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From page 466... ... 7-1 CHAPTER 7 DESIGN EXAMPLES Contents Introduction...................................................................................................................................7-2 Design Example 1 – Trapezoidal Geofoam Embankment............................................................7-2 Step 1 – Background Investigation ...........................................................................................7-2 Step 2 – Select Preliminary Eps Type and Assume a Preliminary Pavement System Design..7-3 Step 3 – Determine a Preliminary Fill Mass Arrangement .......................................................7-4 Step 4 – Foundation Soil Settlement Analysis..........................................................................7-4 Step 5 – Bearing Capacity.......................................................................................................7-11 Step 6 – External Slope Stability ............................................................................................7-12 Step 7 – External Seismic Stability.........................................................................................7-12 Step 8 – Hydrostatic Uplift (Flotation) ...................................................................................7-14 Step 9 – Translation Due to Water (External) Read the entire page →
From page 467... ... 7-2 References...................................................................................................................................7-39 Figures ........................................................................................................................................7-40 Tables..........................................................................................................................................7-49 ___________________________________________________________________________ INTRODUCTION This chapter presents two design examples that illustrate the design of an EPS-block geofoam embankment. The design principles and methods are discussed in detail in Chapters 3 through 6 and summarized in the flow chart illustrated in Figure 3.3. Read the entire page →
From page 468... ... 7-3  Site is in Urbana, Illinois.  Subsurface conditions shown in Figure 7.1. Read the entire page →
From page 469... ... 7-4  From the Design Loads section of Chapter 3, assume an overall unit weight for the pavement system of 3pavementγ 20 kN/m= . STEP 3 – DETERMINE A PRELIMINARY FILL MASS ARRANGEMENT • Start the design process with fill mass (see Figure 3.2) Read the entire page →
From page 470... ... 7-5 demonstrate the use of the procedure to estimate ∆σ′z and the overall settlement described in Chapter 5, a detailed calculation will be performed for Layer 5. Figure 7.2 Subdivision of soft clay layer for settlement analysis. Read the entire page →
From page 471... ... 7-6 3cover cover cover T 0.4 mq γ 18.8 kN/m 7.9 kPa cos cos 18.43 = ∗ = ∗ =θ o fillq 4.4 kPa as previously determined=  From Equation (5.18) , II fill cover q q q 4.4 kPa + 7.9 kPa = 12.3 kPa= + =  From Fig. Read the entire page →
From page 472... ... 7-7 a 15 marctan arctan 1.1479 radians z 6.75 m δ    = = =        From Equation (5.22) Read the entire page →
From page 473... ... 7-8  From Equation (5.27) Read the entire page →
From page 474... ... 7-9  From Figure 7.1, OCR = p vo 1 ′σ =′σ . Therefore, p vo1 1 41.78 kPa 41.78 kPa′ ′σ = ∗σ = ∗ =  At the center of the embankment OCR = 1, therefore, use Equation (5.3) Read the entire page →
From page 476... ... 7-11 strain of less than 1 percent. The immediate or elastic vertical strain can be estimated from Equation (5.9) Read the entire page →
From page 477... ... 7-12 Alternatively, Figure 5.10 can be used. For TEPS = 4.4 m and an 11 m roadway width, Figure 5.10 indicates that s u REQ = 15.3 kPa. Read the entire page →
From page 478... ... 7-13 • Estimate the acceleration at the top of the embankment, aemb. As presented in the External Seismic Stability of Trapezoidal Embankments section of Chapter 5, the EPSblock geofoam can be assumed to behave as a deep cohesionless soil. Read the entire page →
From page 479... ... 7-14 STEP 8 – HYDROSTATIC UPLIFT (FLOTATION) • Determine the weight of the EPS-block geofoam, WEPS. Read the entire page →
