Search Results (3,760)

To address the challenging stope roof support problem associated with the the Upward Two-Step Staggered-Drift Cut-and-Fill Mining Method (UTSCF method) under fractured surrounding rock conditions, this study establishes an elasto-plastic zoning model for drift roof surrounding rock to calculate the thicknesses of the loose zone and plastic hardening zone, proposes a combined support scheme comprising split-set (SS) bolts, metal mesh and cross-timber (CT) caulking for the working condition where backfill on both side walls fails to achieve full roof contact, and analyzes the support performance of this method via FLAC3D numerical simulation. The results indicate that the total thickness of the loose zone (LZ) and plastic zone (PZ) in the roofs of 6 m and 8 m drifts reaches 2.02 m and 2.15 m, respectively; after support application, the maximum principal stress (MPS) of the roof decreases by 49%, the plastic zone volume is reduced by 35.5–47.2%, and the average roof displacement drops by approximately 29%. Field industrial tests have preliminarily verified the engineering adaptability and stability control performance of the proposed support method. The mechanical mechanism of secondary roof contact by wedged cross timbers, as well as the quantitative relationship between theoretical zoning and support adequacy, still requires further verification. Full article

Coastal floodplains face unprecedented threats from deforestation driven by global environmental change. The Sre Ambel floodplain, located in the southwestern coastal region, is one of Cambodia’s main floodplains and plays a critical role in maintaining ecosystem functions pivotal to wildlife and human communities. Over the past three decades, however, it has been at risk due to forest cover loss, which threatens ecosystem processes. This study aimed to investigate temporal and spatial floodplain forest cover loss over the past 24 years using remote sensing data, assess the drivers of deforestation through community social research and a literature review, and assess the anthropogenic influence on deforestation through spatial nonlinear modeling. Approximately 23% (11,182 ha) of forest cover in the Sre Ambel floodplain was lost during 2001–2024. Spatial modeling identified nonlinear conditional associations between mapped forest loss and distances to roads, rivers, villages, and houses. Spatial-block bootstrap analyses supported higher predicted loss probability near roads and at 2 km versus 5 km from village centers, whereas selected river- and house-distance contrasts were not robust. Forest loss peaked during 2006–2010 and again during 2016–2024. Respondents most frequently perceived agricultural expansion, settlement development, land grabbing, timber extraction, and resort development as key deforestation pressures. These results can help guide further floodplain assessment, conservation, restoration, and sustainable land-use planning. Full article

Diospyros glaucifolia Metcalf is a native timber tree of subtropical China of interest for reserve-forest planting, but genetically unevaluated. In a common-garden nursery trial we assessed first-season emergence, growth and seed traits of 84 open-pollinated families (9–17 per provenance) from six provenances, sown in randomized complete blocks (four replicates) as contiguous family plots; because seedlings within a plot are subsamples, effects were tested against the family × block plot. Provenances differed strongly in height and ground diameter (both p < 0.001) and in emergence, which ranged from below 30% in Longquan and Longnan to over 90% in the other four provenances; seed traits also varied among provenances. Height growth followed a logistic curve, with a rapid phase from late June to late August accounting for about two-thirds of first-season height. Once the plot structure was accounted for, family differentiation was modest (family-mean heritability of height about 0.36 and significant; diameter not significant), so early family selection for height is possible but would yield only limited gains, and height showed no consistent latitudinal trend across all six provenances. From an earlier program whose field phase was interrupted, these data give a first genetic evaluation and a baseline for future field testing and germplasm use. Full article

This study investigates the thermal stability and moisture evaporation of naturally aged larch timber exposed to medium-scale radiant panel fire. Temperature was monitored at depths of 1–8 cm in heritage beams from a Gothic timber church to examine phase change, charring, and depth-dependent heat transfer. The experimental device, a medium-scale radiant panel, offered the temperature–time curves with the following parameters: maximum temperature at depths of 1 cm, 2 cm, 4 cm, 6 cm and 8 cm; water evaporation at 1 cm, 2 cm, 4 cm, 6 cm and 8 cm when the samples reached 100 °C; and time of charring at the same depths when the samples reached 300 °C. Temperatures exceeded 600 °C at 1–2 cm depth. The conventional charring temperature (300 °C) was reached on average at 500 s at 1 cm and at 6000 s at 2 cm, while deeper layers remained below charring levels during testing. Moisture evaporation occurred over a temperature interval rather than at a single point, beginning at an average of 100.9 °C and completing near 125.6 °C. A plateau between 100 and 115 °C confirmed that latent heat absorption during water phase change delayed temperature rise and pyrolysis. The results demonstrate that coupled thermo-hygric processes, moisture migration, and char formation strongly influence internal temperature evolution. Full article

