{"title":"Design equations for maximum stress concentration factors for concrete-filled steel tubular K-joints","authors":"","doi":"10.1016/j.jtte.2022.07.007","DOIUrl":null,"url":null,"abstract":"<div><div>Stress concentration factors (SCFs) for welded tubular joints can be decreased by filling the chord with concrete leading to a longer fatigue life. However, there are currently no design formula available in guidelines to predict the SCF of concrete-filled circular hollow section (CFCHS) K-joints, thus limiting their applicability in bridge design. To address this gap, finite element models for CFCHS K-joints were developed and compared against test results to ensure their accuracy. Then, a comprehensive parametric study was conducted to establish relationships between maximum SCFs and four variables: brace-to-chord diameter ratio (<em>β</em>), chord diameter-to-thickness ratio (2<em>γ</em>), brace-to-chord thickness ratio (<em>τ</em>), and the angle between braces and chord (<em>θ</em>). A total of 480 FE models were examined under three loading conditions including brace and chord loading: balanced axial force, chord axial force, and chord bending. Design equations to predict the maximum SCF for CFCHS K-joints were established by multiple regression analyses of the numerical results. A comparison of maximum SCFs between circular hollow section (CHS) and CFCHS K-joints was made, and it was concluded that average reductions of 42% and 33% in maximum SCFs in CFCHS K-joints at the locations of the chord and brace were found compared to CHS joints for balanced axial force, respectively. Finally, a case study illustrating how to use the proposed equations for fatigue safety verification was presented.</div></div>","PeriodicalId":47239,"journal":{"name":"Journal of Traffic and Transportation Engineering-English Edition","volume":null,"pages":null},"PeriodicalIF":7.4000,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Traffic and Transportation Engineering-English Edition","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2095756424000965","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CIVIL","Score":null,"Total":0}
引用次数: 0
Abstract
Stress concentration factors (SCFs) for welded tubular joints can be decreased by filling the chord with concrete leading to a longer fatigue life. However, there are currently no design formula available in guidelines to predict the SCF of concrete-filled circular hollow section (CFCHS) K-joints, thus limiting their applicability in bridge design. To address this gap, finite element models for CFCHS K-joints were developed and compared against test results to ensure their accuracy. Then, a comprehensive parametric study was conducted to establish relationships between maximum SCFs and four variables: brace-to-chord diameter ratio (β), chord diameter-to-thickness ratio (2γ), brace-to-chord thickness ratio (τ), and the angle between braces and chord (θ). A total of 480 FE models were examined under three loading conditions including brace and chord loading: balanced axial force, chord axial force, and chord bending. Design equations to predict the maximum SCF for CFCHS K-joints were established by multiple regression analyses of the numerical results. A comparison of maximum SCFs between circular hollow section (CHS) and CFCHS K-joints was made, and it was concluded that average reductions of 42% and 33% in maximum SCFs in CFCHS K-joints at the locations of the chord and brace were found compared to CHS joints for balanced axial force, respectively. Finally, a case study illustrating how to use the proposed equations for fatigue safety verification was presented.
期刊介绍:
The Journal of Traffic and Transportation Engineering (English Edition) serves as a renowned academic platform facilitating the exchange and exploration of innovative ideas in the realm of transportation. Our journal aims to foster theoretical and experimental research in transportation and welcomes the submission of exceptional peer-reviewed papers on engineering, planning, management, and information technology. We are dedicated to expediting the peer review process and ensuring timely publication of top-notch research in this field.