City of Des Moines. Activity ID: Bridge Rehabilitation: Court Avenue over the Des Moines River

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1 5525 Merle Hay Road Suite 200 Johnston, IA Main Fax H R G R E E N. C O M City of Des Moines Activity ID: Bridge Rehabilitation: Court Avenue over the Des Moines River Schedule Submit for final SHPO, USACE and DNR Permits in June 2017 Submit 50% preliminary plans in July 2017 Letting currently planned for February 20, 2018 Opinion of Probable Construction Cost The estimated cost as submitted with the 2016 TIGER Application was $7,000,000. This cost is based on 2016 dollars, so the construction costs are expected to increase with construction planned for Scope of Repairs The Court Avenue Bridge was built in The bridge is listed on the National Register of Historic Places and therefore is a vital element in the Civic Center Historic District. The structure was reconstructed in The reconstruction project included the replacement of the entire superstructure above the arches and replacement of the ornamental limestone railing. The current condition of the bridge warrants repairs to replace damaged elements, improve the appearance and durability of the limestone portions, and prolong the life of the structure. The recommended repairs to the structure are divided into three categories. The repairs to the concrete portions of the structure will include the following: 1. Remove existing overlay and repair and re-overlay the deck 2. Remove and replace sidewalks 3. Remove and replace the bridge expansion joints. 4. Repair abutments, piers, arch ribs, spandrel walls, columns and floor beams 5. Remove and replace portions of the approach pavement The repairs to the limestone portions of the bridge will include the following: 1. Remove the entire existing barrier rail and replace with either a precast concrete replica of the railing or a railing made from alternative materials. 2. Remove damaged limestone on the bridge fascia and replace with new limestone. 3. Remove and reset misaligned limestone on the bridge fascia. 4. Point the opened and multicolor mortar joints to reset the aging process and realign the mortar color between limestone elements. 5. Use a cleaning system to remove biogrowth soiling and limestone discoloration. Lighting photometrics are being analyzed and will be discussed with the City as lighting concepts are further explored. The options to replace the lighting being evaluated for cost include the following: 1. Removing existing light fixtures and consider replacing with similar style light poles incorporating LED source luminaires. 2. Considering the ability to provide LED light fixtures to provide feature lighting of the railing and bridge fascia. The repairs will not change the visual appearance of the bridge and it is not anticipated that the roadway and sidewalk dimensions will be changed.

2 Court Avenue Bridge Rehabilitation City of Des Moines

3 Existing Limestone Condition Ornamental Railing Section Loss Biogrowth and Discoloration Damage and Movement

4 Existing Topside Condition Deteriorated Bridge Deck Overlay Widespread Spalling of Curbs Water Ponding on Sidewalks

5 Existing Underside Condition Concrete Arch Deterioration Spalls with Exposed Reinforcement Leaking Expansion Joints

6 Existing Lighting Condition High Pressure Sodium Type Light Sources Damaged and Corroded Light Pole Bases Not All Light Fixtures Working Likely Doesn t Meet City Illumination Policy

7 Proposed Railing Repair/Replacement Options: Replace Deteriorated Rail Elements Completely Replace In-Kind Use Precast Concrete and Match Color Alternative Materials like Granite

8 Proposed Sidewalk Replacement Completely Remove 6 Thick Sidewalks Replace with 8 Thick Sidewalk Designed to Carry an Underbridge Inspection Snooper Truck Insure Sidewalk Properly Drains Away from Railing to Curb

9 Proposed Lighting Challenge is to Meet Current Lighting Standards Consider Similar Style Poles with Decorative LED Lights Consider Supplementing Decorative Lights with Standard Street Lights Consider Feature Lighting of Limestone Railing and Façade LED Striplighting or Periodic Downlighting Highlight Bridges Downtown Presence at Night

10 Deck Roadway Cross-Section Keep Existing Lane, Parking, and Sidewalk Geometry

11 Summary of Proposed Repairs Remove Existing Overlay and Repair and Re-Overlay the Deck Remove and Replace Sidewalks Remove and Replace Expansion Joints Repair Abutments, Piers, Arch Ribs, Spandrel Walls, Columns and Floor Beams Remove and Replace Ornamental Railing Repair or Replace Damaged Limestone and Point the Mortar Joints Clean Stains and Biogrowth from the Limestone Façade Remove and Replace Light Fixtures Consider Feature Lighting of Railing and Fascia

12 Questions?