Advances on Structural Engineering, Volume III

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Civil Engineering".

Deadline for manuscript submissions: closed (31 May 2023) | Viewed by 31843

Special Issue Editors

Associate Professor, Department of Civil and Environmental Engineering, South Dakota State University, Brookings, SD 57007, USA
Interests: image-based seismic vulnerability and resiliency assessment; multihazard simulation of renewable energy structures; structural behavior examination of irregular structures; self-consolidating concrete; structural health monitoring; reliability analysis; load rating estimation of various bridge types; field testing and computational analyses; and lateral live-load distribution factor examination
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Structural engineering is centered on analysis, design, and evaluation of engineering structures. This Special Issue in Applied Sciences reports key findings from unpublished studies on advances and applications in all structural engineering fields.

Aware of the comprehensiveness of the suggested topic, we encourage you to send manuscripts containing scientific findings within the broad field of structural engineering, which includes but are not limited to the following: structural analysis and design; bridge engineering; building assessment; earthquake engineering; wind engineering; impact engineering; reliability evaluation; structural monitoring; image analysis; noncontact sensors; control structures; multi-hazard simulation; computational analysis; lab and field testing; multiscale analysis; smart structures; disaster mitigation; and big data evaluation. Both theoretical and practice-oriented papers, including case studies and reviews, are encouraged.

Prof. Dr. Jong Wan Hu
Prof. Dr. Junwon Seo
Guest Editors

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Keywords

  • structural analysis and design
  • structural experiments
  • concrete and composite structures
  • structural control
  • disaster mitigation
  • seismic design
  • structural monitoring
  • smart structures
  • big data evaluation
  • structural performance assessments
  • building and bridge

Published Papers (21 papers)

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Research

27 pages, 9144 KiB  
Article
Experimental Evaluation of Rigidity Center
by Fuat Korkut, Enes Aksoy and Barış Erdil
Appl. Sci. 2023, 13(13), 7452; https://doi.org/10.3390/app13137452 - 23 Jun 2023
Viewed by 949
Abstract
It is known that when a reinforced concrete building exposed to a horizontal load is subjected to torsional moments around its center of rigidity, additional shear stresses occur in the vertical load-carrying elements, such as the columns and shear walls. Therefore, in order [...] Read more.
It is known that when a reinforced concrete building exposed to a horizontal load is subjected to torsional moments around its center of rigidity, additional shear stresses occur in the vertical load-carrying elements, such as the columns and shear walls. Therefore, in order to estimate the additional stresses caused by the torsion, the rigidity center should be calculated precisely. It is known that there are several analytical approaches to calculating the rigidity center location. These approaches do not calculate the rigidity centers close to each other in asymmetric buildings. As significant differences were observed in the calculation of the rigidity center using analytical methods, it was decided to seek verification by conducting an experimental study. In order to calculate and verify the location of the rigidity center, an extensive experimental study was planned. A total of 20 scaled and revised buildings were built, and they were tested in the specially designed test setup. The tested buildings had square, rectangular and irregular floor plans. In addition, vertical load-carrying members were either symmetrically placed on the floor plan or kept asymmetrical to see the effect of their location on the rigidity center. All the buildings were tested under their self-weight, and the corresponding displacements were recorded. Additionally, all the buildings were modeled using ETABS to verify the theoretical background of the rigidity center. From the test results, it was found that the resultant shear force can be calculated by multiplying the displacements of each member of a given story found from the tests on its bending stiffness, and this will give the location of the rigidity center. The rigidity center was found to be identical to the results obtained from the 3D model analysis using ETABS, although it uses a different procedure. As the results from the experiment and 3D model are close to each other, it can be said that the rigidity center of reinforced concrete buildings can be found from simple tests using any material that has almost uniform mechanical properties. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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19 pages, 8992 KiB  
Article
On the Torsional Behavior of the Longitudinal Bridge Girders Used in the LT-Bridge Construction Method
by Michael Rath, Franz Untermarzoner and Johann Kollegger
Appl. Sci. 2023, 13(11), 6657; https://doi.org/10.3390/app13116657 - 30 May 2023
Viewed by 1029
Abstract
A new bridge construction method, combining semi-precast elements and in situ concrete, has been developed at TU Wien, with the aim of decreasing erection time. In the course of construction using this new method, structural conditions arise that render a more detailed investigation [...] Read more.
