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Nonlinear lateral dynamic stiffness of piles
66A
tests on model soil-pile-structure systems. Using the proposed method, seismic response characteristics of an idealized offshore piles U P p l e d structure at a sand site were analyzed. Results indicated that liquefaction as well as pore pressure buildup around a pile can have a large impact on the response of pile-supported structures. Auth. ~6 refs. 8231~8 COMPRESSIBILITY AND BEARING CAPACITY Ismael, N F; Vesic, A S J Geotech Emgmg Div ASCE, V107, NGT12, Dec 1981, P1677-1691 Examines the effect of soil com~essibility on the ultimate bearing capacity of s h a l l ~ fc%mdations by means of small-scale model tests carried out on 2 frictional soils with identical shear stremg%h, but different deformation, characteristics. Tests included surface tests as well as tests with varyiI~ overburden Iressure, on strip amd circular footings. Experimental results are compared with available analytical methods which are assessed for suitability in the light of these results.
8231~9 ~0NLINEAR LATERAL DYNaMiC STIFFNESS OF PILES Angelides, D C; Roesset, ~.T ?E
J Gm~teah Emgmg D l v ASCE, V107, NGTll, Nov
1981, ~.,~3-146o The effect of nonlinear soll behavlour (without sl~ppage of gapping) on the d v ~ m i c response of piles subjected to lateral loads is exI~lored, using a finite element model for the soil region ~d~oining the pile, a consistent boundary m~trix at sO~e distance to reproduce raddation effects, an iterative, equivalent linearization techrdque to estimate the vs.~i~.tion of soil properties with level of strain. Results ob%~ined with this procedure ~re COml>ared with those "~hat would result from application of the ;--y curves and the differences are discussed. Auth.
8231.50 FRICTION CARA-CI'ITOF PILES D R I ~ ; INTO CLAY Kraft, L M; Focht, J A; Amerasir~m, S J Geotech Er~ng Div ASCE, VI07~ EGTII, Nov 198], P~521-15~I Procedures to coml~a~e shaft friction sre reviewed, em~ the effect of pile ler4~th on the development of shs/~ friction on piles in clay is examined in terms of the relative pile-soil stiffness and lateral pile movemerrbs d u r i ~ installation. CorrelatioI~ are developed to relate shaft frietioz, coefficients to pile ler~th, relative pile-soil stiffness, and soil stress history. Procedures are recommended to compute the friction capacity of piles in clay. 8231~1 %~E.OP~TICAL T-Z CUR%~S Kmaft, L M; Ray, R P; Ks~wa, T J Gexbeeh Engng Div ASCE, VIC7, ~3~..!, Nov
1981, P15~3-1561 /'. theoretical precedt~e is developed to generate t-z c ~ e s fur l~edictlng pile movements ~Lnder axial lo~d. The p r o c e d ~ e ~ses an aPlm'oxlmate ome-dime,~ioi~l elastic comtlinn~ afT/roach to define the t-z response up to the maximum t response ard laboratoI-j slmt%lation to defi~e the post-pe~d~ response. The procedure was used wit~ seversl case studies. Predicted response of the pile under Bz(ia] loadir~ was in good s~eement with the measured response.
