Establish Bridge Environmental Impact Estimation Model: National Freeway Concrete and Steel Bridge as an Example

Abstract

ABSTRACT To mitigate the emissions from the bridge construction the sustainability analysis should be considered Three pillars of sustainability used as a parameter that has a function to carry out the assessment of transportation infrastructure system One of the popular mean to evaluate the project sustainability is the life cycle analysis In particular life cycle assessment is widely used to evaluate the environmental impact throughout the entire life of a product from its raw material acquisition to end of life of the product Most bridge infrastructure life cycle assessment (LCA) tools used itemized input to calculate environmental footprint of the project which is inconvenient for a designer to evaluate various design upfront Thus the objective of this study is to evaluate the environmental footprint over the life cycle of the concrete and steel bridge The environmental footprint of the bridge was calculated using itemized based analysis which utilized the cost analysis data This study used two types of bridges with specific superstructure construction technique One is a concrete bridge with PC-box girder using advancing shoring method (ASM) and the other one is steel bridge girder with erection method (EM) The results of this study divided into the description of LCI and LCA The inventory regarding the material and equipment for concrete bridge used to accomplish the LCA calculation for about 55% in the substructure; 50% in the superstructure regarding the items standpoint for the steel bridge the items used to recognize the material inventory has 54% (substructure) and 36% (superstructure) from the total items In terms of euipment inventory the concrete bridge have 70% (substructure) and 79% (superstructure) from the total items In addition the steel bridge consideration the equipment inventory have 67% (substructure) and 77% (superstructure) from the total itemshis results found that during the construction stage GWP and smog emissions of concrete bridge substructures was larger compared to the steel bridge Besides ADPE emissions showed a big portion during the construction phase of steel bridge compared to the concrete bridge For the superstructure parts a large number of GWP emissions on all of the component on the steel bridge compared with the concrete bridge In the other hand the ADPE and smog emissions on the concrete bridge showed a significant amount on the beam In the operation phase three kind of environmental impacts due to the replacing wearing surface and reconstruction of asphalt layers on the steel bridge indicated a large amount compared with the concrete bridge In the EOL phase the greenhouse gases abiotic depletion and smog emissions of foundation on concrete bridge indicated a significant impact than a steel bridge In the other hand three kinds of potential environmental impacts of piers in the steel bridge showed a high amount compared to the concrete bridge The LCA results for superstructures section during the EOL of a steel bridge GWP ADPE and smog emissions has a larger portion in the drainage element bridge fence expansion joint bearing and pavement on the bridge Besides only beam has significant impacts in the concrete bridge compared to the steel bridge

Date of Award	2017 Aug 22
Original language	English
Supervisor	Shih-Hsien Yang (Supervisor)