A new bridge construction method, combining semi-precast elements and in situ concrete, has been developed at TU Wien, with the aim of decreasing erection time. In the course of construction using this new method, structural conditions arise that render a more detailed investigation necessary. By connecting a precast, thin-walled box girder to a bridge segment located on a pier by means of post-tensioning, a joint is created. By casting in situ concrete on the bottom and top slabs, the joint can be bridged with longitudinal reinforcement; however, the unreinforced vertical joints in the webs remain. This detail is a specific characteristic of the LT-bridge construction method and needs to be further investigated and assessed, as the question arises as to how this circumstance affects the torsional bearing behavior of the bridge superstructure. Torsion tests described in the literature consider ordinary box girders with longitudinal reinforcement or post-tensioned segmental bridges without longitudinal reinforcement at the joints. Therefore, the new reinforcement layout at the joints had to be investigated experimentally. Two large-scale thin-walled box girders—one without joints in the webs and the other with unreinforced joints in the webs—were tested, allowing for a direct comparison of conventionally manufactured bridges and those erected with the new bridge construction method. Furthermore, we investigated whether the results of common calculation methods corresponded to the experimental findings. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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17 pages, 7931 KiB  
Article
Studying the Cable Loss Effect on the Seismic Behavior of Cable-Stayed Bridge
by Jaegyun Park, Jaeyong Yoon, Chulho Park and Jungwhee Lee
Appl. Sci. 2023, 13(9), 5636; https://doi.org/10.3390/app13095636 - 03 May 2023
Viewed by 1389
Abstract
As the demand and construction of cable-stayed bridges have increased, research on the safety of cable-stayed bridges in the event of natural disasters such as fires and explosions is actively being conducted. If a cable-stayed bridge is damaged by an unexpected natural disaster [...] Read more.
As the demand and construction of cable-stayed bridges have increased, research on the safety of cable-stayed bridges in the event of natural disasters such as fires and explosions is actively being conducted. If a cable-stayed bridge is damaged by an unexpected natural disaster or accident, it can cause serious traffic congestion and huge economic losses. This study evaluates the usability of the cable-stayed bridge in the event of cable damage. Additionally, seismic performance and the impact of the damage are evaluated by numerical analysis. To achieve this goal, the cable-stayed bridge is modeled using 3D BEAM elements and two-node cable elements. Then, the impact of the damage was evaluated by gradually damaging the cable. The deflection, axial force of the girder, and cable stress changes under far-field ground motion (El-Centro earthquake) were reviewed. A representative dynamic analysis program LS-DYNA was utilized for the numerical analyses. The results show that the loss of a small number of cables does not affect the usability of the bridge. However, if five or more cables are continuously lost, or if an earthquake occurs when cables are already lost, excessive deflections and changes in the girders’ axial forces can cause usability problems. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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19 pages, 6185 KiB  
Article
Out-of-Plane Stability of Circular Steel Tubular Vierendeel Truss Arches Incorporating Torsional Effects of Chords
by Qunfeng Liu, Yun Feng, Chang Wang, Xing Wu and Xiang Ren
Appl. Sci. 2023, 13(8), 5082; https://doi.org/10.3390/app13085082 - 19 Apr 2023
Viewed by 936
Abstract
Torsional stiffnesses of chords contribute considerably to the sectional torsional stiffness of steel tubular Vierendeel truss arches and hence determine their out-of-plane buckling. To obtain a more accurate stability design for the Vierendeel truss arches, torsional effects of chords on their out-of-plane stability [...] Read more.
Torsional stiffnesses of chords contribute considerably to the sectional torsional stiffness of steel tubular Vierendeel truss arches and hence determine their out-of-plane buckling. To obtain a more accurate stability design for the Vierendeel truss arches, torsional effects of chords on their out-of-plane stability and failure mechanisms were investigated theoretically and numerically. This paper firstly derives the theoretical formulas of the sectional torsional stiffness and the out-of-plane elastic buckling loads for the pin-ended circular steel tubular Vierendeel truss arches. It is found that incorporating the torsional stiffness of chords can remarkably enhance the sectional torsional stiffness of the Vierendeel truss arches and their out-of-plane elastic buckling loads by ~41%. Then, the out-of-plane elastic buckling loads are calculated for the pin-ended arches by the equilibrium theorem and for the fix-ended arches by the numerical fitting. In both cases, the sectional torsional stiffness and elastic buckling loads are closely dependent on the transverse-to-chord member stiffness ratio (it/ic). Furthermore, the out-of-plane inelastic buckling behaviors are investigated numerically in the end-fixed Vierendeel truss arches with large it/ic, where the ultimate bearing load in full-span radially uniform manner can be significantly enhanced by ~43% by incorporating the torsional stiffness of chords. The calculated reduction factors confirm the design curve b from GB50017-2017 or Eurocode 3 and can provide a conservative design for the out-of-plane stability of the circular steel tubular Vierendeel truss arches. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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16 pages, 2308 KiB  
Article
Development of Innovative Lateral Resistance Systems Featuring Earthquake-Protective Dampers
by Alireza Farzampour, Iman Mansouri, Seyed Javad Mortazavi, Eleni Retzepis, Mosbeh R. Kaloop and Jong-Wan Hu
Appl. Sci. 2023, 13(6), 3852; https://doi.org/10.3390/app13063852 - 17 Mar 2023
Viewed by 901
Abstract
Several conventional structural systems require sufficient retrofitting design procedures, improvements, and reconstructions to withstand lateral loads and to decrease the occurrence of damage. High strength capacity and ductility for seismic lateral resisting systems improve the structural vulnerabilities and limit damage concentrations in areas [...] Read more.
