17Procedure to evaluate total lateral earth load for anchored systems constructed in weak101cohesive soils18soilmethodsearthValues of KREQ in cohesionlessusingvarioustoevaluate.103pressures.19Horizontal stress coefficient, K, for pressure grouted anchors (after Kulhawy et al.,1983).11120.131Corrosionprotectionrequirements (modifiedafterPTI,1996)21.144Stepsfortheperformancetest.22.147Test procedure for ground anchor proof test.23Load schedule and observation periods for extended creep test forpermanent.149anchor.xiv
xiv 17 Procedure to evaluate total lateral earth load for anchored systems constructed in weak cohesive soils.101 18 Values of KREQ in cohesionless soil using various methods to evaluate earth pressures.103 19 Horizontal stress coefficient, K, for pressure grouted anchors (after Kulhawy et al., 1983) .111 20 Corrosion protection requirements (modified after PTI, 1996) .131 21 Steps for the performance test.144 22 Test procedure for ground anchor proof test.147 23 Load schedule and observation periods for extended creep test for permanent anchor.149
LIST OFFIGURESFigurePage1Components ofa ground anchor12Anchorage components for a bar tendon.36Anchorage components for a strand tendon.4Main types of grouted ground anchors (modified after Littlejohn, 1990)59Cut away view of bar tendon.610Cut away view of strand tendon.7Construction sequence for permanent soldier beam and lagging wall.128.16Comparison of concrete gravity wall and anchored wall for a depressed roadway.9..18Applications of ground anchors and anchored systems10.20Geotechnical boring layout for permanent anchored wall11.27Potential failure conditions to be considered in design of anchored walls12Contribution of ground anchors to wall stability.2813Simplified drained stress-displacement relationship for a stiff clay (modified after CIRIA, 1984) 3514Mobilization of Rankine active and passive horizontal pressures for a smooth retaining wall....3715.37Limitingactiveandpassivehorizontalpressures.3916Active and passive earth pressure coefficients (effect of wall inclination)17..40Activeand passiveearthpressurecoefficients (effectofbackslope inclination)18Cross section of model wall (modified afterFHWA-RD-98-067,1998),.4219Lateral wall movements and earth pressures with excavation at first anchor level (cantileverstage) (modified afterFHWA-RD-98-067, 1998)4220Lateral wall movements and earth pressures during anchor stressing (modified after FHWA-RD-98-067,1998).43XV
xv LIST OF FIGURES Figure Page 1 Components of a ground anchor.4 2 Anchorage components for a bar tendon.5 3 Anchorage components for a strand tendon.6 4 Main types of grouted ground anchors (modified after Littlejohn, 1990).7 5 Cut away view of bar tendon.9 6 Cut away view of strand tendon.10 7 Construction sequence for permanent soldier beam and lagging wall .12 8 Comparison of concrete gravity wall and anchored wall for a depressed roadway.16 9 Applications of ground anchors and anchored systems .18 10 Geotechnical boring layout for permanent anchored wall.20 11 Potential failure conditions to be considered in design of anchored walls.27 12 Contribution of ground anchors to wall stability.28 13 Simplified drained stress-displacement relationship for a stiff clay (modified after CIRIA, 1984) 35 14 Mobilization of Rankine active and passive horizontal pressures for a smooth retaining wall .37 15 Limiting active and passive horizontal pressures.37 16 Active and passive earth pressure coefficients (effect of wall inclination) .39 17 Active and passive earth pressure coefficients (effect of backslope inclination) .40 18 Cross section of model wall (modified after FHWA-RD-98-067, 1998).42 19 Lateral wall movements and earth pressures with excavation at first anchor level (cantilever stage) (modified after FHWA-RD-98-067, 1998).42 20 Lateral wall movements and earth pressures during anchor stressing (modified after FHWARD-98-067, 1998).43
