Structural Conditions Research Articles

Automated 3D Modeling vs. Manual Methods: A Comparative Study on Historic Timber Tower Structure Assessment

The present study focuses on the preservation of historic timber constructions, crucial cultural heritage assets that demand effective structural health monitoring (SHM) to ensure safety and integrity. SHM aims to detect and evaluate potential structural deviations that may compromise performance, requiring both detailed geometric data acquisition and 3D modeling. For this purpose, contactless tools such as photogrammetry, laser scanning, and other topographic methods are employed to gather point cloud data. This research utilizes a terrestrial laser scanner (TLS) to generate 3D models of the historic timber tower of St. Michaeler church in Vienna. A novel automated modeling method is compared with two manual modeling approaches. The first is a traditional as-designed structural model created in Dlubal RSTAB software, and the second is a manually generated as-built model created using a scan-to-BIM application in Revit. While the first model is based on 2D plan documents created from the TLS point cloud, the second and automated models use the point cloud as direct input. The findings demonstrate that this automated model significantly enhances early-stage structural assessment efficiency, providing reliable insights into structural conditions with minimal processing time. This research underscores the potential of automated 3D modeling in preliminary structural assessments of historic timber structures.

Conductance oscillations in helicene-based junctions.

We have carried out a theoretical study into electron transport through molecular junctions based on dithiolated helicenes of varying lengths. We found that, in certain specific structural conditions, in which the orientation and the pitch of the helical structures are kept constant, the transmission at the Fermi level as a function of the molecular length exhibits oscillations which approximately follow an odd-even pattern. However, dispersive interactions alter this trend, ensuing a rather different quasi-periodic oscillating pattern with a sawtooth profile.

Social Positioning and Pathways of Social Mobility of Intermarried Ukrainian Migrants in Poland

The article draws on the narratives of 40 migrants from Ukraine intermarried with Polish citizens, shedding light on their subjective dimensions of mobility and social positioning. The research captures the diversity of migration trajectories and socio-demographics and explores how individuals construct their own definitions of success and failure that guide their actions. It also investigates their perceptions of stratification systems in Ukraine and Poland, offering insights into the structural conditions shaping intermarried migrants’ social positioning and opportunities for advancement. The analysis indicates three non-linear pathways of social mobility through entrepreneurship, utilisation of cultural capital and legalisation of stay, challenging the assumptions on straightforward vertical mobility of intermarried migrants.

Identifikasi Cekungan Sedimen Lokasi Manifestasi Gas Alam Kampung Holtekamp Kota Jayapura Melalui Pemodelan Tiga Dimensi (3D) Berdasarkan Anomali Gravitasi GGMplus

Natural gas is one of the natural resources that are abundant in Indonesia. Papua is one of the regions in Indonesia that has large potential reserves of natural gas, including Jayapura City. The existence of natural gas potential in Jayapura City is indicated by the presence of natural gas bursts that came out during the drilling process of the wells of residents of Holtekamp Village, Muara Tami District, Jayapura City. The gas burst incident that appeared in the Holtekamp Village area was not the first to occur in the Muara Tami District area but the presence of natural gas manifestations has also been found in West Koya. In relation to this, the author took the initiative to conduct geophysical research using the gravity method. This gravity method is used to determine the condition of the subsurface structure regionally. Based on 3D modeling based on GGMplus gravity anomalies, it was obtained that the natural gas manifestation area of Holtekamp Village is in a coastal sedimentary basin and swamp with a depth of 500 meters. In addition, the results of 3D modeling also identified 1 other sedimentary basin with a depth of 1200 meters in the shallow sea area on the Holtekamp coast and 2 other sedimentary basins with depths of 1500 meters and 2500 meters in Youtefa Bay.

Structural Health Assessment of a Reinforced Concrete Building in Valparaíso Under Seismic and Environmental Shaking: A Foundation for IoT-Driven Digital Twin Systems

Structural health monitoring is vital for the safety and longevity of infrastructure, particularly in seismic zones. This study focuses on identifying the dynamic properties of a reinforced concrete building in Chile’s Valparaíso region. Using an experimental approach, the study compares ambient vibration records, seismic events (moment magnitude > 4), and data collected during adjacent construction activities. Force-balanced accelerometers were used for vibration measurements. The analysis employs the Stochastic Subspace Identification with Covariances (SSI-COV) method within an operational modal analysis framework to extract the building’s modal parameters without requiring artificial excitations. This technique effectively identifies modal characteristics under different vibration sources, making it suitable for evaluating the structural condition under diverse loading conditions. The findings reveal the building’s modes and frequencies, offering critical insights for maintenance and management of infrastructure. Little to no variations were observed in the identified frequencies of the building when working with different types of input data. These data support the integration of real-time IoT systems for continuous monitoring, providing a foundation for future digital twin applications. These advancements facilitate early deterioration detection, enhancing resilience in seismic environments.

