Height Variation Research Articles

Comprehensive Inspection Solution for Boiler Water Wall Tube Corrosion

A substantial number of domestic coal-fired boilers, most of which have been in operation for numerous years, are susceptible to corrosion and tube ruptures within their high-temperature environment, often resulting in unplanned shutdowns. Despite the annual planned maintenance shutdowns, which involve routine inspections of water wall and furnace tubes to detect potential corrosion and erosion, the current non-destructive testing methods are generally localized. This approach, particularly with the considerable height variation of the water wall tubes (ranging from approximately 10 to 25 meters), may overlook segments with severe corrosion during localized ultrasonic thickness gauging. Although the experience of inspection teams reduces the chance of defect oversight, the demand for a comprehensive and effective inspection technique remains a priority for boiler operators. This study utilizes the characteristic of guided waves to propagate over a certain distance along pipelines, initiating an exploration into a comprehensive inspection solution for water wall tubes. Finite element simulation results demonstrate the suitability of utilizing a 120 kHz frequency for shear horizontal mode (SH0) testing on the fire side of water wall tubes. This mode effectively screens for localized corrosion within a 3-meter range. In the field of on-site boiler inspection, electromagnetic coils are employed to generate guided waves within water wall tubes. The gathered signals from each electromagnetic guided wave testing (EMGWT) are consolidated into a distribution map, indicating suspicious signal locations. Pulse eddy current testing (PECT) is employed to identify potential issues with guided waves without requiring surface preparation. If PECT reveals anomalies, the affected surface is polished, and phased array ultrasonic testing (PAUT) is conducted to quantitatively measure the remaining wall thickness due to corrosion. The theoretical exploration and on-site inspection outcomes affirm the feasibility of this approach, aimed at enhancing operational safety for boiler water wall tubes and mitigating the risks of tube ruptures and leaks. This comprehensive inspection solution amalgamates three advanced detection technologies, each capitalizing on its unique inspection characteristics to facilitate corrosion screening, corrosion scanning, and wall thickness sizing. Through the integration of these technologies, the overall inspection strategy ensures the utmost level of reliability.

PENGARUH VARIASI TINGGI SUDU TURBIN DARI TINGGI BASIN TERHADAP DAYA DAN EFISIENSI TURBIN VORTEX

Electrical energy is a very important need for human life in various aspects, both on a large and small scale. One of the efforts to reduce the use of fossil fuels is to use natural resources that are not limited and can be renewed. Micro Hydro Power Plant (MHP) is an alternative source of electricity for the community, one of which is a vortex turbine. The vortex turbine is one type of micro hydro turbine that utilizes a whirlpool as a blade drive. This study examines the effect of blade height variations of 25%, 30%, and 35% of the basin height on power and efficiency. The results showed that the largest turbine power at 25% blade height variation from the basin height with a discharge of 0.009 m3/s was 3.294 Watt with an efficiency of 51.10%. The largest turbine power at an angle variation of 30% of the basin height with a discharge of 0.009 m3/s is 3.364 Watt with an efficiency of 50.66%. The largest turbine power at an angle variation of 35% of the basin height with a discharge of 0.009 m3/s is 4.062 Watt with an efficiency of 62.35%. Turbine power based on two-way anova analysis shows that between variations in turbine height and flow discharge have a significant effect on the turbine power produced and turbine efficiency based on two-way anova analysis shows that between variations in turbine height and flow discharge have a significant effect on the turbine efficiency produced.

