Design of Geofoam Embankment for the I-15 Reconstruction I 15 - PowerPoint PPT Presentation

Design of Geofoam Embankment for the I-15 Reconstruction I 15 Reconstruction Steven F. Bartlett, Ph.D., P.E. Research Project Manager, UDOT

I-15 Reconstruction - Quick Facts Si Single Largest Highway Contract in U.S. l L t Hi h C t t i U S • • 17 Miles of Urban Interstate • $1 5 Billion Design-Build $1.5 Billion Design Build • 4 Year Construction Duration (Summer 2001) • 144 Bridges/Overpass Structures g p • 160 Retaining Walls (mostly MSE Walls) • 3.8 Million m 3 of Embankment Fill • 100,000 m 3 Geofoam Embankment 3 G 100 000 f E b k

Primary Uses of Geofoam on the I-15 Project • Reduce Settlement to Protect Buried Utilities • Improve Slope Stability of Embankments • Rapid Construction in Time Critical Areas • Rapid Construction in Time Critical Areas

Settlement Reduction (continued) Subsurface Profile in Salt Lake Valley CPT Tip Resistance, kPa 0 5000 10000 15000 20000 25000 30000 35000 40000 0 Alluvium 5 10 Soft Bonneville Clay Clay (10- (m) 15 Pleistocene Alluvium m thick) m thick) Depth 20 25 Cutler Clay y 30 35 40 40

Settlement Reduction (continued) Settlement on I-15, Salt Lake City (1964 - 1968) , y ( ) 11.6 m 11.6 m Fill Height 2.5 year duration 1.4 m Settlement Primary Settlement

Settlement Reduction (continued) Buried Utilities B Buried Pipeline i d Pi li NEW FILL NEW FILL Buried Pipeline Buried Pipeline Ruptured Pipeline

Settlement Reduction (continued) Buried Utilities along Roadway g y Buried Utilities Utilities Geofoam Embankment from State St. to 200 W. Along Interstate I-80, Salt Lake City, Utah

Improve Slope Stability (continued) Diagram of Potential Instability at Bridges ag a o ote t a stab ty at dges cracks Bridge Deck Failure surface Soft Clay Soft Clay

Improve Slope Stability Details of Geofoam Construction at Bridge Abutments

Rapid Construction (Typical Embankment Construction for I 15) (Typical Embankment Construction for I-15) Geotechnical Wic k Dra ins T ypic a l Wic k Dra in C L 1/2 SLOPE WIDTH NEW EMBANKMENT SHOULDER MINIMUM NEW NEW 1.5 1 5 1.5 SURCHARGE EMBANKMENT 1 1 2 1 EXISTING EMBANKMENT GEOTEXTILE WICK DRAINS

Rapid Construction (Typical Embankment Construction for I-15) (Typical Embankment Construction for I 15) Wick Drain Installation (4 weeks) Grading and Geotextile (4 weeks)) Wall Construction + Settlement Time Concrete Panel Placement (2 weeks) (6 weeks + 24 weeks)

Rapid Construction (Typical Geofoam Construction for I 15) (Typical Geofoam Construction for I-15) 35 cm Concrete Pavement 60 cm Base Material Tilt-up 15 cm Reinforced Concrete Concrete Load Distribution Slab Fascia Fascia Panel Wall Geofoam Block Sloped Embankment (1.5 H to 1 V max.) Wall Footing Bedding Sand (20 cm min.)

Rapid Construction (Typical Geofoam Construction for I-15) (Typical Geofoam Construction for I 15) Block Placement (3 weeks)) Grade Preparation (1 week) Load Distribution Slab Panel Wall Construction (1 Week) Construction (2 weeks)

Rapid Construction (Comparison of Construction Time) (Comparison of Construction Time) 35 (Weeks) 30 Conventional Geofoam 25 tion Time 20 15 Construct 10 5 5 C 0 ation Work ment Total ction Settlem Finish W Prepara T Construc

Design Considerations • Material Type Material Type • Moisture Absorption Moisture Absorption • Dimensions • Buoyancy • Density • Thermal Resistance • Compressive Strength C i St th • Differential Icing Diff ti l I i • Allowable Load & Creep • Chemical Attack • Interface Friction • Flammability • Stability of Internal Slope • Insect Infestation • Bedding Material & Compaction • Ultra Violet Degradation • Concentrated Loads Concentrated Loads • Durability Durability

Design Considerations (Material Type) ( yp ) • Expanded Polystrene (EPS)* Expanded Polystrene (EPS) • virgin feedstock • maximum of 5 percent regrind content i f 5 t i d t t * Extruded Polystrene (XPS) is also available, but was not used on the I-15 project

Design Considerations (EPS Block Dimensions) ( ) 81 cm 488 cm 122 cm Dimension tolerance 0.5 percent Dimension tolerance 0.5 percent • If tolerance is met, no trimming is necessary • If tolerance is not met shop trimming is necessary • If tolerance is not met, shop trimming is necessary

