Damage Assessment of Unreinforced Stone Masonry Buildings After the 2010-2011 Canterbury Earthquakes (original) (raw)
Related papers
2012
Following the Christchurch earthquake of 22 February 2011 a number of researchers were sent to Christchurch, New Zealand to document the damage to masonry buildings as part of "Project Masonry". Coordinated by the Universities of Auckland and Adelaide, researchers came from Australia, New Zealand, Canada, Italy, Portugal and the US. The types of masonry investigated were unreinforced clay brick masonry, unreinforced stone masonry, reinforced concrete masonry, residential masonry veneer and churches; masonry infill was not part of this study. This paper focuses on the progress of the unreinforced masonry (URM) component of Project Masonry. To date the research team has completed raw data collection on over 600 URM buildings in the Christchurch area. The results from this study will be extremely relevant to Australian cities since URM buildings in New Zealand are similar to those in Australia.
Performance of unreinforced masonry buildings during the 2010 Darfield (Christchurch, NZ) earthquake
2011
Canterbury earthquakes a detailed campaign of door to door assessments was conducted in a variety of areas of Christchurch to establish the earthquake performance of residential dwellings having masonry veneer as an external cladding attached to a lightweight timber framing system. Specifically, care was taken to include regions of Christchurch which experienced different levels of earthquake shaking in order to allow comparison between the performance of different systems and different shaking intensities. At the time of the inspections the buildings in the Christchurch region had been repeatedly subjected to large earthquakes, presenting an opportunity for insight into the seismic performance of masonry veneer cladding. In total just under 1100 residential dwellings were inspected throughout the wider Christchurch area, of which 24% were constructed using the older nail-on veneer tie system (prior to 1996) and 76% were constructed using screw fixed ties to comply with the new 1996 standards revision (post-1996), with 30% of all inspected houses being of two storey construction. Of the inspected dwellings 27% had some evidence of liquefaction, ground settlement or lateral spreading. Data such as damage level, damage type, crack widths, level of repair required and other parameters were collected during the survey. A description of the data collection processes and a snapshot of the analysis results are presented within.
2012
The performance of retrofitted unreinforced masonry (URM) bearing wall buildings in Christchurch is examined, considering ground motion recordings from multiple events. Suggestions for how the experiences in Christchurch might be relevant to retrofit practices common to New Zealand, U.S. and Canada are also provided. Whilst the poor performance of unretrofitted URM buildings in earthquakes is well known, much less is known about how retrofitted URM buildings perform when subjected to strong ground shaking.
Performance of masonry buildings during the 2010 Darfield (New Zealand) earthquake
2011
The M7.1 Darfield earthquake shook the town of Christchurch (New Zealand) in the early morning on Saturday 4 th September 2010 and caused damage to a number of heritage unreinforced masonry buildings. No fatalities were reported directly linked to the earthquake, but the damage to important heritage buildings was the most extensive to have occurred since the 1931 Hawke"s Bay earthquake. In general, the nature of damage was consistent with observations previously made on the seismic performance of unreinforced masonry buildings in large earthquakes, with aspects such as toppled chimneys and parapets, failure of gables and poorly secured face-loaded walls, and in-plane damage to masonry frames all being extensively documented. This report on the performance of the unreinforced masonry buildings in the 2010 Darfield earthquake provides details on typical building characteristics, a review of damage statistics obtained by interrogating the building assessment database that was compiled in association with post-earthquake building inspections, and a review of the characteristic failure modes that were observed.
Journal of Performance of Constructed Facilities, 2014
8 9 Seismic retrofitting of unreinforced masonry buildings using posttensioning has been the topic of 10 many recent experimental research projects. However, the performance of such retrofit designs in 11 actual design level earthquakes has previously been poorly documented. In 1984 two stone masonry 12 buildings within The Arts Centre of Christchurch received posttensioned seismic retrofits, which were 13 subsequently subjected to design level seismic loads during the 2010/2011 Canterbury earthquake 14 sequence. These 26 year old retrofits were part of a global scheme to strengthen and secure the 15 historic building complex and were subject to considerable budgetary constraints. Given the limited 16 resources available at the time of construction and the current degraded state of the steel posttension 17 tendons, the posttensioned retrofits performed well in preventing major damage to the overall 18 structure of the two buildings in the Canterbury earthquakes. When compared to other similar 19 unretrofitted structures within The Arts Centre, it is demonstrated that the posttensioning significantly 20
WIT Transactions on the Built Environment, 2001
On the basis of the experience gained on the occasion of the Umbria-Marche, Italy, 1997 earthquake, the research investigates the seismic vulnerability of the masonry buildings realized with traditional non-aseismic techniques. Specific reference is done to the building typologies that are typical of the villages and the towns located in the central Italy area along the Apennines chain. Using the damage analyses already performed by the Authors with reference to the above mentioned earthquake the most frequent crisis mechanisms and the corresponding activation causes are identified. Effectiveness of alternative retrofitting techniques is discussed.
Performance of unreinforced and retrofitted Masonry buildings during the 2010 Darfield earthquake
Bulletin of the New Zealand Society for Earthquake Engineering
A brief history of Christchurch city is presented, including information on the introduction of unreinforced masonry as a popular building material and an estimate of the number of unreinforced masonry buildings in the Canterbury region currently. A general overview of the failure patterns that were observed in unreinforced clay brick and stone masonry buildings in the Christchurch area after the 2010 Darfield earthquake is provided. Case studies of the damage sustained to five unreinforced masonry (URM) buildings that were unretrofitted at the time of the earthquake, including photographic details, is documented. The performance of eight retrofitted URM buildings is then commented on, detailing the building characteristics and retrofit techniques. The case studies include the use of moment resisting frames, steel strong backs and strapping, diaphragm anchoring, surface bonded fibre reinforced polymer (FRP) sheets and cavity ties.
Journal of Earthquake Engineering, 2016
The 2010-2011 Canterbury earthquake sequence caused extensive damage to unreinforced masonry churches. A sample of 80 affected buildings was analysed and their performance statistically interpreted. Structural behaviour is described in terms of mechanisms affecting the so-called macro-elements, and damage probability matrices are computed. Regression models correlating mean damage level against macroseismic intensity are also developed for all observed mechanisms, improving the initial simple-linear formulations through use of multiplelinear regressions accounting for vulnerability modifiers, whose influence is evaluated via statistical procedures. Results presented herein will support the future development of predictive tools for decision-makers, also contributing to seismic vulnerability mitigation at a territorial scale.