Search Results (87)

Amid China’s transition from rapid urbanization to high-quality development, quantifying urban building metabolism is crucial for building resilient resource management systems. However, current research predominantly focuses on eastern cities, largely overlooking non-residential buildings. Here, we apply dynamic material flow analysis (dMFA) to quantify the material stocks of residential and non-residential buildings in two major economic hubs in western China, Xi’an and Chengdu. The stock patterns from 1950 to 2050 and the underlying drivers are further clarified. Model projections suggest that material stocks in both cities will peak around 2040, reaching 2.2 billion tons in Chengdu and 1.08 billion tons in Xi’an, under the intensive scenario. Chengdu reaches stock saturation 2 to 3 years earlier than Xi’an, and the total stocks are approximately twice those of Xi’an. Reinforced concrete and steel structures dominate future building development and increase the accumulation of cement and steel. Sand and gravel still account for the majority of building materials. Demand for new construction materials shows a pronounced double-peak pattern, occurring in 2016 and 2026. Construction waste is projected to rise sharply by mid-century; scenario analysis indicates that an 80% material recovery rate has the potential to largely offset new material demand. Sensitivity analysis identifies building lifetime extension and construction technology improvement as the strategies with the greatest potential for mitigating future waste generation. This study expands the scope of urban building material metabolism research and provides a scientific basis for low-carbon urban planning and construction waste management in China. Full article

Industrial areas, which represent a specific type of urbanised area with an extremely high concentration of material reserves, can be considered key anthropogenic raw material reservoirs in the context of urban mining. Industrial areas, characterised by a high material density and a specific composition of structural systems, show extraordinary potential for providing secondary raw materials with high material and energy value. This increases the need for their systematic evaluation. The aim of the present study was to define the role of the selected industrial area as a strategic node for secondary raw material extraction, to identify the structure and quality of “urban deposits” in the selected location of the Ostrava–Karviná region (CZ), and to provide an analytical framework for its integration into circular planning processes. The methodological approach is based on a combination of pre-demolition audit, material flow mapping, spatial analysis, and structural element characterisation. It is becoming apparent that industrial areas have a high material density and contain significant amounts of recyclable metals, reinforced concrete elements, etc. These stocks are often concentrated in structural systems with predictable geometries, such as serial assembly prefabricated and steel frames, allowing for more accurate estimates of recoverable volumes. The results show that the incorporation of industrial areas into the process of urban mining can significantly reduce the consumption of primary raw materials, mitigate the environmental impacts associated with the extraction of raw materials, and, at the same time, promote the regeneration of industrial areas (or brownfields) through the planned decomposition of structures. The inclusion of urban mining in urban development strategies and the regeneration of industrial sites leads to the prediction that urban mining is one of the key elements for achieving a material-efficient and low-carbon urban environment. Full article

This paper aims to quantify the change in seismic response of a reinforced concrete (RC) building retrofitted by the seismic isolation technique when reinforcement corrosion is considered. In this regard, an 8-story RC building that possesses the characteristics of the existing fixed-base building stock in Türkiye has been identified and hypothetically retrofitted with lead rubber bearings (LRBs). In the numerical models, four different corrosion scenarios to represent the spatial distribution of corrosion on the frame elements of the superstructure and three different corrosion levels considering the mass losses (5, 10 and 20%) due to corrosion are considered; the corresponding reductions in (i) the cross-sectional areas of both the longitudinal and transverse reinforcements and (ii) the mechanical properties of steel and concrete are taken into account. Code-based bidirectional nonlinear response history analyses (NRHAs) are performed by considering the nonlinearity not only in the seismic isolation system but also in the superstructure. Furthermore, LRBs are represented by a force–displacement relation that enables modeling of the deterioration in strength of isolators due to lead core heating during cyclic motion. The results revealed that the spatial distribution of the corrosion is highly effective in amplification of inter-story drift ratios (ISDRs), which can be in the order of 2-fold depending on the level of mass loss. It is found that the seismic isolation technique is still effective in protecting the superstructure against earthquakes even though there is a corrosion problem in frame members. Full article

