1,720,994 research outputs found
Prove dinamiche in sito per la misura delle proprietà meccaniche dei terreni
No full textProblemi d’Ingegneria Geotecnica nelle Aree Sismiche, Int. Centre for Mech. Sciences (CISM), Advanced Professional Training (ATP), Udin
Prove dinamiche in sito per la misura delle proprietà meccaniche dei terreni
No full textProblemi d’Ingegneria Geotecnica nelle Aree Sismiche, Int. Centre for Mech. Sciences (CISM), Advanced Professional Training (ATP), Udin
Evaluation of pseudo-static earth pressure coefficient of cantilever retaining walls
No full textA stress plasticity solution is proposed for evaluating the gravitational and dynamic active earth pressures on cantilever retaining walls with long heel. The solution takes into account the friction angle of the soil, wall roughness, backfill inclination and horizontal and vertical seismic accelerations. It is validated by means of the comparison with both traditional limit equilibrium methods (e.g. Mononobe–Okabe equations) and static and pseudostatic numerical FLAC analyses. For numerical analyses the soil is modelled as an elasto-plastic non-dilatant medium obeying the Mohr–Coulomb yield criterion, while the wall is elastic. The solutions for the horizontal and vertical seismic coefficients are proposed, which allow one to determine the intensity of the active thrust and its inclination δ with respect to the horizontal. It is demonstrated that the latter also depends on the soil friction angle φ. The inclination in seismic conditions δE is greater than the one in static conditions, δS, usually adopted in both cases. As a matter of fact, since wall stability conditions improve with the increase of inclination δ, the present method gives solutions that are less onerous than traditional ones, producing less conservative wall designs. Finally pseudostatic results are compared with proper dynamic analyses (by FLAC code) performed utilising four Italian accelerometric time-histories as input ground motion
Numerical simulation of soil-structure interaction: a parametric study
No full textSoil Structure Interaction (SSI) is a complex phenomenon that may radically change the earthquake response of structural systems, as consequence of the variation of the natural frequency and the damping ratio. One of the most effective means for evaluating SSI is the use of physical models. In this study the physical model considered is formed by an oscillator founded on a group of piles embedded in a horizontally layered deposit of dry sand. The benchmark experimental campaign was carried out at the Bristol Laboratory for Advanced Dynamics Engineering (BLADE) at the University of Bristol (UK), financed by the Seismic Engineering Research Infrastructures for European Synergies (SERIES). An accurate parametric numerical study is performed and the results are discussed. The study investigates the effects of the dynamic properties of the oscillator on the period elongation and piles re-sponse. By means of advanced numerical analyses the outcomes of the present work provide insights into the quantitative evaluation of period elongation and the strength of inertial con-tribute to the bending moment at the pile head, when the system approaches resonance condi-tions
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