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Dynamic response of piles under vertical load
52A
Influence of dynamic loads See also: 941246, 94147.5
941409 Aseismic pile foundation analysis Pender, M J Bull N Z Nat Soc Earthq Engng V26, N1, March, 1993, P49160 An extensive review is presented of techniques for use in analysis of pile foundations which will be subject to dynamic loading. Methods of assessing the stiffness and capacity of piles and pile groups under seismic forces are examined. The object is to provide practical design formulae for easy incorporation into simple design software. Several worked examples are shown. Data from pile testing are used where possible to support the proposed methods.
941410 Dynamic behaviour and response of El Inflernillo Dam Elgamal, A W M; Gunturi, R V Earthq Engng Struct Dynam V22, N8, Aug 1993, P665-684 El Infiernillo, a 145m high rockfill dam built in a narrow, Vshaped canyon, has suffered 8 major earthquakes since its construction. A newly developed simplified 3D model and a 3D finite element model have been used to simulate dynamic response of the dam to a 1975 earthquake and full scale dynamic field tests in 1970. Response characteristics are compared to field data and performance of the models evaluated. The simplified model is also used to simulate response to a 1985 event.
941411 Parametric study of vertical vibrations of circular flexible foundations on layered media Gucunski, N; Peek, R Eartlul Engng Struct Dynam V22, NS, Aug 1993, P685-694 Results are presented of a parametric study of vertical oscillations of a flexible circular plate resting on an elastic half space or an elastic layered system. The ring method is used in solution of the problem. Displacement and soil reaction distributions at the soil-plate interface and the impedance functions are evaluated as material and geometric parameters of the soil system and plate and load distribution on the plate are varied. Comparisons are made with the rigid plate case.
941412 Ol~erved and predicted earthquake response of La Viilita Dam Succarieh, M F; Elgamal, A W; Yan, L Engng Geol V34, NI/2, May 1993, Pll-26 Upstream-downstream earthquake response of the La Villita Dam, a zoned earth and rock fill structure, is analysed. The dam is represented as a one dimensional nonlinear hysteretic shear wedge model and seismic response is calculated in the time domain using recorded bedrock acceleration data as input. Response to stronger shaking is computed for purposes of comparison. A nonlinear elastic-perfectly plastic S D O F model is developed to analyse observed local stick-slip crest deformation and predict future deformation. Predicted responses are similar to those recorded.
941413 Dynamic centrifuge testing of soil-nailed excavations Vucetic, M; Tufenkjian, M R; Doroudian, M Geotech Test J V16, N2, June 1993. P172-187 A series of dynamic centrifuge model tests on soil-nailed excavations is described. The prototype excavation had height H = 7.6m, nail lengths were 0.33-1.0H, and scaling factor was 50. Various levels of horizontal shaking were applied. Equipment, model preparation, testing, and data acquisition are described and limitations and test problems discussed. The soil nailing provided effective reinforcement. The failure was as a block slide with failure surface behind the upper two soil nails and cutting through the third, the lowest. 941414 Filling in the movers and shakers Stedman, L Ground Engng V26, NS, June 1993, P13-16 Earthquakes must be taken into account for all major engineering projects in California. The example of the Keller Canyon landfill site is presented. The side slopes are weathered sandstone rock. Excavation of 9-12m of landslide debris to provide a firm base for the landfill left the water table close to the excavation base and an underdrain system was installed beneath the composite liner. A massive toe berm, eventually 60m high, is necessary to assure stability of landfill slopes in the event of design earthquakes. 941415 Foundation response to rocking vibrations Sridharan, A; Baidya, D K; Raju, D M Indian Geotech J V22, N3, July 1992, P131-153 Analysis of a circular foundation resting on an elastic half space and subjected to steady state vibration by a harmonic moment is presented. Dynamic response is obtained for three different contact pressure distributions and for the weighted average displacement case. Contact pressure distribution is shown to have a significant influence on the frequency and amplitude at resonance. Inertia ratio also affects displacement amplitude at resonance. 