DESIGN, CONSTRUCTION, AND PROCUREMENT CONSIDERATIONS FOR TUNNELING SEGMENTS OF MTA BALTIMORE RED LINE

摘要

The Maryland Transit Administration (MTA) Baltimore Red Line Light Rail Transit(LRT) Project, a proposed 14.1-mile twin-track east-west transit link across DowntownBaltimore between the Federal campus at the Center for Medicare and MedicaidServices and the Bayview Medical Center campus of Johns Hopkins University, featurestwo tunnel sections totaling about four miles. During preliminary engineering, theProgram Management Consultant (PMC) and General Engineering Consultant (GEC)teams explored alternative contracting methods including Design/Build (DB), Design/Bid/Build (DBB) (baseline), Design/Build/Operate/Maintain, and Design/Build/Finance/Operate/Maintain under several financing models including Public-Private Partnerships(P3) to deliver the Project. Challenges and risks presented and evaluated included contractpackaging interfaces, difficult ground conditions (residual and transition soils tomixed-face and hard rock), overlying urban development including sensitive structures,site constraints, and mining techniques.