Several conventional structural systems require sufficient retrofitting design procedures, improvements, and reconstructions to withstand lateral loads and to decrease the occurrence of damage. High strength capacity and ductility for seismic lateral resisting systems improve the structural vulnerabilities and limit damage concentrations in areas subject to seismic conditions. Several types and shapes of structural systems with appropriate ductility and energy dissipation features are currently established as structural fuses to enhance the general performance of the structures and decrease seismic ramifications. To enhance the energy dissipation performance and concentration of the inelasticity, improving the ductile behavior and limiting the unpredictable accumulation of plastic strains is essential. The conventional eccentrically braced systems are examined and reestablished, and the effects of shear fuses used in high-rise buildings are investigated for prototype buildings by implementing the verified simulations. Next, seismic protective fuse systems with innovative dampers consisting of several butterfly-shaped shear links are established. Ultimately, the design guidelines are established based on the conventional eccentrically braced frames (EBFs), which are redesigned with the use of noble seismic protective fuses, and the hysteretic behavior is obtained and compared accordingly. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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19 pages, 18859 KiB  
Article
A Study on Development of New Type Rubber Boot for Sleeper Floating Track System (STEDEF): Materials and Shapes
by Jung-Youl Choi, Sun-Hee Kim, Hee Soo Park and Jee-Seung Chung
Appl. Sci. 2023, 13(5), 3068; https://doi.org/10.3390/app13053068 - 27 Feb 2023
Viewed by 1132
Abstract
Urban railway sleeper floating track (STEDEF) reduces the block vibration transmitted to the subgrade structure by structurally separating the sleeper and the concrete bed, using a rubber boot and a resilient pad. Recently, the replacement of rubber boot material (SBR) after long-term wear [...] Read more.
Urban railway sleeper floating track (STEDEF) reduces the block vibration transmitted to the subgrade structure by structurally separating the sleeper and the concrete bed, using a rubber boot and a resilient pad. Recently, the replacement of rubber boot material (SBR) after long-term wear and tear has become of utmost importance because of durability problems such as deformation, tearing, and abrasion. This study investigates rubber boots—a component of the urban railway sleeper floating track—to resolve these concerns and proposes the material and shape of a novel rubber boot. The proposed rubber boot reduces the maximum displacement and strain by more than 83% and 90%, respectively, compared with the existing rubber boots. In addition, the results of numerical analysis and indoor tests show that type 3 rubber boots can prevent displacement and stress generation in rubber boots. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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22 pages, 5562 KiB  
Article
Comparative Assessment of Variable Loads and Seismic Actions on Bridges: A Case Study in Italy Using a Multimodal Approach
by Daniele Collura and Roberto Nascimbene
Appl. Sci. 2023, 13(5), 2771; https://doi.org/10.3390/app13052771 - 21 Feb 2023
Cited by 3 | Viewed by 1212
Abstract
The structural safety of the infrastructure stock is an important issue in modern seismic performance assessments. Following recent seismic events, reports have highlighted the increased vulnerability of physical infrastructural assets, particularly for many bridges across the Italian road and motorway network. Italy possesses [...] Read more.
