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Dynamic stiffness and damping of piles
64A
Of creep rates and ultimate failure loads was checked against the results of screw auchcr tests carried out by the Division of Building Research, N.R.C.C., at a permafrost site in Thompson, ~%itoba. It was found that the use in the theory of the creep parameters determined by creep-pressuremeter tests performed at the site, resulted in a satiafactcry agreement between the l~edicted and the observed behaviour.Auth. 6O4 NOVAK, M ~ c stiffmess and damping Qf piles. 18F,2T, 12R. CAN. GEOTECH. J .VII, m , NOV. 197~, P574- 59~. Dymamic response Of footings and structures supported by piles can be predicted if dynamic stiffness and damping generated by soil-pile interaction man be defined. An apl~Qximate smalytlcal approach based on linear elasticity is im~esemted, which makes it possible to establish the dimensionless parameters of the problem and to obtain closed-fszm formulas for pile stiffness and damping. All components of the motion in a vertical plane are considered; ~hat is, horizontal as well as vertical translation and rotation of the pile head. The stiffness amd damping of piles are defined in such a way that the design analysis of footings and structures resting on piles can be conducted in the same way as is applied in the case Of shallow foundations. Auth.
605 ~COOWN, A
cribed which was developed for unsaturated and saturated expansive clay with non-linear properties. It is sn extension of Blots consolidation theory to include unsaturated soils and has been checked satisfactorily against available mathematical solutions for saturated soils. Extrapolation to unsaturated soils still requires field verification. A mathematical medal has now been set up by coupling the above soll model to the structural model for various structures; as. reinforced slab-onground foundations. Some pre1~mlnary results obtained from this application are described. 6O8 TAN, SB Settlement due to deep foundation construction. Conference. Session four. 6F,1T,~R. PROC.EIGHTH INT.CONF.ON SOIL MECH.FOUND.ENGNG. MOSCOW, V2.2,1973, P221- 226. This paper describes the case history of the City Hall Building, Singapore, when ground settlements adjacent to the sites of deep excavation fcr foundation construction occurred. The settlements are shown to be a consequence of soft clay formation, depth of excavation, method of construction, and time log in strutting. The pattern of cracks and gaps observed between the various blocks of the building correspond with the settlements that had occurred.
609
WENZ, KP Large scale tests for determination of lateral BARDEN, L loads on piles in soft cohesive soils. ConL ~ , SH ference. Session four. 7F,1T,7R. Sample disturbamce in soft alluvial Clyde Estuary PROC.EIGHTH INT.CONF.ON SOIL MECH.FOUND.ENGNG. clay.-Techmical note. 12F,6R. MOSCOW, v2.2,1973,P247-255. CAN. GEOTECH. J. VII, ~ , NOV. 1974, I~ 51-660. Three large scale tests on steal stud cast-in-place The alluvium of the Clyde Estuary provides the foundatdriven piles have been conducted to determine the ion material for a number of medium rise developments lateral load on piles in soft cohesive soils. The subin the Glasgow area. Standard site investigation and soil used was soft cohesive soll with a layer thicktesting techniques Often result in an expensive fourzlatness of 15-18m. Calculation methods developed by the ion design involving piling. A more sophisticated invesauther in 1963 based on the plasticity theory are used. tigation conducted at Laurieston, has afforded a chance It is shown that lateral forces caused by this soll to compare the disturbance due to different qualities of type and acting on piles of common used dimensions may sampling. The degree of disturbance to macro- stud microincrease sufficiently to cause damage to the piles structure has been assessed using standard photographlc techniques and a scanning electron microscope. The effect which may result in failure. of disturbance on shear strength has been measured using 610 hamd vane and triaxial tests; and on consolidation and PILLAI, SU REGIONAL ENGNG.COLL.CALICUT. IND cumpresslon parameters using Rowe cells of different Ultimate strergth of concrete pile shoes.