Single-number ratings are widely used in building acoustics, but they are meaningful only when the reference-curve procedure is applied correctly and the reported descriptors are matched to the physical problem. This study re-evaluates accredited in situ measurements of airborne and impact sound insulation for a timber-frame interfloor construction at the Archaeological Museum of Istria, Croatia. Applying the measured one-third-octave spectra in 1 dB reference-curve steps according to ISO 717 gives R′w = 55 dB and L′n,w = 62 dB. Both values satisfy the historical Croatian requirements that applied at the time of measurement. For the meeting-room source context, the ISO 717-1 adaptation term C = −3 dB gives R′w + C = 52 dB; Ctr is not used in the internal-partition analysis because it represents a low-frequency-rich, traffic-oriented source spectrum. The impact receiving-room volume is 95.4 m³. A separate diffuse-field scenario estimates how certified broadband absorption would change the unnormalized receiving-room level Li(f); it is not treated as a change in L′n,w, and no band-by-band 60 dB compliance threshold is applied. A separate sensitivity analysis of floating-floor resonance gives f0 = 28–89 Hz over the selected mass–stiffness range, with an as-built estimate of about 53 Hz. The paper therefore distinguishes measured apparent sound insulation, source-spectrum context, receiving-room response, and analytical sensitivity without presenting the scenario calculations as validated acoustic optimization. Full article

Wood structures (processed wood) are increasingly incorporated into Singapore’s sustainable built environment, but their durability is challenged by biodeterioration exacerbated by the tropical climate. We collected 133 decayed wood samples from outdoor wood structures and natural logs at 15 sites including public parks, wooden buildings, and private houses. Fungal communities were characterized using ITS1 amplicon sequencing, with taxonomic assignments initially performed using the UNITE database and subsequently refined using the ITS RefSeq Targeted Loci database, reducing inconclusive genus-level identifications from 55.8% to 44.0%. All but one site exhibited substantial local-scale heterogeneity in fungal communities, with between-site Bray–Curtis dissimilarities ranging from 0.61 to 1.0, demonstrating marked compositional differences among sampling sites, with median within-site Bray–Curtis dissimilarities ranging from 0.60 to 0.98, and samples collected from the same pieces of processed wood or natural log commonly harboring distinct fungal communities. The sole exception was a residential site dominated by Trichaptum byssogenum. PERMANOVA indicated that sampling location and substrate type explained 25.1% and 4.6% of the variation in fungal community composition, respectively, suggesting weak influence of wood treatment. One ascomycete and two basidiomycete isolates were further evaluated for their wood-decaying capacity in vitro. Remarkably, the ascomycete Paecilomyces maximus alone was capable of degrading angsana, balau, spruce, and rubberwood blocks, highlighting the potentially important role of ascomycetes as active primary saprotrophs in wood decomposition, consistent with their dominant presence in our study (eight of the nine widely dominant genera present in four–seven sites). Collectively, these findings reveal the complexity and heterogeneity of tropical wood biodeterioration and provide insights relevant to wood processing, durability assessment, and the management of timber structures in tropical environments. Full article

Recent revisions to the International Building Code (IBC 2021) have allowed high-rise mass timber shear wall structures up to 18 stories and 270 feet, reflecting the growing popularity and wide recognition of the advantages of mass timber construction. However, research on high-rise mass timber lateral force resisting systems (LFRSs) has heavily relied on experimental studies. Numerical modeling techniques for mass timber shear walls remain limited in terms of generality and applicability, which significantly hinders the further development of design and analysis methods for high-rise mass timber structures in medium-to-high seismic regions. In this paper, the strategies and characteristics of different numerical models of cross-laminated timber (CLT) shear walls are systematically reviewed and discussed. To assess the applicability of different models, a basic panelized CLT shear wall is selected as a benchmark for evaluating and comparing different modeling approaches in terms of their global hysteretic response, deformation characteristics, and computational efficiency. Recommendations are provided for the selection of numerical modeling approaches for various design and analysis scenarios. Future research needs in the nonlinear numerical simulation of CLT shear wall structures are identified and discussed. Full article

Accurate structural diagnosis of timber elements in historic buildings requires minimally invasive and operationally reliable assessment methods compatible with heritage conservation principles. This study aims to estimate timber density in situ directly from Resistograph drilling resistance. To achieve this objective, density estimates derived from Woodpecker impact penetration tests were paired with Resistograph drilling resistance measurements through a mesh to develop a point to point correspondence and calibrate a linear model relating density to drilling resistance and enabling its direct application through Resistograph measurements. The database comprised thirteen historic sweet chestnut (Castanea sativa Mill.) beams from the Cloister of Michelangelo in the Baths of Diocletian complex, Rome, Italy. Statistical analyses included the assessment of multiple window sizes, segmented penetration intervals, model calibration, and Leave-One-Beam-Out (LOBO) cross validation. The resulting model enables density estimation using only Resistograph measurements and demonstrated high predictive accuracy, achieving a coefficient of determination of 92%. Full article

