1. Innovative Designs for the 2013 Colorado Flood Damage
National Hydraulics Conference
August, 2016
Veronica Ghelardi, PE
Central Federal Lands
Federal Highway Administration

2. Project Location

3. CO 43 Project Scope
Project Partners: Larimer County, US Forest Service
10 – miles Drake to Glen Haven, Colorado
12 Bridges
Roadway Reconstruction
Riprap Armor
River Restoration
Design/Build

4. Timeline
Flood – September 2013
Construction Start CO 43 – November 2014
Construction Finish CO 43 – July 2016

5. Project Details 250,000 cubic yards of rock excavation 12 New Bridges
5 miles of Heavy 4R
5 miles light 4R & 3R
50,000 cubic yards of roadway armorment

6. Roadway and River Form a Single System
Project Concept
Roadway and River Form a Single System

7. Location of Seed Projects
Due to location of the seed projects, the hydraulic modeling wasn’t straight forward. Each section was modeled independently in SHR-2D and is being brought into one hydraulic model for the county.

8. INNOVATIONS -ROADWAY DESIGN
Bridge #4, Pre-flood
Flip the Road & Stream
Bridge #4 Reconstruction

9. INNOVATIONS - ROW ~80 landowners – over 8 miles of roadway
Discussed highway design with landowners BEFORE negotiations for ROW
Used visual aids - overlaid designs on aerial photos
Performed ROW Certifications in Sections
ROW – Accelerated process, weeks timeframe, 8 miles of road were privately held, ~ 75 affected parcels
Public Meetings, website, Hotline, weekly traffic delay report, PROVIDING PEOPLE with the INFORMATION

10. INNOVATIONS - HYDRAULICS
SRH -2D Modeling
Hydraulics used 2-D modeling (SRH) to provide WSEL to compare road alignments, shear stresses for riprap armoring, and detailed velocity and shear stress analysis for scour
Water Surface Elevations

11. INNOVATIONS - HYDRAULICS
SRH -2D Modeling
Hydraulics used 2-D modeling (SRH) to provide WSEL, shear stresses for riprap armoring, and detailed velocity and shear stress analysis for scour
Shear Stress vs Water Depth

12. INNOVATIONS –Geotechnical & Hydraulics
Rockery Wall in Stream Environment
Driving Forces
Resisting Forces
Lateral earth force (soil)
Weight of rockery
Surcharge force from traffic loading
Inter-rock friction
Seismic loading
Base rock-foundation friction
Hydrodynamic forces

13. Case Number
Flow Height, ft
Inlet Velocity, ft/s
Inlet Angle, deg.
Fill Material(1)
Case 1 12 14
Granular Fill
Case 2
Void
Case 3 20
Case 4 7
11.5
Case 5
(1) Flow velocities within the porous granular fill are usually very low as compared to the main flow. Conservative results are obtained if a narrow void is developed behind the rocks ending at a rough continuous wall that allows for some flow.

14. INNOVATIONS -Geotechnical
Blasting & Excavation

15. INNOVATIONS –Geotechnical –Bridge – Hydraulics
Bridge Foundations –
Collaboration of Hydraulics, Geotechnical and Bridge Disciplines. Bridge – GRS vs Concrete,
Used Worst case scenario for abutment design, used same design for all abutments

19. INNOVATIONS - Bridge
Because crossings were on tangents and curves, bridge worked with roadway to develop a standard width for all bridges
Standardized wingwall flares and made abutments reversible (i.e., same at each bridge) Kept most rebar the same bridge to bridge.
Bridge & Hydraulics worked together to standardize the bridge skews to fall at 20, 30 , or 40 degrees. Only needed 3 bridge designs, not 12.
Girder manufacturer helped determine 1 girder section for all bridges

20. How was the Team Able to Incorporate so Many Innovations?
Respect
Trust
Interdependence
Emotional Intelligence
Continuous Communication
Goal Oriented

21. Questions?