SR-66 (DIAMOND AVENUE) STORM SEWER TUNNEL

Evansville, Indiana

Lyman Henn provided complete design services for this approximately 1-mile long 96-in. inside diameter gravity storm sewer. The project was designed to help alleviate flooding beneath SR-66 (Diamond Avenue), a major highway in Evansville . The new storm sewer tunnel was constructed beneath travel lanes of SR-66, and tied into an existing lift station at the downstream end of the project. Ground conditions consisted of cohesive soils beneath the groundwater table. Project deliverables included a Geotechnical Interpretive Report, Geotechnical Baseline Report, plans, specifications, and estimate of probable construction costs.

Lyman Henn also provided oversight during the approximately 9-month long construction process. Tunneling was conducted using an Earth Pressure Balance tunnel boring machine (EPBM) operated in the open mode. Tunnel initial support consisted of steel ribs and timber lagging. The carrier pipe was RCP, which was installed inside the tunnel after completion of tunnel excavation. The annulus between the carrier pipe and the initial support was backfilled with low density cellular concrete. Upon completion of construction, Lyman Henn provided claims assistance.