941416 Prediction of displacement amplitude of foundations at any frequency Sridharan, A; Baidya, D K; Raju, D M Indian Geotech J V22, N3, July 1992, P154-174 Primary criteria in machine foundation design are limiting the displacement amplitude at operating frequency and preventing resonance. An elastic half space model is used to predict displacement amplitude at any frequency. Results are presented in the form of design charts for horizontal, vertical, rocking, and torsional vibration. Frequency ratio is plotted against amplitude ratio for various modified mass/inertia ratios. Rigid base pressure distribution and weighted average displacement condition, the two most commonly assumed in design, are considered. 941417 Dynamic response of piles under vertical load Khan, A K; Pise, P J Indian Geotech J V22, N4, Oct 1992, P245-265 Dynamic response of a pile in an isotropic, homogeneous, elastic half space and under vertical harmonic loading is analysed. Both straight and curved piles can be handled. Half space parameters under vertical and horizontal modes of vibration are found to depend on frequency of vibration and Poisson's ratio of the soil. Slenderness ratio, wave velocity
53A ratio, and pile tip conditions influence equivalent stiffness and damping functions of the piles and lateral and vertical displacement amplitudes. Results are compared to other theoretical output and a set of experimental data.
941418 Analytical modelling of hammer impact for pile driving Deeks, A J; Randolph, M F lnt J Num Anal Meth Geomech V17, N5, May 1993, P279302 An analytical model of hammer impact is presented based on lumped ram and anvil masses separated by a cushion with internal damping and connected to a dashpot representing the pile. Force-time histories from the model are compared to those from commonly used commercial numerical analyses of hammer models and field data. The model is then used to examine conditions leading to hammer bounce, with associated lower transference of energy to the pile.
941419 Wave equation parameters from driven-rod test Liang, R Y; Sheng, S J Geotech Engng Div ASCE Vl19, N6, June 1993, P10371057 A practical method is presented based on the driven-rod test and attendant high-strain test measurements and C A P W A P signal match procedures to determine the Smith model parameters of piles for wave equation analysis. Empirical relations are developed to allow driven rod data and prototype pile results to be correlated and extrapolated for full scale application.
941420 Improved non-reflecting boundary method for soil-structure interaction analysis Quian, L; Zhang, H Microcomput Civ Engng V8, N4, 1993, P291-297 In dynamic finite element analysis of soil-foundation interaction, the half-infinite space must be replaced by a finite region with a non-reflecting boundary for wave propagation. A nonreflecting boundary method with constant acceleration and constant force applied to the boundary is proposed and a corresponding explicit-implicit algorithm for dynamic analysis presented. Results from this approach are compared to those from accepted but more computationally intensive methods.
941421 Vertical response of single piles: transient analysis by timedomain BEM Lei, Z X; Cheung, Y K; Tham, L G Soil Dynmn Eartlul Engng V12, N1, 1993, P37-49 Transient dynamic response of a pile in a layered half space and under a time-dependent vertical force is analysed with the pile described by finite elements and the half space by a general cylindrical coordinates BEM. Compatibility and equilibrium conditions between the pile shaft and the soil layers are used to assemble the respective equations into only one. Parametric studies examine the effects of ratios of pile to soil Young's modulus and density, pile slenderness, and soil Poisson's ratio. Effects of soil layering and support condition at the pile tip are examined numerically.
941422 Dynamic analysis of axially-loaded footings in the time domain Anandarajah, A Soils Found V33, NI, March 1993, P40-54 A method for time domain analysis of footings under dynamic axial loading is proposed. Radiation effects in the horizontal direction are modelled using infinite elements, which allows the vertical boundary to be placed as close as desired to the footing. The domain outside the boundary must be horizontally layered and behave linearly. An example is evaluated where the entire domain is taken to be an isotropic, linear, viscoelastic material. Results are compared to those of a standard finite element analysis with the vertical boundary placed sufficiently far from the footing.
