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CHALLENGE ACCEPTED:A PROJECT REVIEW OF TDOT’S I‐24 INTERCHANGE AT BROAD AND MARKET STREET
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PROJECT TEAM
TDOT Structures Division Roadway Design
Geotechnical
TODAY’S AGENDA
1. Project Overview2. Challenges throughout the Design
Process• Geology• Field Exploration• Design Decisions
3. Project Communication4. Questions
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PROJECT OVERVIEW
CHALLENGES
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GEOLOGY
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GEOLOGY
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GEOLOGY
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BRIDGE #1
CHALLENGES
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FIELD EXPLORATION
• Interstate Traffic• Night Drilling• Foundry Sand• Other Rehabilitation Projects
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CHALLENGES
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BRIDGE / RETAINING WALL DESIGN
Retaining Wall #1
Bridge #1
Riverwalk
Railroad
Retaining Walls
Challenges:
• How many retaining walls do we have?
• Large Wall Heights
• Soft Soils – Settlement Concerns
• Limited ROW
• Conditions for Seismic Design (Extreme Limit State)
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RETAINING WALL #1 Height: 25‐26ft
RETAINING WALLS 2, 2A, 2B, AND 3A2
Slide 15
A2 add profiles of RW 2, 3, calloutAuthor, 10/27/2019
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RETAINING WALLS
Design Decisions:
• MSE Retaining Wall #1
• MSE / CIP for Other Walls
• Gravity Walls added later
• Excavation of Material and Replacement with Graded Rock
Bridge #1
• Geology –voids
• Difficult Driving
• Tip Elevations??????
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BRIDGE #1
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BRIDGE #1
• TDOT Loading Information• LRFD Bridge for Driving Conditions
R = 0.60 x 50 ksi x Area of the Pile (Good Driving Conditions)R = 0.50 x 50 ksi x Area of the Pile (Severe Driving Conditions)
• Based on the Geology and Material encountered assumed Severe Driving Conditions
• Discussion with Structural Engineers on Project adjacent
Solution:• Decision to increase the pile size to HP 14x73 but keep the loading of an HP 12x53
• Sequence of Construction considering proposed embankments
PROJECT COMMUNICATION
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• Open Communication ‐ Decisions should not be made in a vacuum
Structural Engineers
Roadway Engineers
Other Engineers in your field of Expertise
TDOT
• Design Process – Plan Reviews
• Constructability Reviews with Contractors
QUESTIONS?
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