Timbering of south heading of tunnel during construction, Waterworks Park, Detroit water supply system
Description:
View of timbering of south heading of tunnel during construction, Waterworks Park, Detroit water supply system. Printed on front: "City of Detroit. Department of Water Supply. Land tunnel and structures. Contract RC 12. Dravo Contracting Co., contractors. Photo no. 90. Date: 3-30-31. Photo by Manning Brothers." Typed on back: "14-ft. tunnel south heading. View of timbering in last 18 ft. of tunnel at screen chamber. Timbering placed skin to skin. 12" x 12" timbers except for 12" x 14" cap for first half and 12" x 14" timbers for remainder of stretch. The square timber sets at middle of tunnel section supported a pilot drift excavated first and then enlarged to full tunnel section. Break in timbering showing in roof is at ring of steel sheet piling driven around screen chamber caison [sic]. In background note steel sheet piling driven to support quarter bend excavation."
