Parsons - 2010 Construction Management for AWV.pdf - SCATnow

Bored Tunnel Alternative Design-Build ProjectDesign-Build Construction Management Services SR 99Table E.2 Risk CM Role - Design and Pre-construction CM Role - ConstructionLiner Quality (Fab)• Loss of face pressure/poor mixing in theearth plenum triggers uncontrolled flow ofrunning sand/water into plenumLiner Quality (Install)• Concrete liner sections not installed inaccordance with tolerance or qualityrequirements, leading to improper fit,damage, or leakageThe CM team will:• Review the design-builder’s fabrication and QC/QA plans• Develop Quality Verification (QV) proceduresand a training program for CM staff and WSDOTemployees• Verify that the design-builder designs andprocures robust molds• Verify that the design-builder’s fabricator isqualified and the plant can meet productionschedulesThe CM team must confirm that the designbuilder:• Liner design accounts for handling and installationloads• TBM/liner interface is designed properly• Annular grout design is tested for compatibilitywith the TBM and has enough strength to supportthe liningThe CM team must confirm that the design-builder:• Verifies design geometry, gasket, and connection details• Provides laser 3-D verification of moulds• Ensures proper curing• Reviews and test mix designs• Performs rigorous QC/QA program• Provides liner test ringsThe CM team will:• QV of operations (continuous plant inspection)The CM team must monitor the design-builder’s activityto confirm:• Proper ring selection through telemetry/back-checked by thefield engineer• Crew training/proper installation measurement• Immediately backfill grout through the tail shield, grout hasenough strength to support rings• Annular grout meets specified strength• Continuous rigorous inspection of the liner installation3Hyperbaric Interventions for TBM Maintenance/RepairBenefits to WSDOT• Hyperbaric experience in all roles – safety, management,operational, and medical• High-pressure intervention work• Hands-on experience – Our people have performed the workOur hyperbaric team has been involvedwith over 500 interventions, includingover 70 self-performed interventions upto 4 bar.Parsons has assembled a group of in-house and consultant hyperbaric experts with specific TBM intervention experience indifficult ground conditions. Greg Colzani, acting as a Construction Manager and Resident Engineer, has managed severalprojects (SBTO, East Side CSO, West Side CSO) that have included hyperbaric interventions up to 4.5 bar.Additionally, Jan Babendererde has set-up hyperbaric equipment, monitored hyperbaric work, and has personallyconducted over 60 interventions in excess of 3 bar. Bob Rogers, one of Parsons’ best safety professionals, specializesin construction diving and TBM hyperbaric operations. He has developed and reviewed contractor hyperbaric plansfor tunnel projects including the SBTO, the West Side CSO, and the Brightwater Conveyance in Seattle. Edmond Kay,MD, a hyperbaric medical consultant, has acted as the attending hyperbaric physician for the Beacon Hill, BrightwaterConveyance, and University Link tunnel projects in Seattle for workers exposed up to 6.5 bar.Assessing the RisksKey Risks• Worker safety – Increased health risks• Face stability – during interventions andpost-interventionTBM cutter replacement will require the use of hyperbaric interventions and/orextensive ground stabilization in unstable saturated soils if safe havens of stableground are not available. The first line of defense is to design a robust TBM toreduce wear. Regardless, highly abrasive soils make it necessary to inspect thecutterhead and replace cutter tools. Therefore, the design-builder will need the37