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This paper describes the life-cycle analysis of the risk to highway bridge networks subjected to overweight traffic loads under maintenance budget constraints. The risk to the network is initially evaluated based on the current condition of its constituent bridges and then the life-cycle analysis is performed to identify the level of risk reduction that is possible given a particular budget allocation. The deterioration rate is extracted from National Bridge Inventory data. The risk is monitored as the deterioration of bridges progresses over the years. Bridges are ranked in descending order starting from the bridge whose failure has the highest impact on network risk. Maintenance is scheduled sequentially on the riskiest bridges until the entire budget allocation is depleted. The methodology is illustrated using as an example the highway network of major interstate and state roads in New York State. The paper compares the results of the proposed life-cycle risk analysis for several budget levels. The results show that network risk can be reduced from its present level by 20% if current expenditure rates are maintained. Risk reduction can reach 37% if the budget for bridge rehabilitation is increased to match that recommended in the ASCE report card for America's infrastructure. [ABSTRACT FROM AUTHOR]

Bridges have a significant role in society but are often massive structures requiring a high amount of materials, leading to high consumption of natural resources and high costs. In this respect, the use of high-strength steel (HSS) may represent a significant advantage as it enables to reduce the quantity of materials required for a structure to fulfil its function. Notwithstanding this potential benefit, the use of slender plates allowed by HSS makes I-girders more vulnerable to local bucking phenomena and fatigue issues. Hence, this article aims to discuss the potential advantages of HSS in bridge design, in terms of structural, environmental and economic performances. The discussion is based on a comparative analysis, in which a bridge made of steel grade S355 is compared with two alternative designs made of steel grade S690. The results of the analysis showed that although the use of HSS in bridges enables to save steel, thus providing some environmental advantages, in terms of costs the differences are negligible due to the higher requirements of HSS bridges. [ABSTRACT FROM AUTHOR]

Building design and performance are increasingly being scrutinised from perspectives of both sustainability and hazard resistance. However, the approaches taken to consider these perspectives are disconnected; green building rating systems do not consider hazard resistance in their assessments, while performance-based engineering methods have tended to neglect consideration of environmental impacts. This study presents a framework to assess a building’s life-cycle performance in terms of social, environmental and economic impacts using probabilistic approaches, considering the possible occurrence of an earthquake or other extreme event. The framework is illustrated through a case study of an office building in Los Angeles, designed with and without different types of vegetated (green) roofs, and at risk from varying earthquake hazard scenarios. The case study results demonstrate trade-offs between upfront building costs, material choices, hazard resistance and environmental impact. [ABSTRACT FROM AUTHOR]

Thedecayingstate of our infrastructure paired with rising emphasis on sustainable engineering suggests the need for upgrades which are selected based on their ability to provide adequate performance under natural hazards and minimise negative impacts on the three pillars of sustainability: society, environment and economy. This paper poses a framework based on a multi-objective genetic algorithm to help identify optimal retrofit and repair combinations which ensure public safety while minimising lifetime environmental, economic and social performance measures of sustainability for infrastructure exposed to natural hazards. Assessment of the case-study application results reveals the relationship between life-cycle environmental, economic and social indicators of sustainability for a bridge subject to earthquakes. The framework is anticipated to help guide the selection of retrofit and repair combinations by providing a set of ‘near-optimal’ non-dominated solutions, which enhance sustainability while ensuring public safety and mitigating or repairing damage from natural disasters. [ABSTRACT FROM PUBLISHER]