ALCOSAN Contract 1704 involved the replacement of various components in Eighteen diversion structures within the ALCOSAN Interceptor System. The extent of work varied at each structure and specific details for work were detailed in the plan sheets. A summary of the overall work involved the removal of deteriorated safety handrail, hand-holds, tie-off points, and the installation of new stainless steel safety handrail, tie-off points, hand-holds, steps, and ladders. In addition to the safety upgrades, four of these diversion structures had areas of concrete that had eroded and/or spalled. Concrete restoration work involving bypass pumping was used to allow the installation of a protective epoxy polymer lining system. Spalled concrete was cleaned and repaired prior to the application of the lining system.
After the installation of the lining system, holiday spark testing was done to check for inconsistencies such as pinholes and voids in the coatings. Following the installation of the safety components, work was done by the DLZ inspection staff to conduct confined space entry and pull-out testing of the newly installed components using ASTM E3121 to 3,600lb per OSHA 1910.140(c)(8). Bypass pumping plans were submitted and reviewed by DLZ and the Designer for the project for each location. The bypass pumping plan and MOT plan at Structure M-29 involved various stakeholders and coordination including PennDOT and the City of Pittsburgh. Godwin Road Ramps were used at M-29 to provide a temporary crossing for vehicle access over the bypass in this challenging location.