This study investigates how historical variability in construction materials influences the seismic fragility of reinforced concrete (RC) buildings in Bucharest. Mechanical properties of reinforcing steels (OB37, TOR47, and PC52) and concretes used between 1950 and 2000 are statistically characterized using archival records and experimental data. The analysis highlights significant discrepancies between prescribed and in situ concrete strengths, as well as substantial differences in ductility, overstrength, and strength variability among historical steel types. To evaluate structural implications, a representative 11-storey pre-1970 RC building is modeled using nonlinear static and incremental dynamic analysis. The results show markedly lower capacity and higher fragility in the transversal direction. Time-dependent deterioration is examined by incorporating carbonation-induced reinforcement corrosion using FIB-based formulations. Even moderate corrosion leads to measurable reductions in stiffness, ductility, and lateral capacity, producing higher fragility across all considered damage states. Seismic loss estimations further demonstrate an increase in expected annual losses for both principal directions when corrosion is considered. The findings underscore the need for era-specific material models and deterioration mechanisms to achieve accurate seismic vulnerability assessments of Bucharest’s aging RC building stock. Full article

The management of large and heterogeneous building stocks requires decision-support tools capable of prioritising interventions under limited technical and financial resources. In this framework, the role of structural deterioration is rarely integrated within a unified prioritisation framework. This study proposes a rapid deterioration-based assessment for prioritising maintenance within heterogenous portfolios. The assessment is articulated into two levels. A Project Level (PL) is based on visual inspections and component-level condition ratings, while a Network Level (NL) introduces contextual and functional modifiers related to the relevance of each structural unit within the building stock. A seismic assessment procedure is integrated in proposed decision-making system for optimising intervention planning. The two assessments are integrated through a decision-tree logic providing an overall classification of buildings within portfolios. The proposed framework is applied to an industrial-oriented building stock located in Italy, comprising 79 structural units characterised by significant typological heterogeneity, including masonry, reinforced concrete, precast reinforced concrete, and steel buildings. The application illustrates the internal consistency of the proposed framework and its ability to support a transparent and articulated prioritisation process for maintenance and risk mitigation within heterogeneous building portfolios. Further applications to different building stocks are required to explore the general applicability of the methodology. Full article

In this work, measurements of thermal diffusivity, heat capacity and thermal expansion of 40HM (42CrMo4, 1.7225, AISI 4140) steel manufactured conventionally and via Laser Powder Bed Fusion (L-PBF) were carried out in the temperature range from room temperature (RT) to 1000 °C. Thermophysical properties were tested using specialized test stands from NETZSCH. Thermal diffusivity was studied using both the LFA 427 laser flash apparatus and the LFA 467 xenon flash apparatus. Specific heat capacity was investigated using DSC 404 F1 Pegasus differential scanning calorimeter, and thermal expansion was investigated using the DIL 402 C. Inconel 600 and A310 steel were selected as the reference materials during the thermal diffusivity test using LFA467 in the RT÷500 °C range. The conventionally manufactured 40HM steel, in the form of hot-rolled bar stock, was subjected to standard heat treatment for this steel grade—quenching followed by high-temperature tempering. The additively manufactured 40HM steel was subjected to stress-relief annealing. The results revealed no significant differences between the thermophysical properties of the L-PBF-produced samples in the out-of-plane and in-plane build orientations. Furthermore, no substantial differences were observed between the thermophysical properties of the conventionally produced material and the material manufactured using the L-PBF technique. Full article

