Engineering Inspection Services
The Importance of On-Site Inspections in Construction
On-site inspections are a critical component of any construction project. They ensure safety, quality, and compliance with regulations and project specifications. Regular inspections help identify issues early, preventing costly rework and delays while maintaining adherence to building codes and safety standards.
Key Benefits of On-Site Inspections
1. Safety Enforcement
Safety is paramount in underground construction. Inspections help identify and mitigate site hazards—such as confined-space risks, improper shoring, unstable excavations, exposed utilities, and inadequate signage. Regular safety checks protect crews, reduce liability, and ensure compliance with OSHA and local safety requirements.
2. Quality Assurance
Inspectors confirm that materials, installation methods, and workmanship meet project specifications. This includes verifying pipe alignment and grade, joint integrity, bedding and backfill compaction, and proper installation of manholes, risers, and appurtenances. Early detection of deviations prevents long-term system failures and ensures lasting performance.
3. Regulatory and Code Compliance
All utility installations must comply with municipal standards, sewer district requirements, and environmental regulations. Inspections verify that water and sewer installations meet approved plans, permitting conditions, and applicable building and environmental codes—avoiding potential fines, delays, or project shutdowns.
4. Progress and Schedule Management
Inspections confirm that each project phase—such as excavation, tunnel boring, pipe installation, testing, and backfill—is completed correctly before moving forward. This process keeps crews aligned, ensures efficient sequencing, and helps maintain project timelines and budgets.
5. Cost Control and Risk Reduction
By identifying issues early—such as improper pipe placement, inadequate bedding, or safety noncompliance—inspections minimize rework, material waste, and downtime. This proactive approach helps contractors control costs and maintain profitability.
6. Documentation and Accountability
Each inspection provides a detailed record of field conditions, completed work, and compliance milestones. These reports support communication among contractors, engineers, and sewer districts, ensuring transparency and providing a reliable reference for future maintenance or audits.
Engineering Inspection Solutions
1. Progress Inspections
Performed at critical construction stages such as trenching, tunnel boring, pipe installation, pressure testing, and backfill. These inspections verify that each phase meets specifications before proceeding.
2. Quality Control Inspections
Focused on material integrity and workmanship—confirming proper pipe type and diameter, joint sealing, line and grade, and installation per design drawings and specifications.
3. Safety Inspections
Conducted to ensure compliance with all safety regulations, including trench safety, confined-space entry, traffic control, and equipment operation standards.
4. Code and Regulatory Inspections
Performed by local or district authorities to confirm that construction meets approved plans, environmental regulations, and applicable water and sewer codes.
FEATURED PROJECTS
MSD - Deer Creek tunnel project
The Deer Creek Tunnel spans approximately 3.9 miles, extending from Clayton Road to Interstate 44. Designed to capture and temporarily store excess wastewater during periods of heavy rainfall, the tunnel provides critical relief to the Deer Creek sewer system. Prior to its construction, intense storms frequently overwhelmed the existing infrastructure, resulting in basement backups and sewer overflows. Since its completion in late 2021, the tunnel has significantly improved system capacity and reliability, enhancing flood protection and wastewater management for the surrounding communities of Clayton, Richmond Heights, Brentwood, Maplewood, Webster Groves, and Shrewsbury.
MSD - Jefferson Barracks tunnel project
The Jefferson Barracks Tunnel was developed to address chronic sewer overflows in the Lemay and South St. Louis County area. Extending approximately 17,800 feet (3.37 miles) from just south of I-255 at Koch Road to the Lemay Wastewater Treatment Plant near the confluence of the River des Peres and the Mississippi River, the tunnel provides critical wastewater storage and conveyance capacity for the region.
The previous sewer infrastructure had reached the end of its service life and was no longer capable of managing flows during periods of moderate to heavy rainfall. The new tunnel system increases capacity to collect, transport, and store excess wastewater, significantly reducing overflow events and protecting local waterways from pollution.
Constructed parallel to the Mississippi River, the 7-foot-diameter tunnel is lined with fiberglass pressure pipe for enhanced durability and performance. The alignment presented unique engineering challenges, passing through river bluff karst formations—porous limestone terrain characterized by caves and sinkholes. To overcome these conditions, engineers strategically designed the tunnel alignment below the limestone layer, boring through stable rock between 150 and 230 feet beneath the surface to ensure structural integrity and long-term reliability.
MSD - Lower Meramec Phase 2 tunnel project
As part of MSD Project Clear’s ongoing initiative to reduce basement backups and sewer overflows, the Lower Meramec Tunnel Phase 2 project involves the construction of a 6.8-mile tunnel located approximately 200 feet below ground in South St. Louis County. Extending from Old Towne Fenton to Baumgartner Road, the tunnel is designed to convey wastewater currently treated at the Fenton Wastewater Treatment Plant to the Lower Meramec Wastewater Treatment Plant.
This critical infrastructure improvement enables the decommissioning of the flood-prone Fenton facility while enhancing system reliability and improving the overall water quality of the Meramec River. The project represents a key component of MSD’s long-term plan to modernize wastewater management and protect local communities from overflow events.