Advanced Technology for Cyclones Storm Damage Risk ...
Transcript of Advanced Technology for Cyclones Storm Damage Risk ...
Advanced Technology for Cyclones Storm Damage Risk Reduction Systems and Flood
Protection Levees
Amir Shahkolahi
Global Synthetics, Brisbane, AustraliaE-mail: [email protected]
Drew Loizeaux
Propex, USAE-mail: [email protected]
Flood Protection Levees:OVERTOPPING OF THE L-550 LEVEE IN ATCHISON COUNTY, MISSOURI, DURING A MISSOURI RIVER FLOOD, JUNE 2011 (SOURCE: USACE).
Flood Protection Levees Armouring:• Armouring will increase resiliency against severe wave overtopping caused by
hurricane storm surges.
• Armouring will help reduce scour and protect the integrity of the flood defence structure when confronted with severe wave overtopping.
What is the best Armouring technique?
Armouring Types:• · Grass
• · Soil Cement Treatments
• · Erosion Control Blankets
• · Turn Reinforcement Mat
• · Rock Riprap
• · Gabions
• · Concrete Slope Paving
• · Open Stone Asphalt
• · Fabric Formed Concrete
• · Articulated Concrete Block (ACB)
Research Background:• In 2005: Cyclone/Hurricane Katrina,
Southeast Louisiana, Category 5.
• Approximately 80% of New Orleans was flooded.
• Flood depths exceeding 15 feet in many areas.
• Surge and waves caused 50 major levee
breaches
• Thirty-four of the city's pumping stations were
damaged,
• Rainfall: 14 inches in a 24-hour period.
• More than 1,500 lives were lost.
Research Background• In 2006: US Army Corps of Engineers (USACE) started the $14.5 Billion program,
“Hurricane and Storm Damage Risk Reduction System (HSDRRS)”
Focus:
Strengthening levees, floodwalls, gated structures and pump stations
Goal:
What is the most cost effective, environmentally friendly and high performance solution
Research Background• In 2005-2006: USACE used ArmrMax® Engineered Earth Armouring Solution
(EEAS) on Penn flood levee as the armouring system as a trial.
•What is ArmorMax® EEAS?
ArmorMax® Engineered Earth Armouring Solution (EEAS):
• Combination of:
Engineered Earth Anchors (EEA)
High Performance Turf Reinforcement Mat (HPTRM)
Research Background• In 2008:
Category 3 Cyclone, winds of 208 km/h
What happened to Penn levee
with ArmorMax® EEAS?
Research Background
• No damage and erosion occurred
• ArmorMax® EEAS could protect the levee
• As a results, USACE decided to investigate this system in details and in comparison to other systems
Research details:
Two phases:Phase 1: Full-scale field test: To investigate the requirements of HPTRMs to withstand installation and maintenance (e.g. mowing) loads
Phase 2: Full Scale Overtopping Test: To investigate the performance of these systems under real overtopping condition
Phase 1: Full-scale field test result• HPTRM minimum requirements:
Property Test Method Average Roll Value
Mass per unit area ASTM D6566 ≥ 288 g/m2
Thickness ASTM D6525 ≥ 7.6 mm
Light Penetration (% passing) ASTM D6567 ≤ 45%
Tensile Strength ASTM D6818 ≥ 45 kN/m
Elongation ASTM D6818 ≤ 65%
Resiliency ASTM D6524 ≥ 70%
UV Resistance @2500 hrs ASTM D4355 ≥ 80%
Phase 2: Full-scale Overtopping Test • Colorado State University (CSU)
• Can simulate average overtopping discharges as high as 370 l/s per m
HPTRM Opening/Light Penetration
HPTRMs with smaller percent light penetration (to a minimum necessary value) improved vegetation performance in hydraulic testing
Conclusion:• HPTRM reinforced vegetation systems perform as well as if not better than the rock
armour protection layers for hydraulic applications such as storm water channels and flood protection levees.
• A HPTRM solution is a more cost effective and environmentally friendly solution than traditional hard armour solutions.
• Engineered Earth Armouring Solution (EEAS) which consist of a High Performance Turf Reinforcement Mat (HPTRM) and Engineered Earth Anchors (EEAs) can increase the safety factor of the armouring system against hydraulic forces and also provide slope surface stability.
Conclusion:• Tensile strength is the key component for durability and long-term performance of
HPTRMs, especially for storm water and flood protection applications.
• FHWA minimum requirement for tensile strength of HPTRMs is 45 kN/m.
• UV resistance is another key parameter for the durability of HPTRMs.
• HPTRMs with smaller percent light penetration, improves the vegetation performance in hydraulic testing whether established from seed or turf.
• Light penetration of 10% as minimum and 50% as maximum is suggested for HPTRMs to provide the required short term and long-term performance.