Recent research demonstrates the need for comprehensive frameworks to achieve an appropriate level of resilience(e.g.,energy,seismic)of the European building stock,through integrated retrofitting interventions.Differe...Recent research demonstrates the need for comprehensive frameworks to achieve an appropriate level of resilience(e.g.,energy,seismic)of the European building stock,through integrated retrofitting interventions.Different frameworks have been proposed to identify optimal interventions when several feasible alternatives are available,considering multiple decision variables of different nature,such as social,economic,or technical.Within these efforts and frameworks,less attention has been paid to the post-earthquake recovery time of buildings and communities,thus ignoring the significance of reaching a desired recovery state(e.g.,functional recovery)within a specified time frame.To overcome this limitation,this study estimates post-earthquake recovery times and uses them as one of the decision variables in multi-criteria identification of optimal retrofitting of an existing RC building.The case-study building is representative of the Italian school buildings constructed between the 1960s and 1970s and was analysed under two seismic hazard levels(moderate and high).Following the identification of the main structural deficiencies of the as-built structure through nonlinear static analyses,four seismic retrofit measures were selected.Then,the earthquake-induced downtime of each of the four retrofitted building configurations was assessed,analysing the different recovery times as a function of the seismic hazard level and the recovery state.A downtime-based metric,namely the expected annual downtime,was introduced as decision variable within an available multi-criteria decision-making framework to include the impact of downtime,rank the four retrofit measures and identify the preferable one.展开更多
Based on performance-based seismic engineering, this paper proposes an optimal seismic retrofit model for steel moment resisting frames（SMRFs） to generate a retrofit scheme at minimal cost. To satisfy the acceptance...Based on performance-based seismic engineering, this paper proposes an optimal seismic retrofit model for steel moment resisting frames（SMRFs） to generate a retrofit scheme at minimal cost. To satisfy the acceptance criteria for the Basic Safety Objective（BSO） specified in FEMA 356, the minimum number of upgraded connections and their locations in an SMRF with brittle connections are determined by evolutionary computation. The performance of the proposed optimal retrofitting model is evaluated on the basis of the energy dissipation capacities, peak roof drift ratios, and maximum interstory drift ratios of structures before and after retrofitting. In addition, a retrofit efficiency index, which is defined as the ratio of the increment in seismic performance to the required retrofitting cost, is proposed to examine the efficiencies of the retrofit schemes derived from the model. The optimal seismic retrofit model is applied to the SAC benchmark examples for threestory and nine-story SMRFs with brittle connections. Using the retrofit efficiency index proposed in this study, the optimal retrofit schemes obtained from the model are found to be efficient for both examples in terms of energy dissipation capacity, roof drift ratio, and maximum inter-story drift ratio.展开更多
Optimal retrofit of low-performance units(LPUs)is promising to abate overflow pollutant mass loading of sewer systems during wet-weathers.This study presents a combination of mathematical model and Sobol algorithm to ...Optimal retrofit of low-performance units(LPUs)is promising to abate overflow pollutant mass loading of sewer systems during wet-weathers.This study presents a combination of mathematical model and Sobol algorithm to help identify LPUs of sewer systems and design retrofitting strategies.Therefore,the solution to minimize the overflow pollutant mass loading from sewers systems can be efficiently obtained.The developed method was demonstrated at a catchment served by one wastewater treatment plant in the Chaohu City,Anhui Province of China,with five pumping stations and a total sewer length of 58.3 km.Within the catchment,there are three rivers and a small lake to receive overflows from the sewer system.Among them,one river that was mostly polluted was selected as the object of overflow pollution abatement during wet weather period.After identifying the LPUs of the sewer system and developing retrofitting strategies using Sobol sequence,the mitigation of overflow pollution during wet weather period was analyzed.Results show that the mass loading of chemical oxygen demand(COD)discharged into the target river could be reduced by 40.6%,by implementing optimal retrofit strategy of LPUs,i.e.,increasing the conveyance capacities of two pumping stations by 2.5–3.2 times and augmenting the diameters of 12 sewers by 1.25–1.29 times.To further coordinate the abatement of overflow pollution and retrofit investment,Sobol sensitivity analysis was conducted to screen the dominant LPUs to update the optimal retrofit strategy.By applying the updated strategy,the overflow COD mass loading per overflow event was close to that of non-updated strategy,while the retrofitting length of sewers was reduced by 40%.Therefore,on the basis of the presented method,decision-makers can flexibly develop retrofitting strategies of sewer system to abate overflow pollution during wet weathers in a cost-effective way.展开更多
基金funded by the Italian Civil Protection Department and“PriorBuilt-Prioritisation of the Italian regions for seismic and energy performance upgrading of the existing buildings”funded by ReLUIS.Additionally,it was developed as part of the activities of CONSTRUCT–Instituto de I&D em Estruturas e Construções(UID/04708),CERIS(UIDB/04625)+1 种基金the project SERENE(2022.08138.PTDC)all funded by Fundação para a Ciência e a Tecnologia,I.P./MCTES(PIDDAC).