Spatio-temporal variation of aerosol loading and planetary boundary layer height before, during and after COVID-19 lockdown over the major cities in India

Spatio-temporal variation of aerosol loading and planetary boundary layer height before, during and after COVID-19 lockdown over the major cities in India

Culm Morphological Analysis in Moso Bamboo Reveals the Negative Regulation of Internode Diameter and Thickness by Monthly Precipitation

The neglect of Moso bamboo’s phenotype variations hinders its broader utilization, despite its high economic value globally. Thus, this study investigated the morphological variations of 16 Moso bamboo populations. The analysis revealed the culm heights ranging from 9.67 m to 17.5 m, with average heights under the first branch ranging from 4.91 m to 7.67 m. The total internode numbers under the first branch varied from 17 to 36, with internode lengths spanning 2.9 cm to 46.4 cm, diameters ranging from 5.10 cm to 17.2 cm, and wall thicknesses from 3.20 mm to 33.3 mm, indicating distinct attributes among the populations. Furthermore, strong positive correlations were observed between the internode diameter, thickness, length, and volume. The coefficient of variation of height under the first branch showed strong positive correlations with several parameters, indicating variability in their contribution to the total culm height. A regression analysis revealed patterns of covariation among the culm parameters, highlighting their influence on the culm height and structural characteristics. Both the diameter and thickness significantly contribute to the internode volume and culm height, and the culm parameters tend to either increase or decrease together, influencing the culm height. Moreover, this study also identified a significant negative correlation between monthly precipitation and the internode diameter and thickness, especially during December and January, impacting the primary thickening growth and, consequently, the internode size.

Mathematical explanations for knee osteotomies: "Dear engineer, how would you explain it in a simple way?"

Knee osteotomies are effective procedures to treat different deformities and to redistribute the load at the joint level, reducing the risk of wear and, consequently, the need for invasive procedures. Particularly, knee osteotomies are effective in treating early arthritis related to knee deformities in young and active patients with high functional demands, with excellent long-term results. Precise mathematical calculations are imperative during the preoperative phase to achieve tailored and accurate corrections for each patient and avoid complications, but sometimes those formulas are challenging to comprehend and apply. Four specific questions regarding controversial topics (planning methods, patellar height, tibial slope, and limb length variation) were formulated. An electronic search was performed on PubMed and Cochrane Library to find articles containing detailed mathematical or trigonometrical explanations. A team of orthopedic surgeons and an engineer summarized the available Literature and mathematical rules, with a final clear mathematical explanation given by the engineer. Wherever the explanation was not available in Literature, it was postulated by the same engineer. After the exclusion process, five studies were analyzed. For three questions, no studies were found that provided mathematical analyses or explanations. Through independent calculations, it was demonstrated why Dugdale's method underestimates the correction angle compared to Miniaci's method, and it was shown that the variation in patellar height after osteotomy can be predicted using simple formulas. The five included studies examine postoperative variations in limb length and tibial slope, providing formulas applicable in preoperative planning. New formulas were independently computed, using the planned correction angle and preoperatively obtained measurements to predict the studied variations. There is a strict connection among surgery, planning, and mathematics formulas in knee osteotomies. The aim of this study was to analyze the current literature and provide mathematical and trigonometric explanations to important controversial topics in knee osteotomies. Simple and easy applicable formulas are provided to enhance the accuracy and outcomes of this surgical procedure.

Computational analysis of microchannel heat sinks with constant circular pin fins: Performance evaluation and optimization

This research entails a comprehensive computational simulation aimed at comparing the performance of microchannel heat sinks (MCHS) featuring 55-pin fins, characterized by constant circular pins with a diameter of 15µm, uniform spacing of 50µm, and variable heights ranging from 60 to 35µm. The primary objective was to assess the performance of these models with a reference Mini channel. Mesh independence validation was meticulously executed on MCHS with pin fins to ascertain the accuracy of the computational findings. The simulation encompassed seven Reynolds numbers within the range of 500–1500. The performance evaluation incorporated hydraulic and thermal factors, specifically pressure drop, Nusselt number, and the thermal performance factor (TPF). A holistic assessment of overall performance was achieved through the establishment of a heat sink thermal performance factor, accounting for both hydraulic and thermal aspects. The optimal geometry was determined based on this factor, and corresponding visual representations were generated to illustrate these findings.