LIST OFFIGURES (Continued)FigurePage21Lateral wall movements and earth pressures with excavation at lower anchor level (modifiedafter FHWA-RD-98-067,1998)...4422Lateral wall movements and earth pressures with excavation at design grade (modified after.45FHWA-RD-98-067.1998)23Terzaghi and Peck apparent pressure envelopes (after Terzaghi and Peck, 1967)....5024.51Recommended apparent earth pressure diagram for sands.25.54Measured anchor loadsfor seven projects (after Ulrich, 1989)26.55Wall pressure envelopes (after Winter, 1990)27.56Recommended apparent earth pressure envelopefor stiff to hard clays28.58Henkel'smechanismofbasefailure29.59Values of Ka based on Terzaghi and Peck envelope and Henkel's method.30.61Force equilibrium method for anchored walls (after FHWA-RD-98-065, 1998).31Flow net for a retaining wall (after CIRIA, 1984)...6232Gross and net water pressures across a retaining wall (modified after CIRIA, 1984)....6333Calculation of anchor loads for one-level wall..6634Calculation of anchor loads for multi-level wall.6735.69Types of compression anchors.36.72Mobilization of bond stress for a tension anchor37.76Vertical and horizontal spacing requirements for ground anchors.38.79Calculation of wall bending moments using hinge method39.80Calculation of wall bending moments using tributary area method.40Relationship between lateral earth pressure,wall deflection, and depth ofwall embedment ....8541..86Broms method for evaluating ultimate passive resistance.42.88ComparisonofBromsandWang-Reesemethodforwallinsandxvi
LIST OF FIGURES (Continued) Figure Page xvi 21 Lateral wall movements and earth pressures with excavation at lower anchor level (modified after FHWA-RD-98-067, 1998) .44 22 Lateral wall movements and earth pressures with excavation at design grade (modified after FHWA-RD-98-067, 1998).45 23 Terzaghi and Peck apparent pressure envelopes (after Terzaghi and Peck, 1967).50 24 Recommended apparent earth pressure diagram for sands.51 25 Measured anchor loads for seven projects (after Ulrich, 1989).54 26 Wall pressure envelopes (after Winter, 1990).55 27 Recommended apparent earth pressure envelope for stiff to hard clays.56 28 Henkel’s mechanism of base failure .58 29 Values of KA based on Terzaghi and Peck envelope and Henkel's method.59 30 Force equilibrium method for anchored walls (after FHWA-RD-98-065, 1998).61 31 Flow net for a retaining wall (after CIRIA, 1984).62 32 Gross and net water pressures across a retaining wall (modified after CIRIA, 1984).63 33 Calculation of anchor loads for one-level wall.66 34 Calculation of anchor loads for multi-level wall.67 35 Types of compression anchors.69 36 Mobilization of bond stress for a tension anchor.72 37 Vertical and horizontal spacing requirements for ground anchors.76 38 Calculation of wall bending moments using hinge method.79 39 Calculation of wall bending moments using tributary area method.80 40 Relationship between lateral earth pressure, wall deflection, and depth of wall embedment .85 41 Broms method for evaluating ultimate passive resistance.86 42 Comparison of Broms and Wang-Reese method for wall in sand.88
LIST OFFIGURES (Continued)FigurePage43.88Comparison of Broms and Wang-Reese method for wall in clay44Chart for estimating βcoefficientsoilfrictionangle(after Fellenius.versustype911991)45Chart for estimating Nt coefficients versussoilfriction angle (after Fellenius,type.921991)46.93Adhesion values for piles in cohesive soils (after Tomlinson, 1980)47Modeling the ground anchor force in limit equilibrium analysis (after FHWA-RD-97-130, 1998)9948Limit equilibrium analyses used to evaluate total lateral earth load for anchored systems100constructed in weak cohesive soils analysis (afterFHWA-RD-97-130, 1998).49.102Total passive force for example wall in cohesionless soil50Comparison of limit equilibrium methods for cohesive soils (after FHWA-RD-98-065, 1998)10451.106Analysis of basal stability (modified after Terzaghi et al., 1996)52.108Failure surfaces for external stability evaluations53.110Inverted cone mechanisms for overall rock mass stability54.112Stability of structure subjected to hydrostatic uplift55Forces behind a gravity wall.11556Effect of seismic coefficients and friction angle on seismic active pressure coefficient (after Lam.116and Martin, 1986)57.118Variation of failure surface inclination with horizontal acceleration coefficient58.119Permanent seismic deformation chart (after Hynes and Franklin, 1984)59.120Settlement profile behind braced and anchored walls60.128Examplesofcorrosionprotectionforanchorages61.129Examples of corrosion protection classes I and II for strand tendons62Examples ofcorrosion protectionclasses Iand IIfor bartendons130xvii
