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Title |
Performance Evaluation of Truss Encased Slab with Compression Element Composed of U-shaped Steel and Infilled Concrete in Construction Stage
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Authors |
김문길(Mun-Gil Kim) ; 천성철(Sung-Chul Chun) ; 김영호(Young Ho Kim) |
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DOI |
https://doi.org/10.4334/JKCI.2019.31.6.589 |
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Keywords |
합성구조; 부분PC; 시공하중; 사용성 composite structure; half PC; construction load; serviceability |
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Abstract |
A design procedure for truss encased slab was developed that doesn’t require slab formwork and shoring system, can be applied to parking lots. Truss encased slab is composed of half PC, tension rebar, truss rebar, U-shaped channels and filling concrete. In construction state, the half PC and tension rebars resist the tensile force of the lower part, and the U-shaped channels and filling concrete resist the compression force of the upper part. Among the flexural, shear and truss buckling strengths, the smallest strength is determined as the design strength against the construction load. Flexural tests were conducted to evaluate the performance of the truss encased slab in the construction state. The variables include the widths of the U-shaped channel and the half PC, and the strength of the half PC concrete. Test results show that truss buckling occurs after flexural cracks in all specimens. All specimens had strengths higher than expected truss buckling strength. The average [Experimental Strength]/[Expected Truss Buckling Strength] ratio is 1.25 and the coefficient of variation is 10.1. The [actual cracking strength]/[expected cracking strength] ratios is 0.79, showing that the first crack occurred earlier than expected. However, for all specimens, no cracks occurred in the construction load. The average of the [actual cracking strength]/[construction load] ratio is 3.12, meaning that it had strength 3 times the design load. Test results show that developed truss encased slab secures proper structural behavior against construction load.
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