Building resilient.pptx
- 1. Why Buildings? 40% Building operations alone contribute over 40% of the energy usage of the United States. Energy use of country 38% Building operations alone contribute over 38% of the CO2 generation of the United States. CO2 generation of the country 35% Waste from demolition, construction and remodeling makes up more than 35% of all the non-industrial waste of the US. Non-industrial waste generation Construction and operation of buildings have a main contribution to the environmental impact 40% Construction and remodeling of buildings account for 40% of raw material use of the US. Raw material usage (Hartke, 2020; Traykova & Chardakova, 2014)
- 2. Life Cycle Assessment Construction Embodied Energy – The energy used directly or indirectly in raw material acquisition, production and the assemblage. Accounts for 20% of whole energy consumed during life cycle. Operation Aging of the building provokes an increase of the environmental impact Repair Done to minimize the environmental impact due to aging. But repairs are environmentally costly by themselves. Demolition Due to the energy needed for the process and the wasted materials (Traykova & Chardakova, 2014)
- 3. Construction Operation End of design life/ damaged Options for aged/ damaged buildings Demolish the old structure a rebuild a new structure Demolish and rebuild . Abandon Strengthen the old structure and increase the building life Sustainable retrofitting Enhance the resilience Enhance the resilience for expected disasters at the initial stage and avoiding the damage
- 4. Sustainable Retrofitting Refurbishment of an existing building that aims to reduce environmental impact of that building • The retrofitting process itself may have a significant environmental impact • But sustainable results can be achieved by, 1. Extension of the remaining life time of the building that results in environmental cost for the demolition of the old building and the construction of a new one. 2. Reduction of operational impact (Traykova & Chardakova, 2014)
- 5. Special considerations for sustainable retrofitting 01 Adaptive reuse and adaptation • Minimizing consumption of energy • Reusing of existing materials • Avoiding negative environmental impacts • Reduction of construction waste • Reusing existing sites 02 New construction technologies • Modular construction • Automation with human touch • Pre tensioning/ post tensioning • Sustainable design approaches 03 New construction materials • Lightweight concrete • Composite wraps/ carbon fibre jackets • Epoxy • Ultra-High Performance Fibre Reinforced Concrete
- 6. Case Study 40 years old two storied house in southern Europe Existing Structure (E) • 40 years old • Gross floor area of 164.4 m2 • Two floors • Reinforced concrete structure • Double layer hollow brick walls • Stone- cement foundation • Ceramic tile roof with no insulation • Wooden parquet floor finishes Demolish and rebuild (N) • Design life of 50 years • Reinforced concrete structure • External cavity walls • VIROC panels roof Retrofitting (R) • Another 50 years life expectation • Interior, roof and stairs replaced. (Gaspar & Santos, 2015)
- 7. Case study continued.. • Difference between initial embodied energy of the two scenarios is significant. This difference accounts for the energy disposal of demolished parts and excess new materials. • About 22% of energy saving is achieved by retrofitting over building a new structure • Retrofitting is a more sustainable option (Gaspar & Santos, 2015)
- 8. Case Study Three storied house in Schaarbeek, Brussels (Wastiels et al., 2016) Three options are analysed for the case study incorporating insulation options BB - The building is insulated from the inside. The ground floor is kept uninsulated. ET - The building is insulated by use of an ETICS NC –the original building is demolished and a new building is erected within the same volume. The complete building is insulated.
- 9. Case study continued.. (Wastiels et al., 2016) Impacts on the environment are analysed by ReCiPe methodology and the consideration of individual impact categories according to the 7 CEN indicators • Highest environmental impact is given by new construction scenario. A significance higher amount can be identify in the production phase which includes the demolition. • New construction scenario has the highest impacts for all categories
- 10. Case Study 52 years old multi-storied housing block in Austria (Mørck et al., 2017) • Retrofitting a structure alone is a environmental friendly option since it reduces the incorporated initial embodied energy • But if sustainable approaches uses in retrofitting, operational energy demand also can be reduced. • In this study 85% of the annual energy demand is reduced by following a sustainable retrofitting approach
- 11. Disaster Resilience of Buildings The ability to reduce the magnitude and/or duration of disruptive events. The effectiveness of a resilient infrastructure or enterprise depends upon its ability to anticipate, absorb, adapt to, and/or rapidly recover from a potentially disruptive event (NIAC 2009). Why Disaster Resilience of Buildings is important
- 12. Disaster Resilience and Sustainability To increase the disaster resilience Strengthen the structure More materials More initial embodied energy Sustainability Green roof at the top level High mass concentration at the top High seismic load attraction at the top Not Desirable (Lemay, 2015)
- 13. Disaster Resilience and Sustainability How ? Disaster Debris Demolition Renovation New structure • High energy disposal of waste • High embodied energy of new materials • High operational energy
- 14. Estimation of Environmental Impact Damage model Hazard curves Hazard Fragility curves Structure Estimation of consequences (CSHub, 2020)
- 15. Case Study Reinforced concrete building against seismic hazard (Wei et al., 2016) Properties of normal and enhanced buildings CO2 emissions for different repair measures Probability of seismic events Expected no of damaged building over 40 years design period Expected CO2 emission over design life
- 16. Case Study 8 storied apartment building in L’Aquila against seismic hazard (Bari et al., 2020) Reference building Diagrid enhanced building Shear wall enhanced building Seismic characteristics Future considerations
- 17. Case study continued.. (Bari et al., 2020) High environmental impact due to demolitions and re-building
- 18. Case Study One story residential building in Florida against flood hazard (Matthews et al., 2016) Floor plan of the building Construction material for typical and flood resistant (according to FEMA guidance) designs
Editor's Notes
- #8: the energy needed for maintenance was considered to be 12% of initial embodied energy
- #10: the energy needed for maintenance was considered to be 12% of initial embodied energy
- #13: In one hand to strengthen the building more materials required. High initial embodied energy. Not sustainable In other hand the approaches we do for sustainability can be adversely affect on the resilient. Such as green roof. Some links between sustainability and resilient are in the table for different approaches
- #15: For example, designing a structure to with-stand the anticipated forces induced by a category V hurricane will generally require more materials and resources than a design that only considers a category III hurricane. But if the probability of category 5 hurricane is very low during the design life, the enhancement of the building to withstand against cat 5 hurricane won’t be sustainable.
- #18: the energy needed for maintenance was considered to be 12% of initial embodied energy