823152 ~4BEI~ED FOUNDATIONS UNDER VERTICAL VIBRATION. TEC~[NlC AL ~FJTE Sridhsr~m, A; E~gendra, M V; ChiIma~'amy s C J Gec~eeh E I ~ Div ASCE, V107, NO/riO, Oct
].981, P1429--lh-34 A simplified Irocedure based on energy considerations has been developed for the solution of stead,?~state vibration of a system with combined viscous and C o u I ~ friction dam;ir~, subjected to frequency ~iependemt and frequency depemdent excitation, which yields results essentially the same as the exact solution. The proposed l~thod uses equivalent d s m p i ~ which assumes that if the d a m ~ m g in a system is smmll, the total dmnping effect can be re~esented by that of an equivalent damper. 823]53 DRILI>~ SHAFT IN%~GRITY BY WAVE PROPAGatION METHOD He,me, T M; Stokoe, K E; Reese, L C J Ge(f~ech E ~ Div ASCE, Vl0q, NDT!O, (~;t
198], P1327-13~ Compression wave pro~agatior, methods provide an economical and rapid no:~estructive means ol assesai1~ the structural integrity of drill~l shafts (cast-in-pl~,ce piles) shortly after construction. S e r i a l source-receiver configurations can be employed. ~%,e most successful configuration used involved a mechanical hammer with which vertical impulse was applied at the top of the shaft a,~ vertical velocity transducers which were cast in place in the shaft at preselected depths. Examples of' ~ e results for tests with sound shafts and for shafts with known defects of different sizes are presented. 823154 DYNAMIC POINT RESISTANC~ IN SA59 AND IN CLAY, FOR PILE DRiVEABILITY ANALYSIS Heeren~, E P Oroumd Engr~, VI~, N6, Sept 1981, P30-37, Results of earlier laboratory tests, by the author and other investigators, to determine pile tip damping factors are compared. (Damping factors describe the velocity dependence of point resista~me during driving. ) Ir-situ resistance data of driven piles, co~e penet~ometers and gravity platform skirts, serve as a check on d~unping values found ~n the lsbc~mtory and are useful for providing static point resist~nce values. As a result, p o i ~ dampirg relationships for unplugged ope.D-ended piles in ssnd and clay are proposed. These can then be used to predict pile driveability.
Slopes 823155 q"JO E/hRLY CONTP:IBtFflONS TO ~[E. 5q~A~.Y OF SLOPES. TECHNICAL NOTE Chaniler, R J Geotechnlque, ~ i ,
N4, Dec 1981, P~53-55~
Briefly discusses studies by Morton and by %~ncm~ son on slopes in the east Mid!e.nds area, UK. 823].56 IN.%TABIL~ OF AMUAY CLIFFsIDE Lambe, T W; Silva, F; Msrr, W A J Geotech EI~I~ Div ASCE, VI07, NGT!I, Nov
1981, 71505-1520
tests on model soil-pile-structure systems. Using the proposed method, seismic response characteristics of an idealized offshore piles U P p l e d structure at a sand site were analyzed. Results indicated that liquefaction as well as pore pressure buildup around a pile can have a large impact on the response of pile-supported structures. Auth. ~6 refs. 8231~8 COMPRESSIBILITY AND BEARING CAPACITY Ismael, N F; Vesic, A S J Geotech Emgmg Div ASCE, V107, NGT12, Dec 1981, P1677-1691 Examines the effect of soil com~essibility on the ultimate bearing capacity of s h a l l ~ fc%mdations by means of small-scale model tests carried out on 2 frictional soils with identical shear stremg%h, but different deformation, characteristics. Tests included surface tests as well as tests with varyiI~ overburden Iressure, on strip amd circular footings. Experimental results are compared with available analytical methods which are assessed for suitability in the light of these results.
8231~9 ~0NLINEAR LATERAL DYNaMiC STIFFNESS OF PILES Angelides, D C; Roesset, ~.T ?E
J Gm~teah Emgmg D l v ASCE, V107, NGTll, Nov
1981, ~.,~3-146o The effect of nonlinear soll behavlour (without sl~ppage of gapping) on the d v ~ m i c response of piles subjected to lateral loads is exI~lored, using a finite element model for the soil region ~d~oining the pile, a consistent boundary m~trix at sO~e distance to reproduce raddation effects, an iterative, equivalent linearization techrdque to estimate the vs.~i~.tion of soil properties with level of strain. Results ob%~ined with this procedure ~re COml>ared with those "~hat would result from application of the ;--y curves and the differences are discussed. Auth.