APPLICATION OF MACHINE LEARNING MODELS AND GSA METHOD FOR DESIGNING STUD CONNECTORS

The design of stud connectors is aided by determining the relationship between shear strength and the input variables (number, diameter, height, tensile strength and elastic modulus of the studs, and compressive strength and elastic modulus of the concrete) that influence strength. Since strength is nonlinearly related to the influencing variables, which makes the predictions of the relevant empirical equations unreliable, the use of machine learning (ML) models is preferred. The prediction results of eight machine learning models were evaluated, including linear regression (LR1), ridge regression (RR), lasso regression (LR2), back-propagation artificial neural network (BP ANN), genetic algorithm optimized BP ANN (GA-BP ANN), extreme learning machines (ELM), random forests (RF), and support vector machines (SVM). The results show that the GA-BP ANN model is the most accurate model for prediction with a mean absolute percentage error (MAPE) of 6.17% and an R2 of 0.9599. Based on the GA-BP ANN model and the global sensitivity analysis (GSA) method, a new parameter importance analysis method was developed to compare the magnitude of the effect of different input variables on strength. It was found that stud diameter had the greatest effect on shear strength.

Linear systems characterization of the topographical spatial resolution of optical instruments

Lateral resolving power is a key performance attribute of Fizeau interferometers, confocal microscopes, interference microscopes, and other instruments measuring surface form and texture. Within a well-defined scope of applicability, limited by surface slope, texture, and continuity, a linear response model provides a starting point for characterizing spatial resolution under ideal conditions. Presently, the instrument transfer function (ITF) is a standardized way to quantify linear response to surface height variations as a function of spatial frequency. In this paper, we build on the ITF idea and introduce terms, mathematical definitions, and appropriate physical units for applying a linear systems model to surface topography measurement. These new terms include topographical equivalents of the point-, line-, and edge-spread functions, as well as a complex-valued transfer function that extends the ITF concept to systems with spatial-frequency-dependent topography distortions. As an example, we consider the experimental determination of lateral resolving power of a coherence scanning interference microscope using a step-height surface feature to measure the ITF directly. The experiment illustrates the proposed mathematical definitions and provides a direct comparison to theoretical calculations performed using a scalar diffraction model.

Constant static pressure strategy for residential kitchen exhaust system: Deducing control parameters from required exhaust rate and non-distributed data transmission

Roof fans have gradually replaced the non-powered hood as supplementary power to increase exhaust rate in high-rise residential kitchen shafts. However, an effective control strategy for roof fans is lacking. This paper studies the constant static pressure strategy and deduces its control parameters based on required exhaust rate and non-distributed data transmission. First, the static pressure set value (SV) is investigated under the worst exhaust condition, considering variations in shaft heights and measuring positions (MP). Then, an on/off mechanism is set up based on the measured static pressure and the fan frequency when the exhaust rate is adequate. Results show that under the recommended shaft sizes and design concurrent usage rates, the SVs for users' exhaust rate reaching 500 m³/h are −60, −60, and 0 Pa for 10/18/26-floor shafts when the MP is at a shaft's outlet, and roof fans are turned on when the static pressure reaches 100, 90, and 90 Pa and turned off when the fan frequency is below 32, 30, and 22 Hz. The MP at the shafts' outlet can keep the shaft at a slightly negative pressure. Control parameters for specific applications can be obtained through the proposed calculation process. An 18-floor shaft study found that the constant static pressure strategy can achieve 50 % energy savings compared to the constant frequency operation of the roof fan. These findings contribute to reliable control without users' distributed data transmission and to lower energy consumption of the residential kitchen exhaust system.

