Reclaimed coastal areas are highly susceptible to uneven subsidence caused by the consolidation of soft marine deposits, which can induce differential settlement, structural deterioration, and systemic risks to urban infrastructure. Further, engineering activities, such as construction and loadings, exacerbate subsidence, impacting infrastructure stability. Therefore, monitoring the integrity and vulnerability of linear urban infrastructure after construction on reclaimed land is critical for understanding settlement dynamics, ensuring safe and reliable operation and minimizing cascading hazards. Subsequently, in the present study, to monitor deformation of the linear infrastructure constructed over decades-old reclaimed land in Mokpo city, South Korea (where 70% of urban and port infrastructure is built on reclaimed land), we analyzed 79 Sentinel-1A SLC ascending-orbit datasets (2017-2023) using the Persistent Scatterer Interferometry (PSInSAR) technique to quantify vertical land motion (VLM). Results reveal settlement rates ranging from -12.36 to 4.44 mm/year, with an average of -1.50 mm/year across 1869 persistent scatterers located along major roads and railways. To interpret the underlying causes of this deformation, Casagrande plasticity analysis of subsurface materials revealed that deep marine clays beneath the reclaimed zones have low permeability and high compressibility, leading to slow pore-pressure dissipation and prolonged consolidation under sustained loading. This geotechnical behavior accounts for the persistent and spatially variable subsidence observed through PSInSAR. Spatial pattern analysis using Anselin Local Moran's I further identified statistically significant clusters and outliers of VLM, delineating critical infrastructure segments where concentrated settlement poses heightened risks to transportation stability. A hyperbolic settlement model was also applied to anticipate nonlinear consolidation trends at vulnerable sites, predicting persistent subsidence through 2030. Proxy-based validation, integrating long-term groundwater variations, lithostratigraphy, effective shear-wave velocity (Vs30), and geomorphological conditions, exhibited the reliability of the InSAR-derived deformation fields. The findings highlight that Mokpo's decades-old reclamation fills remain geotechnically unstable, highlighting the urgent need for proactive monitoring, targeted soil improvement, structural reinforcement, and integrated InSAR-GNSS monitoring frameworks to ensure the structural integrity of road and railway infrastructure and to support sustainable urban development in reclaimed coastal cities worldwide.

Setting an expandable polystyrene (EPS) board on box culverts can reduce the vertical earth pressure (VEP) acting on the culvert roof. However, long-term backfill load will induce creep in both the EPS board and the surrounding soil, resulting in a change in the stress state of the culvert-soil system. A mechanical model for the long-term interaction of backfill-EPS board-box culvert was established, and theoretical formulas were derived for calculating the earth pressure around the culvert. Numerical simulation was employed to validate the accuracy of the proposed theoretical approach. Research indicates that, with EPS board, the VEP decreases rapidly then slightly increases with time and eventually approaches an asymptotic value, ultimately decreasing by 33%. However, the horizontal earth pressure (HEP) shows the opposite pattern and ultimately increases by 15%. The foundation contact pressure (FCP) increases nonlinearly and reaches a stable value, ultimately increasing by 10.2%. Without the EPS board, the VEP and HEP are significantly different from those with the EPS board. Although EPS boards can reduce the VEP on the culvert, attention should be paid to the variation of HEP caused by the creep of the EPS board and backfill.

Biomass residues from the agricultural industry, logging and wood processing activities have become a valuable fuel source. If processed under pyrolysis combustion, several products are generated. Bio-oil and gases are essential alternatives to fossil coal-based fuels for energy and electricity production, whose need is constantly growing. Biochar, the porous carbon-based lightweight product, often ends up as a soil fertilizer. However, it can be applied in other industrial sectors, e.g., in plastics production or in modifying cementitious materials intended for construction needs. This work dealt with the application of small amounts of softwood-based biochar up to 2.0 wt.% on hydration kinetics and a wide range of physical and mechanical properties, such as water transport characteristics and flexural and compressive strengths of modified cement pastes. In the comparison with reference specimens, the biochar incorporation into cement pastes brought benefits like the reduction of open porosity, improvement of strength properties, and decreased capillary water absorption of 7-day and 28-day-cured cement pastes. Moreover, biochar-dosed cement pastes showed an increase in heat evolution during the hydration process, accompanied by higher consumption of clinker minerals. Considering all examined characteristics, the optimal dosage of softwood-derived biochar of 1.0 wt.% of Portland cement can be recommended.