8231.50 FRICTION CARA-CI'ITOF PILES D R I ~ ; INTO CLAY Kraft, L M; Focht, J A; Amerasir~m, S J Geotech Er~ng Div ASCE, VI07~ EGTII, Nov 198], P~521-15~I Procedures to coml~a~e shaft friction sre reviewed, em~ the effect of pile ler4~th on the development of shs/~ friction on piles in clay is examined in terms of the relative pile-soil stiffness and lateral pile movemerrbs d u r i ~ installation. CorrelatioI~ are developed to relate shaft frietioz, coefficients to pile ler~th, relative pile-soil stiffness, and soil stress history. Procedures are recommended to compute the friction capacity of piles in clay. 8231~1 %~E.OP~TICAL T-Z CUR%~S Kmaft, L M; Ray, R P; Ks~wa, T J Gexbeeh Engng Div ASCE, VIC7, ~3~..!, Nov
1981, P15~3-1561 /'. theoretical precedt~e is developed to generate t-z c ~ e s fur l~edictlng pile movements ~Lnder axial lo~d. The p r o c e d ~ e ~ses an aPlm'oxlmate ome-dime,~ioi~l elastic comtlinn~ afT/roach to define the t-z response up to the maximum t response ard laboratoI-j slmt%lation to defi~e the post-pe~d~ response. The procedure was used wit~ seversl case studies. Predicted response of the pile under Bz(ia] loadir~ was in good s~eement with the measured response.
823152 ~4BEI~ED FOUNDATIONS UNDER VERTICAL VIBRATION. TEC~[NlC AL ~FJTE Sridhsr~m, A; E~gendra, M V; ChiIma~'amy s C J Gec~eeh E I ~ Div ASCE, V107, NO/riO, Oct
].981, P1429--lh-34 A simplified Irocedure based on energy considerations has been developed for the solution of stead,?~state vibration of a system with combined viscous and C o u I ~ friction dam;ir~, subjected to frequency ~iependemt and frequency depemdent excitation, which yields results essentially the same as the exact solution. The proposed l~thod uses equivalent d s m p i ~ which assumes that if the d a m ~ m g in a system is smmll, the total dmnping effect can be re~esented by that of an equivalent damper. 823]53 DRILI>~ SHAFT IN%~GRITY BY WAVE PROPAGatION METHOD He,me, T M; Stokoe, K E; Reese, L C J Ge(f~ech E ~ Div ASCE, Vl0q, NDT!O, (~;t
198], P1327-13~ Compression wave pro~agatior, methods provide an economical and rapid no:~estructive means ol assesai1~ the structural integrity of drill~l shafts (cast-in-pl~,ce piles) shortly after construction. S e r i a l source-receiver configurations can be employed. ~%,e most successful configuration used involved a mechanical hammer with which vertical impulse was applied at the top of the shaft a,~ vertical velocity transducers which were cast in place in the shaft at preselected depths. Examples of' ~ e results for tests with sound shafts and for shafts with known defects of different sizes are presented. 823154 DYNAMIC POINT RESISTANC~ IN SA59 AND IN CLAY, FOR PILE DRiVEABILITY ANALYSIS Heeren~, E P Oroumd Engr~, VI~, N6, Sept 1981, P30-37, Results of earlier laboratory tests, by the author and other investigators, to determine pile tip damping factors are compared. (Damping factors describe the velocity dependence of point resista~me during driving. ) Ir-situ resistance data of driven piles, co~e penet~ometers and gravity platform skirts, serve as a check on d~unping values found ~n the lsbc~mtory and are useful for providing static point resist~nce values. As a result, p o i ~ dampirg relationships for unplugged ope.D-ended piles in ssnd and clay are proposed. These can then be used to predict pile driveability.
Slopes 823155 q"JO E/hRLY CONTP:IBtFflONS TO ~[E. 5q~A~.Y OF SLOPES. TECHNICAL NOTE Chaniler, R J Geotechnlque, ~ i ,
N4, Dec 1981, P~53-55~
Briefly discusses studies by Morton and by %~ncm~ son on slopes in the east Mid!e.nds area, UK. 823].56 IN.%TABIL~ OF AMUAY CLIFFsIDE Lambe, T W; Silva, F; Msrr, W A J Geotech EI~I~ Div ASCE, VI07, NGT!I, Nov
1981, 71505-1520