Comparative Optical Properties of Amorphous and Crystalline MoO3 Films by Spectroscopic Ellipsometry Study

This paper presents a comprehensive study of the optical properties of amorphous and crystalline MoO3 thin films using spectroscopic ellipsometry. MoO3 films were deposited on SiO2/Si substrates with varying oxide thicknesses using the atomic layer deposition (ALD) method. The study utilized various optical oscillator models, including Lorentz, Tauc–Lorentz and Harmonic, to analyze the dielectric functions and identify midgap states resulting from oxygen deficiencies. The findings highlight significant differences in the optical properties between amorphous and crystalline MoO3 films, demonstrating the impact of structural phases and substrate conditions. Specifically, amorphous films exhibited lower broadening and energy peaks compared to crystalline films, which showed distinct midgap states indicative of higher oxygen vacancy concentrations. These results enhance the understanding of the optical behavior of MoO3 films and their potential applications in advanced optoelectronic devices.

Quantifying Effective Built-in Temperature Difference for Decades- Old Jointed Plain Concrete Pavements in Eastern Washington State

Fifteen Portland cement concrete (PCC) slabs from four Jointed Plain Concrete Pavement (JPCP) sections in the Long-Term Pavement Program (LTPP) located in eastern Washington State were studied in this paper. Dipstick-measured transverse deflection profile along with temperature measurements across slabs’ depths collected during falling weight deflectometer (FWD) testing were used in the study. The youngest section in the study was 24 years old at the time of testing. The objective was to characterize the total effective linear temperature difference (TELTD) and the effective built-in temperature difference (EBITD) in the slabs. EBITD is a temperature differential representing the combined effects of construction built-in, as well as long-term drying shrinkage, and creep equivalent temperature differences. Using ISLAB2000, several iterations were run for each slab to identify the TELTDs that would produce slab curvatures close to those measured in the field. For validation purposes, the found TELTDs were used in Westergaard’s closed-form solution for deflections in the transverse direction. Transverse profiles predicted by ISLAB2000 and Westergaard equations matched well. EBITD, was then obtained by simply subtracting the in-field measured temperature differential from TELTD. Variations of EBITDs were found among the four sections, ranging from +31 to -120 °C (55 to -215 °F). Multiple factors, such as structural features, material properties, construction conditions, and climatic conditions, were identified as influential for the predicted EBITDs.

Unravelling national governments’ positions on EU rule of law enforcement: structural, semi-structural and ideological factors

ABSTRACT The Council’s enforcement inaction regarding the rule of law crisis has been endlessly criticised by scholars and commentators. However, there is currently no theoretically parsimonious explanation of why some national governments oppose enforcement whilst others are more inclined to support it. We address this question by considering structural (time of accession), semi-structural (contributions to, or receipts from, the EU budget and democratic quality) and circumstantial (partisanship, ideology, EU integration stance) conditions. We use Qualitative Comparative Analysis (QCA) to test the impact of these conditions on governments’ positions from 2016 to 2021. Findings show relatively stable preferences on enforcement within Member States, despite changes in the ideology of the ruling party. Time of accession, having a high quality of democracy and being a net contributor to the budget emerges as the most robust combination of conditions to explain strong pro-enforcement preferences. In contrast, governments of newer Member States that are net recipients of funds tend to be more reluctant to enforce the rule of law. While ideology lacks sufficient parsimonious explanatory power, it is particularly relevant for explaining extreme anti-enforcement reactions.