The structural safety of the infrastructure stock is an important issue in modern seismic performance assessments. Following recent seismic events, reports have highlighted the increased vulnerability of physical infrastructural assets, particularly for many bridges across the Italian road and motorway network. Italy possesses one of the most complex and intricate road systems in Europe which was constructed across irregular territories in terms of plan and elevation and of varying dimensions. As such, a comparative case study is presented herein. This case study aims to characterise the seismic vulnerability of the Vizzana-Zampogna viaduct which is part of the A15 Parma-La Spezia motorway, near the locality of Selva Bocchetto. The viaduct is considered representative of the 1970s construction period. It is approximately 342 m in length and is characterized by a flat curvilinear prestressed concrete deck consisting of 15 spans simply supported on reinforced concrete piers. To better understand the seismic structural response of the individual piers of the viaduct, a “multi-modal” nonlinear static analysis was developed, which allows the effects of sectional stresses relative to the variable load profiles of the single modes to be combined through the quadratic modal combination, and to be compared with the relevant limit state. The research aims to qualitatively identify the piers most vulnerable to seismic action and to study the effects that are induced by introducing variable loads and intensity scenarios of different earthquakes. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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23 pages, 7725 KiB  
Article
Enhancing the Fatigue of Mechanical Systems Such as Dispensers Entrenched on Generalized Life-Stress Models and Sample Sizes
by Seongwoo Woo, Dennis L. O’Neal, Yury G. Matvienko and Gezae Mebrahtu
Appl. Sci. 2023, 13(3), 1358; https://doi.org/10.3390/app13031358 - 19 Jan 2023
Cited by 1 | Viewed by 1823
Abstract
To lengthen the life of a mechanical system, parametric accelerated life testing (ALT) is recommended as an established way to help identify structural imperfections and reduce fatigue-related failures. It involves (1) a parametric ALT scheme, (2) fatigue design, (3) ALTs with alterations, and [...] Read more.
To lengthen the life of a mechanical system, parametric accelerated life testing (ALT) is recommended as an established way to help identify structural imperfections and reduce fatigue-related failures. It involves (1) a parametric ALT scheme, (2) fatigue design, (3) ALTs with alterations, and (4) an estimate of whether design(s) achieve the BX lifetime. The application of a quantum-transported time to failure prototype and a sample size expression is also suggested. The improvements in the reliability of a water dispenser made of stainless steel or polypropylene (PP) in a bottom-mount domestic refrigerator was used as a case study. In the first ALT, the hinge and front corner of the dispensing system was cracked. The water dispenser lever was altered by increasing the thickness of its ribs and fillets. In the second ALT, the altered dispensing lever system cracked because there was an insufficient thickness in its front corner for impact loading. The critical design factors for improving reliability were corner fillet rounding and rib thickening in a dispenser lever. As there were no difficulties in the third ALT, the dispenser life was verified to have a B1 life of 10 years. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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28 pages, 9087 KiB  
Article
In-Structure Response Spectra of an Auxiliary Building in a Nuclear Power Plant Considering Equipment–Structure Interaction
by Sook-Jin Ahn and Ji-Hun Park
Appl. Sci. 2023, 13(1), 247; https://doi.org/10.3390/app13010247 - 25 Dec 2022
Cited by 1 | Viewed by 1734
Abstract
A two-degree-of-freedom (two-DOF) equation of motion was derived in the frequency domain using a substructuring technique for efficiently calculating the in-structure response spectrum (ISRS) considering equipment–structure interaction. The model of the primary structure was condensed into a mechanical impedance function and combined with [...] Read more.
A two-degree-of-freedom (two-DOF) equation of motion was derived in the frequency domain using a substructuring technique for efficiently calculating the in-structure response spectrum (ISRS) considering equipment–structure interaction. The model of the primary structure was condensed into a mechanical impedance function and combined with the equipment represented by a single-degree-of-freedom oscillator in the frequency domain. This condensed two-DOF system is applied to the efficient calculation of the ISRS considering the equipment–structure interaction without repeated analysis of the coupled model with full DOFs. This coupled analysis procedure was applied to a finite element model of an auxiliary building in a nuclear power plant to validate both the accuracy and impact on the equipment response. Finally, the adequacy of three representative decoupling criteria on the necessity of coupled analysis was investigated by applying those criteria to the auxiliary building example. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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15 pages, 6695 KiB  
Article
Failure Analysis of Subway Box Structures According to Displacement Behavior on a Serviced Urban Railway
by Jung-Youl Choi, Sun-Hee Kim, Gyu-Nam Yang, Ho-Hyun Lee and Jee-Seung Chung
Appl. Sci. 2022, 12(24), 12637; https://doi.org/10.3390/app122412637 - 09 Dec 2022
Cited by 1 | Viewed by 747
Abstract
The increasing development of underground infrastructure has led to the deformation of subway box structures and surrounding roadbeds, eventually resulting in cracks. Therefore, it is necessary to predict damage through effective analysis and evaluation techniques. This study examined the correlation between displacement behavior [...] Read more.
