An approximate approach has been proposed for the analysis of nonlinear responses of vertically loaded pile groups. The nonlinear pile-soil-pile interaction is modeled by hyperbolic load-transfer functions. To evaluate the practical applicability of the proposed approach, a back analysis of a number of published case histories referring to single pile loading tests was carried out. Discovered by the back analysis were the more appropriate values of the main model parameters. To extend the solution of single pile to the case of a pile group, an equivalent pier interacting with surrounding soil by means of the hyperbolic load transfer functions was considered. The load-settlement response of the equivalent pier can be calculated using solutions for the response of a single pile, but, to take into account the group action due to pile-soil-pile interaction, load-transfer functions have been modified. The behavior of three full scale instrumented pile groups was studied, and the computed results using the prop...

This paper investigates the problems and stresses of the contemporary city, mainly due to natural and health factors, related to climate change and the pandemic COVID19. Besides highlighting the characteristics of climate change and the ongoing pandemic, this study focuses on the analysis of the main effects and consequences that these phenomena have produced on the city and the vulnerabilities of the urban system. To understand how these events have impacted the urban environment, directly and indirectly, this research undertakes to define some specific indicators capable of comparing the phenomena and assessing their repercussions. The Methodology is based on the following focal points: on the analysis of the urban shocks that have affected the cities in the last decade, on the comparison between contemporary survey data and those relating to historical trends, on the definition of the main urban sectors particularly affected by the onset of urban shocks, and on the definition of strategies, actions, and tools deemed to be effective in the implementation of a post-pandemic and climate-proof city. These results were achieved through complementary urban design and tools capable of creating a post-pandemic and climate-proof adaptive city, within a cross-disciplinary approach.

In the last few decades, a great amount of interest has developed in the evaluation of the influence of bearing capacity of shallow foundations on slopes. When a footing is placed near a slope the bearing capacity may be reduced. In fact, the failure mechanism is influenced by the distance of the foundation from the edge of the sloping ground. In order to investigate the effect of the bearing capacity of shallow foundations on slopes, model footing tests were performed. This paper presents the results of the investigation, to establish both qualitative and quantitative relationships between the ultimate load of the soil–foundation system and the location of the footing with respect to the slope. Values of ultimate loads deduced from experimental tests are compared with values derived by a numerical analysis based on the limit equilibrium method. Modified bearing capacity factors which take into account the effect of the sloping ground are proposed.

Pseudostatic approaches for the seismic analysis of pile foundations are attractive for practicing engineers because they are simple when compared to difficult and more complex dynamic analyses. To evaluate the internal response of piles subjected to earthquake loading, a simplified approach based on the “ p-y ” subgrade reaction method has been developed. The method involves two main steps: first, a site response analysis is carried out to obtain the free-field ground displacements along the pile. Next, a static load analysis is carried out for the pile, subjected to the computed free-field ground displacements and the static loading at the pile head. A pseudostatic push over analysis is adopted to simulate the behavior of piles subjected to both lateral soil movements and static loadings at the pile head. The single pile or the pile group interact with the surrounding soil by means of hyperbolic p-y curves. The solution derived first for the single pile, was extended to the case of a pile group by empir...

This paper reports on the results of soil-foundation numerical modelling and the seismic response of a cooling tower founded on piles of a petrochemical facility located in the city of Augusta (Sicily, Italy). The city was affected in the past by some destructive earthquakes (1693, 1848, and 1990) that damaged a large territory of Southeastern Sicily, which was characterized by a very high seismic hazard. With this aim, the paper reports the FEM modelling of the seismic behaviour of the coupled soil-structure system. To determine the soil profile and the geotechnical characteristics, laboratory and in situ investigations were carried out in the studied area. The seismic event occurred in January 1693 and has been chosen as a scenario earthquake. Moreover, a parametric study with different input motions has also been carried out. A Mohr-Coulomb model has been adopted for the soil, and structural elements have been simulated by means of an elastic constitutive model. Two different vertical alignments have been analysed, considering both the free-field condition and the soil-structure interaction. The dynamic response has been investigated in terms of accelerations, response spectra, and amplification functions. The results have also been compared with those provided by Italian technical regulations. Finally, the seismic response of the coupled soil-structure system has been further examined in terms of peak bending moments along the pile foundation, emphasizing the possibility of a kinematic interaction on piles induced by the seismic action.