Identifying fracture-controlled resonance modes for structural health monitoring: insights from Hunter Canyon Arch (Utah, USA)

Abstract. Progressive fracturing contributes to structural degradation of natural rock arches and other freestanding rock landforms. However, methods to detect structural changes arising from fracturing are limited, particularly at sites with difficult access and high cultural value, where non-invasive approaches are essential. This study aims to determine how fractures affect the dynamic properties of rock arches, focusing on resonance modes as indicators of structural health conditions. We hypothesize that damage resulting from fracture propagation may influence specific resonance modes that can be identified through ambient vibration modal analysis. We characterized the dynamic properties (i.e., resonance frequencies, damping ratios, and mode shapes) of Hunter Canyon Arch, Utah (USA), using spectral and cross-correlation analyses of data generated from an array of nodal geophones. Results revealed properties of nine resonance modes with frequencies between 1 and 12 Hz. Experimental data were then compared to numerical models with homogeneous and heterogeneous compositions, the latter implementing weak mechanical zones in areas of mapped fractures. All numerical solutions replicated the first two resonance modes of the arch, indicating these modes are insensitive to structural complexity derived from fractures. Meanwhile, heterogenous models with discrete fracture zones succeeded in matching the frequency and shape of one additional higher mode, indicating this mode is sensitive to the presence of fractures and thus most likely to respond to structural change from fracture propagation. An evolutionary crack damage model was then applied to simulate fracture propagation, confirming that only this higher mode is sensitive to structural damage resulting from fracture growth. While examination of fundamental modes is common practice in structural health monitoring studies, our results suggest that analysis of higher-order resonance modes can be more informative for characterizing fracture-driven structural damage.

Assessment of JPCP Slab and Joint Movement under Multiple Structural and Environmental Conditions

Jointed plain concrete (JPC) pavement slab curling and joint movement have been shown to play a major role in the cracking performance of conventional JPCP pavements and composite HMA/JPC pavements with a renewable surface. These movements have been assessed as part of the SHRP II R21 Composite Pavement project at the University of California Pavement Research Center ATIRC test track. Environmentally induced slab movement both internal and at slab joints was evaluated under several conditions; two slab thicknesses, doweled and undoweled slabs, and overlayed (two thicknesses) and non-overlayed JPC slabs. The aim of this paper is to summarize findings of slab movement research and how this movement is affected by different variables. With the increasing push toward mechanistic design for concrete pavements, the importance of this information becomes ever greater.

Performance of Bonded CRCP Overlay in Texas

As of 2012, there are 17,336 lane miles of Portland cement concrete (PCC) pavement managed by the Texas Department of Transportation (TxDOT), out of a total 196, 821 lane miles in Texas. Many miles of PCC pavement have approached or exceeded their design lives and need rehabilitation. PCC pavements that need rehabilitation now or in the near future were built thinner than today’s standard and are accordingly structurally deficient. Bonded concrete overlay (BCO) provides an optimal rehabilitation option for pavements that are structurally deficient. Over the years, BCO has been utilized in Texas to strengthen existing continuously reinforced concrete pavement (CRCP), with overlay thickness from 2 inches to 8 inches. In general, the performance has been satisfactory; however, in several projects, distresses occurred at early ages and forensic evaluations were conducted, which included continuous deflection testing using rolling dynamic deflection (RDD) and total pavement acceptance device (TPAD), deflection testing using Falling Weight Deflectometer (FWD), and other testing including bond strength testing. The findings include (1) BCO performance depends, to a large extent, on the structural condition of the existing CRCP as indicated by slab deflections evaluated by FWD or TPAD, (2) adequate amount of longitudinal steel reinforcement in BCO layer significantly improves CRCP BCO performance, (3) coarse aggregate type in BCO concrete has a significant effect on BCO performance, and (4) discontinuities in existing pavement, such as joints at bridge approach slabs, were problem areas with distresses in BCO. To ensure good performance of CRCP BCO on PCC pavement, it is recommended that (1) the entire project be evaluated with deflection testing device to identify areas with deflections more than 8 mils at 9,000 lbs for strengthening by removal of existing concrete and base layers and replacement with new concrete, (2) deflection threshold values be developed for CRCP BCO on jointed concrete pavement, and (3) longitudinal steel be provided in BCO.

Reliability Analysis of Residential Buildings under Hurricane Using Embedded FBG Sensors: Remaining Useful Lifetime Analysis

