Search Results (930)

Effective disaster management depends on rapidly understanding earthquake damage, yet traditional methods struggle to operate at scale and rely on expert inspections that become difficult when access is limited or time is critical. Satellite-based damage detection also faces limitations, particularly under adverse weather conditions and delays associated with satellite overpass schedules. This study introduces a machine learning-based approach to assess post-earthquake building damage using real observations collected after the event. The aim is to develop fast and reliable estimation techniques that can be deployed immediately after the mainshock by integrating structural, seismic, and geographic data. Three machine learning models—Random Forest, Histogram Gradient Boosting, and Bagging Classifier—are evaluated across both reinforced concrete and masonry buildings and across multiple spatial levels, including building, district, and city scales. Damage is categorized using practical three-class (traffic light) and detailed four-class systems. The models generally perform better in simpler classifications, with the Bagging Classifier offering the most consistent results across different scales. Although detecting severely damaged buildings remains challenging in some cases, the three-class system proves especially effective for supporting rapid decision-making during emergency response. Overall, this study demonstrates how machine learning can provide faster, scalable, and practical earthquake damage assessments that benefit emergency teams and urban planners. Full article

The Hisayamada Dam (22.5 m high, 75.4 m long), constructed in 1924 as a water supply facility, is a masonry arch–gravity concrete dam with a slender arch shape. Although it was the first theoretically designed arch-type dam in Japan, seismic forces were not considered at the time of construction. This study evaluates its seismic performance using a three-dimensional (3D) dynamic Finite Element Method (FEM) in accordance with current Japanese governmental guidelines. A detailed 3D model incorporating the dam body, surrounding topography, foundation, and reservoir was developed, and expected earthquake motions in three directions were applied simultaneously. The analysis showed that localized tensile stress exceeding the tensile strength occurred near the upstream heel of the dam base. However, these stress concentrations were limited to small regions and did not form continuous damage paths across the dam body. Based on the linear dynamic analysis and engineering judgment, the overall structural integrity and water storage function of the dam are considered to be maintained. Additional analyses were conducted by varying the elastic modulus of the foundation rock and dam concrete to clarify the influence of material stiffness on seismic response and stability. Full article

Compressing a mixture of soil, water, and stabilizer forms compressed stabilized earth blocks (CSEBs), a modernized earthen construction material capable of performance similar to that of engineered masonry with added sustainability achieved by usage of raw materials on-site, reduction in transportation costs of bulk materials to the build site, and improved thermal performance of built CSEB structures. CSEBs have a wide range of potential physical properties due to variations in base soil, mix composition, stabilizer, admixtures, and initial compression achieved in CSEB creation. While CSEB construction offers several opportunities to improve the sustainability of construction practices, assuring codifiable, standardized mix design for a target strength or durability remains a challenge as the mechanical character of the primary base soil varies from site to site. Quality control may be achieved through creation and testing of CSEB samples, but this adds time to a construction schedule. Such delays may be reduced through development of predictive CSEB compressive strength estimation models. This study experimentally determined CSEB compressive strength for six different mix compositions. Compressive strength predictive models were developed for 7-day and 28-day CSEB samples through multiple numerical models (i.e., linear regression, back-propagation neural network) designed and implemented to relate design inputs to 7-day and 28-day compressive strength. Model results provide insight into the predictive performance of linear regression and back-propagation neural networks operating on designed data streams. Performance, robustness, and significance of changes to the model dataset and feature set are characterized, revealing that linear regression outperformed neural networks on 28-day data and that inclusion of downstream data (i.e., cylinder compressive strength) did not significantly impact model performance. Full article

Constructed wetlands (CWs), increasingly adopted as nature-based solutions (NBS) for wastewater treatment, require a rigorous assessment of the durability and structural performance of the materials used in their supporting systems. In contrast to the extensive literature addressing hydraulic efficiency and contaminant removal, the structural behavior of CWs has been scarcely examined, with existing studies offering only general references to reinforced concrete and masonry and lacking explicit design criteria or deterioration analyses. This study integrates evidence from real-world CW installations with a systematic review of 31 studies on the degradation of cementitious materials in analogous environmental conditions, following PRISMA 2020 guidelines, with inclusion criteria based on quantified wastewater-related exposure conditions (e.g., chemical aggressiveness, persistent saturation, and biogenic activity). Results indicate that reinforced concrete, despite its structural capacity, is susceptible to biogenic corrosion, accelerated carbonation, and sulfate–chloride attack under conditions of persistent moisture, with reported degradation rates in analogous wastewater infrastructures on the order of millimeters per year for concrete loss and tens of micrometers per year for reinforcement corrosion. Masonry structures, similarly, exhibit performance constraints when exposed to mechanical overloads and repeated wetting–drying cycles. In contrast, emerging alternatives—such as nanomodified matrices and concretes incorporating supplementary cementitious additives—demonstrate potential to enhance durability while contributing to a reduced carbon footprint, without compromising mechanical strength. These findings reinforce the need for explicit structural design criteria tailored to CW applications to improve sustainability, durability, and long-term performance. Full article

