Predicting Embodied Carbon and Cost Effectiveness of Post-Tensioned Slabs Using Novel Hybrid Firefly ANN

Post-tensioning has become a strong contender for manufacturing reinforced concrete (RC) members, especially for flat slabs in large-span structures. Post-tensioned (PT) slabs can lead to considerable material savings while reducing the embodied carbon (embodied CO2), construction time, and life cycle maintenance and repair costs. In this research, a novel hybrid Firefly–Artificial Neural Network (Firefly–ANN) computational intelligence model was developed to estimate the cost effectiveness and embodied CO2 of PT slabs with different design variables. To develop the dataset, several numerical models with various design variables, including the pattern of tendons, slab thickness, mechanical properties of materials, and span of slabs, were developed to investigate the sustainability and economic competitiveness of the derived designs compared to benchmark conventional RC flat slabs. Several performance measures, including punching shear and heel drop vibration induced by human activity, were used as design constraints to satisfy safety and serviceability criteria. The economic competitiveness of PT slabs was more evident in larger spans where the cost and embodied CO2 emissions decreased by 39% and 12%, respectively, in PT slabs with a 12-m span length compared to conventional RC slabs. Sensitivity analysis also confirmed that the cost and embodied CO2 emissions were very sensitive to the slab thickness by 86% and 62%, respectively.

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Potential Benefits of Plug-In Hybrid Electric Vehicles for Consumers and Electric Power Utilities

Journal of Energy Resources Technology ◽

10.1115/1.4004151 ◽

2011 ◽

Vol 133 (3) ◽

Cited By ~ 17

Author(s):

Jim B. Himelic ◽

Frank Kreith

Keyword(s):

Cost Effectiveness ◽

Co2 Emissions ◽

Electric Vehicles ◽

Hybrid Electric Vehicles ◽

Unit Commitment ◽

Electric Utility ◽

Battery Pack ◽

Hybrid Electric ◽

Power Utilities ◽

The Cost

Plug-in hybrid electric vehicles (PHEVs) have the potential of substantially reducing petroleum consumption and vehicular CO2 emissions relative to conventional vehicles. The analysis presented in this article first ascertains the cost-effectiveness of PHEVs from the perspective of the consumer. Then, the potential effects of PHEVs to an electric utility are evaluated by analyzing a simplified hypothetical example. When evaluating the cost-effectiveness of a PHEV, the additional required premium is an important financial parameter to the consumer. An acceptable amount for the additional upfront costs will depend on the future costs of gasoline and the on-board battery pack. The need to replace the on-board battery pack during the assumed vehicle lifetime also affects the allowed premium. A simplified unit commitment and dispatch model was used to determine the costs of energy and the CO2 emissions associated with PHEVs for different charging scenarios. The results show that electricity can be used to charge PHEVs during off-peak hours without an increase in peak demand. In addition, the combined CO2 emissions from the vehicles and the electric generation facilities will be reduced, regardless of the charging strategy.

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Cost-Effectiveness Evaluation of Seismically Isolated Pool Structures Considering Fluid-Structure Interaction

Seismic Engineering, Volume 2 ◽

10.1115/pvp2002-1434 ◽

2002 ◽

Author(s):

Hyun-Moo Koh ◽

Kwan-Soon Park ◽

Junho Song

Keyword(s):

Cost Effectiveness ◽

Response Spectrum ◽

Mass Matrix ◽

Minimum Cost ◽

Spectral Density Function ◽

Design Variables ◽

Moderate Seismicity ◽

Seismically Isolated ◽

Function Vector ◽

The Cost

A procedure for evaluating cost-effectiveness of seismically isolated pool structures is presented. The ground motion is modeled as the spectral density function matching the response spectrum, which is specified in codes in terms of acceleration and site coefficients. Interaction between flexible walls and contained fluid is considered in the form of added mass matrix. The thickness of wall and the stiffness of isolator are used as main design variables while the minimum cost for comparison is estimated. Transfer function vector of the system is derived and spectral analysis method based on random vibration theories is used for calculating probability of failure. Evaluation results of the examples show that the cost-effectiveness of seismically isolated pool structures is relatively high in regions of low to moderate seismicity.

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Potential Benefits of Plug-In Hybrid Electric Vehicles for Consumers and Electric Power Utilities

Volume 17: Transportation Systems ◽

10.1115/imece2008-66724 ◽

2008 ◽

Author(s):

Jim B. Himelic ◽

Frank Kreith

Keyword(s):

Cost Effectiveness ◽

Co2 Emissions ◽

Electric Vehicles ◽

Hybrid Electric Vehicles ◽

Unit Commitment ◽

Electric Utility ◽

Battery Pack ◽

Hybrid Electric ◽

Power Utilities ◽

The Cost

Plug-in hybrid electric vehicles (PHEVs) have the potential of substantially reducing petroleum consumption and vehicular CO2 emissions relative to conventional vehicles (CVs). The analysis presented in this article first ascertains the cost-effectiveness of PHEVs from the perspective of the consumer. Then, the potential effects of PHEVs to an electric utility are evaluated by analyzing a simplified hypothetical example. When evaluating the cost effectiveness of a PHEV, the additional required premium is the most important financial parameter to the consumer. An acceptable amount for the additional upfront costs will depend on the future costs of gasoline and the on-board battery pack. The need to replace the on-board battery pack during the assumed vehicle lifetime also affects the allowed premium. A simplified unit commitment and dispatch model was used to determine the costs of energy and the CO2 emissions associated with PHEVs for different charging scenarios. The results show that electricity can be used to charge PHEVs during off-peak hours without an increase in peak demand. In addition, the combined CO2 emissions from the vehicles and the electric generation facilities will be reduced, regardless of the charging strategy.

Download Full-text