LIST OF FIGURES (Continued) Figure Page xvii 43 Comparison of Broms and Wang-Reese method for wall in clay.88 44 Chart for estimating b coefficient versus soil type friction angle (after Fellenius, 1991) .91 45 Chart for estimating Nt coefficients versus soil type friction angle (after Fellenius, 1991) .92 46 Adhesion values for piles in cohesive soils (after Tomlinson, 1980).93 47 Modeling the ground anchor force in limit equilibrium analysis (after FHWA-RD-97-130, 1998) .99 48 Limit equilibrium analyses used to evaluate total lateral earth load for anchored systems constructed in weak cohesive soils analysis (after FHWA-RD-97-130, 1998).100 49 Total passive force for example wall in cohesionless soil.102 50 Comparison of limit equilibrium methods for cohesive soils (after FHWA-RD-98-065, 1998)104 51 Analysis of basal stability (modified after Terzaghi et al., 1996).106 52 Failure surfaces for external stability evaluations .108 53 Inverted cone mechanisms for overall rock mass stability.110 54 Stability of structure subjected to hydrostatic uplift .112 55 Forces behind a gravity wall .115 56 Effect of seismic coefficients and friction angle on seismic active pressure coefficient (after Lam and Martin, 1986).116 57 Variation of failure surface inclination with horizontal acceleration coefficient .118 58 Permanent seismic deformation chart (after Hynes and Franklin, 1984).119 59 Settlement profile behind braced and anchored walls.120 60 Examples of corrosion protection for anchorages.128 61 Examples of corrosion protection classes I and II for strand tendons.129 62 Examples of corrosion protection classes I and II for bar tendons.130
LIST OFFIGURES (Continued)FigurePage63.134Decision tree for selection of corrosion protection level (modified after PTI, 1996)64137Skin friction versus strain diagrams for ground anchors65..138Stress propagation in bond length of ground anchor..66.139Evaluationofcritical creeptension.67.140Typical equipment for load testing of strand ground anchor.68.141Typical equipment for load testing of bar ground anchor.69.145Plotting of performance test data (after PTI, 1996)70.146Plotting of elastic and residual movement for a performance test (after PTI, 1996)71.148Plotting of proof test data (after PTI, 1996)72.149Plotting of extended creep test data (after PTI, 1996)73.153Ground anchor acceptance decision tree (afterPTI, 1996)A-2A-1Subsurface stratigraphy and design cross sectionA-2A-4Apparent earth pressure diagram and surcharge pressure diagramA-3Location of unbonded and bond lengths for ground anchorsA-8A-4A-12Embedment depth calculations (Wang-Reese method)A-5A-18Subsurface stratigraphy and design cross section.A-20A-6Secant residual friction angle (after Stark and Eid, 1994)A-22A-7Slope stability analysis of existing site conditionsA-23A-8Apparent earth pressure diagramA-9A-25Calculation of TH3 and M4A-10 Location of unbonded and bond lengths for ground anchorsA-27B-1.B-2Passive wedge failure for a soldier beam in sand (after Reese, , al., 1974).B-2Intersecting failure wedges for soldier beams in sand (after Wang and Reese, 1986).....B-3B-3.B-4Plastic flow around a soldier beam toe (after Wang and Reese, 1986)xvili
LIST OF FIGURES (Continued) Figure Page xviii 63 Decision tree for selection of corrosion protection level (modified after PTI, 1996).134 64 Skin friction versus strain diagrams for ground anchors.137 65 Stress propagation in bond length of ground anchor.138 66 Evaluation of critical creep tension.139 67 Typical equipment for load testing of strand ground anchor.140 68 Typical equipment for load testing of bar ground anchor.141 69 Plotting of performance test data (after PTI, 1996).145 70 Plotting of elastic and residual movement for a performance test (after PTI, 1996).146 71 Plotting of proof test data (after PTI, 1996).148 72 Plotting of extended creep test data (after PTI, 1996).149 73 Ground anchor acceptance decision tree (after PTI, 1996).153 A-1 Subsurface stratigraphy and design cross section. A-2 A-2 Apparent earth pressure diagram and surcharge pressure diagram. A-4 A-3 Location of unbonded and bond lengths for ground anchors. A-8 A-4 Embedment depth calculations (Wang-Reese method). A-12 A-5 Subsurface stratigraphy and design cross section. A-18 A-6 Secant residual friction angle (after Stark and Eid, 1994) . A-20 A-7 Slope stability analysis of existing site conditions. A-22 A-8 Apparent earth pressure diagram. A-23 A-9 Calculation of TH3 and M4 . A-25 A-10 Location of unbonded and bond lengths for ground anchors. A-27 B-1 Passive wedge failure for a soldier beam in sand (after Reese, . al., 1974).B-2 B-2 Intersecting failure wedges for soldier beams in sand (after Wang and Reese, 1986).B-3 B-3 Plastic flow around a soldier beam toe (after Wang and Reese, 1986).B-4