Transcript here - UC Connection

Grade Separation Alternative
A Feasibility Analysis of the
Reconfiguration of Genesee
Avenue at Governor Drive
By: Daniel Aruta, P.E.
Topics for Discussion:
•
•
•
•
What is a Grade Separation?
Construction Impacts
Traffic Analysis
Environmental Impacts
PART 1: What is a Grade Separation?
•
•
•
•
•
A facility which provides a physical vertical separation between two
roadways crossing each other to alleviate traffic congestion and
promote safety
One roadway passes over another crossing roadway, and both
roadways do not meet
The upper roadway crosses over the lower roadway via a bridge
Similar to a diamond interchange on a freeway
A Grade Separation is not a tunnel!
University Avenue in Park Slope
Sample of a Grade Separation
Diamond Interchange of Interstate 15 at El Cajon Blvd in San Diego
El Cajon Blvd
5 Basic Elements of a Grade Separation
Interstate 15 at El Cajon Blvd in San Diego
Bridge
Retaining
Wall
Retaining
Wall
Depressed
Roadway
Ramp
5 Basic Elements of a Grade Separation
Interstate 15 at El Cajon Blvd in San Diego
Retaining
Wall
Ramp
Depressed
Roadway
Bridge
Retaining
Wall
Genesee Ave Grade Separation at Governor Dr
•
•
•
•
•
•
Bridge on Governor Dr passes over Genesee Ave below
2 Lanes on Genesee Ave are depressed to pass under the bridge
4 Ramps
Inside Retaining Walls (4 each)
Outside Retaining Walls (minimum of 4 each)
Total Length from end to end = 1,787 ft.
Begin Walls
Depressed Roadway
Inside Retaining Wall
Ramp
Outside Retaining Wall
Bridge
Plan View
North
Begin Walls
Vertical Separation
•
•
•
Governor Dr above Genesee Ave
2 inside lanes of Genesee Ave below Governor Dr
A bridge over a depressed roadway
Vertical Scale is
Exaggerated!
Existing Roadway
Governor
Drive
Depressed Roadway
Begin Grade Separation
End Grade Separation
Vertical Profile View
Section Through Bridge
Section where Genesee Ave passes under the bridge at Governor Dr
•
•
Length of Bridge (Span) = > 50 ft.
Width of Bridge = ± 110 ft.
Section View
Section Through Retaining Walls
Section of Genesee Ave north and south of Governor Dr (beyond bridge)
Section View
Lengths of Retaining Walls
Inside Retaining Walls:
•
•
South of Governor Dr: 731 ft. long, max height greater than16.5 ft.
North of Governor Dr: 936 ft. long, max height greater than16.5 ft.
North
731’
936’
Plan View
Part 2: Construction Impacts
•
•
•
•
•
•
Utility Relocation
Constructing the Bridge
Constructing the Retaining Walls
Road Closures
Environmental Impacts
Project Duration
Utility Relocation
Two 16” Water Mains
8” Sewer
Electrical Duct Bank
Gas Line
Phone Cables
Water
Phone
Elect
Gas
Governor Dr
•
•
•
•
•
N
Sewer
Water
Phone
Genesee Ave
Constructing the Bridge
•
Drive Sheet Piling into the Ground
Sheet Piling
Section View
Constructing the Bridge
•
•
Drive Sheet Piling into the Ground
Excavate Pit for the Bridge
Section View
Constructing the Bridge
•
•
•
Drive Sheet Piling into the Ground
Excavate Pit for the Bridge
Construct the Bridge
Section View
Constructing the Retaining Walls
•
•
•
•
Drive Sheet Piling into the Ground
Excavate Channel
Construct Inside Retaining Walls and Depressed Roadway
Construct Outside Retaining Walls for Sideslopes and Outside Roadways
Section View
Extent of Sheet Piling in Genesee Ave
For Depressed Roadway: Approx. 1,100 ft. each side of depressed road
For Outer Retaining Walls: Lengths will vary
North
Depressed Roadway
Sheet Piling
Plan View
Environmental Impacts to Consider During
Construction
Impact
•
•
•
•
•
Noise
Vibration
Air Quality
Truck Trips
Contaminated Soils
Example
•
•
•
•
•
Backup Bells on Construction Equipment
Driving Sheet Piling
Diesel Exhaust from Construction Equipment
Thousands of Truck Trips
Soils Mitigation from 4 Gas Stations – Project Delay
Project Duration
•
•
•
•
Utility Relocation = 6± months
Mitigation of Contaminated Soils = ?