The increasing development of underground infrastructure has led to the deformation of subway box structures and surrounding roadbeds, eventually resulting in cracks. Therefore, it is necessary to predict damage through effective analysis and evaluation techniques. This study examined the correlation between displacement behavior and damage in a subway box structure and proposed an analysis technique to predict the damage location and scale of a structure by comparing the results from visual inspection, on-site measurement, and numerical analysis. The proposed technique can be used to compute the external boundary conditions that may induce major deformations in a subway box structure, and to predict and evaluate the members and locations where the damage may occur. In addition, we confirm that the damaged location and scale in a subway box structure can be determined, and that the maintenance of a subway box structure can be achieved by repairing and reinforcing the damaged part. Therefore, the results of this study are expected to help accurately predict damage in subway box structures, thereby contributing to better maintenance and failure prevention of underground infrastructure. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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20 pages, 5401 KiB  
Article
Flexural Behavior of One-Way Slab Reinforced with Grid-Type Carbon Fiber Reinforced Plastics of Various Geometric and Physical Properties
by Kyung-Min Kim and Ju-Hyun Cheon
Appl. Sci. 2022, 12(23), 12491; https://doi.org/10.3390/app122312491 - 06 Dec 2022
Cited by 1 | Viewed by 1008
Abstract
Textile-reinforced concrete (TRC) has many advantages, including corrosion resistance, but TRC is a novel composite material and there is limited experimental research on the flexural behavior of TRC members. This paper aims to experimentally evaluate the flexural behavior of TRC slabs reinforced with [...] Read more.
Textile-reinforced concrete (TRC) has many advantages, including corrosion resistance, but TRC is a novel composite material and there is limited experimental research on the flexural behavior of TRC members. This paper aims to experimentally evaluate the flexural behavior of TRC slabs reinforced with nine types of grid-type carbon fiber-reinforced plastic (CFRP) (hereafter referred to as carbon grid) with varying cross-sectional areas, spacings, tensile strengths, and elastic moduli of longitudinal strands. The experimental results show that the maximum load tends to be higher in specimens reinforced with carbon grids with small cross-sectional areas and spacings of strands but high tensile strength. Cross-sectional area and spacing were also revealed to influence the crack-formation stage behavior. On the other hand, stiffness decreased to approximately 8% or lower than the initial stiffness, with cracking in all carbon grid-reinforced specimens; post-peak behavior also exhibited dependency on tensile stress acting on the carbon grids under the maximum load, based on 80% of the tensile strength. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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23 pages, 5399 KiB  
Article
Systematic Methods to Increase the Lifetime of Mechanical Products Such as Refrigerators by Employing Parametric Accelerated Life Testing
by Seongwoo Woo, Dennis L. O’Neal and Yimer Mohammed Hassen
Appl. Sci. 2022, 12(15), 7484; https://doi.org/10.3390/app12157484 - 26 Jul 2022
Cited by 2 | Viewed by 1341
Abstract
This investigation practically explains the implementation of parametric accelerated life testing (ALT) as an algorithm to recognize design imperfection and rectify it in creating a reliable quantitative (RQ) statement by sample size equation. It covers: (1) a module BX life that X% of [...] Read more.
This investigation practically explains the implementation of parametric accelerated life testing (ALT) as an algorithm to recognize design imperfection and rectify it in creating a reliable quantitative (RQ) statement by sample size equation. It covers: (1) a module BX life that X% of a collection of system items is unsuccessful with an ALT plan, (2) design for fatigue, (3) ALTs with alterations, and (4) discernment as to if the final design(s) obtains the targeted BX lifetime. A (generalized) life–stress formulation by the linear transport process is recommended for the mathematical work of the parametric model. As a case study, an ice-maker including gear system in a refrigerator was utilized. The gear teeth made of cast iron (carbon, 3 wt% and silicon, 2 wt%) was fracturing in a refrigerator ice-maker. To reproduce the field failure and rectify the problematic designs in the marketplace, a parametric ALT was carried out. At the first ALT, the gear teeth made of cast iron partly cracked and fractured under severe cold conditions (below −20 °C) in the freezer. It was modified by changing the material from cast iron to a sinter-hardened powder metallurgy nickel steel because high fatigue strength in the low temperature was required. At the second ALT, we discovered the fractured helix made of polycarbonates (PC). As a modification, strengthened rib on the front and side of the helix the thickness of gear teeth was attached. At the third ALT, there was no concern, and the life of the auger motor including gear system was manifested to have a B1 life 10 years. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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18 pages, 9973 KiB  
Article
Pure Electric Sweeper Performance Analysis and Test Verification of Dust Extraction Port
by Jin Ye, Jiabao Pan, Hejin Ai and Jiamei Wang
Appl. Sci. 2022, 12(10), 5188; https://doi.org/10.3390/app12105188 - 20 May 2022
Cited by 4 | Viewed by 1572
Abstract
Purely electric sweepers are widely used in the urban sanitation industry due to their emission-free nature and ease of miniaturisation. The dust suction port is the key to the dust suction system of the sweeper, and improving the design level of the dust [...] Read more.
