To safeguard historic centers with masonry buildings in medium-high seismic areas, the local seismic response (LSR) should be used. These portions of the urban areas are commonly characterized by complex subsurface features (i.e., underground cavities, buried anthropic structures, and archeological remains) that could be responsible for unexpected amplifications at period intervals similar to the building's ones. In this study, San Giustino's Square (Chieti, Italy) was considered due to the differentiated damage caused by the 2009 L'Aquila earthquake mainshock (6 April 2009 at 3:32 CEST, 6.3 Mw). Out of the eight buildings overlooking the square, the structure that suffered the heaviest damage was the Justice Palace. Two-dimensional finite element analyses have been carried out in San Giustino's square to predict the LSR induced by the seismic shear wave propagation. The influence of the Chieti hill, the anthropogenic shallow soil deposit, and the manmade cavity were investigated. The results outlined that the amplifications of the seismic shaking peaked between 0.2 and 0.4 s. The crest showed amplifications over a wide period range of 0.1-0.8 s with an amplification factor (FA) equal to 2. Throughout the square, FA = 2.0-2.4 was predicted due to the cavities and the filled soil thickness. The large amplified period range is considered responsible for the Justice Court damage.

Determining the seismic performance level of shaft structures is crucial due to their vital role in ensuring a water supply. Since these are underground structures, the loads they encounter and the structural modeling processes differ significantly from those of above-ground structures. Accordingly, the primary aim of this paper is to introduce a new modeling methodology for the seismic performance assessment of shaft structures, considering all relevant parameters. This unique approach also incorporates pertinent sections from various applicable local seismic codes. For this purpose, a total of 15 shaft structures located on the historic Atik Valide Waterway, constructed in 1583, were examined. To create numerical models of the shafts, soil exploration parameters were utilized, and the shaft surface-soil interaction was represented by nonlinear p-y springs. An integral part of the presented methodology involved segmenting the shafts at regular intervals, with each segment defined as a separate story. The analysis results demonstrated that the modeling methodology is accurate and aligns well with the observed conditions of the shafts. Considering the significant risk of extensive damage to sewerage systems in urban areas due to soil liquefaction during seismic events, this study is anticipated to serve as a valuable reference in the literature by introducing a new, accurate methodology for identifying potential seismic risks.

Chiaia station is one of the art stations of Line 6 of the Naples underground network; it was constructed in a 50-m-deep excavation, a few meters from historic buildings and 4.5 m from the main facade of a sixteenth-century Basilica. The excavation, carried out partially in loose to medium dense sands overlying the soft rock formation of Neapolitan Yellow Tuff (NYT), was supported by a retaining wall made of contiguous bored piles braced with internal struts and prestressed ground anchors. The excavation sequence was quite complex due to archeological findings and to the presence of anthropic cavities used over the centuries to quarry NYT blocks. One of the key goals of the design was to limit movements around the shaft to prevent damage in the historical buildings. Long-term monitoring data obtained during nearly 9 years confirm the success of the overall construction process. A rather complex three-dimensional (3D) finite-element model with constitutive relationships for both the upper sandy layers and the soft rock is presented in the paper; this model was adopted to back-analyze the data from the monitoring and explore the influence of some of the key features of the case study. The role of the building bending and shear stiffness, of the soft rock stiffness, and of further apparently minor issues-such as the seepage and the ground anchors' prestress-were investigated and discussed with the support of the model calculations. Observed settlements at the end of the excavation were in the range 10-15 mm, and in the long term they increased by 20%-50% to as much as 20 mm. The deflection ratios were very small, in the range 0.05 parts per thousand-0.15 parts per thousand, and no visible damages to the buildings were recorded. These values were reproduced by the finite-element model only after the introduction of the relevant building stiffness.