Construction of Grade Separation = 2± years
Total Project Duration = 2.5+ years
Road Closures during Construction
•
•
Genesee Ave from Radcliff La to south of University City HS
Intersection of Governor Dr and Genesee Ave
Disruption to Vehicular and Pedestrian Traffic
Loss of Access to Schools and Businesses
Economic Hardship on Local Businesses
Huge Detriment to the Community
1,800 ft.
Plan View
North
•
•
•
•
North/South Access during Construction
•
•
•
No Bridge on Regents Rd
1,800 ft. of Genesee Ave closed
Intersection of Governor Dr and Genesee Ave closed
Police, Fire and
Paramedic Service
to University City
will be severely
challenged
during construction
Alternate Routes during Construction
•
•
•
Interstate 5 Freeway
Interstate 805 Freeway
State Route 52
Detour!
Part 3: Traffic Analysis – Post Construction
•
•
•
•
Existing Traffic Movements at Intersection of Genesee & Governor
Proposed Traffic Movements at Intersection of Genesee & Governor
Level of Service and Lane Reductions at Split Points
Elimination of Bus Stops
Existing N-S Traffic Lanes at Intersection
•
•
•
•
•
•
2 Southbound Through Lanes
2 Left Turns – SB Genesee to EB Governor
1 Southbound Right Turn
2 Northbound Through Lanes
1 Left Turn – NB Genesee to WB Governor
1 Northbound Right Turn
Existing Intersection
Proposed N-S Traffic Lanes at Intersection
•
•
•
•
1 Southbound Combined Through/Right Turn Lane
1 Left Turn – SB Genesee to EB Governor
1 Northbound Combined Through/Right Turn Lane
1 Left Turn – NB Genesee to WB Governor
Grade Separation
UC Golden Says:
…and…
Do The Math:
NB: 78% of 33,000 = 25,740 ADT
SB: 70% of 33,000 = 23,100 ADT
Street Classification and Level of Service (LOS)
•
•
•
Level of Service “E” = 10,000 ADT for 1 Lane
NB Traffic: 25,740 ADT > 10,000 ADT
SB Traffic: 23,100 ADT > 10,000 ADT
NB: 2.57 x Failure Volume
SB: 2.31 x Failure Volume
Lane Reduction at Split Point
Decision: Do I take the underpass or do I take the ramp to Governor Dr?
“Governor Dr ”
As most cars from two lanes
vie for position into one lane,
this will effectively create a
“lane reduction” at the split
point and traffic will back
up!
UC Golden:
Split Point
3 Bus Stops on Genesee Ave are Eliminated
Post Construction
Part 4: Environmental Impacts – Post Const.
•
•
•
Noise
Neighborhood Character
Tree Removal
Noise
•
•
Sound acoustics are accentuated off retaining walls
Increase in traffic volumes over time due to urban growth will increase
ambient noise levels
Neighborhood Character
•
•
•
•
University City is a residential community
Only small retail except for commercial district on Greenwich Dr
UC is not a major traffic generator like Golden Triangle
Grade Separation will “urbanizes” the character of the neighborhood
Should future University City appear like this?
Tree Removal
•
•
•
•
88 Conifer Trees
22 Eucalyptus Trees
5 Sycamore Trees
3 Others
118 trees will be removed
The End