Exhibit E-Bridge Site #3 Kings Mill Inspection Report.pdf
PDF 5 MB Posted
- Solicitation number
- IFB-PRL-25-628
- Issued by
- Colorado
About this file
This document is an inspection memo and scope of work for the Kings Mill Bridge, located on the Farmers High Line Canal Trail in Westminster, Colorado. The single-span prestressed concrete double tee beam bridge is 40 feet long and 7 feet wide, with timber rails on steel posts and 12-inch diameter concrete caisson abutments. The inspection, conducted on 3/12/2025 by team leader D. Krause, revealed significant structural deterioration, including map cracking on the deck, disconnected timber rails, vertical cracks in beam stems, and erosion around the abutments.
The bridge is in overall poor condition, with notable deficiencies including crushed bearing pads, exposed rebar, delaminated top flanges, and significant undermining of approach sidewalks and abutment backwalls. The inspection recommends several critical repairs: installing 6-inch concrete curbs on the north approach sidewalk, implementing embankment protection, repairing erosion under approach sidewalks, replacing approach sidewalks, encasing Abutment 2 caissons with reinforced concrete, and securing the west top timber handrail. Due to the severity of concrete disintegration and erosion, the report suggests scheduling routine inspections every 12 months to monitor the bridge's condition and prevent further deterioration.
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King’s Mill, Farmers High-Line Canal Bridge Repair Inspection Memo and Scope of Work
Structure Summary:
Kings Mill bridge carries Farmers High Line Canal trail over Farmers High Line Canal in Westminster, Colorado, providing access to Kings Mill park. The bridge is located at 39° 51’ 33.92” N, 105° 5’ 47.87” W and approximately 0.1 miles east of Field Street. The structure is inventoried south to north, superstructure is named Stem A to B from west to east, substructure is numbered Abutment 1 to 2 from south to north. Below is a summary of main structural components.
• (1) Prestressed concrete double tee beam
• 1 span
• 40’-0” structure length
• 7’-0” out-out width
• 2” concrete deck on 1 ¾” top flange
• Timber rails on steel posts mounted to top flange
• Abutments are 12” average diameter concrete caissons with cast-in-place concrete backwalls
• 5’-4” wide concrete approach sidewalks
Condition Summary:
• NBI Deck Condition: 6
• NBI Superstructure Condition: 6
• NBI Substructure Condition: 4
• NBI Channel Condition: 7
Deck has medium to wide map cracks throughout with minor abrasion.
Timber rails have minor checks and shakes throughout. West top rail at 3rd post from north is disconnected; post exterior connection has (1) bolt not engaged.
Recipient Page | 2
Beam top flange interior fillets have insignificant to medium longitudinal cracks, widest near the abutments; end 10 to 15 feet has efflorescence. Beam top flange at both ends between stems is delaminated for full width x 2 inches. Beam exterior top flanges have shallow popout spalls with exposed bars. West beam top flange at north rail post has 35 inch x 2 inch x 5 inch deep area of spalled and removed concrete with exposed, cut rebar.
Double tee beam stems bear on elastomeric pads at caissons. Stems at Abutment 2 bearings have medium vertical cracks. Abutment 2 bearing pads are crushed and split.
Abutment 1 caissons are mostly buried and not visible for inspection. Abutment 2 caissons have (2) bars extending out of concrete; north bar is poured into backwall, south bar extends under beam stems. Caissons are irregular shape and concrete is disintegrating with exposed aggregate and voids. Column 2A is exposed 25 inches, Column 2B is exposed 23.5 inches due to erosion behind backwall. Abutment 2 backwall is only supported by (1) bar out of the caissons, all fill has eroded away. Backwall concrete is broken and hanging.
South approach sidewalk at backwall is undermined up to 4 feet transversely; backwall to approach joint has a 1 inch gap. North approach and Abutment 2 backwall are undermined up to 6 foot long x 4 foot high x full width;
approach sidewalk east edge is broken off with wide cracks. Northwest bank has an erosion channel formed along the approach sidewalk directed at Column 2A and under structure.
Controlled flow runs west to east through a well-defined channel with vegetated banks. Channel was dry at time of inspection. Trees and vegetation are growing under structure.
Recommendations:
1. Direct runoff away from structure to prevent future erosion.
• 6” Concrete Curbs on North Approach Sidewalks: (90 feet)
• Embankment Protector Type 5 (M-615-2)
2. Repair erosion under approach sidewalks and behind backwalls to stabilize approaches.
• Structural Backfill
• Approach Sidewalk Replacement
3. Encase Abutment 2 caissons with reinforced concrete to create additional strength and stability.
• Concrete Encasement with 4 foot Extensions
4. Secure west top timber handrail at 3rd post from north to keep railing intact.
Recipient Page | 3
Kings Mill bridge is in overall poor condition due to the abutment caisson concrete disintegration and heavy erosion. Installing preventative measures for runoff prior to the rainy season is high priority for this structure. It is recommended that Kings Mill be scheduled for routine inspections on a 12 month interval due to the severity of erosion and concrete disintegration.
Bridge Location:
Westminster Open Space Farmers High Line Canal Trail over Farmers High Line Canal
Kings Mill Team Leader: D. KRAUSE Inspection Date: 3/12/2025
Westminster Open Space, Task 1
Trail looking north.
Trail looking south.
Kings Mill Team Leader: D. KRAUSE
Elevation looking east.
Elevation looking west.
Kings Mill Team Leader: D. KRAUSE
Superstructure looking north.
Channel looking west upstream.
Kings Mill Team Leader: D. KRAUSE
Channel looking east downstream.
Deck has medium to wide map cracks.
Kings Mill Team Leader: D. KRAUSE
West top rail shake, typical.
West top rail at 3rd post from north is disconnected.
Kings Mill Team Leader: D. KRAUSE
West rail 3rd post from north exterior nut is not engaged.
Top flange fillet medium longitudinal crack.
Kings Mill Team Leader: D. KRAUSE
Top flange longitudinal crack efflorescence at end 15 feet.
Top flange at north end is delaminated.
Kings Mill Team Leader: D. KRAUSE
Exterior top flange shallow popout spall with exposed bars.
West top flange at north post is spalled with cut rebar.
Kings Mill Team Leader: D. KRAUSE
Stem B at Abutment 2 has medium vertical crack, Stem A similar.
Stem A Abutment 2 bearing pad is crushed.
Kings Mill Team Leader: D. KRAUSE
Abutment 1 general.
Abutment 2 general.
Kings Mill Team Leader: D. KRAUSE
Abutment 2 backwall is broken and hanging.
South approach sidewalk east side undermined up to 4 feet.
Kings Mill Team Leader: D. KRAUSE
Abutment 1 joint has 1 inch gap.
North approach and Abutment 2 backwall undermining general.
Kings Mill Team Leader: D. KRAUSE
North approach sidewalk is broken with wide cracks.
Northwest bank erosion channel.
File details come from the government source that posted it. Updated .