steel reinforcement; more images...

Images, UC QuakeStudies

A photograph of a pile of twisted steel reinforcement and other rubble at the entrance to the Smiths City car park on Dundas Street. In the background a section of the collapsed car park has not been demolished yet. Many cars are still parked on the top floor.

Images, UC QuakeStudies

A photograph of the partially-demolished Smiths City car park, taken from Dundas Street. The front section of the car park has mostly been cleared, though there is still a scattering of rubble and steel reinforcement. The back section has collapsed, but the floors are largely intact, with many cars still parked on the top floor.

Images, UC QuakeStudies

A photograph looking east down Dundas Street. Piles of twisted steel reinforcement have been placed on both sides of the street. Several earthquake-damaged cars, recovered from the Smiths City car park, have been stacked on the left. On the other side of the street is an excavator grapple and bucket. In the distance two excavators are sorting through the rubble.

Images, UC QuakeStudies

A photograph of the earthquake damage to the concrete beams in a room in the PricewaterhouseCoopers Building. Sections of the concrete have crumbled to reveal the steel reinforcement underneath. A number of the ceiling panels are missing and another is hanging loose. Some of the bars that hold the ceiling panels are also hanging loose.

Images, UC QuakeStudies

The old Railway Station clock tower on Moorhouse Avenue with plywood and steel reinforcement covering two sides, a crane hanging over top. The brickwork suffered extensive cracking during the earthquake making it in need for reinforcement. The clock has stopped at around 16:35, the time of the earthquake.

Images, UC QuakeStudies

The old Railway Station clock tower on Moorhouse Avenue with plywood and steel reinforcement covering two sides, and a crane hanging over top. The brickwork suffered extensive cracking during the earthquake making it in need of reinforcement. The clock has stopped at around 16:35, the time of the earthquake.

Images, UC QuakeStudies

The old Railway Station clock tower on Moorhouse Avenue with plywood and steel reinforcement covering two sides, and a crane hanging over top. The brickwork suffered extensive cracking during the earthquake making it in need of reinforcement. The clock has stopped at around 16:35, the time of the earthquake.

Research papers, The University of Auckland Library

During the 2010/2011 Canterbury earthquakes, several reinforced concrete (RC) walls in multi-storey buildings formed a single crack in the plastic hinge region as opposed to distributed cracking. In several cases the crack width that was required to accommodate the inelastic displacement of the building resulted in fracture of the vertical reinforcing steel. This type of failure is characteristic of RC members with low reinforcement contents, where the area of reinforcing steel is insufficient to develop the tension force required to form secondary cracks in the surrounding concrete. The minimum vertical reinforcement in RC walls was increased in NZS 3101:2006 with the equation for the minimum vertical reinforcement in beams also adopted for walls, despite differences in reinforcement arrangement and loading. A series of moment-curvature analyses were conducted for an example RC wall based on the Gallery Apartments building in Christchurch. The analysis results indicated that even when the NZS 3101:2006 minimum vertical reinforcement limit was satisfied for a known concrete strength, the wall was still susceptible to sudden failure unless a significant axial load was applied. Additionally, current equations for minimum reinforcement based on a sectional analysis approach do not adequately address the issues related to crack control and distribution of inelastic deformations in ductile walls.

Images, UC QuakeStudies

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.

Research papers, University of Canterbury Library

Research following the 2010-2011 Canterbury earthquakes investigated the minimum vertical reinforcement required in RC walls to generate well distributed cracking in the plastic hinge region. However, the influence of the loading sequence and rate has not been fully addressed. The new minimum vertical reinforcement limits in NZS 3101:2006 (Amendment 3) include consideration of the material strengths under dynamic load rates, but these provisions have not been validated at a member or system level. A series of tests were conducted on RC prisms to investigate the effect of loading rate and sequence on the local behaviour of RC members. Fifteen axially loaded RC prisms with the designs representing the end region of RC walls were tested under various loading rates to cover the range of pseudo-static and earthquake loading scenarios. These tests will provide substantial data for understanding the local behaviour of RC members, including hysteretic load-deformation behaviour, crack patterns, failure mode, steel strain, strain rate and ductility. Recommendations will be made regarding the effect of loading rate and reinforcement content on the cracking behaviour and ductility of RC members.

Research papers, The University of Auckland Library

Reinforced concrete (RC) frame buildings designed according to modern design standards achieved life-safety objectives during the Canterbury earthquakes in 2010-11 and the Kaikōura earthquake in 2016. These buildings formed ductile plastic hinges as intended and partial or total building collapse was prevented. However, despite the fact that the damage level of these buildings was relatively low to moderate, over 60% of multi-storey RC buildings in the Christchurch central business district were demolished due to insufficient insurance coverage and significant uncertainty in the residual capacity and repairability of those buildings. This observation emphasized an imperative need to improve understanding in evaluating the post-earthquake performance of earthquake-damaged buildings and to develop relevant post-earthquake assessment guidelines. This thesis focuses on improving the understanding of the residual capacity and repairability of RC frame buildings. A large-scale five-storey RC moment-resisting frame building was tested to investigate the behaviour of earthquake-damaged and repaired buildings. The original test building was tested with four ground motions, including two repeated design-level ground motions. Subsequently, the test building was repaired using epoxy injection and mortar patching and re-tested with three ground motions. The test building was assessed using key concepts of the ATC-145 post-earthquake assessment guideline to validate its assessment procedures and highlight potential limitations. Numerical models were developed to simulate the peak storey drift demand and identify damage locations. Additionally, fatigue assessment of steel reinforcement was conducted using methodologies as per ATC-145. The residual capacity of earthquake-strained steel reinforcement was experimentally investigated in terms of the residual fatigue capacity and the residual ultimate strain capacity. In addition to studying the fatigue capacity of steel reinforcement, the fatigue damage demand was estimated using 972 ground motion records. The deformation limit of RC beams and columns for damage control was explored to achieve a low likelihood of requiring performance-critical repair. A frame component test database was developed, and the deformation capacity at the initiation of lateral strength loss was examined in terms of the chord rotation, plastic rotation and curvature ductility capacity. Furthermore, the proposed curvature ductility capacity was discussed with the current design curvature ductility limits as per NZS 3101:2006.