Search Results (275)

Optimizing cable forces in cable-stayed bridges is challenging due to structural nonlinearity and the limitations of traditional methods, which often focus on isolated performance indicators. This study proposes an integrated framework combining Gaussian process regression (GPR) with an enhanced whale optimization algorithm improved by the Salp Swarm Algorithm (EWOSSA). GPR is first used to model the nonlinear relationship between cable forces and structural responses. The EWOSSA then efficiently optimizes the GPR-based model to identify optimal cable forces. A case study on a cable-stayed bridge with a 2 × 145 m main spans demonstrates the effectiveness of the proposed approach. Compared with conventional methods such as the internal-force equilibrium and zero-displacement methods, the EWOSSA-GPR framework achieves superior performance across multiple structural metrics. It ensures a more uniform cable force distribution, reduces girder displacements, and improves bending moment profiles, offering a comprehensive solution for optimal structural performance in cable-stayed bridges. Full article

China’s rapid urbanization has given rise to the phenomenon of “urban villages”, which are often regarded as chaotic fringe areas in traditional studies. With the rise of the concept of resilient cities, the value of urban villages as potential carriers of sustainable development has been re-examined. This study adopted research methods such as field investigations, in-depth interviews, and conceptual sampling. By analyzing the interlinked governance relationship between Xiamen City and the urban villages in the Bay Area, aspects such as rural housing improvement, environmental governance, residents’ feedback, geographical pattern, and spatial production were evaluated. A field investigation was conducted in six urban villages within the four bays of Xiamen. A total of 45 people in the urban villages were interviewed, and the spatial status of the urban villages was recorded. This research found that following: (1) Different types of urban villages have formed significantly differentiated role positionings under the framework of regional governance. Residential community types XA and WL provide long-term and stable living spaces for migrant workers in Xiamen; tourism development types DS, HX, BZ, and HT allow the undertaking of short-term stay tourists and provide tourism services. (2) These urban villages achieve the construction of their resilience through resisting risks, absorbing policy resources, catering to the expansion of urban needs, and co-construction in coordination with planning. The multi-cultural inclusiveness of urban villages and their transformation led by cultural shifts have become the driving force for their sustainable development. Through the above mechanisms, urban villages have become the source of resilience and sustainability of healthy cities and provide a model reference for high-density urban construction. Full article

Under prolonged loading and various environmental factors, the performance of stay cables gradually deteriorates, which impacts the safety of the bridge structure. To investigate the influence of cable damage on the static performance of cable-stayed bridges, a finite element model of a cable-stayed bridge with damaged cables was established. The element death method is used to simulate cable damage, examining the impact of various damage scenarios on the static performance of the cable-stayed bridge. The objective is to identify cable locations that have a greater impact on the structure, providing a basis for assessing the bridge’s safety and developing cable replacement strategies. The research indicates that damage to long cables has a more significant impact on the static performance of the cable-stayed bridge compared to damage to short cables. Additionally, damage to the side span cables has a more pronounced effect on the structure than damage to the mid-span cables. The influence of cable damage on cable forces is primarily reflected on the same side of the cable plane within the same bridge tower as the damaged cable. Changes in cable forces result in variations in the deflection of the main girder and the displacement of the main tower. When multiple cables are damaged, the impact on the static performance of the structure is similar to that of single-cable damage. In instances of longitudinal symmetric damage and adjacent cable impairment, the cables transition into a critical state, resulting in more pronounced alterations in the deflection of the main girder and the displacement of the main tower. Original symmetric damage has a relatively small impact on the static performance of the entire bridge, so it is recommended to adopt a symmetric approach for cable replacement projects. Considering the impact of damage to a single cable and multiple cables on the static structure, it is possible to initially determine the location and extent of the cable damage. Based on the damage patterns, a cable replacement plan can be designed. It is recommended to use a symmetry-based approach for the cable replacement, as this method results in minimal impact on the overall static performance of the bridge, thereby ensuring the safety of the bridge structure. Full article