文摘Recent research demonstrates the need for comprehensive frameworks to achieve an appropriate level of resilience(e.g.,energy,seismic)of the European building stock,through integrated retrofitting interventions.Different frameworks have been proposed to identify optimal interventions when several feasible alternatives are available,considering multiple decision variables of different nature,such as social,economic,or technical.Within these efforts and frameworks,less attention has been paid to the post-earthquake recovery time of buildings and communities,thus ignoring the significance of reaching a desired recovery state(e.g.,functional recovery)within a specified time frame.To overcome this limitation,this study estimates post-earthquake recovery times and uses them as one of the decision variables in multi-criteria identification of optimal retrofitting of an existing RC building.The case-study building is representative of the Italian school buildings constructed between the 1960s and 1970s and was analysed under two seismic hazard levels(moderate and high).Following the identification of the main structural deficiencies of the as-built structure through nonlinear static analyses,four seismic retrofit measures were selected.Then,the earthquake-induced downtime of each of the four retrofitted building configurations was assessed,analysing the different recovery times as a function of the seismic hazard level and the recovery state.A downtime-based metric,namely the expected annual downtime,was introduced as decision variable within an available multi-criteria decision-making framework to include the impact of downtime,rank the four retrofit measures and identify the preferable one.
基金National Research Foundation of Korea(NRF)under Grant No.2016R1A6A3A11932881
文摘Based on performance-based seismic engineering, this paper proposes an optimal seismic retrofit model for steel moment resisting frames（SMRFs） to generate a retrofit scheme at minimal cost. To satisfy the acceptance criteria for the Basic Safety Objective（BSO） specified in FEMA 356, the minimum number of upgraded connections and their locations in an SMRF with brittle connections are determined by evolutionary computation. The performance of the proposed optimal retrofitting model is evaluated on the basis of the energy dissipation capacities, peak roof drift ratios, and maximum interstory drift ratios of structures before and after retrofitting. In addition, a retrofit efficiency index, which is defined as the ratio of the increment in seismic performance to the required retrofitting cost, is proposed to examine the efficiencies of the retrofit schemes derived from the model. The optimal seismic retrofit model is applied to the SAC benchmark examples for threestory and nine-story SMRFs with brittle connections. Using the retrofit efficiency index proposed in this study, the optimal retrofit schemes obtained from the model are found to be efficient for both examples in terms of energy dissipation capacity, roof drift ratio, and maximum inter-story drift ratio.
基金Project supported by the National Natural Science Foundation of China(Grant No.52170103),the National Key Research and Development Program of China(Grant No.2021YFC3200703)supported by the Scientific Research Program of Changjiang Institute of Survey,Planning,Design and Research(Grant No.CX2020Z24)+2 种基金the China Postdoctoral Science Foundation(Grant No.2023M730366)the Natural Science Foundation of Hubei Province(Grant No.2023AFB475)the Postdoctoral Innovation and Practice Position in Hubei Province(Grant No.2023CXGW04).
文摘Optimal retrofit of low-performance units(LPUs)is promising to abate overflow pollutant mass loading of sewer systems during wet-weathers.This study presents a combination of mathematical model and Sobol algorithm to help identify LPUs of sewer systems and design retrofitting strategies.Therefore,the solution to minimize the overflow pollutant mass loading from sewers systems can be efficiently obtained.The developed method was demonstrated at a catchment served by one wastewater treatment plant in the Chaohu City,Anhui Province of China,with five pumping stations and a total sewer length of 58.3 km.Within the catchment,there are three rivers and a small lake to receive overflows from the sewer system.Among them,one river that was mostly polluted was selected as the object of overflow pollution abatement during wet weather period.After identifying the LPUs of the sewer system and developing retrofitting strategies using Sobol sequence,the mitigation of overflow pollution during wet weather period was analyzed.Results show that the mass loading of chemical oxygen demand(COD)discharged into the target river could be reduced by 40.6%,by implementing optimal retrofit strategy of LPUs,i.e.,increasing the conveyance capacities of two pumping stations by 2.5–3.2 times and augmenting the diameters of 12 sewers by 1.25–1.29 times.To further coordinate the abatement of overflow pollution and retrofit investment,Sobol sensitivity analysis was conducted to screen the dominant LPUs to update the optimal retrofit strategy.By applying the updated strategy,the overflow COD mass loading per overflow event was close to that of non-updated strategy,while the retrofitting length of sewers was reduced by 40%.Therefore,on the basis of the presented method,decision-makers can flexibly develop retrofitting strategies of sewer system to abate overflow pollution during wet weathers in a cost-effective way.