Purely electric sweepers are widely used in the urban sanitation industry due to their emission-free nature and ease of miniaturisation. The dust suction port is the key to the dust suction system of the sweeper, and improving the design level of the dust suction port of the sweeper can effectively improve the operational performance of the sweeper. Using the company’s self-developed Ruiqing S26 pure electric sweeper as the research object, a CFD (Computational Fluid Dynamics) method was used to analyse the influence of the dust suction port structure parameters (front baffle tilt angle, outlet diameter) and sweeper operation parameters (driving speed, operating pressure) on the dust suction effect of the sweeper, and was verified through real vehicle tests. The results of the study show that changing the angle and outlet diameter results in a change in the flow field characteristics and, consequently, the same change in the removal efficiency, with 65° and 160 mm being the optimum angle and outlet diameter, respectively. The tests investigated the flow field characteristics of the dust extraction opening and the removal efficiency. This study can provide theoretical reference for performance optimisation and parameter matching of the sweeper. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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10 pages, 5869 KiB  
Article
Experimental Study on Settlement Behavior of Ballasted Tracks with Polymer Compound-Coated Gravel
by Jung-Youl Choi
Appl. Sci. 2022, 12(9), 4418; https://doi.org/10.3390/app12094418 - 27 Apr 2022
Viewed by 1616
Abstract
The ballast used in ballasted railway tracks transmits load from the rails and ties to the subgrade during train travel, and directly affects the overall track support performance and elastic behavior of the ballasted track. Due to the material limitations of the ballast, [...] Read more.
The ballast used in ballasted railway tracks transmits load from the rails and ties to the subgrade during train travel, and directly affects the overall track support performance and elastic behavior of the ballasted track. Due to the material limitations of the ballast, it is difficult to quantitatively manage its performance, status, and shape maintenance, and the use of the ballast requires continuous maintenance and management work. In this study on a proposed ballast material, ballast box tests and numerical analyses were performed to examine the performance of the ballast that has a gravel coating layer and can be used semi-permanently while maintaining the shape of the ballast against impacts, abrasion, and friction. The results show that the coated ballast’s performance ensured constant stiffness in comparison to that of a normal ballast. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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10 pages, 2756 KiB  
Article
A Fatigue Reliability Assessment for Rail Tension Clamps Based on Field Measurement Data
by Ji-Hyeon Kim, Yeun-Chul Park, Mancheol Kim and Hyoung-Bo Sim
Appl. Sci. 2022, 12(2), 624; https://doi.org/10.3390/app12020624 - 10 Jan 2022
Cited by 7 | Viewed by 1525
Abstract
Tension clamps play an important role in maintaining the track gauge by fixing the rails to the sleepers. Damage to the tension clamps was observed on an urban railway. The cause of the fracturing of the tension clamps was identified and reliability analyses [...] Read more.
Tension clamps play an important role in maintaining the track gauge by fixing the rails to the sleepers. Damage to the tension clamps was observed on an urban railway. The cause of the fracturing of the tension clamps was identified and reliability analyses on the fatigue failure of the tension clamps were performed. The stress ranges were estimated by measuring the strain at the locations where most of the fractures occurred during train operation. Afterward, a statistical model of the stress ranges was developed using the measured data. The statistical parameters of the stress ranges for the reliability analysis were estimated based on the field measurement data. The reliability indexes were calculated for the inner and outer rails and for the inside and outside track gauges of each rail. The variations of the reliability index for the years in service and the number of cycles were investigated. The results of the reliability analyses showed a consistency with the field observations. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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16 pages, 8149 KiB  
Article
Experimental Studies of Scale Effect on the Shear Strength of Coarse-Grained Soil
by Shuya Li, Tiancheng Wang, Hao Wang, Mingjie Jiang and Jungao Zhu
Appl. Sci. 2022, 12(1), 447; https://doi.org/10.3390/app12010447 - 04 Jan 2022
Cited by 3 | Viewed by 1841
Abstract
Shear strength is an essential index for the evaluation of soil stability. Test results of the shear strength of scaled coarse-grained soil (CGS for short) are usually not able to accurately reflect the actual properties and behaviors of in situ CGS due to [...] Read more.