A numerical model based on the heuristic molecule (HM) concept is proposed to evaluate the in-plane and Coulomb-like shear behavior of masonry panels. The model extends the well-established Rigid-Body-Spring Model (RBSM), which demonstrated good effectiveness in the seismic analysis of masonry structures. The proposed advancement introduces two diagonal bond-springs specifically designed to improve the representation of shear damage mechanisms. The performance of this enhanced formulation was assessed through numerical simulations of small-scale shear panel tests experimentally tested in the literature under varying levels of pre-compression, for which dedicated nonlinear stress–strain laws for axial, shear, and diagonal bond-springs were implemented. The results indicate that the proposed model provides an accurate description of the observed behavior while maintaining a limited number of degrees of freedom, thus ensuring computational efficiency. These promising outcomes highlight the model’s potential for future applications, including large-scale dynamic analyses. Full article

This paper investigates the behavior of PM-type polyurethane flexible joints connecting structural components. Although flexible polyurethanes are known for their energy dissipation capacity and ability to accommodate large deformations—particularly under seismic actions—research addressing their performance under shear loading remains limited. The primary objective of this work was to characterize these joints under varying levels of normal stress, identify failure modes, and estimate key mechanical parameters. Nine masonry triplet specimens, composed of concrete units and PM-type polyurethane, were subjected to shear testing using a procedure adapted from EN 1052-3. Tests were carried out at three precompression levels: 0.2, 0.6, and 1.0 N/mm². Tensile tests were further performed to calibrate material models. The results showed that increasing precompression led to higher ultimate shear loads. All specimens failed due to shear failure at the unit–flexible joint interface, with no damage observed in the masonry units. Based on linear regression following EN 1052-3, the initial shear strength was determined to be 0.729 N/mm², corresponding to a friction coefficient of 0.14. Full article

Earthquake effects were investigated in single-story masonry buildings with walls of different heights and thicknesses. Five different masonry building models were created, with wall thicknesses ranging from 16 cm to 32 cm and wall heights ranging from 260 cm to 340 cm. In total, 25 different masonry building models were analysed using the STA4 CAD programme in accordance with the 2018 Turkish Earthquake Code. C-30 concrete and S-420 steel were used in the designed building models. A 12 cm thick reinforced concrete slab was designed. A live load of 0.2 t/m² was designed on the slab. The mortar strength of the brick wall was taken as 30 MPa. A comparison of a reference building model with a height of 260 cm and a wall spacing of 16 cm with a building model with a floor spacing of 340 and a wall spacing of 32 cm shows that earthquake resistance can be increased by approximately 72%, and this increase in shear strength reaches approximately 89% and 95% in the “x” and “y” direction, respectively. When the wall thickness was doubled from 16 cm to 32 cm, the highest strength increases of approximately 94% was observed in the model with a wall height of 300 cm. Full article

Many masonry buildings exist worldwide. Safety assessments are crucial for renovation and upgrading. On-site testing reveals material properties and historic loads, enabling updates to structural resistance models for more accurate evaluations. (1) This paper details updating resistance models with Bayesian theory and the proof load method. (2) It proposes three verification levels: high, medium, and low, using on-site material and load data. (3) Suitable resistance partial factors for each verification level are suggested. (4) The method is validated through practical case studies of masonry structure evaluations. The results show that (1) the mean value of the resistance of the existing masonry members updated by “Bayesian theory” and “Proof load methods” increases while the coefficient of variation decreases. (2) The reliability index of existing masonry components increases with the increase in the proof load and decreases with the increase in the coefficient of variation in material property uncertainty. (3) For “High verification level” and “Moderate verification level”, the resistance partial factors for existing masonry structure assessment can be taken as 1.67 and 1.70, respectively. (4) That updated partial factors can be used for structures. Full article

