Soil heterogeneity, due to variations in the subsurface stratigraphy or properties within a layer, can trigger or amplify differential settlements that affect buildings and infrastructure and can thus lead to (increase in) damage. The state-of-the-art mainly focuses on the effect of heterogeneous properties within a layer on engineering problems. From this, it is known that the variation in properties can increase the vulnerability of a structure. However, nearly always variations in the soil lithological conditions are disregarded, while they can influence subsidence potentially even more. Lithological variations are relevant both at the scale of individual buildings as well as different scales (city, regional, country), for which often detailed soil information is not available. Thus, for a better prediction of potential building damage related to subsidence, knowledge about the scale and influence of lithological variations is needed. This paper describes an approach to quantify and investigate the influence of lithological heterogeneity at the scale of a single building. Moreover, this exploratory study evaluates the influence of lithological heterogeneity on the spatial variability of settlements, intending to upscale the approach to regional application. Two independent datasets at high resolution (site-specific) and low resolution (national level) are used to retrieve the stratigraphic conditions for the area selected for the analyses. One-, Two- and Three-dimensional numerical models, based on the collected information are used to simulate the consolidation process and settlement due to a uniform load imposed on the surface level of the study area. Additional analyses investigate the influence of loading conditions and groundwater table. The parameter correlation length is used to quantify the spatial variability of the soil layer thickness and then of the computed settlements. The analyses reveal that the spatial variability of the soil strata thickness matches that of the computed settlements, ranging from 2 to 10 meters. In other words, the lithological variability of the soil leads to differential settlements occurring at the scale of man-made structures such as houses, roads, and embankments. Thus, the results encourage including the contribution of lithological heterogeneity in models and predictions of differential settlement at the scale of individual structures. Moreover, the statistical properties, in terms of mean, spread and distribution shape, of the settlement computed through in-situ specific models, match with those derived at the national scale. These results are expected to support the identification of areas potentially influenced by lithological soil heterogeneity, thus showing potential for upscaling to regional or national levels.
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.
This paper presents the findings of field observations conducted in the aftermath of the earthquakes that struck the Pazarcik (Mw7.7) and Elbistan (Mw7.6) in Kahramanmaras province, Turkey on February 6th, 2023. The earthquakes, occurring on the East Anatolian Fault Zone (EAFZ), resulted in more than 50,000 losses of life and damage of more than 1.5 million properties across 11 provinces in Turkey. Field observations presented herein encompass seismological and strong ground motion data, geotechnical observations, as well as damage assessments of underground and above ground structures in various provinces and districts. The types and reasons of the structural damages were discussed. The study also examined the effects of high acceleration values and distribution of strong ground motions on the performance of structures. Soil liquefaction problems were observed in many locations such as Golbasi and Iskenderun. The paper highlights the geology, tectonics, strong motion characteristics, surface deformations, geotechnical and structural aspects, and the evaluation of lifelines in the affected area. Furthermore, the authors provide initial recommendations for improving disaster management, evaluating building stock, prioritizing urban transformation, strengthening infrastructure systems, addressing soil-building interaction issues, ensuring security measures during search and rescue efforts, utilizing satellite imagery effectively, considering seismic effects on water infrastructure, and taking a holistic approach to earthquake effects in industrial facilities.
Tunneling operations in modern construction demand meticulous evaluation of their impact on nearby structures. A primary concern is the potential for soil subsidence, which could damage adjacent buildings. Complicating matters is the challenge of accurately modeling such settlement and the consequent damage, a critical process for informed decision-making during construction projects. By employing Bayesian updating, we refine our models by acquiring posterior distributions for key parameters. We put forth an analytical method for profiling ground settlement and follow this by calculating the strain on an equivalent beam, which serves as a proxy for building damage. This results in a distribution of strain values that allows for an assessment of how varying certain length parameters affects the probability of maintaining a safe distance between the tunneling activities and the surrounding buildings. With this probabilistic approach, one can propose a recommended safety distance as a guideline for construction practices.
Leakage into underground constructions can result in time-dependent settlements in soft clays. In urban areas with spatial variability in geologic stratification, groundwater conditions and soil compressibility, differential settlements may occur, causing damage to buildings. Current methods for damage assessment that rely on 1D formulations for settlement prediction are not representative for drawdown-induced settlements in heterogeneous environments. Thus, in this paper, we propose a stand-alone approach to integrating spatially distributed, non-Gaussian settlement data into early-stage building damage assessments at a district scale. Deformations computed using a 2D coupled hydro-mechanical finite element model with an advanced constitutive model were then employed to get the time-dependent settlements computed as a 3D grid (along x- and y-directions) over a large area. Building damage was then calculated from these green-field simulations with typically used damage parameters for each building-specific settlement profile and comparing these with damage criteria. The approach was applied to 215 buildings in central Gothenburg, Sweden by simulating scenarios of 10 kPa and 40 kPa pore pressure drawdown in the lower (confined) aquifer. Several scenarios were studied, and the correlation between damage parameters and damage criteria was assessed. Finally, a sensitivity study on grid resolution was performed, as well as a validation against observed damage data. The proposed methodology offers an effective way for early-stage damage assessments at a large area for non-Gaussian settlements so that further investigations and mitigation measures can be targeted to the buildings and locations at the highest risk for damage.
Ground-borne vibrations resulting from construction activity or road traffic may set vibrations in buildings. The effects of these induced vibrations on buildings may range from no effect to minor cosmetic damage to serious damage, depending on factors such as the amplitude and time-dependence of the vibration, the building structure and the type of soil it rests on, and the duration of exposure. Various codes and standards from various countries set recommendations regarding the exposure of buildings to soil-induced vibrations with emphasis on the characteristics of the vibration signals for limiting their effects on the building structure and for not reducing the comfort of their tenants. These facts are shortly reviewed in this presentation in conjunction with the effects of vibrations on the human body.