Yuya HAYASHI
Evaluation of ultimate strength Characteristic of composite I-shape girders under positive and negative bending moment by experiments.
Masatugu NAGAI,Eiji IWASAKI
The construction cost reduction demand in recent years, in a steel system bridge, the rationalization girder , for example, composite I-girder was developed. To a further cost reduction demand, in this laboratory, To introduce plastic design into composite I-girder, experiment and analysis are done for composite I-girder.
In this study, first of all, about positive bending moment acts to composite I-girder, an examination concerning ultimate strength characteristic when Plastic Neutral Axis (PNA) was in slab was done. Next, about negative bending moment acts to composite I-girder, It was examined whether I may calculate by [steel girder + reinforce bar] section. Moreover, about , an examination concerning ultimate strength characteristic when combined bending moment and shear force acts to composite I-girder. Finally, because a original manner is adopted as method of deciding number of stud in this study, the influence that this influence gives to synthetic effect and ultimate strength of concrete and I-girder is considered.
The followings are the results obtained by this study.
1) About positive bending moment cases acts to composite I-girder, It was confirmed to reach plastic bending calculated disregarding concrete of tension area even when Plastic Neutral Axis (PNA) was in slab.
2) Value of experiment and value of calculation showed a good agreement though ultimate strength of composite I-girder that received negative bending moment was calculated in [steel girder + reinforce bar] section where concrete of tension area was disregarded. Therefore, it can be said it is good in ultimate strength evaluation to disregard concrete.
3) The correlation action was not seen when bending moment and shear force acts to composite I-girder.Therefore, it is thought that directionality to be able to disregard verification in this study was able to be shown. However, it will be necessary to examine noncompact section in the future.
4) A original manner is adopted as method of deciding number of stud in this study, concrete and I-girder composite behavior
within the range of elasticity was able to be confirmed. Moreover, the ultimate strength achieved plastic moment.
Please use "previous botton" to return the previous page