941423 Effects of earthquakes on settlements and axial pile response in clays Poulos, H G Trans lnst Engrs Aust Civ Engng VCE35, N1, March 1993, P43-48 A relatively simple procedure is presented for estimation of magnitude and rate of settlement developed in a clay layer under earthquake excitation. A pore pressure generation equation of Matsuda and Ohara is used in the finite difference consolidation analysis. Effects of earthquake magnitude on excess pore pressure and settlement are first evaluated, then the influence of these parameters on short-term and long-term response of piles. Adverse effects on pile performance are indicated for earthquake magnitude greater than 6 on the Richter scale.
941424 Full scale testing for the dynamic characterization of foundation piles Panzeri, P; Pezzoli, P Proc 3rd International Symposium on Field Measurements in Geomechanics, Osio, 9-11 September 1991 V2 , P697-706. Publ Rotterdam: A A Balkema, 1991 Full scale dynamic tests on single piles and pile groups are described. The tests, in which sinusoidal forces were applied at the top of the piles, were aimed at experimental determination of the mechanical impedance of the piles. A new experimentalnumerical procedure is proposed for evaluation of the influence coefficients of elastic resistance of a pile due to the presence of other piles in the group. A new experimental rig for static-dynamic combined testing is illustrated.
941425 Soil/structure seismic investigation of safety-related structures Serhan, S J; Chen, C Proc 6th ASCE Speciaflty Conference on Probabilistic Mechanics and Structural and Geotedmical Reliability, Denver, 8-10 July 1992 P396-399. Publ New York: ASCE, 1992 Earthquake events and response of two nuclear plants in the USA (V.C. Summer, South Carolina and Perry, Ohio) and at Krsko, Siovenia, are analysed. The high frequency, low energy events were non-damaging for passive equipment and rugged active components. The high frequency component was transmitted to the inside of the structures even on a soil site. Dominant frequencies of the massive structures differ greatly from those of the excitation considered. Strong soil-structure interaction was observed at Krsko and reproduced by the computer code SHAKE. Structural response in the rocking mode is seen.
Influence of dynamic loads See also: 941246, 94147.5
941409 Aseismic pile foundation analysis Pender, M J Bull N Z Nat Soc Earthq Engng V26, N1, March, 1993, P49160 An extensive review is presented of techniques for use in analysis of pile foundations which will be subject to dynamic loading. Methods of assessing the stiffness and capacity of piles and pile groups under seismic forces are examined. The object is to provide practical design formulae for easy incorporation into simple design software. Several worked examples are shown. Data from pile testing are used where possible to support the proposed methods.
941410 Dynamic behaviour and response of El Inflernillo Dam Elgamal, A W M; Gunturi, R V Earthq Engng Struct Dynam V22, N8, Aug 1993, P665-684 El Infiernillo, a 145m high rockfill dam built in a narrow, Vshaped canyon, has suffered 8 major earthquakes since its construction. A newly developed simplified 3D model and a 3D finite element model have been used to simulate dynamic response of the dam to a 1975 earthquake and full scale dynamic field tests in 1970. Response characteristics are compared to field data and performance of the models evaluated. The simplified model is also used to simulate response to a 1985 event.
941411 Parametric study of vertical vibrations of circular flexible foundations on layered media Gucunski, N; Peek, R Eartlul Engng Struct Dynam V22, NS, Aug 1993, P685-694 Results are presented of a parametric study of vertical oscillations of a flexible circular plate resting on an elastic half space or an elastic layered system. The ring method is used in solution of the problem. Displacement and soil reaction distributions at the soil-plate interface and the impedance functions are evaluated as material and geometric parameters of the soil system and plate and load distribution on the plate are varied. Comparisons are made with the rigid plate case.