From page 480... ... 7-15 Figure 5.49 indicates OREQ = 310 kN/m of roadway • Determine if the pavement system and soil cover provide an adequate overburden force to resist hydrostatic uplift.  Determine the weight of the soil cover, Wcover. Read the entire page →
From page 481... ... 7-16 Table 7.3 Summary of interface friction angles, δ, considered between the EPS blocks and the foundation soil. • Determine the additional overburden force required above the EPS blocks to obtain a factor of safety against translation due to water of 1.2, OREQ. Read the entire page →
From page 482... ... 7-17 weight. Therefore, use Equation (5.67) Read the entire page →
From page 483... ... 7-18 • Determine the additional overburden force required above the EPS blocks to obtain a factor of safety against translation due to wind of 1.2, OREQ. From Equation (5.81) Read the entire page →
From page 484... ... 7-19 evaluated herein to demonstrate the use of these equations. Thus, the wind failure mechanism will not be considered in the design of this embankment. Read the entire page →
From page 485... ... 7-20 • Assume the interface friction angle, δ, between the EPS blocks is 30 degrees (from Chapter 2) Read the entire page →
From page 486... ... 7-21 height of the pavement system must be subtracted from the total overburden weight. Therefore, use Equation (5.67) Read the entire page →
From page 487... ... 7-22  From Equation (3.4) Read the entire page →
From page 488... ... 7-23  Determine the weight of the soil cover, Wcover. Thickness of EPS, TEPS = H – Tpavement = 2.5 m – 0.6 m = 1.9 m  From Equation (5.64) Read the entire page →
From page 489... ... 7-24 system/separation material and separation material/EPS. The type of separation material, if one is required, will typically not be initially known. Read the entire page →
From page 491... ... 7-26 STEP 14 – LOAD BEARING • Sub-Step 1: Estimate traffic loads. For this section of roadway, use AASHTO H 20-44 standard loading. Read the entire page →
From page 492... ... 7-27 2D D CD LL Q Q 69.4 kNA 3.65 m q 19 kPaσ= = = = Figure 7.3 Cross-section of rear axle of two standard H 20-44 trucks on the proposed 11 m wide roadway embankment. Determine an equivalent rectangular loaded area using Fig. Read the entire page →
From page 493... ... 7-28 Combined set No. Read the entire page →
From page 494... ... 7-29 A summary of σtotal for the various pavement systems is presented in Table 7.6. If applied stresses were found to overlap between adjacent tire sets in Sub-step 3, the largest σLL is used. Read the entire page →
From page 495... ... 7-30 flexible pavement system consisting of 178 mm thick asphalt concrete and 432 mm granular base is the most cost effective of the four pavement systems considered, and (3) EPS70 is required for the most cost effective flexible pavement system. Read the entire page →
From page 496... ... 7-31  Determine the depths within the EPS where stress overlap occurs. Using the 1H:2V assumed stress distribution method, stress overlap between two adjacent loaded areas occurs at a depth Z equal to the spacing, S, between the two loaded areas. Read the entire page →
From page 498... ... 7-33 ( ) combined 1 2,3 4 1 3B B B B S S 0.73 m 0.12 m= + + + + + − 1.22 m + 2.44 m + 1.22 m + 0.61 m + 0.61 m + (0.61 m) Read the entire page →
From page 500... ... 7-35 support the combined stresses. As shown in Table 7.8, both an EPS70 and EPS50 was selected at Z = 0.61 m for the two dual tire load combinations analyzed. Read the entire page →
From page 502... ... 7-37 geofoam bridge approach fill on an abutment. Determination of earth pressures is required in Step 2 of the abutment design procedure. Read the entire page →
From page 503... ... 7-38 2 D,Sand D,Sand 1 1H H = 3.85 kN/m 2.795 m=1.08 kN/m of wall 10 10 ω ′= ∗ ∗ ∗ ∗ • Determine the horizontal force generated by the EPS-block geofoam fill. As indicated in Chapter 6, the horizontal force from the EPS blocks is neglected because it is negligible. Read the entire page →
From page 504... ... 7-39  It can be seen from Figure 7.9 that the largest horizontal force is applied by the live load surcharge. Read the entire page →
From page 505... ... FIGURE 7.1 Proj 24-11.doc S = 15 kPa = 16 kN/m e = 1.7 C = 0.35 C = 0.04 = 1 t = 15 years C /C =0.04 sat 3 0 c r p c Sand Soft Clay 15m Soi l C ov er Pavement System Soil Cover T = 11 m T =0.61 m T =4.4 m H = 5 m EPS blocks pavement EPS p vo u OCR = W 7-40 Read the entire page →
