Phase 1 Through coordination with Iowa DNR staff and independent testing and analysis, the Respondent shall assess each of the following tunnel features in need of repair, and provide recommendations for improvement, removal, or replacement in a Phase 1 Analysis Report to be provided to the Iowa DNR Engineering Department: 1. Architectural fascia stone veneer archways over tunnel entrances - Currently, stone is separating from tunnel vault structure behind. Historical construction attached these stones to supporting structures using mortar. Assessment is needed by qualified engineer to determine whether stones can be re-anchored to structure behind, or if replacing the stones with similar new stones and modern anchoring system is a more practical and durable solution. Include recommendations for repair or replacement in Phase 1 assessment report and provide estimated service life after recommended repairs have been completed. Also provide recommended inspection and maintenance procedures in the report. 2. Limestone pieces accumulating at entrance pilasters and at ledges above tunnel entrances - Limestone accumulating in these areas appears to be falling from natural limestone bluff above. Assess the natural limestone bluff for safety concerns including the possibility of larger sections of bluff falling into the roadway. In Phase 1 assessment report, provide recommended design solutions to mitigate limestone deterioration, detachment, and accumulation. Design solutions shall minimally impact the natural and architectural character of the tunnel and limestone bluff. Also provide recommended inspection and maintenance procedures in the report. 3. Entrance portal limestone 'wing' walls each side of tunnel (4 total) - Each of the wing walls presents different design challenges. Assess each wall individually for structural integrity and stability, damage caused by vegetation, risk of future damage from vegetation, and general extent of each wall's deterioration. Include recommendations for repair or replacement of each section of wall in Phase 1 assessment report and provide estimated service life after recommended repairs have been completed. Also provide recommended inspection and maintenance procedures in the report. 4. Architectural limestone walls above archways - A small stacked limestone retaining wall above the archway on each side of the tunnel needs to be inspected and assessed for safety. Determine whether the structural integrity of the wall is weak or weakening and what level of risk there is for stones falling into roadway or walls toppling. Proposed strategies to improve the structure of the walls includes but is not limited to: Tuck-pointing all horizontal and vertical joints, inconspicuously reinforcing the walls with structural steel or concrete systems, replacing deteriorating stones or sections of wall. Include recommendations for repair or replacement in Phase 1 assessment report and provide estimated service life after recommended repairs have been completed. Design solutions shall minimally impact the natural and architectural character of the historical archways. Also provide recommended inspection and maintenance procedures in the report. 5. Repair of cracks and resurfacing of tunnelway walls and overhead structure – Inspect and assess cracking occurring in tunnelway walls and overhead surface. Determine severity of cracks found, their effect on the structural integrity of the tunnel, and propose patching procedures or other remedies to improve the visual appearance and structural integrity of the tunnelway. Refer to the Iowa DOT Inspection Report attached to this RFP and provide any condition discrepancies in Phase 1 assessment report. Also provide recommendations for replacement or repair, and maintenance recommendations in report.
