The Estimated Carbon Cost of Concrete Building Demolitions following the Canterbury Earthquake Sequence

Abstract

The 2010/2011 Canterbury Earthquake Sequence caused severe economic impacts and community disruption in Christchurch, New Zealand due to damage from liquefaction and strong shaking. Following the earthquake, approximately 7500 dwellings and 1400 commercial properties were demolished, resulting in 4 million tons of building debris. Using the Canterbury event, and the subsequent building demolitions in Christchurch as a case study, this research quantifies the embodied carbon and energy costs associated with the post-earthquake demolition of buildings prior to the end of their intended design life. A building data set consisting of 142 reinforced concrete buildings that were demolished following the event was used to estimate the total amount of structural and non-structural debris resulting from the demolitions. A framework was developed to calculate the global warming potential of the demolished buildings considering embodied CO2 and energy in the building materials, impacts of the processes used in construction of the building, and CO2 emissions of the transport and waste management processes. A life cycle assessment tool was used to calculate the environmental costs in the production and transport module, the spatial distribution of the waste based on the building locations was calculated to determine transport distances to disposal facilities, and the waste disposal and recycling benefits were calculated using values from a life cycle inventory database. The results of the research revealed the demolition of concrete buildings had staggering environmental costs in terms of embodied CO2 and energy, which make the case for both resilient design strategies that reduce waste and pollution following earthquakes, and incorporating environmental impacts into demolition decisions.

Reuse of Steel in the Construction Industry: Challenges and Opportunities

“…These carbon values are currently all attributed to the end-of-life of the building (module C). Very few research outputs are available on quantifying the upfront carbon impact of demolition (Broniewicz & Dec, 2022;Gonzalez et al, 2021).…”

Incorporating potential environmental impacts in building seismic design decisions

“…Calculating the potential environmental impacts of waste management is complex and requires the spatial distribution of materials, the pathway by which the materials reach their end of life state, and the recycling rates. Previous work has shown that the environmental impacts from this module account for approximately 5% of the total life cycle emissions (Gonzalez et al 2022), and for this reason have been excluded here, but could be included in future analyses. In cases where comparisons are being made between different structural materials, the inclusion of the recycling process should be included to capture full life cycle impacts, for example the end of life impacts for a steel building considering recycling and waste management could be significantly different than for an equivalent concrete building.…”

“…The aftermath of the Canterbury Earthquakes in New Zealand (2010/2011), the L'Aquila earthquake in Italy (2009) and the 2011 East Japan earthquake revealed the considerable losses caused by earthquakes. Gonzalez et al (2022) investigated the environmental costs of demolitions following the 2010/2011 Canterbury Earthquake and demonstrated the significant consequence of premature demolitions following earthquakes resulting from waste management and construction materials. Wei et al (2016a, b) questioned whether the building LCA could assess the environmental performance accounting for natural disasters.…”

Multi-criteria decision-making approach for optimal seismic/energy retrofitting of existing buildings

“…Potential hazard-induced additional effects on the environment are, however, still mostly neglected, although recent hazardous events, including earthquakes, demonstrated worldwide their significant impact due to post-disaster rehabilitation activities. For instance, Gonzalez et al (2022) provided an estimate of the staggering environmental impacts due to concrete buildings demolition after the Canterbury Earthquake Sequence of 2010-2011 in New Zealand, while Di Ludovico et al (2017aLudovico et al ( , 2017b showed the relevant costs of repair and strengthening of damaged buildings after the 2009 L'Aquila earthquake in Italy. However, available models for life cycle assessment (LCA) procedures for buildings, aimed at the quantification of environmental impacts of construction and operational phases throughout buildings' life cycle, have traditionally not included such potential earthquake-induced effects.…”