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Modified settlement criteria for buildings on soft ground
264A 895281 Pile loading tests - practice in Nigeria Balogun, L A
895285 Settlement criteria for large oil storage tanks Chen, H M; Pan, C C: Chung, ST
Proc Ninth Regional Conference for Africa o n Soil Mechanics and Foundation Engineering, Lagos, September 1987 VI, P301-305. Publ Rotterdam: A A Balkema, 1987
Proc Ninth Southeast Asian Geoteclmical Conference, Bangkok, 7-11 December 1987 VI. P4.41-4.52. Pub[ Bangkok." Southeast Asian Geotechnical Society, 1987
Pile load testing procedures employed in Nigeria are reviewed. The maintained load technique is most commonly used, with piles usually loaded to proof load, a multiple of the assumed working load, rather than to failure. A method to estimate ultimate load carrying capacity is proposed, and when used to re-analyse existing data. shows that piles in Nigeria are often underestimated.
A new set of criteria for use in foundation design and performance is suggested. The criteria have been derived from previous studies and are verified by application to 11 storage tanks in Taiwan. Patterns of tank settlement, divided into shell and bottom plate settlement, are described.
895282 Design of short piles in expansive soils: a probabilistic approach Ali, E M; Abbadi, S E M
Proc Ninth Regional Conference for Africa o n Soil Mechanics and Foundation Engineering, Lagos, September 1987 VI, P307-311. Publ Rotterdam: A A Balkema, 1987 Short piles are often used for foundations on expansive soils. Deterministic models are usually employed in design. A statistical model is developed to calculate the probability of failure, and illustrated for a housing development in Sudan. The method requires values for swelling pressure and cohesion.
895283 Behaviour of piles in residual and lateritic deposits of Nigeria Ajayi, L A
Proc Ninth Regional Conference for Africa o n Soil Mechanics and Foundation Engineering, Lagos, September 1987 VI, P313-318. Publ Rotterdam: A A Balkema. 1987 Piled foundations are increasingly being used in Nigeria. The behaviour of driven and bored piles in lateritic and sedimentary soils was investigated with loading tests on a variety of piles at 3 sites, 2 laterites and I sandy. Results show that friction piles perform better than end bearing piles, and that the auger pressure grouted pile is most suitable for the heterogeneous, desiccated and stiff tropical deposits of Nigeria.
895284 Settlements of structures and their predictions in Bangkok subsoils Sambhandharaksa, S; Pongrujidorn, T; Chaloeywares, P
Proc Ninth Southeast Asian Geotechnical Conference, Bangkok, 7-11 December 1987 VI, P4.25-4.40. Publ Bangkok: Southeast Asian Geotechnical Society, 1987 Settlement of pile foundations for highrise buildings in Bangkok was measured and results compared with predicted data. Soil conditions were determined by boring to the first stiff clay layer and with laboratory tests, and settlements obtained from linear interpolation of data from reference piles during and after construction. Poulos' and Terzaghi's methods were used to predict settlement, and predicted and observed time settlement curves compared. Results show that the soils settle rapidly and that negative skin friction should be considered. Poulos' method gave good results for soils behaving elastically, whilst Terzaghi's method gave a better estimate of final settlement of pile foundations with tips in overstressed clays.
895286 Modified settlement criteria for buildings on soft ground Sadiq, M I
Proc Ninth Southeast Asian Geoteclmical Conference, Bangkok, 7-11 December 1987 VI, P4.73-4.82. Publ Bangkok: Southeast Asian Geotechnical Society, 1987 Concepts of tolerable settlement criteria are outlined, and modified criteria proposed. The modified criteria are considered more appropriate for foundations on soft ground composed of loose sand and soft clay, and are based on differential settlement and loading conditions. The criteria are illustrated for a site with a mat foundation on loose sand and soft clays, showing that the proposed approach provides realistic tolerable settlement criteria, leading to increased values of load carrying capacity and savings in foundation costs.
895287 Tests on model instrumented piles in calcareous soil Poulos, H G; Chan, K F
Univ Sydney School of Civil and Mining Engng Research Report R567, April 1988.28P Tests on model piles jacked into reconstituted marine calcareous sediments are described, Single piles were examined during installation, under static loading, and under load- and displacement-controlled cyclic loading. Significant residual stresses exist in the pile after installation. Low skin friction is developed, primarily due to reduction of lateral stress during installation. Skin friction is reduced during cyclic loading, the reduction being a function of displacement rather than load level. Skin friction is significantly increased by soil consolidation after pile installation.
895288 Cyclic axial loading analysis of piles in sand Pouios, H G
Univ Sydney School of Civil and Mining Engng Research Report R575, July 1988, 34P A boundary element analysis for the behaviour of a single pile or symmetrical pile group in sand under cyclic axial loading is presented. Degradation of skin friction, base resistance and soil modulus, influence of loading rate, and accumulation of plastic strain are taken into account. Laboratory data for degradation of skin friction are reviewed, and it is seen that degradation depends on cyclic displacement, cycle number, pile type, and soil type. The importance of determining whether skin friction degradation depends on absolute cyclic displacement or cyclic displacement relative to pile diameter is emphasised.
