Proceedings of the 26th Annual Members' Conference, 2001, St. Louis, MO "Designing Deep ~ Building Deep", (DFI)
Access and Riser Shafts - Detroit River Outfall #2
Edmund J. Cardoza Jr, John E. Luebbe
The Millgard Corporation in Joint Venture with Traylor Bros., Inc. of Evansville, Indiana and Jay Dee Contractors, Inc. of Livonia, Michigan is in the process of installing two (2) 10’-0” diameter Access Shafts and six (6) 12’-6” diameter Riser Shafts for the Detroit River Outfall #2 project. The project also includes a 21’-0” diameter tunnel in rock which connects the shafts to the DWS Sewage Treatment Plant and will allow additional treated effluent to be deposited in the Detroit River. The shafts vary in depth between 252’ and 266’ below ground surface and river level respectively, penetrating approximately 50 to 100 feet of overburden soils including hardpan, and extending to a maximum penetration of 185’ into limestone bedrock. Upon drilling completion, 8’0” and 10’-0” diameter heavy wall steel pipe, in sections, is inserted and grouted in place to form the final shaft lining. Two (2) Access Shafts were installed on land, and the six (6) Riser Shafts are being installed from a specially designed work platform set in 45’ of water and supported by piling driven to rock. The platform design allows for two (2) riser locations to be worked on from each setup to minimize the number of platform moves. Overburden drilling on the land shafts was performed by a TMC Calweld 200CH Crane Attachment mounted on a Manitowoc 4100W Crane with support by a Manitowoc M-250 Crane. All shafts require permanent heavy wall steel casing through the overburden soils, and for the offshore work an additional piece of temporary casing is utilized from the platform deck to below the mudline. Overburden excavation for the riser shafts is accomplished by clam shell. Rock is excavated by a Wirth Model PBA928 Pile Top Drilling Rig utilizing reverse circulation techniques and two sizes of cutterheads. Plumbness measurements of the drilled shafts has ranged from 0.06% to0.6% of the total depth. Contract requirements do not allow the return of rock cuttings to the riverbed so a barge-mounted system sesparates drilling fluid and spoil to allow transport to land for disposal. The off-shore operation is supported by both a 4000W Manitowoc Ringer Crane and a 3900 Manitowoc Crante mounted on barges for spoil and material transport. Work on this project is anticipated to be completed in the fall of 2000.
|article #933; publication #56 (AM-2001)|