Timber-structure buildings are a common traditional architectural type in China whose value has shifted from residential use toward cultural heritage preservation, historical research, and cultural-tourism exhibition. In subtropical regions such as Fujian and Hunan, these structures are exposed to year-round humid conditions that promote moisture-induced decay, making routine maintenance and strengthening essential. The scientific gap addressed here is that the durability–reversibility coupling of nano-SiO₂-modified CFRP–timber systems under sustained high-humidity exposure has not been systematically quantified, and no single-variable dose–response framework currently exists for isolating the contribution of nano-silica modification from connector effects. Conventional fiber-reinforced polymer (FRP) strengthening techniques are irreversible in application and prone to interfacial debonding in high-humidity environments. This study proposes a recoverable strengthening system employing nano-silica-modified carbon fiber-reinforced polymer (modified CFRP) composites applied to a detachable bolt-sleeve connection structure. Five specimen groups (blank control, unmodified CFRP, and M-CFRP-1, M-CFRP-3, M-CFRP-5 with 1.0%, 3.0%, and 5.0% nano-silica mass fractions) were subjected to accelerated aging for 120 days at 90.0 ± 3.0% relative humidity, followed by shear, compressive, and flexural tests complemented by SEM, DMA, moisture absorption measurement, thermal conductivity testing, one-way ANOVA with Tukey’s HSD post hoc test, ISO 13788 Glaser condensation risk analysis, and 1D heat-balance modeling. The M-CFRP-3 group exhibited the lowest equilibrium moisture content (6.8%), the highest retention of flexural (82%), shear (78%), and compressive (82%) strengths, and a diurnal inner-surface temperature swing of only 4.8 °C. The M-CFRP-3 envelope eliminated surface condensation throughout the diurnal cycle (dew point 19.15 °C), while the bare-timber envelope experienced 4.08 h/day of condensation risk; a 1D heat-balance analysis confirmed that the combined effect of narrowed moisture-induced conductivity gap and CFRP thermal inertia accounted for the observed temperature swing reduction. Disassembly of the bolt-sleeve system limited timber substrate damage to below 15% and supported three complete disassembly–reassembly cycles. The application of modified CFRP with 3 wt% nano-silica combined with a detachable bolt-sleeve connection simultaneously achieves durability, reversibility, and hygrothermal stability. This study advances a quantitative single-variable framework linking nano-SiO₂ dose to moisture-barrier, mechanical, and hygrothermal responses, providing a transferable methodology for designing reversible strengthening systems for heritage timber in humid climates. providing a feasible strategy for the maintenance and strengthening of traditional timber-structure buildings in high-humidity climatic regions. Full article

This narrative market review examines the transition of the European sawn softwood market using reported 2021–2024 data, preliminary 2025 values, and a 2026 market outlook. The analysis combines the International Softwood Conference (ISC) 2025 EOS/ETTF market survey, producer and trader outlooks, Baltic market evidence, Wood from Finland Conference (WFFC) 2026 presentations, and selected peer-reviewed literature. The datasets are kept within their original geographic and product scopes and are not merged into a synthetic European total. In the ISC European country set, sawn softwood production declined from 97.7 million m³ in 2021 to a preliminary 88.3 million m³ in 2025 (−9.6%), while reported consumption declined from 82.9 to 68.6 million m³ (−17.2%). The difference between production and reported consumption increased from 14.8 to 19.7 million m³; this is treated only as a dataset-specific accounting difference, not as a trade balance, export surplus, or inventory measure. In the first half (H1) of 2025, EOS/Eurostat data showed a diversified extra-EU export structure by value, led by the United Kingdom and the United States. Baltic evidence documents post-2022 sourcing reorientation, while source-reported 2026 outlooks indicate uneven construction recovery and tighter spruce availability in parts of Central Europe. Construction-related implications are discussed only where sources explicitly address species availability, grading, processing, or building-market conditions; the available market datasets do not quantify structural-grade volumes. Full article