Modeling of nanoblood flow in an artery in presence of eco-friendly and biocompatible hybrid nanoparticles

Transferring biological fluid through arteries is a topic that has garnered serious interest in recent times, especially when it pertains to applications such as drug delivery. In our body, arteries serve as the primary conduits for blood flow and this study aims to model the blood flow in this situation. The working fluid is essentially pure blood, which acts as a base fluid, supplemented with nanoparticles of Titanium Dioxide (TiO2) and Gold (Au). Nanoparticles could change the thermal and rheological properties of blood which might be particularly advantageous for ensuring smoother flow or optimal distribution of drug molecules within the bloodstream. In the present work, a porous channel is considered with parallel walls that exhibit varying permeability on boundaries. Such a design enables the nanoblood to enter and exit the channel, mimicking certain natural processes like transvascular fluid exchange. Additionally, the variable height of the channel that expands and squeezes uniformly could be reminiscent of the pulsatile nature of blood flow seen in our arteries due to heartbeats. To understand the dynamics of this hybrid nanoblood flow, the governing equations are converted into a set of nonlinear ordinary differential equations using the similarity transformation approach. For solving these transformed equations, the research harnesses the BVP4C built-in function in MATLAB software. Through this computational approach, the research provides insights into the velocity and temperature profile of the fluid, the distribution of normal pressure, wall shear stress, and the Nusselt number concerning various parameters. The findings of the present study can be significant and useful in biological sciences and technologies and the detailed results are presented completely in the article’s body.

Energy efficient walking: combining height variation of the center of mass and curved feet

Energy efficient walking: combining height variation of the center of mass and curved feet

Performance Analysis of Fiber Laser Micro-Marking on Aluminium 7075 Alloy

Analyzing the performance of fiber laser micro-marking on aluminium alloy under focus–defocus conditions entails determining the way varying the focus position during the marking process impacts the overall performance. A special process variable defocus height refers to the distance between the focal point of the laser beam and the surface of the material being marked. In micro-marking, the focal point can be moved above or below the surface to generate distinct effects. The paper determines the optimal parameters for laser micro-marking on aluminium 7075 alloy, including laser power, pulse frequency, scan speed, defocus height (the distance between the top surface and the focal point), and duty cycle, for mark quality and characteristics such as depth and mark width. Experimental results showcase that laser parameters affect mark width and depth nonlinearly. In addition, small variations in laser power, scanning speed, or focus height, have led to moderate changes in dimensions of the mark geometry. A target mark of 40[Formula: see text][Formula: see text]m in width and 25[Formula: see text][Formula: see text]m in depth is achieved by combining optimum settings like a power of 23.862[Formula: see text]w, a duty factor of 45%, a pulse frequency of 76.0506[Formula: see text]Khz, a scanning speed of 0.70[Formula: see text]mm/s, and a defocus height of 0.7[Formula: see text]mm.

Orthorectification of Bridges from High Resolution Satellite Images

Abstract. High-resolution satellite imagery requires high-resolution height reference data to create orthorectified images. High-precision digital surface data and LiDAR data are expensive to acquire quickly and accurately. Facility databases, on the other hand, are very efficient because once established, the information can be utilized persistently. The temporal resolution between the structure in the database and the captured image affects the ortho resolution created. Landmarks such as bridges are rarely subject to changes after construction. This makes facility database a suitable material to generate orthophotos of bridge structures. In this paper, we used a bridge database to perform orthorectification for structures with height variations. We removed relief displacement from satellite imagery at different angles and verified orthorectification feasibility for bridges of different heights and lengths. The orthoimage was overlaid with a topographic map to verify the orthorectification visually. As a result, we confirmed that the facility database was able to generate orthophotos of the bridges. The length and slope of bridge structures indicated the need for precise database updates in the future research.

Structure of Graphene Grown on Cu(111): X-Ray Standing Wave Measurement and Density Functional Theory Prediction.

We report the quantitative adsorption structure of pristine graphene on Cu(111) determined using the normal incidence x-ray standing wave technique. The experiments constitute an important benchmark reference for the development of density functional theory approximations able to capture long-range dispersion interactions. Electronic structure calculations based on many-body dispersion-inclusive density functional theory are able to accurately predict the absolute measure and variation of adsorption height when the coexistence of multiple moiré superstructures is considered. This provides a structural model consistent with scanning probe microscopy results.