Transitioning toward a circular economy requires not only solutions involving technical component reuse but also mechanisms that reduce risk and increase confidence among market stakeholders. Steel-faced sandwich panels, widely used in façades and roofs, constitute a significant urban material stock, yet their reuse is constrained by information asymmetry, liability concerns, and the absence of verifiable condition data. In this study, we develop an integrated end-to-end workflow—combining controlled panel recovery, Unmanned Aerial Vehicle (UAV) inspection, deep learning-driven damage detection, and Building Information Modeling (BIM)-linked material passports—to enable traceable, evidence-based reuse decisions. Validated through a pilot façade assembly and disassembly process, the methodology successfully quantified 4845.90 cm² of mechanical damage across 10 panels, with all orthomosaic and detection outputs fully integrated into the digital passport environment. By standardizing component-level condition records, this approach reduces perceived risk and provides the technical assurance necessary to unlock a trusted second-hand marketplace for sandwich panels. Framed within an urban metabolism perspective, the findings demonstrate how digital transparency can bridge the gap between material recovery and market valuation. Full article

Current national-scale building stock models mainly focus on structural materials, overlooking the significant resource potential of Mechanical, Electrical, and Plumbing (MEP) systems. These systems are resource-intensive and contain standardized components with high-value materials such as copper and steel, yet their potential remains largely untapped due to fragmented data. This study introduces the novel systematic framework to estimate MEP components at high granularity and national scale. It integrates harmonized public data, machine-learning imputation (>90% accuracy under sparse conditions), and parametric rules reflecting building type, energy system, and construction decade. A Swiss case study yields scalable material stock estimates and lifespan-based turnover projections, showing strong consistency with existing GHG benchmarks. The framework highlights contrasting patterns across regions and building types, indicating where policy and industry can upscale reuse and recovery. Its modular design enables transferability and integration with circular economy planning and material-efficiency targets. Full article

Structural steel reuse can gain large embodied-carbon savings, yet it is still not widely adopted since approval depends on the quality of the evidence, how uncertainty is handled, and if the design requirements are followed, not just on resistance. Reclaimed members frequently lack dependable documentation regarding material grade, loading history, boundary conditions, connection status, and degradation. For reuse decisions, conservative default assumptions protect safety but frequently eliminate qualified reuse options. This research examines data-driven and physics-informed computational methods from a decision-making standpoint, contending that their significance resides in facilitating an auditable approval process, not in supplanting deterministic verification. We differentiate feasibility, acceptability, and approval as distinct engineering phases. Data-driven models are thought of as tools for quickly screening candidates, surrogate evaluation, inverse reasoning, and stock-to-demand matching. Their goal is to reduce the list of candidates and prioritize evidence collection. Physics-informed approaches are examined as admissibility filters that impose restrictions of equilibrium, compatibility, stability, and plausible boundary-condition envelopes; therefore, minimizing mechanically invalid predictions under partial information. Next, we consider uncertainty quantification and explainability to be essential for reuse decisions. We suggest practical outputs for approval packages, such as resistance bounds within specified assumption envelopes, sensitivity rankings of decision-critical unknowns, low-support flags, and evidence actions for conditional acceptance. This document is organized into a process from audit to approval. It also states the open issues in reuse-specific datasets, standardized evidence capturing, decision-relevant validation under degradation, and regulatory acceptance. The resulting framework clarifies how advanced computational tools can enable adaptable, conservative, and transparent steel reuse in practice. Full article

