1,721,195 research outputs found
Geotechnical aspects of underground railway construction in the urban environment: the examples of Roma and Napoli
No full textThis paper presents some of the geotechnical aspects of underground railway construction in the urban environment,
drawing from recent experience gathered during the design of the new Line C of Rome Underground and the construction of Line 1
of Naples Underground. For Rome Underground, the paper summarizes the main results of a study of the interaction between tunnel
construction and a monumental structure at the surface. The assessment of the potential damage induced by tunnelling was
approached following stages of increasing complexity, from simple and well-established semi-empirical methods to 2D and 3D
numerical soil–structure interaction analyses. A significant joint effort from archaeologists and geotechnical and structural
engineers was required to define reliable models of the monument and of the subsoil ground conditions. For Naples Underground,
this paper describes the construction techniques that were implemented to build the open excavations required to accommodate the
stations, including artificial ground freezing, and illustrates some of the analyses that were carried out to interpret the observations
of the ground behaviour and of the behaviour of the structures during construction
ANALYSIS AND PERFORMANCE OF PILED RAFTS DESIGNED USING INNOVATIVE CRITERIA
No full textIn this paper the main criteria adopted for the design and some aspects of the observed behaviour of the piled foundations of a cluster of circular steel tanks are reported. They were designed to store sodium hydroxide, a toxic liquid with a unit weight of 15.1 kN/m3. Shallow foundations would have been safe against a bearing capacity failure, while the predicted settlement were beyond the allowed limit. Accordingly piles were designed to reduce the settlement and improve the overall performance of the foundations. While conventional capacity based design approach lead to a total of 160 piles to support the 5 tanks the settlement based design approach lead to a total of 65 piles sachieving significant savings on the cost of the project.
The settlements of four out of the five tanks were measured and for two out of the five tanks the load sharing among the raft and the piles was also observed. Both the analyses carried out at the design stage and the back-analyses of the observed behaviour were based on the interaction factors method as implemented in the com-puter code NAPRA (Russo, 1998
Discussione sull’articolo “Contribution to piled raft design” di W. Prakoso & F.H. Kulhawy
No full text
Bearing capacity of piled rafts on soft clayey soils
No full textA numerical code for the prediction of the settlement of pile groups and piled rafts is presented. The code is based on the interaction factors method; the non-linearity is simulated as suggested by Caputo and Viggiani, that is, concentrating it at the pile-soil interface. In the linear range, the accuracy is checked against known benchmark solutions. A standard procedure, based on the results of load tests on single piles, is suggested for the evaluation of soil properties and for the implementation of the analysis in real cases. Nineteen well-documented case histories are then analysed, calculating for each of them a linear elastic, an equivalent linear elastic and a non-linear solution. Five out of the 19 cases are illustrated in some detail, to allow a deeper insight into the procedure. In all but one of the analysed cases the predicted values of the average settlement are within ±20% of the observed values. The maximum differential settlement is predicted with slightly lesser accuracy. For foundations characterized by a relatively high safety factor, linear and non-linear analyses are essentially equivalent. Some evidence suggests that the low-strain shear modulus, obtained by in situ shear wave velocity measurements, can be successfully employed in the prediction of the settlement. When the safety factor is low, the consideration of non-linearity becomes mandatory
Discussione sull’articolo “Contribution to piled raft design” di W. Prakoso & F.H. Kulhawy
No full textLaboratory investigations in genetic syndromes: examples of clinical approach in the neonatal unit.
No full text
- …
