비대칭 단면을 가지는 매입형 합성기둥의 압축-휨 강도 평가에 대한 실무적 접근 방법

Practical Approach for Evaluation of Axial-Flexural Strength of Encased Composite Columns with Asymmetric Cross-Sections

In the process of embedding a steel column in an excavated hole during the top-down construction, it often occurs that the geometric center of the encased column and the center of the steel core is misaligned. In the case of an asymmetric composite section where the steel is not in the center, the compression-bending strength is different due to the effect of eccentricity, but there is not much data that engineers can refer to. Based on the design formulae for symmetric composite sections provided in the current KSSC Composite Structural Manual, in order to reflect the effect of asymmetric sections, this paper proposes to add points approximating the P-M interaction diagram and provides formulae for the axial forces and moments of each point. For verification, the error rate was reviewed for 200 cases of sections that depend on the amount of steel, column size, material strength, and eccentricity. As a result of examining the error, it was found that the unconservative error decreased as the eccentricity increased. This tendency can also be confirmed in the P-M interaction curve according to the eccentricity of the example cross section.