From page 506... ... FIGURE 7.2 PROJ 24-11.doc 7-41 Read the entire page →
From page 507... ... FIGURE 7.3 PROJ 24-11.doc Center of Embankment Dual Tires 1.83 m1.83 m 0.61 m 1 2 3 4 T = 11 mw Tire Set No. Read the entire page →
From page 508... ... FIGURE 7.4 PROJ 24-11.doc 0.5 B 0.5 B 0.5 B BB Dual Tires Pavement System Center-to Center Spacing B = Width of equivalent rectangular loaded area for one set of dual tires. Note: If center-to-center spacing < B, stresses imposed by the two dual tire sets overlap. Read the entire page →
From page 509... ... FIGURE 7.5 PROJ 24-11.doc Note: L1 = L2 = L3 = L4 = 1.61 m. These loaded area lengths are not shown in this figure. Read the entire page →
From page 510... ... FIGURE 7.6 PROJ 24-11.doc Q = 69.4 kNQ = 138.8 kNQ = 69.4 kN 42,31 2.44 m 2.44 m z = 0.12 m S = 0.61 m B = 1.22 mB = 2.44 m S = 0.61 m B = 1.22 m1 1 2,3 3 4 7-45 Read the entire page →
From page 511... ... FIGURE 7.7 PROJ 24-11.doc 100 mm Sand Bed and/or geotextile (if necessary) EPS 40 400 mm Soil Cover 610 mm (min) Read the entire page →
From page 512... ... FIGURE 7.8 Proj 24-11.doc 3030 mm2460 mm Leveling Sand = 45θ o Base Course Concrete Approach Slab EPS 70 Sand Base Soil Backfill =18.8 kN/m =35 6240 mm Bituminous Pavement 50 mm φ γ ot 3 33 05 m m 27 45 m m 20 5 m m 30 5 m m 7-47 Read the entire page →
From page 513... ... FIGURE 7.9 Proj 24-11.doc HL D, ConcH D, SandH A, SoilP = 1.47 kN/m H = 27 95 m m 93 1. 7 m m 13 97 .5 m m 0.61 m Live Load Surcharge, ( = 18.8 kN/m ) Read the entire page →
From page 514... ... TABLE 7.1 PROJ 24-11.doc Layer No. Layer Thickness (m) Read the entire page →
From page 515... ... TABLE 7.2 PROJ 24-11.doc Layer No. Layer Thickness (m) Read the entire page →
From page 516... ... TABLE 7.3 PROJ 24-11.doc Case Number Description of Interface Potential Type of Interface Materials Estimated δ (degrees) Source of δ Notes 1 EPS-block geofoam placed directly on the soil foundation. Read the entire page →
From page 517... ... TABLE 7.4 PROJ 24-11.doc Case Number Description of Interface Potential Type of Interface Materials Estimated δ (degrees) Source of δ Notes 1 Pavement system placed directly on the EPS blocks Crushed stone or sand/EPS 30 (3) Read the entire page →
From page 518... ... TABLE 7.5 PROJ 24-11.doc Failure Mode δ (degrees) kh FS′ I 25 0.09 4.7 II 30 0.09 Not critical III 20 0.09 3.6 7-53 Read the entire page →
From page 519... ... TABLE 7.6 PROJ 24-11.doc Pavement System and Thickness of Asphalt Concrete σLL (kPa) σLL if stress overlap occurs between interior dual tire sets (kPa) Read the entire page →
From page 520... ... TABLE 7.7 PROJ 24-11.doc EPS Type Needed Cost $/m2 per 610 mm Thickness Pavement System and Thickness of Asphalt Concrete Asphalt Thickness (mm) Cost $/m2 per mm Thicknes s Cost $/m2 Concrete Separation Layer Thickness (mm) Read the entire page →
From page 521... ... TABLE 7.8 PROJ 24-11.doc Dual Tire Load Combination Q (kN) Read the entire page →

From page 466...

... 7-1 CHAPTER 7 DESIGN EXAMPLES Contents Introduction...................................................................................................................................7-2 Design Example 1 – Trapezoidal Geofoam Embankment............................................................7-2 Step 1 – Background Investigation ...........................................................................................7-2 Step 2 – Select Preliminary Eps Type and Assume a Preliminary Pavement System Design..7-3 Step 3 – Determine a Preliminary Fill Mass Arrangement .......................................................7-4 Step 4 – Foundation Soil Settlement Analysis..........................................................................7-4 Step 5 – Bearing Capacity.......................................................................................................7-11 Step 6 – External Slope Stability ............................................................................................7-12 Step 7 – External Seismic Stability.........................................................................................7-12 Step 8 – Hydrostatic Uplift (Flotation) ...................................................................................7-14 Step 9 – Translation Due to Water (External)