This study investigates the underlying causes of pier displacement and cracking in a highway link bridge. The initial geological assessment ruled out slope instability as a contributing factor to pier movement. Subsequently, a comprehensive analysis, integrating in situ soil investigation and finite element modeling, was conducted to evaluate the influence of additional fill loads on the piers. The findings reveal that the additional filled soil loads were the primary driver of pier tilting and lateral displacement, leading to a significant risk of cracking, particularly in the mid- of the piers. Following the removal of the filled soil, visual inspection of the piers confirmed the development of circumferential cracks on the columns of Pier 7, with the crack distribution closely aligning with the high-risk zones predicted by the finite element analysis. To address the observed damage and residual displacement, a reinforcement strategy combining column strengthening and alignment correction was proposed and validated through load-bearing capacity calculations. This study not only provides a scientific basis for analyzing the causes of accidents and bridge reinforcement but, more importantly, it provides a systematic method for analyzing the impact of additional filled soil loads on bridge piers, offering guidance for accident analysis and risk assessment in similar engineering projects.

Tunnel lining structures, which are subjected to the combined effects of water and soil pressure as well as a water-rich erosion environment, undergo a corrosion-induced damage and degradation process in the reinforced concrete, gradually leading to structural failure and a significant decline in service performance. By introducing the Cohesive Zone Model (CZM) and the concrete damage plastic model (CDP), a three-dimensional numerical model of the tunnel lining structure in mining method tunnels was established. This model takes into account the multiple effects caused by steel reinforcement corrosion, including the degradation of the reinforcement's performance, the loss of an effective concrete cross section, and the deterioration of the bond between the steel reinforcement and the concrete. Through this model, the deformation, internal forces, damage evolution, and degradation characteristics of the structure under the effects of the surrounding rock water-soil pressure and steel reinforcement corrosion are identified. The simulation results reveal the following: (1) Corrosion leads to a reduction in the stiffness of the lining structure, exacerbating its deformation. For example, under high water pressure conditions, the displacement at the vault of the lining before and after corrosion is 4.31 mm and 7.14 mm, respectively, with an additional displacement increase of 65.7% due to corrosion. (2) The reinforced concrete lining structure, which is affected by the surrounding rock loads and expansion due to steel reinforcement corrosion, experiences progressive degradation, resulting in a redistribution of internal forces within the structure. The overall axial force in the lining slightly increases, while the bending moment at the vault, spandrel, and invert decreases and the bending moment at the hance and arch foot increases. (3) The damage range of the tunnel lining structure continuously increases as corrosion progresses, with significant differences between the surrounding rock side and the free face side. Among the various parts of the lining, the vault exhibits the greatest damage depth and the widest cracks. (4) Water pressure significantly impacts the internal forces and crack width of the lining structure. As the water level drops, both the bending moment and the axial force diminish, while the damage range and crack width increase, with crack width increasing by 15.1% under low water pressure conditions.

The main causes of damage include poor site selection, such as building on fault lines or on fill soil, as well as deficiencies in design, materials, and workmanship. Damage levels are also linked to the economic conditions of the region. In the 1939 earthquake, there were high casualties due to the magnitude of the earthquake, lack of engineering design in traditional structures and unsuitable soil conditions. Similarly, in the 1992 earthquake, unexpected damage occurred due to faulty designs created by inexperienced engineers who lacked sufficient knowledge of the seismic behavior of structures, errors in craftsmanship and workmanship, and unsuitable residential area selection for construction. These problems continue today and put most of the building stock at risk in case of a major earthquake. Seismic steel isolators are used in two new buildings in the city; if they are effective, they should be made mandatory in new construction. Otherwise, consideration should be given to relocating the city to the more stable southern rocky areas, which were unaffected in both 1939 and 1992.

