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Probabilisitc analysis of reliability of shallow foundation in a random static context
36A 891285 Investigation of structural integrity of pile foundations using a vibration method Lilley, D M; Kilkenny, W M; Ackroyd, R F Pro¢ Int Conference on Foundations and Tunnels, London, 2426 March 1987 VI, P177-183. Publ Edinburgh: Engineering Technics Press, 1987
891289 Determination of the shape of cast in-situ foundation piles using the sonic echo technique van Koten, H; Wood, W R Proc lnt Conference on Foundations and Tunnels, London, 2426 March 1987 V1, P205-210. Publ Edinburgh: Engineering Technics Press, 1987
The presence of cracks and other defects in piles may be detected by using resonant frequency techniques. A review of the technique and some existing laboratory data are presented. A field programme using 22 cast in situ concrete piles containing defects and 3 uniform control piles has been undertaken. Soil mechanical properties were determined to ensure that consistent geotechnical data were obtained, and steady state vibration testing used since it is very accurate. Equipment and preliminary results are described.
The sonic echo technique is an established method of checking the integrity of piles. The shape of the reflected waveform is influenced by pile geometry and soil friction. A method of removing significant effects of soil friction and analysing the remaining signal to derive the geometry is described. Case histories demonstrate its effectiveness.
891286 Pile integrity testing - horses for courses Williams, H; Stain, R T Proe lnt Conference on Foundations and Tunnels, London, 2426 March 1987 V]. P184-191. Publ Edinburgh: Engineering Technics Press, 1987
891290 Prediction of the bearing capacity of a pile from dynamic measurements using a non-linear direct matrix integration procedure Delpak, R; Rowlands, G O; Lake, G C Proc lnt Conference on Fonmt~io~ and Tuuels, Loadon, 2426 March 1987 Vl, P211-218. Publ Edinburgh: Engineering Technics Press, 1987
Many methods of pile integrity testing have been used, impulse and ultrasonic methods being most common, but there is no established standard method. Impulse techniques Echo, Transient Dynamic Response, Parallel Seismic - and Sonic Coring tests are described. Recommendations are made, bearing in mind that no method is suitable for all situations and that pile type and dimensions, soil conditions, and degree of information required must be considered. Case histories are presented.
A mathematical model which may be used to predict the bearing capacity of piles from measurements made during driving is presented. The pile is discretised as a lumped mass system and the soil simulated by a bilinear elastoplastic model. By varying the parameters within the program, such as damping, good correlation can be obtained between predicted results and field measurements.
891287 Non-destructive pile load test in a sedimentary basin Andam, K A Proe lnt Conference on Foundations and Tunnels, London, 2426 March 1987 VI, P192-199. Publ Edinburgh: Engineering Technics Press, 1987
891291 Dynamic testing of bearing capacity of bored piles Seitz, J M Proc int Conference on Foundations and Tunnels, London, 2426 March 1987 VI, P219-227. Publ Edinburgh: Engineering Technics Press, 1987
Bridge foundations in a basin of silty sand to 3m, then silty clay, silty sand, plastic clay, then shale at about 15m are described. Load tests on a test pile gave a working load in good agreement with that predicted by dynamic formulae. Where pile extension was necessary, it was found that required skin friction was developed within the concrete curing time (28 days), which made redriving difficult. A rapid cure cement suggested in this case.
The theoretical background, instrumentation, and equipment for conducting dynamic tests on piles are described. Cases of dynamic and static testing of large diameter bored piles in sand and clay are reported. Load settlement curves calculated from dynamic measurements using the CAPWAP analysis are in good agreement with static test results. Some advice is offered on design of dynamic pile load tests.
891288 Monitoring and analysis of pile driving during installation Poskitt, T J; Yip, K L Proc lnt Conference on Foandotions and Tunnels, London, 2426 March 1987 VIo P200-204. Publ Edinburgh: Engineering Technics Press, 1987
891292 Probabilistic analysis of reliability of shallow foundation in a random static context Boulefkhad, T; Faugeras, J C; Fogli, M; Pouget, P Proc ECONMIG 86, Smttlart, 16-18 ~ p t e ~ 19866 V2, 13P. Publ Stuttgart: University o/Stuttgart, 1986
A rig to develop suitably robust strain and acceleration monitoring equipment for use during pile driving is described, together with a computer system for real time data processing, based on the wave equation. This may be used to predict soil properties during driving and best values of mobilised skin friction and end bearing capacity. Results from a test pile in hard clay gave a much lower bearing capacity than expected. This is explained by the presence of a thin soft zone at the pile wall, caused by lateral movement of the pile.
The basics of probabilistic analysis are first introduced. Cotnell's index (mean/standard deviation of a variable) is selected as a reliability measure. The problem considered is that of a shallow foundation on a layered soil, within which tests have been made at different depths. Choice and formulation of the limit state function are described. A Monte Carlo simulation is used to examine the influence of random variability of the parameters of the model on bearing capacity of the foundation.
