Yosuke NAKAHANA
Experimental Study on Bending and Shear Correlated Strength of Composite I-Girder
Masatsugu NAGAI
Presently, steel bridge's design adopts allowable stress design method in Japan. Therefore introduction of plasticity design is necessary for further cost-cutting in the bridge construction. In order to introduce the plasticity design, our laboratory has gone study with composite I-girder. Last year, they studied the ultimate bending strength and ductility condition. In 1996, they did an experiment of shear strength. The results showed that Basler's equation is suitable for appraisal of shear strength.
So. Deterioration of bending strength is to be expected by correlated action of shear when combined bending moment and shear force acts to composite I-girder. However, presently, study with composite I-girder of correlated strength are very few in number. So, this study executed loading test that three kinds of composite I-girder with different proportion of bending moment and shear force for clarification of correlated strength and validity of check by 4th-power correlation rule. In addition, this research executed shear test that composite girder of aspect ratio(¦Á)=1.5, 2.0 and double-composite girder for ascertainment of shear appraisal by Basler's equation.
The followings are the results obtained by this study.
1) In the experiment of three kinds of composite I-girder with different proportion of bending moment and shear force, bending strength reached plasticity moment irrespective of shear action. And, this study couldn't showed correlated action of bending and shear or deterioration of strength by correlated action.
2) In this study, 4th-power correlation rule is safe check about correlated action. But, it's necessary to try still more experimentation and analysis. Because, parameters of this experiment are limited.
3) Shear strength of composite girder of aspect ratio(¦Á)=1.5, 2.0 and double-composite girder were greater than Basler's shear strength. Therefore Basler¡Çs equation is safe check about shear strength.
4) In the above regard, quantitative discussions are an issue in the future about degree of safe side. It's necessary to demonstrate the efficacy of function of slab on shear and effect of flame including slab
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