Poplar (Populus × euramericana) is grown in the irrigated, short-rotation plantations of the Vega de Granada, southern Spain. Its recent recognition as structural timber (clones MC and Luisa Avanzo, tensile class T10, 2024) is rarely traced back to the forest resource that shapes it. This case study re-reads primary silvicultural, geometric and mechanical data through a single chain, from plantation to structural component, and adds two original, scenario-based estimates of carbon and transport footprint—not a complete life-cycle assessment. A clonal ordering in stiffness measured on standing trees does not survive conversion: on sawn timber the two certified clones differ by 1.3% (8213 against 8319 N/mm²), and the larger in-tree gap is consistent with a substantial contribution from the moisture state of the stem at measurement, rather than from genotype alone. What does propagate is the low density of the resource (374 ± 31 kg/m³ at 12% moisture), which shapes the hybridisation strategy, placing poplar in the low-stress core and Pinus nigra in the outer laminations; and the modest, variable sawing dimensions, which resolve sections by lamination rather than solid timber. Local sourcing yields an estimated transport-stage (A4) difference of 90–99 kg CO₂e/m³ over central-European import, and no structural poplar EPD was found in the main European registries consulted at the time of writing. Taken together, the evidence is consistent with silviculture—rotation age, log position and water regime, more than clonal choice—operating as the primary lever of structural design. Full article

The documentation and condition assessment of residential built heritage are often hindered by fragmented records, limited object–data traceability, and weak interoperability between modelling, inspection, database, and analytical environments. This study develops and functionally evaluates an interoperable HBIM-based workflow for constructive characterization and condition-data management. The workflow integrates ARCHICAD, IFC exchange, BIMvision, the BimOndare plug-in, SQLite, and Power BI. It was tested through a pilot demonstrator based on a real multi-storey residential building in San Sebastián, Spain, whose structural configurations and material assignments were deliberately extended to represent reinforced-concrete, steel, timber, and masonry systems. The IFC GlobalId served as the relational key between modelled components and externally stored records. The demonstrator comprised 1281 IFC elements, 183 inspection records, and 354 photographs. Object–data correspondence was additionally verified on 12 structural components with multiple associated records. The implementation demonstrated functional interoperability across the tested environments and supported component-level consultation and building-level filtering by element type, material, location, inspection information, and intervention-related attributes. The study demonstrates the technical feasibility of the proposed information architecture, while longitudinal persistence, model versioning, full-building diagnostic interpretation, usability, and comparative performance require further validation. Full article

The growing interest in point-supported cross-laminated timber (CLT) floor systems and the desire for open space designs led to the development of on-site adhesive solutions such as the TS3™ system, which joins panels along their minor-axis direction. Load duration affects the design of such floors at both the serviceability and the ultimate limit states. In the Canadian Standard for Engineering Design in Wood (CSA O86), load-duration effects are considered via a factor that lowers the resistance and a creep factor (K_Cr = 2.0) that increases the deflection; yet, the long-term behaviour of adhesive connections between CLT panels has not been tested. Here, creep was monitored for fourteen months on TS3™-connected CLT panels loaded in flat-wise bending under dry service conditions. The creep factors were on average below 1.8, not exceeding the CSA O86 creep factor. The residual short-term resistance and apparent bending stiffness after long-term loading were determined as 102% and 108%, respectively, of a reference group, demonstrating that long-term loading had no detrimental effect on the short-term performance. These findings are based on mean-level comparisons for the tested CLT species and stress grade and should be regarded as indicative of the long-term behaviour of TS3™-connected CLT panels in dry indoor conditions. Full article

Domestic forest conservation can reorganize international sourcing when downstream timber demand remains active after harvesting restrictions. This article examines whether China’s natural-forest conservation and commercial logging restrictions coincided with a reallocation of raw-log sourcing toward suppliers with higher pre-policy physical climate risk. Using BACI HS2002 bilateral trade data for HS 4403 raw logs and supplier-level pre-policy GCPRI measures, the analysis compares China’s supplier allocation with that of comparable foreign raw-log importers in a same-product cross-country difference-in-differences-in-differences (DDD) framework. China’s post-policy supplier allocation shifted relatively more toward suppliers with higher pre-policy GCPRI than did the allocation of comparable foreign importers in the baseline observed-flow specification. Additional revision checks show that the result remains positive in a zero-share supplier panel, weakens in the pre-2020 sample, and is not robust to a China-specific supplier-risk trend or importer-placebo inference. Conventional diversification measures moved in the opposite direction: concentration fell, effective supplier counts increased, top supplier shares declined, and the supplier quartile with the highest measured physical climate risk gained share. A decomposition attributes most of the observed change to incumbent supplier reweighting. The evidence therefore documents a sourcing-composition pattern rather than a clean causal effect or direct environmental-damage result. Supplier diversification and the physical climate-risk profile of sourcing are distinct dimensions of sustainable supply-chain assessment. Full article