Introduction: Mpox virus (MpoxV), an emerging zoonotic pathogen, has recently caused global concern due to increasing outbreaks beyond its traditional endemic regions. While transmission primarily occurs via close contact, fomites are also suspected of contributing. This study aims to evaluate the effectiveness of UV-C irradiation on MpoxV-contaminated surfaces. Methods: the virucidal activity of UV-C (254 nm) irradiation on MpoxV applied to plastic, glass, and stainless-steel surfaces was assessed. Using a viral stock of 2.49 × 10⁵ TCID₅₀/mL, the samples were exposed to increasing UV-C doses. Viral titers were quantified through TCID₅₀ and plaque assays. Results: A UV-C dose of 6.34 mJ/cm² achieved a >2-log reduction of viral load, below the detection limit (31.6 TCID50/mL), on all tested surfaces. EC₉₀ values were determined as 3.33 mJ/cm² (plastic), 0.81 mJ/cm² (stainless steel), and 1.98 mJ/cm² (glass). No viable virus was detectable post-treatment at these doses on plastic and stainless steel while the titer was significantly reduced on glass. Conclusions: UV-C irradiation at low doses effectively inactivated MpoxV on various fomites. These findings support UV-C as a rapid and effective environmental disinfection strategy in healthcare and community settings to prevent indirect transmission of MpoxV. Full article

The EU’s green transition hinges on secure access to critical raw materials; vanadium is pivotal for microalloyed steels and emerging long-duration energy storage (VRFBs). Methods: We combine a market and technology review with PESTEL and Porter-5+2 analyses, complemented by a value-chain assessment and a SWOT-to-CAME strategy for the EU. Results: Vanadium supply is highly concentrated (VTM-derived, largely in CN/RU/ZA), prices are volatile, and >85% of demand remains tied to steel; yet VRFBs could shift demand shares by 2030 if costs—dominated by electrolyte—are mitigated. EU weaknesses include lack of primary mining and refining capacity; strengths include research leadership, regulatory frameworks and circularity potential (slag/catalyst recovery, electrolyte reuse). Conclusions: A resilient EU strategy should prioritize circular supply, selective upstream partnerships, battery-grade refining hubs, and targeted instruments (strategic stocks, offtake/price-stabilization, LDES-ready regulation) to de-risk vanadium for grid storage and low-carbon infrastructure. This study also discusses supply chain concentration and price volatility, and outline circular-economy pathways and decarbonization policy levers relevant to the EU’s green energy transition. Full article

In the manufacturing of iron core for high-power transformers, a cutting stock problem arises where large-width silicon steel coils must be cut into narrower coils, known as strips. Typically, the required length of each strip far exceeds that of a single coil. Therefore, the problem necessitates additional consideration of how to split the strips and arrange them on the large coils, with the goal of minimizing the total number of strips. In this paper, we propose a discrete artificial bee colony algorithm to address this problem. The algorithm replaces the stochastic roulette wheel with biased selection in the onlooker bee phase and introduces partially mapped crossover in both the onlooker and scout bee phases. These enhancements facilitate more effective utilization of information from high-quality solutions, thereby improving the algorithm’s stability and its capacity to obtain higher-quality results. Experimental results show that compared to existing methods reported in the literature, the proposed approach reduces the total number of strips by an average of over 3.9% and 7.6% for Set 2 and Set 3, respectively, while also exhibiting a faster convergence rate than other competitive algorithms. Full article