Morphological and genetic characterization of jackfruit (Artocarpus heterophyllus) in the Kayunga and Luwero districts of Uganda

BackgroundJackfruit (Artocarpus heterophyllus) is an economically valuable fruit tree in Uganda. However, the production of jackfruit in Uganda is low. Additionally, because of deforestation, genetic erosion of the resource is predicted before its exploitation for crop improvement and conservation. As a prerequisite for crop improvement and conservation, 100 A. heterophyllus tree isolates from the Kayunga and Luwero districts in Uganda were characterized using 16 morphological and 10 microsatellite markers.ResultsThe results from the morphological analysis revealed variations in tree height, diameter at breast height (DBH), and crown diameter, with coefficient of variation (CV) values of 20%, 41%, and 33%, respectively. Apart from the pulp taste, variation was also observed in qualitative traits, including tree vigor, trunk surface, branching density, tree growth habit, crown shape, leaf blade shape, fruit shape, fruit surface, flake shape, flake color, flake flavor and pulp consistency/texture. Genotyping revealed that the number of alleles amplified per microsatellite locus ranged from 2 to 5, with an average of 2.90 and a total of 29. The mean observed (Ho) and expected (He) heterozygosity were 0.71 and 0.57, respectively. Analysis of molecular variance (AMOVA) indicated that 81% of the variation occurred within individual trees, 19% among trees within populations and 0% between the two populations. The gene flow (Nm) in the two populations was 88.72. The results from the ‘partitioning around medoids’ (PAM), principal coordinate analysis (PCoA) and genetic cluster analysis further revealed no differentiation of the jackfruit populations. The Mantel test revealed a negligible correlation between the morphological and genetic distances.ConclusionsBoth morphological and genetic analyses revealed variation in jackfruit within a single interbreeding population. This diversity can be exploited to establish breeding and conservation strategies to increase the production of jackfruit and hence boost farmers’ incomes. However, selecting germplasm based on morphology alone may be misleading.

Response of Shallow-Water Temperature and Significant Wave Height to Sequential Tropical Cyclones in the Northeast Beibu Gulf

Using shallow-water buoy observations, reanalysis data, and numerical models, this study analyzes the variations in sea temperature and significant wave height (SWH) caused by two sequential tropical cyclones (TCs) ‘Lionrock’ and ‘Kompasu’ in October 2021 in the northeast Beibu Gulf, South China Sea. The results show that the sea surface temperature (SST) cooling of the nearshore waters was larger than the offshore water in the basin of the gulf, with the cooling amplitude and rate decreasing and the cooling time lagging behind wind increasing from coast to offshore. The near-surface temperature at the buoy station had a maximum decrease of 2.8 °C after ‘Lionrock’, and the decrease increased slightly to 3 °C after the stronger wind of ‘Kompasu’. The total decrease of 4.6 °C indicates that the sequential TCs had a superimposed effect on the cooling of the Beibu Gulf. The heat budget analysis revealed that the sea surface heat loss and the Ekman pumping rate in the nearshore waters during ‘Kompasu’ (−535 W/m2 and 5.8 × 10−4 m/s, respectively) were significantly higher than that (−418 W/m2 and 4 × 10−4 m/s) during ‘Lionrock’. On the other hand, the SST cooling (−1.2 °C) during the second TC is smaller than (−1.6 °C) the first weaker TC in the gulf basin, probably due to the deepening of the mixed layer. During the observation period, the waves in the Beibu Gulf were predominantly wind-driven. The maximum SWHs reached 1.58 m and 2.3 m at the bouy station near shore during the two TCs, and the SWH variation was highly correlated to the wind variation with a correlation of 0.95. The SWH increases from the nearshore to offshore waters during the TCs. The SAWN and ARCIRC coupled model results suggest that wave variations in the Beibu Gulf are primarily influenced by water depth, bottom friction, and whitecapping. Two days after the TCs, sea surface cooling and high waves appeared again due to a cold air event.