Composite reinforcement concrete square piles exhibit excellent bending resistance and deformation capacity, along with construction advantages such as ease of transportation. In recent years, they have been widely adopted in building pile foundation applications. However, their seismic behavior, particularly under multi-directional excitation, remains inadequately explored. This study employs large-scale shaking table tests to evaluate the seismic response of a single composite reinforcement square pile embedded in a soft clay foundation under different horizontal excitations (0 degrees and 45 degrees) and two distinct ground motions (Wenchuan Songpan and Chi-Chi) to assess directional anisotropy and resonance effects, with explicit consideration of soil-structure interaction (SSI). The key findings include the following: the dynamic earth pressure along the pile exhibits a distribution pattern of large at the top, small at the middle and bottom. And SSI reduced pile-soil compression by 20-30% under 45 degrees excitation compared to 0 degrees. The dynamic strain in outer longitudinal reinforcement in pile corners increased by 30-60% under 45 degrees excitation compared to 0 degrees. Under seismic excitation considering SSI, the bending moment along the pile exhibited an upper-middle maximum pattern, peaking at depths of 3-5 times the pile diameter. Axial forces peaked at the pile head and decreased with depth. While bending moment responses were consistent between 0 degrees and 45 degrees excitations, axial forces under 45 degrees loading were marginally greater than those under 0 degrees. The Chi-Chi motion induced a bending moment about four times greater than the Songpan motion, highlighting the resonance risks when the ground motion frequencies align with the pile-soil system's fundamental frequency.

On 6 February 2023, two major earthquakes struck southeastern T & uuml;rkiye along the East Anatolian Fault, causing widespread structural damage, including the partial collapse of the historic Habibi Neccar Mosque in Antakya. This study presents a simulation-based approach to rapidly assess the seismic vulnerability of this partially damaged historic masonry structure. Due to the complexity and urgent condition of such heritage buildings, a simplified finite element (FE) modeling methodology is employed to evaluate structural behavior and support immediate stabilization decisions. Response spectrum analysis is applied to simulate and interpret stress distribution and deformation patterns in both undamaged and damaged states. The simulation results highlight significant tensile stress concentrations exceeding 0.2 MPa at dome-arch joints and vaults-primary indicators of localized failures. Additionally, the analysis reveals increased out-of-plane deformations and the influence of soil amplification in the remaining walls, both of which further compromise the structural integrity of the building. The findings demonstrate that simplified FE simulations can serve as practical and efficient tools for early seismic assessment of historic structures, contributing to rapid decision making, risk mitigation, and cultural heritage preservation in earthquake-prone areas.

This study investigated the effects of natural polysaccharides-guar gum (GG) and xanthan gum (XG)-on the properties and structure of illitic clay. Clay samples were prepared using five different GG and XG solutions, with polysaccharide concentrations of 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%. The physical, mechanical, and hygroscopic properties of the samples were evaluated, along with water erosion resistance and structural characteristics, using SEM analysis. The addition of GG or XG significantly increased compressive strength and water erosion resistance, reduced shrinkage, and slightly improved the bulk density compared to the control clay sample. The results showed that compressive strength increased by 28-63% and 46-84% with the incorporation of GG and XG solutions, respectively. These findings suggest that environmentally friendly clay-based building materials can be effectively produced even using small amounts of natural polysaccharides.

Accurate structural health monitoring (SHM) is crucial for ensuring safety and preventing catastrophic failures. However, conventional parameter identification methods often assume a fixed-base foundation, neglecting the significant influence of soil-structure interaction (SSI) on the dynamic response, leading to inaccurate damage assessments, especially under seismic loading. Therefore, we introduce a novel approach that explicitly incorporates SSI effects into parameter identification for frame structures, utilizing an optimized variational mode decomposition (VMD) technique. The core innovation is the application of the Subtraction Average-Based Optimizer (SABO) algorithm, coupled with permutation entropy as the fitness function, to optimize the critical VMD parameters. This SABO-VMD method was rigorously validated through a shaking table test on a 12-story frame structure on soft soil. Comparative analysis with EMD and conventional VMD demonstrated that SABO-VMD provides a superior time-frequency representation of the structural response, capturing non-stationary characteristics more effectively. A novel energy entropy index, derived from the SABO-VMD output with SSI, was developed for quantitative damage assessment. It revealed 8.1% lower degree of structural damage compared to the fixed-base assumption. The proposed SABO-VMD-based approach, by explicitly accounting for SSI, offers a substantial advancement in SHM of frame structures, leading to more reliable safety evaluations and improved seismic resilience.