Search

found 1460 results

Research papers, The University of Auckland Library

New Zealand’s stock of unreinforced masonry (URM) bearing wall buildings was principally constructed between 1880 and 1935, using fired clay bricks and lime or cement mortar. These buildings are particularly vulnerable to horizontal loadings such as those induced by seismic accelerations, due to a lack of tensile force-resisting elements in their construction. The poor seismic performance of URM buildings was recently demonstrated in the 2011 Christchurch earthquake, where a large number of URM buildings suffered irreparable damage and resulted in a significant number of fatalities and casualties. One of the predominant failure modes that occurs in URM buildings is diagonal shear cracking of masonry piers. This diagonal cracking is caused by earthquake loading orientated parallel to the wall surface and typically generates an “X” shaped crack pattern due to the reversed cyclic nature of earthquake accelerations. Engineered Cementitious Composite (ECC) is a class of fiber reinforced cement composite that exhibits a strain-hardening characteristic when loaded in tension. The tensile characteristics of ECC make it an ideal material for seismic strengthening of clay brick unreinforced masonry walls. Testing was conducted on 25 clay brick URM wallettes to investigate the increase in shear strength for a range of ECC thicknesses applied to the masonry wallettes as externally bonded shotcrete reinforcement. The results indicated that there is a diminishing return between thickness of the applied ECC overlay and the shear strength increase obtained. It was also shown that, the effectiveness of the externally bonded reinforcement remained constant for one and two leaf wallettes, but decreased rapidly for wall thicknesses greater than two leafs. The average pseudo-ductility of the strengthened wallettes was equal to 220% of that of the as-built wallettes, demonstrating that ECC shotcrete is effective at enhancing both the in-plane strength and the pseudo-ductility of URM wallettes. AM - Accepted Manuscript

Images, UC QuakeStudies

A photograph looking east down Cashel Street towards the intersection of Colombo Street. A section of one of the buildings on the left has collapsed and the rubble has spilled onto the street. A van has been crushed by the fallen rubble. The message, 'clear', has been spray-painted on the windscreen of the van. In the foreground signs from several shops are still on the street. There is also earthquake damage to the building on the right. Sections of this building's facade have crumbled and the bricks have spilled onto the street below, damaging the awning.

Images, UC QuakeStudies

A photograph of paper hearts pegged on the cordon fence around the Chinese Methodist Church on Papanui Road. Quotes on the hearts read, "'Even though I walk through the valley of the shadow of death, I will fear no evil for you are with me.' Psalm 23", "'We can do no great things; only small things with great love.' Mother Teresa, and, "'Peace begins with a smile,' Mother Teresa". In the background, the earthquake damage to the Christchurch Chinese Methodist Church can be seen. The wall of the gable has crumbled, the bricks spilling onto the grass below.

Images, UC QuakeStudies

A photograph looking south down Manchester Street taken shortly after the 22 February 2011 earthquake. A crowd of people have gathered on the road. A brick building to the right has partially collapsed, rubble spilling onto the street.

Images, UC QuakeStudies

A photograph of a earthquake damaged building on Tuam Street taken shortly after the 22 February 2011 earthquake. Bricks from the top of the façade have crumbled, falling into the street below and crushing some parked cars.

Images, UC QuakeStudies

A photograph of a severely-damaged building on Armagh Street. The building's facade has completely fallen away, and the bricks have fallen onto the footpath in front. USAR codes have been spray painted on an exposed wall.