Justification of design parameters of a two-stage cyclone vortex funnel using computer simulation

It has been established that in mini-feed mills with a productivity of up to 5 t/h, pneumatic transport systems with a cyclone unloader are more promising due to the lower emission of finely dispersed components. However, there are fewer such workshops on the market due to the smaller loading -volume of horizontal mixers on which cyclones are installed compared to vertical mixers that perform the function of cyclone-unloaders, in which emissions of fine dust into the work area are higher, which negatively affects working conditions, health of workers, as well as fire safety of premises. To reduce emissions of fine dust into the exhaust pipe of the cyclone, a technical solution in the form of a two-stage cyclone was proposed. A preliminary experimental test on a laboratory model showed an increase in particle collection by 32% about the serial cyclone-unloader CR under the same initial conditions and in the same standard size. As part of the design of a full-size version of the proposed two-stage cyclone, computer modeling of the separation process was carried out in the FlowSimulation software environment with dimensions close to the commercially produced cyclone BCR-450 to identify the influence of the geometric parameters of the -vortex funnel on the process of separation of fine particles from the transporting air flow with variable geometric dimensions diameter and height of the vortex funnel in the range from 100 to 270 and from 100 to 235 mm, respectively. Preliminary rational geometric parameters of the vortex funnel diameter equal to 180 mm and height equal to 150 mm of the proposed technical solution with a hydraulic resistance coefficient of8.4 are substantiated.

Observing And Characterizing Infragravity Waves Through Different Sampling Devices: A Case-Study Off The Belgian Coast

Infragravity waves are surface waves with relatively longer periods in comparison to periods of the spectrum-dominant gravity waves. They are characterized by oscillations between 20 and 300 seconds (0.0033 Hz < f < 0.05 Hz), amplitudes that range from a few millimeters to tens of centimeters, and wavelengths of kilometers (Munk, 1950; Holman and Bowen, 1982; Ardhuin et al., 2014). Their forcing is linked to, amongst others, nonlinear interaction between sea swell waves, varying wave heights causing the breaking point of the waves to vary with height, and height variation of incoming waves (Bertin et al., 2018). Infragravity waves play an important role in coastal dynamics (Svendsen, 2005) and have been reported to trigger nearshore hazards such as beach and dune erosion (de Vries et al. 2008; Roelvink et al., 2009), development of seiches in harbors (Melito et al., 2006; Cuomo and Guza, 2017), wave-driven coastal inundation (Gent, 2001; Stockdon et al., 2006), and ice shelves collapsing (Bromirski et al., 2010). Therefore, revealing infragravity wave characteristics is of utmost importance to understand their potential to generate hazards in a certain region, especially at sites strongly influenced by human occupation and activities. Their consideration in coastal safety planning can avoid damages, as several locations have already experienced in the past (Yamanaka et al., 2019). Implementing optimal sampling strategies for observing and characterizing infragravity waves might be challenging. By nature, these waves are hard to measure accurately due to their low amplitude. Their evolving characteristics in an environment marked by pronounced bathymetric features, such as the sand bank systems off the Belgian coast, add a degree of complexity that requires testing of different approaches, and at different sites. Within this context, this work first revisits observational approaches, instrumentation, logistics, and sampling techniques that have been used to study this phenomenon on the Belgian Coast. The advantages, challenges and limitations of different approaches are discussed, and best practices for collecting high-quality data in the field are addressed. To do so, this study explores multi-sensor in situ deployments conducted at four selected sites off the Belgian coast (Figure 1) (Nieuwpoort, Raversijde (inshore and offshore Stroombank), and Trapegeer) within the context of the “Influence of infragravity sea waves during storms on the hydro- and morphodynamic processes along hybrid soft-hard coastal defence structures with a shallow foreshore” project, an FWO-funded initiative being conducted in collaboration between UGent, VLIZ, and KULeuven and with support of Agency for Coastal and Maritime Services (AMDK). More specifically, field observations were conducted using multipurpose mooring frames equipped both with (i) Acoustic Doppler Current Profiles (ADCPs) to sample pressure (0.1% FS), current, and sea surface elevation through acoustic surface tracking and (ii) high-accuracy quartz pressure sensors (accuracy 0.01 % FS). Both ADCPs and pressure sensors were set to measure continuously at 4 Hz being, therefore, able to capture both infra- and gravity waves. Furthermore, the moorings were collocated with standard wave buoys from AMDK. Data was collected continuously for about 3 months, covering storm and calm wave conditions. Finally, the measurements from ADCPs (pressure and acoustic) and pressure sensors were compared and used to derive the infragravity wave characteristics, as well as cross-validated against wave buoy data.

