EXECUTIVE SUMMARY

The project successfully addressed significant structural defects identified during a CCTV survey, including partial collapses, missing brickwork, mortar loss, and water ingress from an adjacent water main. Despite encountering numerous uncharted services, voids beneath the carriageway, and a burst water main, the project team adapted methodologies, maintained programme progression, and achieved safe delivery. Strong stakeholder engagement, innovative construction decisions, and environmental controls were key contributors to success.

PROJECT BACKGROUND

A 2023 CCTV survey of the existing sewer infrastructure highlighted widespread deterioration, structural instability, and active water infiltration. These findings informed the development of a targeted repair and replacement strategy. The sewer asset served a heavily built-up urban environment with sensitive adjacent structures and active businesses, necessitating careful planning, phased delivery, and close stakeholder coordination.

PROJECT TIMELINE

Start on Site: 26 May 2025

• Start on Site: 26 May 2025
• Programme Duration: Approximately 17 weeks
• Completion: September 2025

Key Milestones:

• Phase 1 works completed and area reopened to public use
• Sewer excavation, replacement, and lining undertaken in stages
• Road reinstatement and demobilisation planned for mid to late September 2025
• Handover to Scottish Water September 2025

GOALS AND OBJECTIVES

• Repair and upgrade failing sewer infrastructure to extend asset life
• Minimise disruption to traffic, pedestrians, and local businesses
• Maintain public and workforce safety throughout complex urban works
• Reduce long-term maintenance requirements through structural lining
• Deliver works efficiently within a constrained urban environment

CHALLENGES OVERCOME

• Discovery of approximately seven uncharted services over 85 metres, including live gas infrastructure
• Significant voids beneath the road caused by a burst water main
• Managing changing scope while maintaining programme momentum
• Working immediately adjacent to buildings where excavation posed settlement risks
• Balancing road closure requirements with continued access for businesses
• Mitigation included vacuum excavation, revised construction sequencing, alternative lining solutions, enhanced shoring designs, and proactive engagement with stakeholders and elected representatives.

ENVIROMENTAL BENEFITS

• Discovery of approximately seven uncharted services over 85 metres, including live gas infrastructure
• Replacement of excavation activities with boil lining in high-risk utility zones reduced time, risk, and disruption
• Rapid turnaround for bespoke shoring design (one week design, two days installation) prevented programme delay
• Reduced energy use and deliveries by minimising excavations and concrete pours
• Phased construction maintained productivity while allowing public access

Efficiency Benefits of the Project

• Replacement of excavation activities with boil lining in high-risk utility zones reduced time, risk, and disruption
• Rapid turnaround for bespoke shoring design (one week design, two days installation) prevented programme delay
• Reduced energy use and deliveries by minimising excavations and concrete pours
• Phased construction maintained productivity while allowing public access

COMMERCIAL IMPLICATIONS

• Final projected value: circa £875,000, reflecting additional works and compensation events
• Multiple compensation events raised for uncharted services, voids, additional lining, water main repairs, and remobilisation
• Monthly applications submitted and managed collaboratively between contractor and Scottish Water commercial teams

CONCLUSION

The Hamilton Road Sewer Rehabilitation project demonstrates effective delivery of complex urban infrastructure works under challenging conditions. Through adaptive engineering solutions, strong safety performance, environmental sensitivity, and proactive stakeholder engagement, the project team successfully mitigated risk while delivering long-term asset improvements. The project provides a strong example of best practice in urban sewer rehabilitation and collaborative contract management.