941412 Ol~erved and predicted earthquake response of La Viilita Dam Succarieh, M F; Elgamal, A W; Yan, L Engng Geol V34, NI/2, May 1993, Pll-26 Upstream-downstream earthquake response of the La Villita Dam, a zoned earth and rock fill structure, is analysed. The dam is represented as a one dimensional nonlinear hysteretic shear wedge model and seismic response is calculated in the time domain using recorded bedrock acceleration data as input. Response to stronger shaking is computed for purposes of comparison. A nonlinear elastic-perfectly plastic S D O F model is developed to analyse observed local stick-slip crest deformation and predict future deformation. Predicted responses are similar to those recorded.
941413 Dynamic centrifuge testing of soil-nailed excavations Vucetic, M; Tufenkjian, M R; Doroudian, M Geotech Test J V16, N2, June 1993. P172-187 A series of dynamic centrifuge model tests on soil-nailed excavations is described. The prototype excavation had height H = 7.6m, nail lengths were 0.33-1.0H, and scaling factor was 50. Various levels of horizontal shaking were applied. Equipment, model preparation, testing, and data acquisition are described and limitations and test problems discussed. The soil nailing provided effective reinforcement. The failure was as a block slide with failure surface behind the upper two soil nails and cutting through the third, the lowest. 941414 Filling in the movers and shakers Stedman, L Ground Engng V26, NS, June 1993, P13-16 Earthquakes must be taken into account for all major engineering projects in California. The example of the Keller Canyon landfill site is presented. The side slopes are weathered sandstone rock. Excavation of 9-12m of landslide debris to provide a firm base for the landfill left the water table close to the excavation base and an underdrain system was installed beneath the composite liner. A massive toe berm, eventually 60m high, is necessary to assure stability of landfill slopes in the event of design earthquakes. 941415 Foundation response to rocking vibrations Sridharan, A; Baidya, D K; Raju, D M Indian Geotech J V22, N3, July 1992, P131-153 Analysis of a circular foundation resting on an elastic half space and subjected to steady state vibration by a harmonic moment is presented. Dynamic response is obtained for three different contact pressure distributions and for the weighted average displacement case. Contact pressure distribution is shown to have a significant influence on the frequency and amplitude at resonance. Inertia ratio also affects displacement amplitude at resonance. 941416 Prediction of displacement amplitude of foundations at any frequency Sridharan, A; Baidya, D K; Raju, D M Indian Geotech J V22, N3, July 1992, P154-174 Primary criteria in machine foundation design are limiting the displacement amplitude at operating frequency and preventing resonance. An elastic half space model is used to predict displacement amplitude at any frequency. Results are presented in the form of design charts for horizontal, vertical, rocking, and torsional vibration. Frequency ratio is plotted against amplitude ratio for various modified mass/inertia ratios. Rigid base pressure distribution and weighted average displacement condition, the two most commonly assumed in design, are considered. 941417 Dynamic response of piles under vertical load Khan, A K; Pise, P J Indian Geotech J V22, N4, Oct 1992, P245-265 Dynamic response of a pile in an isotropic, homogeneous, elastic half space and under vertical harmonic loading is analysed. Both straight and curved piles can be handled. Half space parameters under vertical and horizontal modes of vibration are found to depend on frequency of vibration and Poisson's ratio of the soil. Slenderness ratio, wave velocity
53A ratio, and pile tip conditions influence equivalent stiffness and damping functions of the piles and lateral and vertical displacement amplitudes. Results are compared to other theoretical output and a set of experimental data.
941418 Analytical modelling of hammer impact for pile driving Deeks, A J; Randolph, M F lnt J Num Anal Meth Geomech V17, N5, May 1993, P279302 An analytical model of hammer impact is presented based on lumped ram and anvil masses separated by a cushion with internal damping and connected to a dashpot representing the pile. Force-time histories from the model are compared to those from commonly used commercial numerical analyses of hammer models and field data. The model is then used to examine conditions leading to hammer bounce, with associated lower transference of energy to the pile.
941419 Wave equation parameters from driven-rod test Liang, R Y; Sheng, S J Geotech Engng Div ASCE Vl19, N6, June 1993, P10371057 A practical method is presented based on the driven-rod test and attendant high-strain test measurements and C A P W A P signal match procedures to determine the Smith model parameters of piles for wave equation analysis. Empirical relations are developed to allow driven rod data and prototype pile results to be correlated and extrapolated for full scale application.