Shear strength is an essential index for the evaluation of soil stability. Test results of the shear strength of scaled coarse-grained soil (CGS for short) are usually not able to accurately reflect the actual properties and behaviors of in situ CGS due to the scale effect. Therefore, this study focuses on the influence of the scale effect on the shear strength of scaled CGS, which has an important theoretical significance and application for the strength estimation of CGS in high earth-rock dam engineering. According to previous studies, the main cause of the scale effect for scaled CGS is the variation of the gradation structure as well as the maximum particle size (dmax), in which the gradation structure as a characteristic parameter can be expressed by the gradation area (S). A total of 24 groups of test soil samples with different gradations were designed by changing the maximum particle size dmax and gradation area S. Direct shear tests were conducted in this study to quantitatively explore the effect of the gradation structure and the maximum particle size on the shear strength of CGS. Test results suggest that the shear strength indexes (i.e., the cohesion and internal friction angle) of CGS present an increasing trend with the improvement of the maximum particle size dmax, and thus a logarithmic function relationship among c, φ, and dmax is presented. Both cohesion (c) and internal friction angle (φ) are negatively related to the gradation area (S) in most cases. As a result, an empirical relationship between c, φ, and S is established based on the test results. Furthermore, a new prediction model of shear strength of CGS considering the scale effect is proposed, and the accuracy of this model is verified through the test results provided by relevant literature. Finally, the applicability of this model to different types of CGS is discussed. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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21 pages, 10387 KiB  
Article
Dynamic Wheel-Rail Force-Based Track-Irregularity Evaluation for Ballasted Track on Serviced Railway by Adjacent Excavation
by Jung-Youl Choi, Dong-Ryong Park, Jee-Seung Chung and Sun-Hee Kim
Appl. Sci. 2022, 12(1), 375; https://doi.org/10.3390/app12010375 - 31 Dec 2021
Cited by 2 | Viewed by 1428
Abstract
This study investigates a load-based, track-irregularity-analysis technique for ballasted tracks on a serviced railway line with respect to excavation work conducted in adjacent sites. A numerical analysis and field measurements (railbed-settlement-monitoring sensor, track-geometry-measurement system, wheel-load measurements) were analyzed comparatively to demonstrate the correlation [...] Read more.
This study investigates a load-based, track-irregularity-analysis technique for ballasted tracks on a serviced railway line with respect to excavation work conducted in adjacent sites. A numerical analysis and field measurements (railbed-settlement-monitoring sensor, track-geometry-measurement system, wheel-load measurements) were analyzed comparatively to demonstrate the correlation between the track irregularities and the Wheel-Rail interaction force. In this way, we highlight the necessity for load-based track-irregularity-management methods. The analyzed results show that the maximum dynamic wheel load was measured in the range of approximately 10 m before and after the location where the maximum track irregularities occurred, and that even if the maintenance criteria of track irregularities were satisfied, the design dynamic wheel load could still be exceeded depending on the train speed, thus indicating that track damage can be caused by the impact load. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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9 pages, 2817 KiB  
Article
Numerical Simulation of Rockfill Materials Based on Fractal Theory
by Hongxing Han, Yun Ma, Wei He, Weifang Yang and Xudong Fu
Appl. Sci. 2022, 12(1), 289; https://doi.org/10.3390/app12010289 - 29 Dec 2021
Cited by 2 | Viewed by 1136
Abstract
With the use of the particle flow code in two dimensions, a fractal model is established with the number of particles of different particle fractions used as the statistics to study the fractal characteristics of particle size distribution. Numerically simulated specimens obtained by [...] Read more.
With the use of the particle flow code in two dimensions, a fractal model is established with the number of particles of different particle fractions used as the statistics to study the fractal characteristics of particle size distribution. Numerically simulated specimens obtained by four scale methods are subjected to the relative density test and the biaxial compression test to explore the influences of fractal dimension D on the macroscopic and mesomechanical properties of specimens, as well as to study the relationship between fractal dimension D and different mechanical performance indexes. Results show that the particle size distribution of each of the four groups after scale exhibits fractal characteristics, with the fractal dimension D ranging from 1.27 to 2.03. The number of fine particles in the specimen increases with the fractal dimension D, the particle aggregates become more compact, the macroscopic mechanical properties of the specimens are improved, and a linear relationship exists between the fractal dimension D and different mechanical performance indexes. A large fractal dimension D corresponds to a great mesoparticle coordination number. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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21 pages, 8068 KiB  
Article
A New Design Problem in the Formulation of a Special Moment Resisting Connection Device for Preventing Local Buckling
by Salvatore Benfratello, Luigi Palizzolo and Santo Vazzano
Appl. Sci. 2022, 12(1), 202; https://doi.org/10.3390/app12010202 - 25 Dec 2021
Cited by 6 | Viewed by 1870
Abstract
In the present paper an improved formulation devoted to the optimal design problem of a special moment resisting connection device for steel frames is proposed. This innovative device is called a Limited Resistance Plastic Device (LRPD) and it has been recently proposed and [...] Read more.