Commonly, accelerometers are used to determine the tension force in cables through an indirect process; however, it is necessary to know the mechanical parameters of each element, such as mass and length. Typically, obtaining or measuring these parameters is not feasible. Therefore, this research proposed an alternative methodology to indirectly estimate them based on historical information about the so-called classic instruments (accelerometers and hydraulic jack). This case study focused on the Rio Papaloapan Bridge located in Veracruz, Mexico, a structure that has experienced material casting issues due to inadequate heat treatment in some cable top anchor over its lifespan. Thirteen cables from the structure were selected to evaluate the proposed methodology, yielding results within 3.8% of difference compared to direct tension estimation generated by a hydraulic jack. Furthermore, to enhance data collection, this process was complemented using a computer vision methodology. This involved remotely measuring the vibration frequency of cables from high-resolution videos recorded with a smartphone. The non-contact method was validated in a laboratory using a vibrating table, successfully estimating oscillation frequencies from video-recording with a fixed camera. A field test on eight cables of a bridge was also conducted to assess the performance and feasibility of the proposed method. The results demonstrated an RMS Error of approximately 2 mHz and a percentage difference in the tension force estimation below 3% compared to an accelerometer measurement approach. Finally, it was determined that this composed methodology for indirect tension force determination is a viable option when: (1) cables are challenging to access; (2) there is no line of sight between the camera and cables outside the bridge; (3) there is a lack of information about the mechanical parameters of the cables. Full article

The COVID-19 pandemic and the resulting stay-at-home orders disrupted religious life across the United States, forcing congregations to rapidly adapt to unprecedented challenges. While existing research has explored the pandemic’s impact on individual religiosity, this article centers on how congregations were reshaped by the pandemic—sometimes temporarily, sometimes permanently. Drawing on nationally representative survey data from the Exploring the Pandemic Impact on Congregations project and the long-running Faith Communities Today initiative, this article analyzes trends in worship attendance, other forms of commitment to and engagement with congregations, congregational openness to change, and clergy well-being. The findings show that in-person worship attendance continues to decline, while online worship was adopted widely during the pandemic and remains common. Programming, volunteering, and financial giving have rebounded but still fall short of pre-pandemic levels or current needs. Many congregations embraced change early in the pandemic but have since reverted to old routines. Clergy are in relatively good health, yet growing numbers are reconsidering their futures in ministry. These shifts reveal the pandemic’s lasting impact on congregational life and raise critical questions for clergy, lay leaders, and researchers about institutional resilience, innovation, and leadership sustainability. The findings underscore the complex and evolving nature of post-pandemic ministry. Full article

Long-term processes, manifesting themselves in slow geometrical alterations and changes in internal forces, have been known and observed to take place mainly in large bridges made of prestressed concrete, but they also occur, albeit to a smaller degree, in steel bridges. Two sets of data, coming from, respectively, multi-year geodetic surveys and the structural health monitoring of a cable-stayed bridge (forces in its stays), were compared. Using the collocation method, displacements consistent with the results of the geodetic measurements were input into a numerical model of the bridge. Then, changes in the forces in the stays, which should accompany the displacements, were computed. The computed changes were compared with the actual changes in the mean force values in the stays of the bridge recorded over an eight-year period of its structural health monitoring. The two sets of data were found to be not in satisfactory good agreement. The main factors making it difficult to reach full agreement were the very small relative values of the observed geometrical alterations (the deformation, i.e., the increase in deflection, of the 375 m long span amounting merely 10–15 mm after eight years of periodic measurement) and the very small changes (amounting to about 0.5% for 8 years of monitoring) in the mean forces in the stays, as well as the possible mistakes in the survey. Despite these difficulties, the employed collocation method proved to be effective. It was also found that the long-term geometrical alterations and the changes in the forces in the stays do not adversely affect the safety of the bridge and its use. Full article