This study presents an integrated intervention strategy for the adaptive reuse of vernacular architecture in a state of ruin, focusing on the fortified village of Moya (Cuenca, Spain). The proposal is framed within a rural revitalization program aimed at educational and cultural tourism uses, with the goal of reactivating abandoned built fabric through the incorporation of new functions that generate social value and contribute to territorial development. The proposed methodology combines archival research, digital documentation, material characterization, and a constructive solution based on the insertion of a reversible, structurally autonomous timber volume within the existing stone masonry. Through material characterization, a differentiated consolidation protocol is developed to stabilize the ruins while maintaining historical legibility. The new architectural volume, built with prefabricated cross-laminated timber (CLT) and insulated with locally sourced expanded cork, is designed to meet contemporary standards of energy efficiency, reversibility, and environmental responsibility, while remaining fully independent from the original structure. The intervention offers a replicable model for sustainable rural regeneration, balancing conservation ethics with functional adaptation. Future lines of research include the dynamic simulation of the energy performance of the inserted dwelling, with the aim of assessing its contribution to climate neutrality and net-zero emissions targets. Full article

Reinforced concrete buildings with masonry-induced soft-storey irregularities exhibit extreme seismic vulnerability, a critical risk often underestimated by conventional code-based design. Standard equivalent static methods typically fail to capture the intense concentration of seismic demand at the flexible ground level, leading to unconservative designs that do not meet performance objectives. This research proposes a corrective linear–static methodology to address this deficiency. A new Equivalent Lateral Force profile (ELF_i1) was developed, derived from modal analyses of 235 representative soft-storey archetypes to accurately account for stiffness heterogeneity. This profile was integrated with a realistic response modification coefficient (R_i1 = 5.04), determined to be 37% lower than the normative R-factor (R = 8) prescribed by code. Nonlinear static analyses confirmed that conventional design resulted in “irreparable” damage (mean Global Damage Index = 0.82). In contrast, redesigning the structure using the proposed ELF_i1 and R_i1 methodology successfully mitigated damage concentration, upgrading structural performance to a “repairable” state (mean Global Damage Index = 0.52). Finally, Incremental Dynamic Analysis validated the approach; the redesigned structure satisfied FEMA P695 collapse prevention criteria, achieving an Adjusted Collapse Margin Ratio (ACMR) of 2.10. This study confirms the proposed method is a robust and practical design alternative for soft-storey mechanisms within a simplified linear framework. Full article

In response to ground pressure problems such as an abnormal increase in working face support resistance and severe roadway floor heave induced by the lateral composite structure of the multi-layer thick and hard roof in the 11,223 working face of Xiaojihan Coal Mine, based on the triangle area slip theory, this study reveals that the lateral triangle area forms a composite structure of “cantilever beam + masonry beam”. The stress transfer and unloading mechanism of the high- and low-position thick and hard rock stratum fracturing was clarified. A technical scheme is proposed and implemented to weaken the high- and low-position thick and hard rock strata through horizontal Long Directional Borehole synergistic fracturing and optimize stress transfer. The results show that (1) the lateral overlying rock forms a triangular slip area under the clamping of the cantilever and masonry beam structures. This composite structure is the main reason for the increase in the support resistance at the end of the working face and the stress concentration of the roadway surrounding rock. (2) The influence law that the load of the triangular slip area is mainly influenced by the length of the broken block, and the breaking angle was clarified. The distribution characteristics of the load in the lateral triangle area under the fracturing of thick and hard rock strata at different horizons are mastered. When the length of the key block is reduced by 40%, the supporting force F₁ of the rock mass below the broken block on it is reduced by 62.5%, and the supporting force F₂ and the frictional force F₃ of the end part on the broken area of the triangle area are reduced by 34.6%. (3) The fracturing of high- and low-position thick and hard rock strata can collaboratively weaken the stress accumulation at high and low positions. Fracturing the low-position thick and hard rock strata can cut off the low-position “cantilever beam” structure, and fracturing the high-position thick and hard rock strata at the same time can transfer the load of the “masonry beam”. Through simulation, it is seen that the stress peaks at the end of the working face and the roadway surrounding rock during synergistic fracturing are, respectively, reduced by 12.2% and 28.9%. (4) An industrial test of directional drilling hydraulic fracturing of lateral thick and hard rock strata is carried out, achieving the regulation effect that the average value of the support resistance at the end of the cycle is reduced from 27.2 MPa to 22.7 MPa, and the floor heave amount of the reused roadway is reduced by 62.3%. The research results can provide a reference for the advanced treatment of the strong ground pressure area of the multi-layer thick and hard roof. Full article