© 1989 Pergamon Press plc. Reproduction not permitted
891289 Determination of the shape of cast in-situ foundation piles using the sonic echo technique van Koten, H; Wood, W R Proc lnt Conference on Foundations and Tunnels, London, 2426 March 1987 V1, P205-210. Publ Edinburgh: Engineering Technics Press, 1987
The presence of cracks and other defects in piles may be detected by using resonant frequency techniques. A review of the technique and some existing laboratory data are presented. A field programme using 22 cast in situ concrete piles containing defects and 3 uniform control piles has been undertaken. Soil mechanical properties were determined to ensure that consistent geotechnical data were obtained, and steady state vibration testing used since it is very accurate. Equipment and preliminary results are described.
The sonic echo technique is an established method of checking the integrity of piles. The shape of the reflected waveform is influenced by pile geometry and soil friction. A method of removing significant effects of soil friction and analysing the remaining signal to derive the geometry is described. Case histories demonstrate its effectiveness.
891286 Pile integrity testing - horses for courses Williams, H; Stain, R T Proe lnt Conference on Foundations and Tunnels, London, 2426 March 1987 V]. P184-191. Publ Edinburgh: Engineering Technics Press, 1987
891290 Prediction of the bearing capacity of a pile from dynamic measurements using a non-linear direct matrix integration procedure Delpak, R; Rowlands, G O; Lake, G C Proc lnt Conference on Fonmt~io~ and Tuuels, Loadon, 2426 March 1987 Vl, P211-218. Publ Edinburgh: Engineering Technics Press, 1987
Many methods of pile integrity testing have been used, impulse and ultrasonic methods being most common, but there is no established standard method. Impulse techniques Echo, Transient Dynamic Response, Parallel Seismic - and Sonic Coring tests are described. Recommendations are made, bearing in mind that no method is suitable for all situations and that pile type and dimensions, soil conditions, and degree of information required must be considered. Case histories are presented.
A mathematical model which may be used to predict the bearing capacity of piles from measurements made during driving is presented. The pile is discretised as a lumped mass system and the soil simulated by a bilinear elastoplastic model. By varying the parameters within the program, such as damping, good correlation can be obtained between predicted results and field measurements.
891287 Non-destructive pile load test in a sedimentary basin Andam, K A Proe lnt Conference on Foundations and Tunnels, London, 2426 March 1987 VI, P192-199. Publ Edinburgh: Engineering Technics Press, 1987
891291 Dynamic testing of bearing capacity of bored piles Seitz, J M Proc int Conference on Foundations and Tunnels, London, 2426 March 1987 VI, P219-227. Publ Edinburgh: Engineering Technics Press, 1987
Bridge foundations in a basin of silty sand to 3m, then silty clay, silty sand, plastic clay, then shale at about 15m are described. Load tests on a test pile gave a working load in good agreement with that predicted by dynamic formulae. Where pile extension was necessary, it was found that required skin friction was developed within the concrete curing time (28 days), which made redriving difficult. A rapid cure cement suggested in this case.
The theoretical background, instrumentation, and equipment for conducting dynamic tests on piles are described. Cases of dynamic and static testing of large diameter bored piles in sand and clay are reported. Load settlement curves calculated from dynamic measurements using the CAPWAP analysis are in good agreement with static test results. Some advice is offered on design of dynamic pile load tests.
891288 Monitoring and analysis of pile driving during installation Poskitt, T J; Yip, K L Proc lnt Conference on Foandotions and Tunnels, London, 2426 March 1987 VIo P200-204. Publ Edinburgh: Engineering Technics Press, 1987
891292 Probabilistic analysis of reliability of shallow foundation in a random static context Boulefkhad, T; Faugeras, J C; Fogli, M; Pouget, P Proc ECONMIG 86, Smttlart, 16-18 ~ p t e ~ 19866 V2, 13P. Publ Stuttgart: University o/Stuttgart, 1986
A rig to develop suitably robust strain and acceleration monitoring equipment for use during pile driving is described, together with a computer system for real time data processing, based on the wave equation. This may be used to predict soil properties during driving and best values of mobilised skin friction and end bearing capacity. Results from a test pile in hard clay gave a much lower bearing capacity than expected. This is explained by the presence of a thin soft zone at the pile wall, caused by lateral movement of the pile.
The basics of probabilistic analysis are first introduced. Cotnell's index (mean/standard deviation of a variable) is selected as a reliability measure. The problem considered is that of a shallow foundation on a layered soil, within which tests have been made at different depths. Choice and formulation of the limit state function are described. A Monte Carlo simulation is used to examine the influence of random variability of the parameters of the model on bearing capacity of the foundation.
© 1989 Pergamon Press plc. Reproduction not permitted