Background/Objectives: This study aimed to investigate the skating determinants and differences between male and female bandy players in the spatiotemporal variables during acceleration and maximum sprint skating velocity. Methods: Seventy-four female bandy players (age: 18.9 ± 4.1 years; height: 1.67 ± 0.06 m; body mass: 63.2 ± 7.4 kg; training experience: 13.4 ± 3.9 yrs.; and 26 elite and 48 junior elite) and 111 male bandy players (age: 20.7 ± 5.0 years; height: 1.80 ± 0.05 m; body mass: 76.4 ± 8.4 kg; training experience: 13.8 ± 5.0 yrs.; and 47 elite and 66 junior elite players) performed linear sprint skating over 80 m. Split times were measured every ten metres by photocells to calculate velocities for each step and spatiotemporal skating variables (glide times and length, step length, and frequency) by IMUs attached to the skates. The first six steps (acceleration phase), the six steps at the highest velocity (maximal speed phase), and the average of all steps were used for analysing glide-by-glide spatiotemporal variables. Results: These revealed that male players exhibited higher acceleration and maximal skating velocity than female players. A higher acceleration in men was accompanied by shorter gliding time, longer step length, and higher step frequency. When skating at maximal speed, male players had a longer step length and gliding time and length. The sub-group analysis revealed that step frequency did not correlate with skating velocity, acceleration, or maximal speed phases. On the other hand, glide and step lengths significantly correlated with skating velocity in both phases (r ≥ 0.60). Conclusions: In general, for faster skating in bandy, it is generally better to prioritise glide and step length than stride frequency. Hence, players should be encouraged to stay low and have more knee flexion to enable a longer extension length and, therefore, a longer path and more horizontal direction of applied force to enhance their acceleration ability. Full article

Obesity-Related Multimorbidity (ORM) is understood as the group of secondary diseases caused by metabolic alterations that arise from obesity. Nowadays there is a growing incidence of people with ORM who seek health services. Since this condition substantially impacts nutritional status and therefore in the survival prognosis during the hospital stay, ORM represents a challenge for health professionals. This forces doctors to specify nutritional recommendations according to clinical characteristics in individuals with obesity and types of comorbidities. Therefore, the objective of this narrative review is to present the current evidence-based recommendations that support the hospital nutritional care process for individuals with ORM. It concludes that nutritional treatment is complex and gaps in the research regarding this population group still exist. Because there are no specific guidelines for nutritional screening tools, calculating total energy requirements (alternatives to indirect calorimetry), determining fluid, protein, and immunonutrient requirements, the use of parenteral nutrition in ORM with kidney, liver, and heart failure and sarcopenic obesity that should be addressed in the new literature. For now, the standard practice in these cases is to prioritize the problem to be treated according to the maximum clinical benefit. Despite this, it is established that the nutritional care process must be systematic to be clear and objective. This document is addressed to all healthcare professionals who make up the multidisciplinary nutritional support team. Full article

Background: Next-day discharge post-robotic-assisted thoracic surgery (RATS) anatomical lung resections are shown to be achieved in young and fit patients. This study aims to compare next-day discharge RATS anatomical lung resection patients matched with patients who stayed longer. Methods: A retrospective analysis of patients who underwent RATS anatomical lung resection by a single surgeon was conducted. Based on the variables found to be different, two propensity-matched groups were created: a next-day discharge group and a group of patients with longer stays. Results: This study included 202 patients, 49 (24.3%) of whom were discharged the next day. The mean age was 68.3 ± 9.8 years, and 114 (56.4%) patients were females. Based on the variables found different, two matched groups with 46 patients for age, gender, performance score, American Society of Anesthesiologists score, number of co-morbidities and Forced Expiratory Volume in 1 sec were created. Re-admissions, complications, and death rates were similar, but next-day discharge patients had more sublobar resections (65.2% vs. 37%, p = 0.029), shorter procedures (132 vs. 179 min, p = 0.048), and morning theater slots (71.7% vs. 32.6, p = 0.018). These were shown to be independent predictors of next-day discharge. Major air leak issues also kept patients in the hospital longer (23.9% vs. 6.5%, p = 0.024). Conclusions: Next-day discharge following RATS anatomical lung resection appeared to have no increased risk of re-admissions or complications, irrespective of fitness, age, or other patient characteristics. Patients receiving short-duration surgery and morning sublobar resections without major air leak issues have higher chances of achieving next-day discharge. Full article

