geosynthetics applications in civil engineering by sirmoi_geosynthetics ea ltd
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A presentation on the use of geosynthetics in civil engineering. An introduction to value engineering technologiesTRANSCRIPT
Geosynthetics Applications in Civil Engineering; An Introduction to value Engineering (VE) Technologies
Solutions that Last
GEOSYNTHETICS EAST AFRICA Ltd
TEXTILE AND LEATHER CONFERENCE 2013 ORGANIZED BY KENYA BUREAU OF STANDARDS VENUE :BOMA HOTEL DATES: Thursday, 29th August 2013
Presentation:
Sirmoi Wekesa Technical Director Geosynthetics EA Ltd
Introduction to Geosynthetics
Part I
ASTM (2006) D 4439 defines a geosynthetic as a planar product manufactured from a polymeric material used with soil, rock, earth, or other geotechnical-related material as an integral part of a civil engineering project, structure, or system.
A number of geosynthetics are available, including geotextiles, geogrids, geomembranes, geonets, geomeshes, geowebs, and geocomposites.
DIFFERENT TYPES OF GEOSYNTHETICS
Geotextile Geonet Geocell Geogrids
Geocomposite Erosion Control Geosynthetics
GEOGRID TYPES
Different Types of Geogrids used for ground
Improvement:;; and
(a) Triaxial (b) Biaxial (c) Uniaxial
New Four-axial New Quaxial
Applications Of Geosynthetics
GROUND STABILIZATION/ IMPROVEMENT
GROUND STABILIZATION/ IMPROVEMENTβ¦.CNTD
PAVEMENTS: ROADS, PARKING BAYS, HARD STANDINGS
PAVEMENTS: RUNWAYS, APRONS & TAXIWAYS
HEAVY DUTY PAVEMENTS: PORTS AND HABOURS
PAVEMENTS: ASPHALT REINFORCEMENT
RAILWAYS
EROSION CONTROL
RETAINING, RE WALLS AND BRIDGE ABUTMENTS
BUILDING FOUNDATION IMPROVEMENTS
VALUE ENGINEERED BENEFITS
VALUE ENGINEERING BENEFITS
Construction cost-time savings through the reduction of required pavement material quantities, whilst maintaining enhanced structural performance.
Elongated pavement structural life β span particularly as a result of incorporating the filtration/separation geotextile.
Reduction in maintenance requirements as a result of enhanced structural performance.
Environmental conservation - mainly due to reduction in material quantities and erosion control.
Appropriate application of
geosynthetics can realize the
following benefits.
Construction Time Savings Benefits
Enhanced Geotechnical Engineering Properties
VALUE ENGINEERED BENEFITS Description Quantity placed per day
[m3]
Area [m2] Layer thickness[m] Quantity in volume [m3] Time taken in Days [in
weeks]
Import place and
compact ground
stabilization material
[cement]
300 311,550 0.2 62,310 200 days [28weeks]
Import place and
compact granular
material for sub-base
193 311,550 0.4 124,620 646 days
[92 weeks]
Excavation to spoil of
poor quality material
1000 51,031 1.5 76,546.50 77 days
[11 weeks]
Import, place and
compact capping layer or
backfill material
578 51,031 2.0 102,062 177 days
[25 weeks]
TOTAL DURATION TAKEN TO CONSTRUCT THE PAVEMENT* 156 weeks
VALUE ENGINEERED BENEFITS Description Quantity placed
per day [m3]
Area [m2] Layer
thickness[m]
Quantity in
volume [m3]
Time taken in
Days [in weeks]
Import place
and compact
granular
material for
sub-base
193 311,550 0.3 93,465 484 days
[69 weeks]
Top Soil
stripping and
disposal or
grading*
680 51,031 0.15 7,654.65 12 days
[2 weeks]
TOTAL DURATION TAKEN TO CONSTRUCT THE PAVEMENT* 71 weeks
*This might not be necessary especially if the water table is very high. Grading normally
helps to create the platform for grid placement.
β’ Time saved is approximately 50%.
Construction Cost Savings Benefits
Enhanced Geotechnical Engineering Properties
VE BENEFITS β ROAD OVER SWAMP CROSSING
The proposed road was crossing a 1.2km swampy stretch.
The soils were peat with low bearing capacities with CBRs of about 0.5%.
The design assumed the peat thickness to be 1.0m before getting on to hard ground.
The actual thickness was deeper than 1.0m; instead it went beyond 3m.
The contractor wanted to finish the section before the rains started.
