An update on the Tower of Pisa

The Leaning Tower of Pisa has been stabilised in the years 1999–2000 by an International Committee appointed by the Italian Government. An analysis of the whole history of the monument, starting from its construction in the XII century and including the results of the modern monitoring of XIX and XX century led the Committee to the conclusion that the Tower is affected by a phenomenon of instability of the equilibrium, depending on the deformability and not on the strength of the foundation soils. The stabilisation intervention, totally respectful of the integrity of the monument, consisted in slightly decreasing the inclination of the Tower by underexcavating a small volume of soil beneath the north side of the foundation. The paper briefly reports the analysis and the intervention; the observation of the behaviour in the twenty years elapsed since then allows some preliminary evaluation of the future behaviour

The restoration of San Paolo Church in Pisa: Geotechnical aspects

San Paolo a Riva d'Arno is an important medieval church located in Pisa, on the south bank of the Arno river. Its existence is documented before 1032, most probably around 925: its actual configuration, however, was reached only at the end of 14th century. Structural diseases, following damages by bombing during World War II, have affected the church over the last decades; cracks in the perimeter walls and problems to the wooden frames of the roof are progressively appearing. After recent earthquakes the evolution of the statical situation has forced the authorities to close the church to the public. A comprehensive investigation on both the subsoil and the structure has been carried out with the aim of conceiving, designing and implementing suitable remedial works. Particular attention has been given to the collection of quantitative data about the foundation: layout, depth, thickness and state of conservation of the masonry. Geophysical techniques, such as electric tomography and ground penetrating radar, have been attempted with doubtful results; a special technique, consisting in small diameter holes drilled through the masonry with an instrumented drilling machine, was eventually developed. To investigate earthquake effects, a thorough analysis of local amplification of seismic action has been performed. Local seismic response of the subsoil has been analysed by different techniques applied to two different subsoil models; the results obtained evidence of significant differences among the different analyses and in comparison with the prescriptions of the Italian Seismic Code

Laterally loaded single pile response considering the influence of suction and non-linear behaviour of reinforced concrete sections

A hybrid BEM-p-y curves approach was developed for the single pile analysis with free/fixed head restraint conditions. The method considers the soil non-linear behaviour by means of p-y curves in series to a multi-layered elastic half-space. The non-linearity of reinforced concrete pile sections, also considering the influence of tension-stiffening, has been considered. The model reproduces the influence of suction by increasing the stress state and hence the stiffness of shallow soil-layers. Suction is modeled using the Modified-Kovacs model. The hybrid BEM-py curves method was validated by comparing results from data of 22 load tests on single piles. In addition, a detailed comparison is presented between measured and computed data on a large-diameter reinforced concrete bored single pile

Liquefaction Potential Assessment of Silty and Silty-Sand Deposits: A Case Study

he paper shows a case study concerning the liquefaction potential assessment of deposits which mainly consist of non plastic silts and sands (FC > 35 %, Ip < 10 %, CF negligible). The site under study has been characterized by means of in situ tests (CPTU, SPT and DPSH), boreholes and laboratory tests on undisturbed and remolded samples. More specifically, classification tests, cyclic undrained stress-controlled triaxial tests and resonant column tests have been performed. Liquefaction susceptibility has been evaluated by means of several procedures prescribed by codes or available in technical literature. The evaluation of liquefaction potential has been carried out by means of three different procedure based on in situ and laboratory tests

Evaluating degree of compaction of levees using cone penetration testing

Permeability and strength parameters of compacted soils (i.e., levees as well as other earthworks) may be correlated to the degree of compaction. Since the use of conventional and recent testing methods for the assessment of density and water content of earthworks, under construction, cannot be applied to existing levees, an expeditious and accurate method for the assessment of the degree of compaction of existing and new levees, after their completion, appears extremely useful. The purpose of this research is to develop a simple tool for the assessment of the degree of compaction of "compacted", partially saturated, fine grained soils. This paper illustrates the proposed method which combines in situ testing such as electric CPT or CPTu with laboratory penetration testing performed with a mini-cone in a calibration chamber (CC). © 2018, Taiwan Geotechnical Society

General Report - Session 3

This General Report summarizes the 84 papers accepted for the Session 3 focused on: - 3a. Case Histories on Failure and Remediation of Slopes, Dams, Embankments and Landfills (53 papers), - 3b. Case Histories on Failure and Remediation of Retaining Structures, Slurry Walls, and Deep Excavations, Dewatering, Stability (27 papers), - 3c. Improving the Stability and Maintenance of Monuments (4 papers). The papers originate from 26 countries (11 European countries, 3 American countries, 11 Asian countries and 1 African country). The papers cover a number of relevant topics divided into three different sub - sessions. As for the two papers included in Session 3c, only one deals with maintenance and retrofit of historical monuments. Indeed paper 3.03c is more pertinent to session 3b. On the other hand some papers included in Session 3a could also be considered in Session 3b and vice versa

Evaluation of the degree of compaction of levees by a CPT- based method

Permeability and strength parameters of compacted soils may be correlated to their degree of compaction. Unfortunately, the use of conventional and recent testing methods for the assessment of density and water content of earthworks under construction cannot be applied to existing levees. Therefore, the development of an expeditious and accurate method for the assessment of the degree of compaction of existing and new levees, after their completion, appears extremely useful. The purpose of this research is to develop a simple tool for the assessment of the degree of compaction of “compacted”, partially saturated, fine grained soils. The proposed method combines in situ testing like electric CPT or CPTu with laboratory penetration testing performed with a mini–cone in a calibration chamber

Importance of full scale tests for the design of levees

This paper illustrates a case history, based on full-scale tests (trial embankment). More specifically, the settlements of a full-scale trial embankment on a very compressible soil (organic clay) for a period of 5 years are reported. The observed settlements are compared with those obtained from an A type prediction, as well as a B type prediction. The analysis results suggest the importance of an appropriate modelling of secondary settlements of organic soils. The difficulties in obtaining good quality undisturbed samples of organic clay and the peculiar creep behaviour point out the importance of full-scale tests

The role of collective bargaining in Europe in the promotion of flexibility, workplace productivity and the welfare of workers in the workplace

In order to compensate for the gradual loss of the purchasing power of wages and the reduction of benefits (social security, welfare, etc.), in many countries (not only in Europe), it is given the attempt, through Incentives of a normative and fiscal nature, to recognize collective bargaining, especially the corporate, territorial and employers, the privileged place to promote the flexibility, efficiency and welfare of workers at the place of work