A48 Site
Site overview
The A48 site is in a private parking lot on Martindale Street in Pittsburgh. Like other sites along the tunnel route, it will serve as an entry point into the tunnel system, capturing combined sewage from the existing sewer system and directing it into the tunnel deep below ground.
Construction at A48 will include a connection to the existing combined sewer system, a vertical shaft approximately 25 feet wide and 140 feet deep, and a connection to the main Ohio River Tunnel.
Once construction is complete, the site will operate largely out of sight, playing an important role in helping keep combined sewage out of the river during wet-weather events.
Martindale St, Pittsburgh Directions: Google Maps Apple Maps
Beneath the surface
Go beyond the construction fence and explore the A48 site.
Underground Cross Section
This cross-section illustrates how the A48 drop shaft connects surface sewer infrastructure to the deep Ohio River Tunnel. During wet weather events, flows are directed through the regulator and down the vertical shaft before entering the tunnel system for transport to ALCOSAN's wastewater treatment plant. The illustration also highlights the surrounding soil and bedrock layers, helping explain how engineers safely construct and maintain deep underground infrastructure while minimizing impacts at the surface.
Aerial Site Plan
This aerial illustration provides an overview of the A48 construction site and how it integrates with ALCOSAN's Regional Tunnel System. The plan identifies the drop shaft location, tunnel vent, regulator, and temporary construction limits while showing nearby roadways, rail infrastructure, and surrounding development. The drop shaft will direct wet weather flows into the deep tunnel system, where they can be transported to ALCOSAN's wastewater treatment plant instead of overflowing into local waterways.
What to expect during construction
Nearby residents and businesses may experience construction impacts, including intermittent noise during shaft excavation, potential noise from authorized nighttime work and increased truck traffic during certain phases of construction.
ALCOSAN is committed to working with nearby residents and businesses to minimize disruption and will keep stakeholders informed about what to expect during each phase of the project.
Permitted work hours at this site will be:
General work hours*
- 6:00 a.m. to 8:00 p.m., Monday through Friday
- 7:00 a.m. to 8:00 p.m., Saturday and Sunday
*Impact-producing construction activities, such as pile driving and jackhammering, are limited to 8:00 a.m. to 6:00 p.m., Monday through Saturday. Controlled blasting activities are limited to 7:00 a.m. to 7:00 p.m., Monday through Friday, and 9:00 a.m. to 5:00 p.m. on Saturdays. Work hours exclude legal holidays; limited exceptions, including emergencies, may apply.
Extended hours for specific activities
Certain activities at the A48 site will occur outside of the general work hours. These include:
- Authorized underground work and support activities: Certain underground construction and support activities may occur during extended hours.
- Surface activities: Any authorized surface activities occurring during extended hours will be limited to on-site work.
What's happening at A48
Closures, public meetings and construction updates for the A48 site.