VE BENEFITS β ROAD OVER SWAMP CROSSING
COST AS PER CONVENTIONAL DESIGN
DESCRIPTION UNITS LENGTH[m] WIDTH[m] DEPTH[m] QUANTITY RATE TOTAL
Excavate 1m thick to spoil m3 1200 15 1 18000 $ 5.33 $ 96,000.00
Fill 1m thick of rock m3 1200 15 1 18000 $ 16.00 $ 288,000.00
TOTAL AMOUNT $ 384,000.00
VE BENEFITS β ROAD OVER SWAMP CROSSING
COST AS PER THE GEOSYNTHETICS DESIGN
DESCRIPTION UNI
TS
LENGT
H[m]
WIDTH
[m]
DEPTH
[m] QITY RATE TOTAL
Tensar TX 170 Geogrids
[Supply and Placement] m2 1200 15 - 18000 $ 13.26 $ 238,653.60
TOTAL AMOUNT AS PER THE TENSAR PROPOSAL
$ 238,653.60
AMOUNT SAVED $ 145,346.40
PERCENTAGE OF AMOUNT SAVED [%] 37.85 %
VE BENEFITS β ROAD OVER SWAMP CROSSING
TRAFFIC BENEFIT RATIO (TBR)
ππππ18 = ππ Γ π0 + 9.36 Γ πππ ππ + 1 β
0.2 +πππβπππΌ
2.7
0.4+1094
ππ+15.19
+ 2.32 Γ πππππ β 8.07
π18π = ππππππ π¬πΊπ¨π³ ππππππ
π18π /π
= πππππππ π¬πΊπ¨π³ ππππππ
ππ΅π =ππ /π
25ππ
ππ 25ππ = ππ. ππ
π18ππππππππππ= ππ΅π Γ π18π’πππππππππππ
=
πππππππ π¬πΊπ¨π³ ππππππ
The AASHTO method , which considers the
pavement as a multi-layer elastic system with
an overall structural number (SN) that reflects
the total pavement thickness and its resiliency
to repeated traffic loading, is employed.
VERIFICATION OF TRAFFIC BENEFIT RATIO (TBR) AND BASE COURSE REDUCTION (BCR)
Determination of TBR and BCR based on Base Course remaining life structural thickness
0
250
0.0 1.0 2.0 3.0 4.0 5.0 6.0
Rem
ain
ing
Life
Bas
e C
ou
rse
Stru
ctu
ral
Thic
knes
s, fsc
XTD2
No. ESAL Load Cycles (Traffic Passes) X106
Remaining Life Base Course Structural Thickness
Thickness StructuralDepreciation Curves
Terminal Thickness
Unreinforced
Unreinforced EXTRAPOLATED
Curve
125mm
102.0mm
200mm
Scenarioβ’ No. filtrations/separation/reinforcement geosynthetics in unreinforcedβ’ Loss in base course structural thickness predominantly due to black cotton soil ingressionβ’ Reinforced pavement structure includes geotextile for filtration/separation and stress mobilization of black cotton soil
152mm
Legend
β’ = Remainig Life Layer Coefficient Ratio
β’ = Design Thickness
β’ = Reinforced Design Thickness
β’ = Unreinforced Design Thickness
β’ = Reinforced Structural Capacity Factor
β’ = Unreinforced Structural Capacity Factor
Premature FAILURE due to BCS subgrade
Geosynthetics Reinforced
Example of Structural Benefits
Enhanced Geotechnical Engineering Properties
Comparison of Unreinforced and Reinforced UCS for swampy BCS for Drilling Project of White Nile Oil in Jonglei State, Southern Sudan
No. Unreinforced [Mpa]
Reinforced [Mpa]
Description % Increase Remarks
1 1.45 No soil reinforcement
2 1.45 2.1 Geogrid SS20G, 1/3H 45 >30<100
3 1.45 2.15 Geogrid SS20G, 1/5H 48 >30<100
4 1.45 2.2 Double Geogrid SS20G, 1/3H, 2/3H
52 >30<100
5 1.45 1.55 Mat 1/3H 7 >30<100
6 1.45 1.85 Mat 1/5H 28 β30<100
7 1.45 2.1 Double Mat 1/3H, 1/5H 45 >30<100
NEAT BLACK COTTON SOIL SAMPLES
Comparison of Unreinforced and
Reinforced UCS for swampy BCS for
Drilling Project of White Nile Oil in
Jonglei State, Southern Sudan
White Nile Oil in Jonglei State, Southern Sudan
Value Engineering Benefits-Environmental Benefits
Subgrade Improvement β Reduction in Quantity of Capping Layer
πππΊππΆππ
= 2253 Γ π β0.455Γ2= πππππ πππΊππΆππ
= 2253 Γ π β0.455Γ9= ππ. πππ