1989 Pergamon Press plc. Reproduction not permitted
895285 Settlement criteria for large oil storage tanks Chen, H M; Pan, C C: Chung, ST
Proc Ninth Regional Conference for Africa o n Soil Mechanics and Foundation Engineering, Lagos, September 1987 VI, P301-305. Publ Rotterdam: A A Balkema, 1987
Proc Ninth Southeast Asian Geoteclmical Conference, Bangkok, 7-11 December 1987 VI. P4.41-4.52. Pub[ Bangkok." Southeast Asian Geotechnical Society, 1987
Pile load testing procedures employed in Nigeria are reviewed. The maintained load technique is most commonly used, with piles usually loaded to proof load, a multiple of the assumed working load, rather than to failure. A method to estimate ultimate load carrying capacity is proposed, and when used to re-analyse existing data. shows that piles in Nigeria are often underestimated.
A new set of criteria for use in foundation design and performance is suggested. The criteria have been derived from previous studies and are verified by application to 11 storage tanks in Taiwan. Patterns of tank settlement, divided into shell and bottom plate settlement, are described.
895282 Design of short piles in expansive soils: a probabilistic approach Ali, E M; Abbadi, S E M
Proc Ninth Regional Conference for Africa o n Soil Mechanics and Foundation Engineering, Lagos, September 1987 VI, P307-311. Publ Rotterdam: A A Balkema, 1987 Short piles are often used for foundations on expansive soils. Deterministic models are usually employed in design. A statistical model is developed to calculate the probability of failure, and illustrated for a housing development in Sudan. The method requires values for swelling pressure and cohesion.
895283 Behaviour of piles in residual and lateritic deposits of Nigeria Ajayi, L A
Proc Ninth Regional Conference for Africa o n Soil Mechanics and Foundation Engineering, Lagos, September 1987 VI, P313-318. Publ Rotterdam: A A Balkema. 1987 Piled foundations are increasingly being used in Nigeria. The behaviour of driven and bored piles in lateritic and sedimentary soils was investigated with loading tests on a variety of piles at 3 sites, 2 laterites and I sandy. Results show that friction piles perform better than end bearing piles, and that the auger pressure grouted pile is most suitable for the heterogeneous, desiccated and stiff tropical deposits of Nigeria.
895284 Settlements of structures and their predictions in Bangkok subsoils Sambhandharaksa, S; Pongrujidorn, T; Chaloeywares, P
Proc Ninth Southeast Asian Geotechnical Conference, Bangkok, 7-11 December 1987 VI, P4.25-4.40. Publ Bangkok: Southeast Asian Geotechnical Society, 1987 Settlement of pile foundations for highrise buildings in Bangkok was measured and results compared with predicted data. Soil conditions were determined by boring to the first stiff clay layer and with laboratory tests, and settlements obtained from linear interpolation of data from reference piles during and after construction. Poulos' and Terzaghi's methods were used to predict settlement, and predicted and observed time settlement curves compared. Results show that the soils settle rapidly and that negative skin friction should be considered. Poulos' method gave good results for soils behaving elastically, whilst Terzaghi's method gave a better estimate of final settlement of pile foundations with tips in overstressed clays.
895286 Modified settlement criteria for buildings on soft ground Sadiq, M I
Proc Ninth Southeast Asian Geoteclmical Conference, Bangkok, 7-11 December 1987 VI, P4.73-4.82. Publ Bangkok: Southeast Asian Geotechnical Society, 1987 Concepts of tolerable settlement criteria are outlined, and modified criteria proposed. The modified criteria are considered more appropriate for foundations on soft ground composed of loose sand and soft clay, and are based on differential settlement and loading conditions. The criteria are illustrated for a site with a mat foundation on loose sand and soft clays, showing that the proposed approach provides realistic tolerable settlement criteria, leading to increased values of load carrying capacity and savings in foundation costs.
895287 Tests on model instrumented piles in calcareous soil Poulos, H G; Chan, K F
Univ Sydney School of Civil and Mining Engng Research Report R567, April 1988.28P Tests on model piles jacked into reconstituted marine calcareous sediments are described, Single piles were examined during installation, under static loading, and under load- and displacement-controlled cyclic loading. Significant residual stresses exist in the pile after installation. Low skin friction is developed, primarily due to reduction of lateral stress during installation. Skin friction is reduced during cyclic loading, the reduction being a function of displacement rather than load level. Skin friction is significantly increased by soil consolidation after pile installation.
895288 Cyclic axial loading analysis of piles in sand Pouios, H G
Univ Sydney School of Civil and Mining Engng Research Report R575, July 1988, 34P A boundary element analysis for the behaviour of a single pile or symmetrical pile group in sand under cyclic axial loading is presented. Degradation of skin friction, base resistance and soil modulus, influence of loading rate, and accumulation of plastic strain are taken into account. Laboratory data for degradation of skin friction are reviewed, and it is seen that degradation depends on cyclic displacement, cycle number, pile type, and soil type. The importance of determining whether skin friction degradation depends on absolute cyclic displacement or cyclic displacement relative to pile diameter is emphasised.
1989 Pergamon Press plc. Reproduction not permitted