Mohammed Safi

Life cycle assessment as a decision support tool for bridge procurement: environmental impact comparison among five bridge designs

PurposeThe conventional decision-making for bridges is mostly focusing on technical, economical, and safety perspectives. Nowadays, the society devotes an ever-increased effort to the construction sector regarding their environmental performance. However, considering the complexity of the environmental problems and the diverse character of bridges, the related research for bridge as a whole system is very rare. Most existing studies were only conducted for a single indicator, part of the structure components, or a specific life stage.MethodsLife Cycle Assessment (LCA) is an internationally standardized method for quantifying the environmental impact of a product, asset, or service throughout its whole life cycle. However, in the construction sector, LCA is usually applied in the procurement of buildings, but not bridges as yet. This paper presents a comprehensive LCA framework for road bridges, complied with LCA ReCiPe (H) methodology. The framework enables identification of the key structural components and life cycle stages of bridges, followed by aggregation of the environmental impacts into monetary values. The utility of the framework is illustrated by a practical case study comparing five designs for the Karlsnäs Bridge in Sweden, which is currently under construction.Results and discussionThis paper comprehensively analyzed 20 types of environmental indicators among five proposed bridge designs, which remedies the absence of full spectrum of environmental indicators in the current state of the art. The results show that the monetary weighting system and uncertainties in key variables such as the steel recycling rate and cement content may highly affect the LCA outcome. The materials, structural elements, and overall designs also have varying influences in different impact categories. The result can be largely affected by the system boundaries, surrounding environment, input uncertainties, considered impact indicators, and the weighting systems applied; thus, no general conclusions can be drawn without specifying such issues.ConclusionsRobustly evaluating and ranking the environmental impact of various bridge designs is far from straightforward. This paper is an important attempt to evaluate various designs from full dimensions. The results show that the indicators and weighting systems must be clearly specified to be applicable in a transparent procurement. This paper provides vital knowledge guiding the decision maker to select the most LCA-feasible proposal and mitigate the environmental burden in the early stage.

Cost-Efficient Procurement of Bridge Infrastructures by Incorporating Life-Cycle Cost Analysis with Bridge Management Systems

Life-cycle cost analysis (LCCA) has recognized potential for rationalizing bridge procurement, but its use in this context is far from systematic. The integration of LCCA findings in decisions is o ...

Development of the Swedish bridge management system by upgrading and expanding the use of LCC

Although many bridge management systems (BMSs) contain some forms of life-cycle costing (LCC), the use of LCC in bridge engineering is limited. Life-cycle costing in many BMSs has mainly been applied within the bridge operation phase to support decisions related to existing bridges. Life-cycle costing has several useful applications within the bridge entire life, from cradle to grave. This article introduces the Swedish Bridge and Tunnel Management System (BaTMan). A comprehensive integrated LCC implementation scheme will be illustrated, taking into account the bridge investment and management process in Sweden. The basic LCC analysis tools as well as other helpful techniques are addressed. A real case study is presented to demonstrate the recent improvement of BaTMan practically in the function of whether to repair or to replace a bridge. Cost records for 2508 bridges are used as input data in the presented case study. Considering the same records, the average real and anticipated initial costs of different bridge types in Sweden will schematically be presented.

Integration of Life-Cycle Cost Analysis with Bridge Management Systems: Case Study of Swedish Bridge and Tunnel Management System

Many countries use bridge management systems (BMSs), and many of these systems involve some form of life-cycle cost (LCC) analysis. Use of LCC analysis in bridge engineering is rare, however; the technique has been applied primarily in the operation phase to support decisions about bridges that already exist. Yet LCC analysis can be applied across the life of a bridge. This paper introduces the Swedish Bridge and Tunnel Management System (BaTMan). A comprehensive, integrated LCC implementation scheme takes into account the bridge investment and management processes in Sweden. The basic economic analytical tools as well as other helpful LCC analysis techniques are described. A case study demonstrates improvements in BaTMan as a factor in the decision whether to repair or to replace a bridge. Cost records for 1,987 bridges were used as input data in the case study. On the basis of the same records, the average real and anticipated initial costs of various bridge types in Sweden are presented schematically.