-Resizes. On the basis of the s ~ stud the improved site investigations two foundation designs have been pre- pert. 22F,4~. RESEARCH ~ N ~ D E F ~ . C I V . E N G N G . , R E G I O N A L ENGN3. pared and their cost compared. Auth. COLI/~E, CALICUT. ~ , OCT. 1973, 24P. The casing tubes for the cast-in-sltu concrete foundat6O6 ion piles for the Docks of the Cochin Shipyard were POULOs, HG proposed to be driven with a pre-cast concrete pile DAVI S, EH shoe at the bottom. Two sizes of piles, 500ran diaTheory Of piles in swelling and shrinking molls. meter and 600n~n diameter were to be driven. A study Conference. Session fotlr. IOF.19R. was undertaken to determine the ultimate strength and F~OC.EIG~n~ INT.CO~F.ON SOIL ~ T ~ . F O U N D . E ~ . behaviour umder loading of the concrete pile shoes. MOSCOW, V2.2,1973, P169-176. Full scale tests were conducted for the 500me diameter In this paper a method of analysing the movement of a pile shoes stud model studies for the larger 600ram diapile in swelling soil is presented. The analysis is meter piles. Free these studies it has been concluded based on the simplifying assumption that the soil can be that the concrete shoes have adequate ultimate strength. treated as an elastic material but modifications to the Auth. analysis are described which allow consideration of such factors as non-homogeneity, slip at the pile-soil interfame amd c~-h~mg or tensile failure of the pile. The major factors affecting pile movements are illustrated by presentir~ a number of idealized theoretical sol~tions. Comparisons between the predicted characteristics Of behavlour of piles in swelling soils show encouraging agreement with the behaviour observed in a number of full-scale fleid tests. 6O7 RICHARDS, BO Model for slab foundations on expansive clays. Conference. Session four. 12F,17R. PROC.EIGHTH INf.CONF.ON SOIL MECH.FOUND.ENGN3.. MOSCOW~ V2.2,1973, P185-191. In this paper a deterministic mathematical model is des-
611 CHAKRAVORTY, AK GHOSH, A Finite difference solution for circular plates on elastic foundations o 6F, 2T, 2R. INf. J. ~.METH.ENGN3 .Vg, NI, 1975, P73-84. A finite differeuce method of analysis for any circular plate wlth ar~ kind of loading on semi-lnfinite elastic fourzlatlons, has been developed. The equations have been developed, and the results obtained, in non-dlmensional farm. The results have been cc~pared with available experimental results and agreement Is found to be very good. The method can be modified to apply to Wlr~ler type foumdations and problems of circnlar plates of various thickness.
Of creep rates and ultimate failure loads was checked against the results of screw auchcr tests carried out by the Division of Building Research, N.R.C.C., at a permafrost site in Thompson, ~%itoba. It was found that the use in the theory of the creep parameters determined by creep-pressuremeter tests performed at the site, resulted in a satiafactcry agreement between the l~edicted and the observed behaviour.Auth. 6O4 NOVAK, M ~ c stiffmess and damping Qf piles. 18F,2T, 12R. CAN. GEOTECH. J .VII, m , NOV. 197~, P574- 59~. Dymamic response Of footings and structures supported by piles can be predicted if dynamic stiffness and damping generated by soil-pile interaction man be defined. An apl~Qximate smalytlcal approach based on linear elasticity is im~esemted, which makes it possible to establish the dimensionless parameters of the problem and to obtain closed-fszm formulas for pile stiffness and damping. All components of the motion in a vertical plane are considered; ~hat is, horizontal as well as vertical translation and rotation of the pile head. The stiffness amd damping of piles are defined in such a way that the design analysis of footings and structures resting on piles can be conducted in the same way as is applied in the case Of shallow foundations. Auth.
605 ~COOWN, A
cribed which was developed for unsaturated and saturated expansive clay with non-linear properties. It is sn extension of Blots consolidation theory to include unsaturated soils and has been checked satisfactorily against available mathematical solutions for saturated soils. Extrapolation to unsaturated soils still requires field verification. A mathematical medal has now been set up by coupling the above soll model to the structural model for various structures; as. reinforced slab-onground foundations. Some pre1~mlnary results obtained from this application are described. 6O8 TAN, SB Settlement due to deep foundation construction. Conference. Session four. 6F,1T,~R. PROC.EIGHTH INT.CONF.ON SOIL MECH.FOUND.ENGNG. MOSCOW, V2.2,1973, P221- 226. This paper describes the case history of the City Hall Building, Singapore, when ground settlements adjacent to the sites of deep excavation fcr foundation construction occurred. The settlements are shown to be a consequence of soft clay formation, depth of excavation, method of construction, and time log in strutting. The pattern of cracks and gaps observed between the various blocks of the building correspond with the settlements that had occurred.
