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Cyclic load-induced settlement of a square foundation on geogrid-reinforced sand. Technical note
101A Some problems associated with applying separate load and safety factors are illustrated. This CSA standard dictates that design should include risk analysis of the foundation system. A simple form of such an analysis for a caisson-retained sand structure is shown. 942319 Ultimate bearing capacity of shallow foundations on sand with geogrid reinforcement. Note Omar, M J; Das, B M; Puri, V K; Yen, S C Can Geotech J V30, N3, June 1993, P545-549
Results of some recent model tests on square and strip foundations supported by geogrid-reinforced sand are presented and compared. Effective depth of reinforcement for maximum bearing capacity, maximum width of reinforcement layer necessary to mobilize maximum bearing capacity ratio, and maximum depth of placement of first layer to take advantage of the reinforcing effect are evaluated. 942320 Analysis of pile-soil interaction under lateral loading using infinite and finite elements Chen, L; Poulos, H G Comput Geotech V15, N4, 1993, P189-220
The mechanisms of pile-soil interaction and effects of group action on ultimate lateral soil resistance are examined using an approach combining finite elements and the mapped infinite elements of Damjanic and Owen. The basis of the mathematical procedure is outlined. Results are presented for single isolated piles and pile groups of various layouts. Ultimate lateral load resistance is generally lower for a pile within a group than for a similar isolated pile. Results compare reasonably well with initial model test data. 942321 Cyclic iond-indnced settlement of a square foundation on geogrid-reinforced sand. Technical note Puri, V K; Yen, S C; Das, B M; Yeo, B Geotext Geomem V12, N6, 1993, P587-597
Laboratory model tests on square foundations on sand with or without geogrid reinforcement are reported. The foundation was subject to an allowable static load then a cyclic load superimposed. For any given static load, ultimate permanent settlement increased with increasing amplitude of cyclic load. The critical number of load cycles to induce permanent settlement was similar for reinforced and unreinforced sands, but ultimate permanent settlement was significantly reduced by reinforcement. 942322 Behaviourai prediction and performance of structures on improved ground and search for new technologies Rao, B G Indian Geotech J V23, NI, Jan 1993, P1-194
The 15th Indian Geotechnical Society Lecture. A comprehensive examination of foundation types and performance for improved ground is presented. Structures on strata improved by granular piles with and without rigid skirts, pad foundations on soft saturated marine clay, rigid rafts on soft clay, timber pile skirting with a ring beam on soft clayey silt, column footings and flexible rafts on ground with granular piles, and underpinning techniques arc described. Innovative or alternative approaches arc also considered, such as geopads, self-setting slurry soil piles with gcotextile-reinforced cap, soil nailing, minipilcs, and spliced piles. 141 refs.
942323 Assessment of shape and quality of bored concrete piles by integrity testing Prakash, C; Rastogi, P C; Sharma, A K Indian Geoteck J V23, N2, April 1993, P213-234
Low strain integrity tests based on a one dimensional stress wave approach are widely used to assess shape and quality of cast-in-situ concrete piles. Such tests using the Foundation Pile Diagnositc System (FPDS) have been carried out on specially cast straight and undcrreamed piles with no known defects, exhumed undcrreamcd piles, and production underreamed piles. The accuracy of this simple, rapid, and efficient technique is discussed with reference to the experimental data. 942324 Determination of size of footings Pandian, N S; Sridharan, A; Sathidevi, U Indian Geotech J V23, N2, April 1993, P252-276
Bearing capacity of a footing depends on its size and shape, as well as on the soil properties. Various equations with shape and depth factors have been developed to predict bearing capacity. Using these, design charts have been generated by computer to minimise the work necessary to select allowable width of footings. The method to calculate the required width from a settlement criterion is also discussed. 942325 Bearing capacity of clay with variable surcharge of finite extent. Technical note. Madhar, M R; Datye, K R Indian Geotech J V23, N2, April 1993, P277-284
Most analyses of beating capacity of footings consider the surcharge pressure to be uniform and of infinite extent. In some cases surcharge pressure may decrease with distance from some central point and cover a finite area. A simple theory for beating capacity of soft clay subject to uniform or linearly or exponentially decreasing surcharge stress is presented. A composite bearing capacity factor in terms of maximum of and extent of surcharge pressure is obtained. Results are depicted in terms of improvement in bearing capacity ratio. 942326 Cyclic response of axially loaded pile groups Lee, C Y J Geotech Engng Div ASCE VlI9, N9, Sept 1993, P13991413
A simplified cycle-by-cycle total stress hybrid load transfer approach for analysis of pile groups in clay subject to cyclic axial loading is presented. The loading pattern may be uniform or irregular. Accumulation of permanent displacement and reduction in pile friction arc considered using the degradation of secant modulus and shaft limited stress. Loading rate effects are not considered. The procedure is validated against results of model tests and repeated monotonic loading tests on a pile group in overconsolidated clay. 942327 Settlement of pile groups - practical approach Lee, C Y J Geotech Engng Div ASCE V119, 179, Sept 1993, P14491461