Every year, the lack of reliable and affordable structural health monitoring systems to assess the resilience of residential buildings in coastal areas results in extensive damage from strong winds and hurricanes. This work investigates the use of embedded fiber Bragg grating (FBG) sensors for the structural health monitoring of residential timber buildings for reliability assessment. The remaining useful lifetime (RUL) of buildings after being impacted by hurricane has been estimated using long short-term memory (LSTM) neural network. A proof-of-concept experimental setup has validated the system’s performance and functionality. Multiple one-story and two-story scaled-down (~1:20) prototype timber buildings were constructed and placed in a wind tunnel to assess their structural performance and stability under wind speeds ranging from 0 to 150 mph. FBG sensors attached to the buildings measured strain in real time. The measured strain data are used to estimate the building’s reliability. A mathematical Health Indicator is introduced to determine the level of structural integrity and health under varying load and structural conditions. The FBG sensors demonstrated accurate measurement and real-time monitoring of strain changes in selected structural elements during high wind speeds. Assessment results can inform condition-based maintenance, safety evaluations, and stability reports. Additionally, the system can issue real-time warnings for potential failures and damages, thereby enhancing the overall resilience of residential buildings. Received: 27 September 2024 | Revised: 2 December 2024 | Accepted: 27 December 2024 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data are available from the corresponding author upon reasonable request. Author Contribution Statement Abolghassem Zabihollah: Conceptualization, Validation, Investigation, Resources, Writing – original draft, Writing – review & editing, Visualization, Supervision, Project administration. Yu Shi: Methodology, Software, Formal analysis, Data curation, Writing – original draft, Writing – review & editing, Visualization.

What factors enable or limit the role of intermediaries in strengthening transformative capacities? Case studies of intermediaries in two Cambodian cities

Urban transformative capacities can be strengthened through the role of intermediaries, who are individuals or organisations that work between agencies and identify ways to form coalitions and broker knowledge, drive reforms across scales, and address power disparities. There is limited research to date to understand the factors that enable or limit the role of intermediaries in urban sustainability transformations. Through comparing the roles of intermediaries and their evolution in two case studies cities of urban Cambodia – Battambang and Sihanoukville – through the lens of the urban transformative capacities’ framework of Wolfram (Cities 51: 121–130, 2016), we have identified key factors that impact the effectiveness of these intermediaries. Through qualitative interviews and focus groups, we have found that long-term, place-based, and networked engagement, with political trust and support, is important, alongside the need to demonstrate results and build momentum for transformation through pilots and collaboration. Underpinning these factors are the local power dynamics and structural conditions, as well as the capabilities and attributes of the intermediary actors.

The results of the inspection of the structures of the extension to the public building in Lutsk

Information on the inspection results of the extension inspection to the public building is presented. The results of the visual survey are provided. The defects identified during the inspection are described. The technical condition of the load-bearing structures is analyzed. Measures to restore the technical characteristics of the inspected structures are proposed.

Binocular Video-Based Automatic Pixel-Level Crack Detection and Quantification Using Deep Convolutional Neural Networks for Concrete Structures

Crack detection and quantification play crucial roles in assessing the condition of concrete structures. Herein, a novel real-time crack detection and quantification method that leverages binocular vision and a lightweight deep learning model is proposed. In this methodology, the proposed method based on the following four modules is adopted: a lightweight classification algorithm, a high-precision segmentation algorithm, a semi-global block matching algorithm (SGBM), and a crack quantification technique. Based on the crack segmentation results, a framework is developed for quantitative analysis of the major geometric parameters, including crack length, crack width, and crack angle of orientation at the pixel level. Results indicate that, by incorporating channel attention and spatial attention mechanisms in the MBConv module, the detection accuracy of the improved EfficientNetV2 increased by 1.6% compared with the original EfficientNetV2. Results indicate that using the proposed quantification method can achieve low quantification errors of 2%, 4.5%, and 4% for the crack length, width, and angle of orientation, respectively. The proposed method can contribute to crack detection and quantification in practical use by being deployed on smart devices.

Deep hydrocarbon charging and accumulation in complex fault blocks, the northern part of the eastern Liaohe depression, China

Deep exploration in complex fault-block regions is critical for global oil and gas development. As a representative region characterized by complex fault-block development, the northern part of the eastern Liaohe depression poses challenges in understanding the charging time and migration channels of deep hydrocarbons due to its intricate structural and reservoir conditions. For this purpose, this study utilizes diverse geological data from recent explorations, employing the petrological characteristics of inclusions, homogenization temperatures, and simulations of the thermal burial history to investigate the charging times of deep hydrocarbons. It combines the diagenetic processes of the reservoir with tectonic evolution to reveal the charging pathways and dynamic processes of deep hydrocarbons in the northern part of the eastern Liaohe depression. The results indicate that there are two charging periods in the study area: the late Oligocene (32.9–27.5 Ma) and from the late Neogene to the present (8.7–0 Ma). During these critical periods, faults with high activity intensity and low fault section normal stress were in an open state, which can serve as pathways for the vertical long-distance migration of hydrocarbons. In the first charging period, a substantial volume of hydrocarbon expelled from the source rocks migrates vertically into the deep sandstone reservoir through opening faults, exhibiting characteristics of source–reservoir separation. Subsequently, a brief uplift at the end of the Oligocene halted hydrocarbon generation. In the second charging period, as the source rocks further matured, a substantial volume of natural gas was injected into the deep reservoirs. At this period, the faults approached the seal, preventing hydrocarbons from migrating vertically and allowing them to enter the deep sandstone reservoirs adjacent to the source rocks, reflecting characteristics of source–reservoir proximity.

