Effect of load combinations on distortional behaviors of simple-span steel box girder bridges

Jeonghwa Lee, Heesoo Kim, Keesei Lee, Young Jong Kang

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


When eccentric live loads are applied on the deck overhang of steel-box girder bridges, torsional moments, comprising pure torsional and distortional moments are generated on the box sections. The torsional moment on the bridge girders distorts the box girder cross-sections, inducing additional normal stress components and causing instability of the box girder sections in severe cases. Hence, it is essential to install intermediate diaphragms in the box sections to minimize dis-tortional behaviors. Although the applied live loads are critical parameters that influence intermediate diaphragm spacings, the effects of live load combinations have rarely been addressed in the design of intermediate diaphragm spacings. Thus, load combinations should be evaluated to design the intermediate diaphragm spacing of the box girder bridges more thoroughly. In this study, the load combination effects on the distortional behavior and adequate intermediate diaphragm spacing were evaluated through a finite element analysis (FEA). Composite rectangular box girder bridges with different cross-sectional aspect ratios (H/B) and spans (L) were analyzed in the para-metric study. It was found that the truck load, which represents the concentrated load, significantly influences the distortional warping normal stress, normal stress ratio, and intermediate diaphragm spacing. In addition, the FEA results showed that the controlling load combinations could be varied with the span.

Original languageEnglish
Article number1238
Issue number8
Publication statusPublished - 2021 Aug

Bibliographical note

Funding Information:
This study was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) and funded by the Ministry of Education (No. 2019R1I1A1A01059684) and supported by a grant provided by POSCO Corporation. The authors wish to express their gratitude for the financial support.

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.


  • Distortion
  • Intermediate diaphragm
  • Single span
  • Spacing
  • Steel-box girder

ASJC Scopus subject areas

  • General Materials Science
  • Metals and Alloys


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