In the present paper an improved formulation devoted to the optimal design problem of a special moment resisting connection device for steel frames is proposed. This innovative device is called a Limited Resistance Plastic Device (LRPD) and it has been recently proposed and patented by some of the authors. It is thought to be preferably located at the extremes of the beam, connecting the beam end cross section with the relevant column. The typical device is a steel element characterized by symmetry with respect to three orthogonal barycentric planes and constituted by a sequence of three portions with abrupt cross section changes. The main novelty of the present proposal is related to the design of special geometry for the optimal device ensuring that it possesses a reduced resistance with respect to the relevant connected beam element, is characterized by an equivalent bending stiffness equal to the one of the connected beam elements and exhibits full plastic deformations avoiding any local instability phenomenon. The optimal design is formulated as a minimum volume one and is subjected to suitable constraints on the geometry of the device and on its elastic and plastic behavior. The optimization problem is a strongly non-linear programming one and it is solved by adopting an interior-point algorithm that is available in the MATLAB Optimization Toolbox. The numerical simulations are devoted to the most used standard steel profiles (IPE, HE) and the results prove the great reliability of the proposed device. In addition, the relevant elastic and plastic domains of the designed devices are defined, and the expected behavior of the device is verified by appropriate 3D finite element models in the ABAQUS environment. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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11 pages, 6878 KiB  
Article
Evaluation of Structural Behavior and Fatigue Performance of a KR-Type Rail Clip
by Sang-Hyeok Kim, Xiao-Jun Fang, Yeun-Chul Park and Hyoung-Bo Sim
Appl. Sci. 2021, 11(24), 12074; https://doi.org/10.3390/app112412074 - 18 Dec 2021
Cited by 4 | Viewed by 1911
Abstract
Rail clips are essential components of rail fastening systems that clamp the rails to sleepers. Fatigue damage of rail clips has been recently reported in railway lines. However, there has been a lack of research investigating this fatigue issue. The KR-type rail fastening [...] Read more.
Rail clips are essential components of rail fastening systems that clamp the rails to sleepers. Fatigue damage of rail clips has been recently reported in railway lines. However, there has been a lack of research investigating this fatigue issue. The KR-type rail fastening system has been recently developed and used in some domestic railways. This study aimed at evaluating the structural behavior and fatigue performance of the KR-type rail clip. The assembly test performed in the laboratory showed that the stresses induced in the rail clips after tightening, particularly at the stress concentration locations, exceeded the yield stress, indicating that the rail clip could be vulnerable to fatigue cracking when combined with the stress range during repeated trainloads. The finite element analysis results, which revealed a good correlation with the experiments, were used to evaluate the fatigue performance of the rail clip by adopting the modified Goodman fatigue criteria. The fatigue evaluation results indicated that when the vertical rail displacement during train operation exceeded 2 mm, the rail clips could potentially suffer from fatigue failure. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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16 pages, 6347 KiB  
Article
Experimental Study on the Behavior of Polyurethane Springs for Compression Members
by Young Hun Ju and Jong Wan Hu
Appl. Sci. 2021, 11(21), 10223; https://doi.org/10.3390/app112110223 - 01 Nov 2021
Cited by 4 | Viewed by 2138
Abstract
In this study, the characteristics of the compression behavior of polyurethane springs that can be used as compression members of seismic devices, such as dampers and seismic isolators, were identified, and the effect of the design variables on the performance points of polyurethane [...] Read more.
In this study, the characteristics of the compression behavior of polyurethane springs that can be used as compression members of seismic devices, such as dampers and seismic isolators, were identified, and the effect of the design variables on the performance points of polyurethane springs was investigated. Compressive stiffness and specimen size were set as the design variables of the polyurethane spring, and the performance indicators were set as maximum force, residual strain, and energy dissipation. A total of 40 specimens with different conditions were fabricated and a cyclic loading test was performed to obtain the force-displacement curve of the polyurethane spring and to check the performance indicator. Significant strength degradation was confirmed after the first cycle by repeated loading, and it was confirmed that compressive stiffness and size demonstrated a linear proportional relationship with maximum force. In addition, the design variables did not make a significant change to the recovered strain, including residual strain, and residual strain of about 1% to 3% occurred. Energy dissipation showed a tendency to decrease by about 60% with strength degradation after the first cycle, and this also demonstrated no relationship with the design variables. Finally, the relationship between the design variables and performance indicators set in this study was reviewed and suggestions are presented for developing a simple design formula for polyurethane springs. Full article
(This article belongs to the Special Issue Advances on Structural Engineering, Volume III)
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