The Trepponti bridge in Comacchio (Italy) is a significant masonry landmark characterised by a complex geometry. Its structure comprises five irregularly connected segments, creating pronounced geometric discontinuities. Accurately modelling this configuration is challenging due to the highly complex mechanical behaviour of masonry. This study presents a robust computational strategy for the nonlinear structural assessment of such heritage bridges. The methodology integrates a parametric meshing environment (PoliBrick plugin) with nonlinear finite-element analysis in Straus7. An initial discretisation is generated through PoliBrick, undergoes geometric optimisation to produce an analysis-ready model. The bridge is homogeneously modelled and meshed through macro-blocks obeying a Mohr–Coulomb failure criterion. Material parameters are defined according to the LC1 knowledge level stipulated by the Italian structural code. Differential settlement scenarios are simulated by imposing controlled vertical displacements on individual and paired piers. This approach enables evaluation of structural displacement, stress distribution, and crack propagation. The analyses reveal a markedly asymmetric structural response, identifying two specific piers as critical vulnerable elements. The proposed framework demonstrates that parametric meshing effectively reconciles accurate geometric representation with computational efficiency. It offers a practical tool for guiding the conservation and safety evaluation of irregular vaulted masonry bridges. Full article

Total floor areas of existing masonry structures in China cover 25 billion square meters. A significant proportion of these structures were classified as Grade C or D following a safety assessment. The compaction of masonry mortar occurs concurrently with an increase in vertical loads from upper-story walls and floor slabs. This condition may alter the actual compressive bearing capacity due to the compaction effect on the mortar of ground-floor walls. However, this effect is not addressed in the Chinese Code for Design of Masonry Structures. This study involved designing 12 brick walls using mortar with design strength grades of M2.5, M5, and M7.5, as determined by compressive testing. Each group simulated the ground-floor walls of four-, five-, and six-story masonry structures, considering the combined effects of vertical loads and mortar compaction, respectively. The results showed that, during mortar curing in ground-floor walls, the cracking load and ultimate load capacity of the wall models increased with progressively increasing loads from upper-floor walls and slabs. This is possibly due to the compaction effect on the mortar, which benefits the mortar density and the bonding performance between the mortar and brick. Due to the higher initial porosity and weaker bonding of low-strength mortar, the cracking load capacity of low-strength mortar walls under preloading increased significantly more than was observed in high-strength mortar walls. Conversely, owing to the high correlation between ultimate load and compressive strength, higher mortar strength had a more significant effect on the ultimate loads of the brick wall specimens under preloading. An increase in ultimate load capacity exhibited a linear relationship with the number of structural layers. This study can inform the safety assessment of existing masonry walls. Full article

The dynamic characterization of historical buildings located in a complex geological and seismological context is essential to assess seismic vulnerability and to guide conservation strategies. This study presents a non-invasive, ambient vibration-based, investigation of the Norman Castle of Aci Castello (Sicily, Italy), applying Horizontal to Vertical Spectral Ratio (HVSR), Horizontal to Horizontal Spectral Ratio (HHSR), and Random Decrement Method (RDM) to evaluate the structure’s dynamic behavior and potential Soil–Structure Interaction (SSI) effects. The fundamental site frequency, estimated within a broad plateau in the range 2.05–2.70 Hz, does not overlap with the structural frequencies of the castle, which range approximately from 6.30 Hz to 9.00 Hz in the N–S structural direction and from 3.50 Hz to 8.50 Hz in the E–W direction, indicating absence of global SSI resonance. However, the structure exhibits a complex multimodal response, with direction-dependent behavior evident both in spectral peaks and in damping ratios, ranging from 2.10–7.73% along N–S and 0.90–5.84% along E–W. These behaviors can be interpreted as possibly linked to structural complexity and the interaction with the fractured volcanic substrate, characterized by shallow cavities, as well as to the material degradation of the masonry. In particular, the localized presence of subsurface voids may induce a perturbation of the low-frequency ambient vibration wavefield (e.g., microseisms), producing a localized increase in spectral amplitude observed at Level I. The analysis indicates the absence of global SSI resonance due to the lack of overlap between site and structural fundamental frequencies, while significant local SSI effects, mainly related to cavity-induced wavefield perturbation, are observed and may represent a potential vulnerability factor. These findings highlight the relevance of vibration-based diagnostics for heritage vulnerability assessment and conservation strategies. Full article