609
WENZ, KP Large scale tests for determination of lateral BARDEN, L loads on piles in soft cohesive soils. ConL ~ , SH ference. Session four. 7F,1T,7R. Sample disturbamce in soft alluvial Clyde Estuary PROC.EIGHTH INT.CONF.ON SOIL MECH.FOUND.ENGNG. clay.-Techmical note. 12F,6R. MOSCOW, v2.2,1973,P247-255. CAN. GEOTECH. J. VII, ~ , NOV. 1974, I~ 51-660. Three large scale tests on steal stud cast-in-place The alluvium of the Clyde Estuary provides the foundatdriven piles have been conducted to determine the ion material for a number of medium rise developments lateral load on piles in soft cohesive soils. The subin the Glasgow area. Standard site investigation and soil used was soft cohesive soll with a layer thicktesting techniques Often result in an expensive fourzlatness of 15-18m. Calculation methods developed by the ion design involving piling. A more sophisticated invesauther in 1963 based on the plasticity theory are used. tigation conducted at Laurieston, has afforded a chance It is shown that lateral forces caused by this soll to compare the disturbance due to different qualities of type and acting on piles of common used dimensions may sampling. The degree of disturbance to macro- stud microincrease sufficiently to cause damage to the piles structure has been assessed using standard photographlc techniques and a scanning electron microscope. The effect which may result in failure. of disturbance on shear strength has been measured using 610 hamd vane and triaxial tests; and on consolidation and PILLAI, SU REGIONAL ENGNG.COLL.CALICUT. IND cumpresslon parameters using Rowe cells of different Ultimate strergth of concrete pile shoes.-Resizes. On the basis of the s ~ stud the improved site investigations two foundation designs have been pre- pert. 22F,4~. RESEARCH ~ N ~ D E F ~ . C I V . E N G N G . , R E G I O N A L ENGN3. pared and their cost compared. Auth. COLI/~E, CALICUT. ~ , OCT. 1973, 24P. The casing tubes for the cast-in-sltu concrete foundat6O6 ion piles for the Docks of the Cochin Shipyard were POULOs, HG proposed to be driven with a pre-cast concrete pile DAVI S, EH shoe at the bottom. Two sizes of piles, 500ran diaTheory Of piles in swelling and shrinking molls. meter and 600n~n diameter were to be driven. A study Conference. Session fotlr. IOF.19R. was undertaken to determine the ultimate strength and F~OC.EIG~n~ INT.CO~F.ON SOIL ~ T ~ . F O U N D . E ~ . behaviour umder loading of the concrete pile shoes. MOSCOW, V2.2,1973, P169-176. Full scale tests were conducted for the 500me diameter In this paper a method of analysing the movement of a pile shoes stud model studies for the larger 600ram diapile in swelling soil is presented. The analysis is meter piles. Free these studies it has been concluded based on the simplifying assumption that the soil can be that the concrete shoes have adequate ultimate strength. treated as an elastic material but modifications to the Auth. analysis are described which allow consideration of such factors as non-homogeneity, slip at the pile-soil interfame amd c~-h~mg or tensile failure of the pile. The major factors affecting pile movements are illustrated by presentir~ a number of idealized theoretical sol~tions. Comparisons between the predicted characteristics Of behavlour of piles in swelling soils show encouraging agreement with the behaviour observed in a number of full-scale fleid tests. 6O7 RICHARDS, BO Model for slab foundations on expansive clays. Conference. Session four. 12F,17R. PROC.EIGHTH INf.CONF.ON SOIL MECH.FOUND.ENGN3.. MOSCOW~ V2.2,1973, P185-191. In this paper a deterministic mathematical model is des-
611 CHAKRAVORTY, AK GHOSH, A Finite difference solution for circular plates on elastic foundations o 6F, 2T, 2R. INf. J. ~.METH.ENGN3 .Vg, NI, 1975, P73-84. A finite differeuce method of analysis for any circular plate wlth ar~ kind of loading on semi-lnfinite elastic fourzlatlons, has been developed. The equations have been developed, and the results obtained, in non-dlmensional farm. The results have been cc~pared with available experimental results and agreement Is found to be very good. The method can be modified to apply to Wlr~ler type foumdations and problems of circnlar plates of various thickness.