Analysis on single-box double-cells unequal-wall-thickness girder due to bending and restrained torsion by finite nodal-line method(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2018年01期
- Page:
- 59-66
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Analysis on single-box double-cells unequal-wall-thickness girder due to bending and restrained torsion by finite nodal-line method
- Author(s):
- GONG Yao-qing; LUO Ya-nan
- School of Civil Engineering, Henan Polytechnic University, Jiaozuo 454003, Henan, China
- Keywords:
- bridge engineering; single-box double-cells girder; unified analytical beam; finite nodal-line method; restrained torsion
- PACS:
- U448.213
- DOI:
- -
- Abstract:
- In order to investigate the mechanics characteristics such as deformation and stress distributions of a real single-box double-cells unequal-wall-thickness girder subjected to bending in its asymmetric plane and restrained torsion around its axis, a unified analytical beam model and a finite nodal-line method were employed. The unified analytical beam model neither make any assumptions about the out-of-plane deformation or stress distribution of the beam, nor limit the aspect ratio of the beam. Displacement field of the whole beam was determined by the numerical approximation using finite single-variable basic unknown functions. Stress field of the beam was determined by the strain field corresponding to the displacement field and the constitutive relation of beam material. The exemplar study of a box girder revealed the global deformation features, the cross-section warping characteristics, and the stress distribution of girder. Torsional center of the cross section was determined as well, and the formula for obtaining the location of torsional center was developed. The results show that as long as a single-box double-cells unequal-wall-thickness girder is subjected to transverse loading (transverse force or torque) in its asymmetric plane, the whole box girder does not have the problem of pure bending deformation in the asymmetric plane. Bending deformation and torsional deformation of the cross section about the axis of rotation are always coupled together. Cross section of the box girder produces warping deformation, and the normal stress and shear stress induced by lateral loading are nonlinearly distributed on the cross section. Location of the torsional center and the maximum values of both normal stress and torsional shearing stress of the cross section change with the size of flange and cells, especially the wall thickness of cells. The method proposed is especially suitable for solving the mechanical analysis problems of short box girders with aspect ratio less than 3. For the mechanical analysis problems of medium-long and long box girders without considering non-restrained torsion, the method proposed not only reduces to the related problems of Timoshenko beam and Bernoulli-Euler beam, but also can solve the problem of restrained torsion which cannot be solved by the traditional beam theory of these two kinds.
Last Update: 2018-02-06