program for replacing earthen levees with megamold ...€¦ · by. frank k. johnson, p.e. /dr....
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ByFrank K. Johnson, P.E. /Dr. Minhaj Kirmani, P.E.
Program for Replacing Earthen Leveeswith
MegaMold® Monolithic Composite Concrete & Steel Flood Control Structures
State of LouisianaOffice of Coastal Protection and Restoration
Louisiana Applied Coastal and Engineering Sciences Division
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Presented to
MegaMold® Levee Replacement Program
Louisiana Coastal Master Plan Objectives
Reduce economic and community losses due to storm based flooding
• Protect concentrated assets• Protect distributed assets• Protect strategic assets
CPRA Plan
Seeking comprehensive solutions that achieve the dual objectives of • Coastal restoration• Hurricane protection
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Current Earthen Levees Fail to Protect Against Catastrophic Flooding
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Earthen Levee
Overtopping due to limited heights
Breached by surface erosion
Security dependent on maintenance
Levee Failure During Hurricane Katrina
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I-Walls
Overturned due to limited passive pressure with additional unanticipated hydrostatic pressure in gaps along face
Overtopping causing erosion contributed to the loss of passive pressure
Levee Failure During Hurricane Katrina
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Increase the height of existing earthen beams;
Long history of use;
Relatively Inexpensive materials;
Stable configuration
Conventional Means for Protecting Community Against 100-Year Storm
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T-Walls to replace I-Walls
Strong
Resists Erosion
Limited footprint
Flood Walls Constructed atop Existing Earthen Levees to Provide Protection Against 100-Year Storm
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HWL
CanalExisting Levee
Raised Levee
Existing Width
Increased Width
Requires Land
Significant weight may cause settlement problems
Urban truck traffic
And still erodible
Earthen Berm Disadvantages
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Very expensive construction
Time consuming construction
Requires pile support
T-Wall Disadvantages
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Flood Control
Permanently eliminate the threat of catastrophic flooding in low lying urban areas
Coastal Restoration
Prevent erosion and facilitate restoration of coastal areas
MegaMold® Objectives
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MegaMold® Monolithic Composite
Concrete & Steel Flood Control Structure
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Ideal for replacing either earthen levees or flood walls
Possible to design for 500 year storm
Stronger and more durable than earthen structures
Faster more economical construction
Multi-functional
MegaMold ®Monolithic Concrete & Steel Composite
Flood Control Structures
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A Simplified Means for Constructing Composite Monolithic Cast-in-Place Concrete Flood Control Structures Underwater
Introduction
The MegaMold® AdvantageModular Stay-in-Place Construction MoldsModular Structural Steel Molds for Constructing Monolithic Concrete Structures
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Pilot Project Installing MegaMold ® Stay-in-Place Flood Control Construction Mold Module
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Pilot Project Casting Concrete into MegaMold ® Stay-in-Place Flood Control Construction Mold Module
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Pilot Project Casting Roof Slab Concrete into MegaMold® Stay-in-Place Flood Control Construction Mold Module
confidential
Pilot Project Completed Construction: Monolithic Composite Concrete and Steel Flood Control Segment
(in less than 8 hours)
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Accelerate construction of cast-in-place concrete works;
Increase productivity at work site using off-site fabrication of modular structural components;
Simplify planning and scheduling of field operations;
Reduce weather related delays;
Minimize traffic disruption during construction;
Reduce infrastructure development costs;
Provide long term protection against corrosion and deterioration;
Reduce long term maintenance costs;
Meet or exceeds FHWA and AASHTO standards.