Capping Layer
With Geosynthetic reinforcement Without Geosynthetic Reinforcement
Projects in Kenya
PROJECT MATERIALS YEAR
1. Garsen Bridge
Gauff β China Roads and Bridges
Tensar GM Tube Gabions 1987
2. Garsen / Lamu Junction
Gauff
Asphalt Reinforcement
Experimental Tensar AR1 grids
1987
3. Aberdares β Nairobi Pipeline
Horward Humphreys β Sogea
Soil Erosion Control
Tensar Mat
1989
4. Thika β Makutano
Gibbs β TM AM
Swamp Crossing Reinforcement
Tensar SS2 Biaxial Geogrids
1990
5. Westlands β Limuru Dual Carriageway
Gauff β Federecci
Embankment Reinforcement
Tensar SS2 Biaxial Geogrids
1991
6. Westlands β Limuru Dual Carriageway
Gauff β Federecci
Asphalt Reinforcement
Tensar AR1 Geogrids
1992
7. Eldoret β Burnt Forest Reconstruction
Gauff - Strabag
Swamp Crossing Reinforcement
Tensar SS2 Biaxial Geogrids
1993
8. Webuye β Malaba Reconstruction
Nicholas OβDwyer β Federecci
Swamp Crossing Reinforcement
Tensar SS2 Biaxial Geogrids
1993
9. Baricho β Mombasa Access Pipeline Rd
Gauff β Sogea
River Crossing Embankment
Tensar SS2
1998
10. Garsen β Lamu Road
Gauff β China Road and Bridge
Embankment Reinforcement
Tensar SS30-SS40 and 55RE
2003
11. Meru β Mikinduri β Maua Road [Phase 1]
KeRRA β H-Young & Co EA
Slope Protection & Erosion Control
Tensar T-mat 400
2010
12. Lake Turkana BGP Marine Seismic Project
BGP _ Tullow Oil Company
Construction of sand access roads and heavily loaded plat
forms β Tensar TriAx TX 160
2012
Projects in Uganda
PROJECT MATERIALS YEAR
1. Kabale β Katuna Road
Typsa OβSullivan & Graham β Stirling
Slip Failure Reconstruction with Tensar Geocell Mattress 1999
2. Kabale β Katuna Road
Typsa OβSullivan & Graham β Stirling
Slip Reinforcement wrap around
Tensar RE uniaxial Geogrid
2000
3. Kampala β Masaks Road
Stirling
Swamp Crossing Embankment
Tensar SS20 Biaxial Geogrid
2000
4. Mbarara β Ibanda Road
ACE Engineers - Energoprojekt
Embankment Failure Reconstruction
Tensar SS20 Biaxial Geogrid
2000
5. Malaba β Bugiri Road
Gauff - Strabag
Swamp Crossing Reinforcement
Tensar SS2 Biaxial Geogrids
2000
6. Fort Portal β Kyejojo Road
ACE Engineers - Energoprojekt
Embankment Failure Reconstruction
Tensar 80RE
2001
7. Kabala Water Project
Bella Consult - Spencon
Tensar SS30 2001
8. Semliki Oil Drilling
BMS Mineral Services
Tensar SS30 2002
9. Bugiri β Jinja Road
Gauff β Basil
Embankment Widening over Black Cotton Soil
Tensar SS20Biaxial Geogrid
2004
10. Kampala Relief Road
BCEOM - Salini
Embankment Foundation Reinforcement over Swamps
Tensar SS20Biaxial Geogrid
2005
11. Kampala Ring Road
Salini
Swamp Crossing reinforcement
Tensar TriAx TX 160 Geogrid
2010
Projects in East and Central Africa than have utilized Geosynthetics
Timboroa β Eldoret Road [1993]
Webuye β Malaba Road [1993]
Thika β Makutano Road [1990]
Westlands β Limuru Dual Carriageway [1992]
Garsen β Lamu Road [2003]
Meru β Mikinduri Road [2010]
Isiolo Airport [2011]
Tullow Oil β Loading Platform for Oil rigs and Access Roads in Lake Turkana [2012]
Kabale β Katuna Road [1999]
Mbarara β Ibanda Road [2000]
Malaba β Bugiri Road [2000]
Kampala Relief Road [2005]
Bugiri β Jinja Road [2004]
THANK YOU
BY SIRMOI WEKESA
Technical Director and Civil Engineer,
GEOSYNTHETICS EA LTD
Email: [email protected]