An approach for settlement of pile groups embedded in an isotropic elastic half space is presented which provides adequate accuracy without the expense of complete rigorous analysis. It is based on a superposition of interaction factors of
Results of some recent model tests on square and strip foundations supported by geogrid-reinforced sand are presented and compared. Effective depth of reinforcement for maximum bearing capacity, maximum width of reinforcement layer necessary to mobilize maximum bearing capacity ratio, and maximum depth of placement of first layer to take advantage of the reinforcing effect are evaluated. 942320 Analysis of pile-soil interaction under lateral loading using infinite and finite elements Chen, L; Poulos, H G Comput Geotech V15, N4, 1993, P189-220
The mechanisms of pile-soil interaction and effects of group action on ultimate lateral soil resistance are examined using an approach combining finite elements and the mapped infinite elements of Damjanic and Owen. The basis of the mathematical procedure is outlined. Results are presented for single isolated piles and pile groups of various layouts. Ultimate lateral load resistance is generally lower for a pile within a group than for a similar isolated pile. Results compare reasonably well with initial model test data. 942321 Cyclic iond-indnced settlement of a square foundation on geogrid-reinforced sand. Technical note Puri, V K; Yen, S C; Das, B M; Yeo, B Geotext Geomem V12, N6, 1993, P587-597
Laboratory model tests on square foundations on sand with or without geogrid reinforcement are reported. The foundation was subject to an allowable static load then a cyclic load superimposed. For any given static load, ultimate permanent settlement increased with increasing amplitude of cyclic load. The critical number of load cycles to induce permanent settlement was similar for reinforced and unreinforced sands, but ultimate permanent settlement was significantly reduced by reinforcement. 942322 Behaviourai prediction and performance of structures on improved ground and search for new technologies Rao, B G Indian Geotech J V23, NI, Jan 1993, P1-194
The 15th Indian Geotechnical Society Lecture. A comprehensive examination of foundation types and performance for improved ground is presented. Structures on strata improved by granular piles with and without rigid skirts, pad foundations on soft saturated marine clay, rigid rafts on soft clay, timber pile skirting with a ring beam on soft clayey silt, column footings and flexible rafts on ground with granular piles, and underpinning techniques arc described. Innovative or alternative approaches arc also considered, such as geopads, self-setting slurry soil piles with gcotextile-reinforced cap, soil nailing, minipilcs, and spliced piles. 141 refs.
942323 Assessment of shape and quality of bored concrete piles by integrity testing Prakash, C; Rastogi, P C; Sharma, A K Indian Geoteck J V23, N2, April 1993, P213-234
Low strain integrity tests based on a one dimensional stress wave approach are widely used to assess shape and quality of cast-in-situ concrete piles. Such tests using the Foundation Pile Diagnositc System (FPDS) have been carried out on specially cast straight and undcrreamed piles with no known defects, exhumed undcrreamcd piles, and production underreamed piles. The accuracy of this simple, rapid, and efficient technique is discussed with reference to the experimental data. 942324 Determination of size of footings Pandian, N S; Sridharan, A; Sathidevi, U Indian Geotech J V23, N2, April 1993, P252-276
Bearing capacity of a footing depends on its size and shape, as well as on the soil properties. Various equations with shape and depth factors have been developed to predict bearing capacity. Using these, design charts have been generated by computer to minimise the work necessary to select allowable width of footings. The method to calculate the required width from a settlement criterion is also discussed. 942325 Bearing capacity of clay with variable surcharge of finite extent. Technical note. Madhar, M R; Datye, K R Indian Geotech J V23, N2, April 1993, P277-284
Most analyses of beating capacity of footings consider the surcharge pressure to be uniform and of infinite extent. In some cases surcharge pressure may decrease with distance from some central point and cover a finite area. A simple theory for beating capacity of soft clay subject to uniform or linearly or exponentially decreasing surcharge stress is presented. A composite bearing capacity factor in terms of maximum of and extent of surcharge pressure is obtained. Results are depicted in terms of improvement in bearing capacity ratio. 942326 Cyclic response of axially loaded pile groups Lee, C Y J Geotech Engng Div ASCE VlI9, N9, Sept 1993, P13991413
A simplified cycle-by-cycle total stress hybrid load transfer approach for analysis of pile groups in clay subject to cyclic axial loading is presented. The loading pattern may be uniform or irregular. Accumulation of permanent displacement and reduction in pile friction arc considered using the degradation of secant modulus and shaft limited stress. Loading rate effects are not considered. The procedure is validated against results of model tests and repeated monotonic loading tests on a pile group in overconsolidated clay. 942327 Settlement of pile groups - practical approach Lee, C Y J Geotech Engng Div ASCE V119, 179, Sept 1993, P14491461
An approach for settlement of pile groups embedded in an isotropic elastic half space is presented which provides adequate accuracy without the expense of complete rigorous analysis. It is based on a superposition of interaction factors of