The MegaMold® AdvantagesModular Stay-in-Place Construction Molds
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The MegaMold ® AdvantageModular Stay-in-Place Construction Molds
Eliminate Costly Conventional Construction Practices
No Rebar Work on Site No Formwork and Shoring Work on Site
No Incremental Construction
Panelized Encasement Component Structural Steel
Component
Composite Module
MegaMold®Modular Stay-in-Place
Construction Mold
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Typical Applications
FRP Buildings
Bridge Decks
Platforms and Walkways
Bridge Enclosure Systems
Tank Covers
Cellular Enclosures
Secondary Containment
MegaMold®Fiber Reinforced Plastic (FRP) Panelized Encasement
Elements
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Existing Channel Bottom
Existing Condition
MegaMold® Monolithic Cast-in-Place Concrete Flood Control Structure
Typical Construction Sequence
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Dredging to Base Soil
MegaMold ® Monolithic Cast-in-Place Concrete Flood Control Structure
Typical Construction Sequence
23Dredging
Place Leveling Pad
Install MegaMold ® Modular Construction Mold
Module Installation
MegaMold ® Monolithic Cast-in-Place Concrete Flood Control Structure
Typical Construction Sequence
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Place Gravel Subgrade
Backfill Base Material
MegaMold ® Monolithic Cast-in-Place Concrete Flood Control Structure
Typical Construction Sequence
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Cast Concrete Foundation Slab
MegaMold ® Monolithic Cast-in-Place Concrete Flood Control Structure
Typical Construction Sequence
26Tremie Concrete Construction
Controlled Concrete Fill
Continue Casting Concrete Walls
MegaMold ® Monolithic Cast-in-Place Concrete Flood Control Structure
Typical Construction Sequence
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Final Concrete Placement
Dewater for Backfilling
Continue Casting Concrete Roof Slab
MegaMold ® Monolithic Cast-in-Place Concrete Flood Control Structure
Typical Construction Sequence
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Place Backfill
Final Condition
MegaMold ® Monolithic Cast-in-Place Concrete Flood Control Structure
Typical Construction Sequence
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Monolithic concrete construction
Lightweight
Stable configuration
Compatible with sheet pile cutoff
Additional Benefits
Rapid construction
Versatile configuration
Construction in the wet
Multi-functional
MegaMold ®Monolithic Cast-in-Place Concrete & Steel Composite Flood Control Structures
Combine the Advantages of Earthen Berms and T-Walls
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MegaMold ®Monolithic Cast-in-Place Concrete & Steel Composite
Flood Control Structures
Permanently eliminate the threat of catastrophic flooding from 500-year storms or greater;
Are more durable and reliable than earth, sand and rock structures;
Are not subject to overtopping, breaching or undermining;
Are more economical to construct than repairing and upgrading existing earthen levees;
Are custom-engineered to serve as all-weather roadways, protected utility corridors, and/or foundation structures for commercial and residential buildings.
Are constructed quickly without stressing the environment or local community
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Analysis of a Typical Gulf Coast Condition17th Street Outfall Canal
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Composite Concrete Cofferdam
Feasibility Study
New Orleans
Levee Replacement Program
Weidlinger Associates, Inc. Cambridge, MA
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MegaMold®
Typical Section and Soil Profile of Existing17th Street Outfall Canal Levee
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Proposed MegaMold® concrete cofferdam
Existing levee
FILL
ORGANIC GRAY CLAY
SAND
Finite Element Model
Existing Levee and MegaMold® Flood Control Structure
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Finite Element Mesh
Existing Levee and MegaMold® Flood Control Structure
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Original Condition
ORGANIC SOILSGRAY CLAY
SAND
Stage by Stage Analysis
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Construction of Present Levee
Tot
al D
isp
lace
men
t (f
t)
Stage by Stage Analysis
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Dredging at toe prior to installation ofMegaMold ® Flood Control Structure
Tot
al D
isp
lace
men
t (f
t)
Soil to be removed
Stage by Stage Analysis
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Tot
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isp
lace
men
t (f
t)
Construction of MegaMold ® Flood Control Structure
Completed concrete cofferdam
Stage by Stage Analysis
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Tot
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isp
lace
men
t (f
t)
Removal of existing levee
Stage by Stage Analysis
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Dewater and Fill between Levee and MegaMold ® Cofferdam
Tot
al D
isp
lace
men
t (f
t)
Proposed backfill soil after completion of MegaMold ® concrete cofferdam
Stage by Stage Analysis
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Final condition
Tot
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isp
lace
men
t (f
t)
Stage by Stage Analysis
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A
B
Predicted Horizontal Displacement Increment at Flood Level
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Predicted MegaMold® Concrete Cofferdam Displacement Increments
at Flood Level
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” Hmax =0.42 in
” Vmax =0.03 in
The MegaMold® Solution
Prevent Catastrophic Flooding
Contain Waters of Outfall Canal Between Two MegaMold ®
Monolithic Concrete & Steel Flood Control Structures
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