During long-span arch bridge construction, repeated adjustments of large cantilevered segments and nonuniform cable tensions can lead to deviations from the desired arch profile, reducing structural efficiency and increasing labor and material costs. To precisely control the process of cable-stayed buckle construction in long-span arch bridges and achieve an optimal arch formation state, a constrained optimization for the buckle and anchor cable forces under one-time tension is developed in this paper. First, by considering the coupling effect of the cable-stayed buckle system with the buckle tower and arch rib structure, the control equations between the node displacement and cable force after tensioning are derived based on the influence matrix method. Then, taking the cable force size, arch rib closure joint alignment, upstream and downstream side arch rib alignment deviation, tower deviation, and the arch formation alignment displacement after loosening the cable as the constraint conditions, the residual sum of squares between the arch rib alignment and the target alignment during the construction stage is regarded as the optimization objective function, to solve the cable force of the buckle and anchor cables that satisfy the requirements of the expected alignment. Applied to a 310 m asymmetric steel truss arch bridge, the calculation of arch formation alignment is consistent with the ideal arch alignment, with the largest vertical displacement difference below 5 mm; the maximum error between the measured and theoretical cable forces during construction is 4.81%, the maximum difference between the measured and theoretical arch rib alignments after tensioning is 3.4 cm, and the maximum axial deviation of the arch rib is 5 cm. The results showed the following: the proposed optimization method can effectively control fluctuations of arch rib alignment, tower deviation, and cable force during construction to maintain the optimal arch shape and calculate the buckle and anchor cable forces at the same time, avoiding iterative calculations and simplifying the analysis process. Full article

For complex structures, the solution process of existing cable force optimization methods for low-tower cable-stayed bridges is characterized by a significant number of matrix operations, which require substantial computing power and time. As a result, achieving a more accurate solution becomes exceedingly difficult. To tackle this challenge, we propose a new cable force optimization method that enhances the stress distribution of the cable-stayed cables in the completed state of the bridge. This approach minimizes the need for frequent adjustments to cable forces and alterations to the linear elevation of the beam bridge during construction. In this study, the low-tower cable-stayed bridge of the Lanjiang Bridge serves as the engineering background. By integrating finite element analysis with a multi-objective optimization method, we propose an optimization approach for the real-time correction of cable forces during the construction of long-span low-tower cable-stayed bridges. Within this optimization framework, the cable forces during construction are treated as variable parameters, while the linear elevation of the completed bridge is imposed as a constraint. The improved grey wolf algorithm is integrated with the finite element algorithm, and the key parameters of the support vector machine are optimized using this method, resulting in the optimal parameter combination predicted based on the training samples. The results indicate that after optimizing the support vector machine model using the improved grey wolf algorithm, the cable force distribution of the cable-stayed cables becomes more uniform, with a variance of 19.96. Additionally, the maximum displacement change of the main beam under the influence of the dead load is reduced by 33.48%. This method demonstrates high optimization efficiency and produces favorable outcomes, highlighting its value in calculating cable forces and guiding construction processes during the erection of cable-stayed cables for similar bridges. Full article

