Author(s)

Zhaoxia Zhang

Corresponding Author

Zhaoxia Zhang

Abstract

Municipal bridge projects in urban core areas and along river channels face multiple challenges, including complex geological conditions, tight construction sites, sensitive traffic organization, and strict ecological protection and emission standards. Traditional design concepts, with structural safety as the sole goal, struggle to fully meet the comprehensive goals of safety, economy, and environmental protection. This study, focusing on a 26.7-kilometer-long urban expressway viaduct project, developed an integrated technical model combining structural mechanics analysis, prefabricated construction, green construction assessment, and life cycle costing. Life cycle costing and high-performance fiber-reinforced cementitious composites were incorporated into the overall design technology system. A standardized internal force and deflection calculation formula, a carbon emission accounting model based on emission factors, and a life cycle cost present value analysis model were constructed. Combined with prefabricated construction and HPFRCC key node strengthening measures, the design schemes of municipal bridges under complex construction backgrounds were compared and their effectiveness tested. The prefabricated scheme can shorten the construction period of the main project from 300 days to 105 days, a reduction of about 65%. The traffic closure time was shortened from 180 days to 60 days, a reduction of 67%. Carbon emissions were reduced by 29%, from 1.20 tons per kilometer to 0.85 tons per kilometer. The LCC curve showed a turning point in economic benefits in the 7th to 9th year of service. If the crack initiation stress of HPFRCC is increased to 14MPa, its toughness index will increase to 83%, effectively reducing tensile damage. The constructed comprehensive technical route of "life cycle, digital twin, prefabrication, and high-toughness materials" provides a simulatable and popularizable practical guide for the design, construction, and maintenance of municipal bridges in urban core areas and geologically complex environments.

Keywords

Municipal Bridge; Complex Construction Conditions; Overall Design; Prefabricated; HPFRCC; Green Construction; Life Cycle Cost