Pathways to Progress: Unveiling Structural Change in Africa Through Economic Transformation, Technology, Talent, and Tourism

African economies are undergoing significant structural transformation, transitioning from agriculture to manufacturing, services, and technology-driven industries. Driven by urbanization, technological innovation, and global trade, this shift offers opportunities for sustainable growth but faces challenges such as infrastructure gaps and institutional hurdles. This paper examines the dynamics of structural change in 54 African countries, focusing on the roles of technology, talent, and tourism. Using World Bank data, factor and cluster analyses reveal five latent components: structural conditions, public sector capacities, dynamic conditions, urbanization, and growth. The analysis categorizes countries into six clusters, from Developing Economies to African Powerhouses. The findings emphasize the critical role of technology in boosting productivity, the importance of talent development through education and workforce integration, and the potential of sustainable tourism to drive transformation. This research provides a comprehensive framework for understanding Africa’s structural transformation, offering actionable insights to address disparities and promote equitable development across the continent.

A Comparative Study of Malay/Chinese and Malay/Indian Ethnic Conflicts and Relations in Malaysia's Multi-Ethnic Society

Since Malaysia's independence, the relationship between the Malay and Chinese ethnic groups (Malay/Chinese) and the relationship between the Malay and Indian ethnic groups (Malay/Indian) have been two of the most significant political issues in the country. While both belong to the category of indigenous groups and immigrant relations in Malaysia, there are fundamental differences between these two relationships. This paper argues that the Malay/Chinese relationship is a long-standing ethnic conflict caused by social class disputes, characterized by economic disparities, cultural clashes, and structural factors such as colonial history. In contrast, the Malay/Indian relationship is primarily a short-term regional conflict triggered by unexpected events. The ethnic stratification in the Malay/Chinese relationship, formed on the basis of economic differences, has become a structural condition, and the historical friction since the British and Japanese colonial periods has further exacerbated the situation. For Malaysia to build a truly equal and mutually respectful multicultural society, many areas still require significant efforts.

Deep guided wave convolution neural network committee-based multi-path fusion diagnosis method for fatigue corner crack

Accurate diagnosis of crack size is a critical task for guided wave (GW)-based structural health monitoring (SHM). However, fatigue cracks would have complex morphology due to complex structural geometries and loading conditions, in which multiple dimension characteristics, like crack length, depth, and angle are involved. It is challenging to quantitatively evaluate these characteristics with GW signals from a single excitation-sensing path. This paper proposes a novel deep guided wave convolution neural network (CNN) committee-based multi-path GW fusion diagnosis method, aiming at quantitative evaluation of dimension characteristics of the complex fatigue damage. GW signals from multiple excitation-sensing paths are synthesized as a high-dimension input image to enhance the effects of the fatigue crack. Besides, the deep GW-CNN committee is developed for damage quantification, in which each GW-CNN is trained with a portion of the training dataset to reduce the impact of small sample size. The proposed method is validated on fatigue tests of landing gear beam specimens under variable amplitude loading, which is designed referring to the critical region of a real aircraft and its fatigue crack presents as a corner crack. The leave-one-out validation results show the effectiveness of the proposed method, especially improvements in the diagnosis of small cracks.

'The people wore no armour, or none that I recognized': How perspective contributes to the exploration of dis/embodiment in Ta-Nahisi Coates's Between the World and Me

Considering the work of Ta-Nehisi Coates’s Between the World and Me (2015), the text considers the conditions of working from a place of acknowledged subjectivity. In doing so, Coates demonstrates that any notion of working from a ‘universal’ position is a literary fantasy from which writers of colour have been excluded. Coates deploys complex facets of dis/embodiment to evoke the experience of moving through the world in his particular body, while presenting the structural and systemic conditions that preface, and often, obstruct, that movement.