Structural health monitoring (SHM) systems are very useful for evaluating the performance of bridges in service. In this paper, the SHM system implemented on the Poyang Lake Second Bridge is investigated, and the monitored data are analyzed for performance evaluation, damage identification, and model updating of the bridge. First, the measured data are examined for environmental effects, structural behaviour, and modal identification. Based on the bridge construction information, a finite element (FE) model is constructed for the cable-stayed bridge. Subsequently, the regularized model updating approach is employed to calibrate the constructed numerical model by using the measured modal data. Several vibration-based methods for structural damage identification are proposed to inversely identify the simulated damage within the cable-stayed bridge using the test data. The results indicate that the measured structural responses, such as cable forces and bridge deck deflections, vary over time and highlight discrepancies in the initial FE model. This FE numerical model can then be effectively adjusted using the proposed model updating method, which enhances the connection between the real cable-stayed bridge and the modified FE numerical model. From the modal data, the simulated damage in the main structural members of the cable-stayed bridge can be correctly identified using the proposed methods. Full article

To address the limitations of traditional concrete barriers in practical applications, this study proposes a novel semi-assembled concrete barrier utilizing ultra high performance concrete (UHPC) as the barrier shell material. The thin shell of the barrier is prefabricated using UHPC and filled with normal concrete (NC) to form a protective structure. Finite element software is employed to simulate collisions between three models and the barrier, and the barrier safety is preliminarily assessed according to the Standard for Safety Performance Evaluation of Highway Barriers. A full-scale vehicle collision test validated the model, and an analysis was conducted. The results demonstrate that the established model exhibits a high accuracy. The peak value of the 25 ms collision force in this simulation can be used as the basis for static load design. None of the three vehicles exhibited overriding or riding phenomena nor did they deviate from their guide frames, and following collisions with three different vehicles, no overall damage was observed on the semi-assembled barrier. Occupant impact velocity (OIV) remained below 12 m/s, while occupant ride-down acceleration (ORA) stayed under 200 m/s². The barrier meets SB protection-level requirements; thus, the findings can offer theoretical support for promoting the widespread adoption of this new type of barrier. Full article

Assessing the functions of forest ecosystems is important for a proper understanding of their role in the natural environment and society. Ecotourism emphasizes minimizing negative impacts on the environment and supports environmental education. Modern information and communication technologies, including forest apps, are helping in this regard. Precision forestry uses GIS technologies and remote sensing to obtain spatial data, identify the components of the natural environment, and evaluate the changes that they are subject to. A tool enabling the evaluation of synergy between ecosystem functions and tourism, in addition to traditional field research and surveys, is remote sensing. This paper aims to show the feasibility of evaluating the synergy of ecosystem and tourism services in forests using remote sensing as an alternative to traditional terrestrial measurements. This study’s temporal scope is from 2019 (i.e., the introduction of the pilot program on making forests available for bushcraft and survival activities in Poland) until the beginning of 2024. Thus, it covers the time when the State Forests program called “Stay Overnight in the Forest” related to dispersed camping in forests was in force. Additionally, online surveys were conducted using the Microsoft Forms platform among representatives of all forest districts participating in implementing the “Stay Overnight in the Forest” program from 1 May 2021. This program is a crucial element of the contemporary tourist and recreational offer of the State Forests in Poland and influences the course of the ecosystem and tourist services in the forests. From the recorded digital images, it is possible to obtain information about threats in forest ecosystems caused by natural disasters, such as windstorms and fires. The precise provision of information about degraded forest areas can contribute to the more efficient management of forest reclamation works and the restoration of damaged stands. On the other hand, the rehabilitated forest can be a destination point for educational trails in forests. Full article

A cable tension calculation method based on an influence matrix and the interior point method is proposed for the optimization of cable tension of cable-stayed bridges with multiple performance indicators. Taking a hybrid beam cable-stayed bridge as an example, an objective function based on the bending energy of the tower and beam was established using an influence matrix. Constraints on the range and uniformity of cable force values, the deformation amplitude of the main beam and tower, and the local bending moment of the main beam were established. A cable force optimization model for a completed cable-stayed bridge was formed, and the interior point method was applied to calculate the optimization model. The results show that using an influence matrix and the interior point method to optimize the cable tension of cable-stayed bridges is feasible. The bridge state corresponding to the cable tension solved by this method meets the set evaluation criteria for the bridge state, and some constraint conditions obtain boundary values. This method is simple, practical, and easy to program and implement. Full article