941420 Improved non-reflecting boundary method for soil-structure interaction analysis Quian, L; Zhang, H Microcomput Civ Engng V8, N4, 1993, P291-297 In dynamic finite element analysis of soil-foundation interaction, the half-infinite space must be replaced by a finite region with a non-reflecting boundary for wave propagation. A nonreflecting boundary method with constant acceleration and constant force applied to the boundary is proposed and a corresponding explicit-implicit algorithm for dynamic analysis presented. Results from this approach are compared to those from accepted but more computationally intensive methods.
941421 Vertical response of single piles: transient analysis by timedomain BEM Lei, Z X; Cheung, Y K; Tham, L G Soil Dynmn Eartlul Engng V12, N1, 1993, P37-49 Transient dynamic response of a pile in a layered half space and under a time-dependent vertical force is analysed with the pile described by finite elements and the half space by a general cylindrical coordinates BEM. Compatibility and equilibrium conditions between the pile shaft and the soil layers are used to assemble the respective equations into only one. Parametric studies examine the effects of ratios of pile to soil Young's modulus and density, pile slenderness, and soil Poisson's ratio. Effects of soil layering and support condition at the pile tip are examined numerically.
941422 Dynamic analysis of axially-loaded footings in the time domain Anandarajah, A Soils Found V33, NI, March 1993, P40-54 A method for time domain analysis of footings under dynamic axial loading is proposed. Radiation effects in the horizontal direction are modelled using infinite elements, which allows the vertical boundary to be placed as close as desired to the footing. The domain outside the boundary must be horizontally layered and behave linearly. An example is evaluated where the entire domain is taken to be an isotropic, linear, viscoelastic material. Results are compared to those of a standard finite element analysis with the vertical boundary placed sufficiently far from the footing.
941423 Effects of earthquakes on settlements and axial pile response in clays Poulos, H G Trans lnst Engrs Aust Civ Engng VCE35, N1, March 1993, P43-48 A relatively simple procedure is presented for estimation of magnitude and rate of settlement developed in a clay layer under earthquake excitation. A pore pressure generation equation of Matsuda and Ohara is used in the finite difference consolidation analysis. Effects of earthquake magnitude on excess pore pressure and settlement are first evaluated, then the influence of these parameters on short-term and long-term response of piles. Adverse effects on pile performance are indicated for earthquake magnitude greater than 6 on the Richter scale.
941424 Full scale testing for the dynamic characterization of foundation piles Panzeri, P; Pezzoli, P Proc 3rd International Symposium on Field Measurements in Geomechanics, Osio, 9-11 September 1991 V2 , P697-706. Publ Rotterdam: A A Balkema, 1991 Full scale dynamic tests on single piles and pile groups are described. The tests, in which sinusoidal forces were applied at the top of the piles, were aimed at experimental determination of the mechanical impedance of the piles. A new experimentalnumerical procedure is proposed for evaluation of the influence coefficients of elastic resistance of a pile due to the presence of other piles in the group. A new experimental rig for static-dynamic combined testing is illustrated.
941425 Soil/structure seismic investigation of safety-related structures Serhan, S J; Chen, C Proc 6th ASCE Speciaflty Conference on Probabilistic Mechanics and Structural and Geotedmical Reliability, Denver, 8-10 July 1992 P396-399. Publ New York: ASCE, 1992 Earthquake events and response of two nuclear plants in the USA (V.C. Summer, South Carolina and Perry, Ohio) and at Krsko, Siovenia, are analysed. The high frequency, low energy events were non-damaging for passive equipment and rugged active components. The high frequency component was transmitted to the inside of the structures even on a soil site. Dominant frequencies of the massive structures differ greatly from those of the excitation considered. Strong soil-structure interaction was observed at Krsko and reproduced by the computer code SHAKE. Structural response in the rocking mode is seen.