Design Considerations ( (EPS Density) y) Property ASTM Type XI Type I Type VIII* Type II Type IX Test Test C 578 Nominal C303 / D 12 16 20 24 32 Density 1622 (kg/m 3 ) Minimum C303 / D 11 15 18 22 29 Density 1622 (kg/m 3 ) 3 ) (k / * Type VIII was used for I-15 Reconstruction

Design Considerations ( (EPS Minimum Compressive Strength) p g ) Property ASTM Type XI Type I Type VIII Type II Type IX Test kPa C 165 / 35 69 90* 104 173 (10% (10% D 1621 D 1621 Strain) * Type VIII was used for I-15 Reconstruction St Strain Rate for Testing = 5 mm / minute i R t f T ti 5 / i t

Design Considerations (EPS Minimum Compressive Strength (EPS Minimum Compressive Strength Versus Density) (Source: Bartlett et al. 2000)  d = 7.3 * D - 47 where D = Density in kPa.

Design Considerations ( (Allowable Stress and Creep) p) Source: Negussey (1997) Type VIII Type VIII EPS  d = stress 0.4  d 0.4  d @ 5% strain Simplified Formula : * Allowable Stress Must Allowable Stress = 0.4  d Maintained Below 1% Allowable Stress = 0.4 x 120 = 48 kPa Axial Strain to Minimize Long-Term Creep

Design Considerations (Allowable Stress and Creep) ( p) Allowable Stress (Dead Load + Live Load) < 0.4  d Dead Load = Weight of Load Distribution Slab + Dead Load Weight of Load Distribution Slab + Weight of Base Material + Weight of Pavement. Dead Load = 30 % of  d = 0.3  d Live Load = Traffic Loads Live Load = 10 % of  d = 0.1  d

Design Considerations (Creep Data from Norway) ( p y) Measured Data (3.5 years) Theoretical Model (Source: Aaboe, 2000)

Design Considerations (Creep Data from Norway) ( p y) Theoretical Model Theoretical Model (Source: Aaboe, 2000)

Design Considerations (Interface Friction) ( )  n Lateral Force EPS BLOCK  • Interface Friction Need for Design Against Sliding  =  n tan   = sliding shear resistance g  n = normal stress tan  (Design Value)  degrees (Design Value)  degrees (Design Value)

Design Considerations (Interface Friction) ( ) D Design Value = 31 deg. i V l 31 d Source: Negussey (1997) Source: Negussey (1997)

Design Considerations ( (Stability of Internally Sloped y y p Embankments) Back Slope 1.0 Vertical 1.0 Vertical Force = 0 1.5 Horizontal 1 5 Horizontal (Do Not Allow (Do Not Allow Transfer of Horizontal M Maximum Back Slope = 1.5 H to 1.0 Vertical i B k Sl 1 5 H t 1 0 V ti l Force) for Embankment to Guarantee Internal Slope Stability

Design Considerations (Stability of Internally Sloped ( y y p Cuts and Hillsides) Reinforced Slope Soil Nails, Soil Anchors, or Other or Other Reinforcement Cut Slope or Cut Slope or Landslide

Design Considerations (Bedding Material and Compaction) ( g p ) Bedding Sand Function g • free draining sand or fine gravel • provides leveling course • provides drainage id d i Bedding Sand (20 cm min.)

Design Considerations (Bedding Material and Compaction) ( g p ) Gradation Specification for Bedding Sand Gradation Specification for Bedding Sand Sieve Size Sieve Size 50mm 50mm 13mm 13mm 6mm 6mm 2mm 2mm 0.425mm 0.425mm 0.075 mm 0.075 mm % Passing 95 - 100 65-100 50-100 40-70 10-40 0-5 (Percent Passing) * Materials with more than 20 percent of the samples containing between5 and 7 percent minus 0.075 mm material shall not be between5 and 7 percent minus 0.075 mm material shall not be accepted for use.

Design Considerations (Bedding Material and Compaction) ( g p ) Light Weight Light-Weight Compaction Grade Preparation and Leveling Equipment (*Maximum lift thickness = 20 cm)

Design Considerations (Concentrated Loads) ( ) • Uncovered geofoam damages easily from tire loads • Do not use heavy equipment atop geofoam until the load distribution slab is placed • Use light-weight construction equipment g g q p • Protect with plywood sheeting

Design Considerations (Moisture Absorption - Above High ( p g Groundwater Elevation) (Source: Aaboe, 2000)

Design Considerations (Moisture Absorption - Below ( p Groundwater) (Source: Aaboe, 2000)

Design Considerations (Moisture Absorption (Moisture Absorption - Design Values) Design Values) • Installation of EPS above high groundwater • Design Moisture Content = 1 percent by volume • Installation of EPS that is periodically submerged • Design Moisture Content = 5 percent by volume Design Moisture Content 5 percent by volume • Installation of EPS below groundwater • Design Moisture Content • Design Moisture Content = 10 percent by volume 10 percent by volume

Design Considerations (Buoyancy) (Buoyancy) F resisting resisting 100-year groundwater design flood event F uplift Drainage Sand F resisting = 1.3 x F uplift