This study examines Phase B of the GREENERGY project focusing on the seismic performance and structural health monitoring of a renovated single-story RC frame with brick masonry infills that received significant strategic structural interventions. The columns were confined with basalt fiber ropes (FR, 4 mm thickness, two layers) in critical regions, the vertical interfaces between infill and concrete were filled with polyurethane PM forming PUFJ (PolyUrethane Flexible Joints), and glass fiber mesh embedded in polyurethane PS was applied as FRPU (Fiber Reinforced PolyUrethane) jacket on the infills. Further, greenery renovations included the attachment of five double-stack concrete planters (each weighing 153 kg) with different support-anchoring configurations and of eight steel frame constructions (40 kg/m²) simulating vertical living walls (VLW) with eight different connection methods. The specimen was subjected to progressively increasing earthquake excitation based on the Thessaloniki 1978 earthquake record with peak ground acceleration ranging from EQ0.07 g to EQ1.40 g. Comprehensive instrumentation included twelve accelerometers, eight draw wire sensors, twenty-two strain gauges, and a network of sixty-one PZTs utilizing the EMI (Electromechanical Impedance) technique. Results demonstrated that the structure sustained extremely high displacement drift levels of 2.62% at EQ1.40 g while maintaining structural integrity and avoiding collapse. The PUFJ and FRPU systems maintained their integrity throughout all excitations, with limited FRPU fracture only locally at extreme crushing zones of two opposite bottom bricks. Columns’ longitudinal reinforcement entered yielding and strain hardening at top and bottom critical regions provided the FR confinement. VLW frames exhibited equally remarkably resilient performance, avoiding collapse despite local anchor degradation in some investigated cases. The planter performance varied significantly, yet avoiding overturning in all cases. Steel rod anchored planter demonstrated superior performance while simply supported configurations on polyurethane pads exhibited significant rocking and base sliding displacement of ±4 cm at maximum intensity. PZT structural health monitoring (SHM) sensors successfully tracked damage progression. RMSD indices of PZT recordings provided quantifiable damage assessment. Elevated RMSD values corresponded well to visually observed local damages while lower RMSD values in columns 1 and 2 compared with columns 3 and 4 suggested that basalt rope wrapping together with PUFJ and FRPU jacketed infills in two directions could restrict concrete core disintegration more effectively. The experiments validate the advanced structural interventions and vertical forest renovations, ensuring human life protection during successive extreme EQ excitations of deficient existing building stock. Full article

Existing Mediterranean reinforced concrete buildings with masonry infills exhibit critical seismic vulnerabilities, yet real-time damage detection capabilities remain limited. This study validates a novel dense piezoelectric transducer (PZT) network concept for early damage detection in deficient RC structures under progressive seismic loading. A three-dimensional single-story RC frame with brick infills, representative of pre-Eurocode Mediterranean construction (non-ductile detailing, inadequate transverse reinforcement), was tested at serviceability limit states (SLSs) (Phase A) using a dynamic pushover approach with the 1978 Thessaloniki earthquake record, progressively scaled from EQ0.1g to EQ1.1g within the GREENERGY vertical forest renovation project. The specimen featured 48 PZTs using electromechanical impedance (EMI) methodology, 12 accelerometers, 8 displacement sensors, and 20 strain gauges. Progressive infill deterioration initiated at EQ0.5g while steel reinforcement remained elastic (max 2350 μstrain < 2890 μstrain yield). Maximum inter-story drift reached 11.37‰ with negligible residual drift (0.204‰). The PZT network, analyzed through Root Mean Square Deviation (RMSD), successfully detected internal cracking and infill-frame debonding before visible manifestation, validating its early warning capability. Floor acceleration amplification increased from 1.26 to 1.57, quantifying structural stiffness degradation. These SLS results provide critical baseline data enabling the Phase B implementation of sustainable vertical forest retrofitting strategies for aging Mediterranean building stock. Full article

This paper reports a statistical analysis of a database archiving information on the strengths of the materials in existing Italian bridges having pre- and post-tensioned concrete beams. Data were collected in anonymous form by analyzing a stock of about 170 bridges built between 1960 and 2000 and located in several Italian regions. To date, the database refers to steel reinforcing bars, concrete, and prestressing steel, whose strengths were gathered from design nominal values, acceptance certificates, and in situ test results, all derived by consulting the available documents for each examined bridge. At first, this paper describes how the available data were collected. Then, the results of a statistical analysis are presented and commented on. Moreover, goodness-of-fit tests are carried out to verify the assumption validity of a normal distribution for steel reinforcing bars and prestressing steel, and a log-normal distribution for concrete. The database represents a valuable resource for researchers and practitioners for the assessment of existing bridges. It may be applied for the use of prior knowledge within a framework where Bayesian methods are included for reducing uncertainties. The database provides essential information on the strengths of the materials to be used for a simulated design and/or for verification in the case of limited knowledge. Goodness-of-fit tests make the collected information very useful, even if probabilistic methods are applied. Full article