Study on Non-Stationary Wind Speed Models and Wind Load Design Parameters Based on Data from the Beijing 325 m Meteorological Tower, 1991–2020

As the capital of China and a densely populated major city, the characteristics of Beijing’s near-surface wind field change significantly with the increase in the density of underlying urban structures. The high randomness of natural wind makes it extremely difficult to develop a universally applicable wind-resistant load design code based on topographic factors and architectural features. This article takes the wind speeds recorded at 15 different height levels within the urban area by the 325 m meteorological tower in Beijing from 1991 to 2020 as the research subject. It quantifies the wind speed trends at different heights and introduces time-varying functions to establish a non-stationary wind speed model based on the optimal model. Additionally, it compares the basic wind speeds and wind pressure height variation coefficients obtained from measurements with the standards. The results show that, during the past 30 years of urbanization, the near-surface wind speed in the Beijing area has shown a decreasing trend. The model incorporating time-varying functions exhibited the best fit and demonstrated good predictive capabilities, with its calculated basic wind speeds being relatively high. The wind pressure height variation coefficient values in Beijing are between Class C and Class D terrains, being closer to Class C at lower altitudes. The conclusion reveals that urbanization has a significant impact on wind speeds, primarily concentrated at lower height levels, and that the basic wind speeds calculated based on standards underestimate the actual conditions when this impact is not considered. Although the average wind speed’s wind profile index across the entire time series is mostly greater than the fixed value of 0.3 given by Class D, this represents an overestimated wind profile index for maximum wind speeds.

Shear performance of tapered box girders with corrugated steel webs in extradosed cable-stayed bridges under cable forces

The integration of box girders with corrugated steel webs (CSWs) and an extradosed cable-stayed design gives rise to an innovative and distinctive bridge design, recognized as the extradosed cable-stayed bridge with CSWs. The synergistic integration of the technical benefits facilitates expanding the maximum span and enhancing the adaptability of this structural configuration. Subjected to cable forces, the main bridge superstructure featuring a box girder with CSWs experiences vertical shear, substantial axial force, and bending moments. Shear buckling on the CSWs emerges as a prominent issue influencing design considerations. In response to heightened internal forces near support, the main girder is typically configured with variable height. The Resal effect in the tapered girder leads to additional shear stresses from axial forces and bending moments, consequently modifying the effective shear stress on the CSWs. Therefore, traditional basic calculation assumptions that solely account for the vertical component of cable forces in shear stress calculations are frequently inaccurate. This study presents a modified theoretical method for calculating shear stress in tapered box girders with CSWs subjected to cable forces by considering the Resal effect. The proposed modified method incorporates not only the vertical shear but also considers bending moments and axial forces. The finite element simulation and experimental results showcase its remarkable accuracy, concurrently validating the presence of the Resal effect in tapered box girders with CSWs under cable forces. Additionally, this study quantitatively analyzes the shear force redistribution phenomenon induced by vertical shear, axial force, and bending moments considering the Resal effect. This reveals the shear performance of tapered box girders with CSWs under cable forces. The study is expected to provide a strategy and theoretical guideline for rapidly and efficiently obtaining the shear stresses of tapered box girders with CSWs in extradosed cable-stayed bridges under cable forces.