دانلود رایگان مقاله طراحی انحنای اسمی ستون HSC مدور محدود با تسمه های فلزی پس تنیده

Abstract

This article proposes new parameters for the practical design of circular high-strength concrete (HSC) columns confined with an innovative Steel Strapping Tensioning Technique (SSTT) using a nominal curvature approach. Previous experimental research has proven the effectiveness of the SSTT at providing active confinement and enhancing the ductility of HSC columns, but to date no practical procedures are available so that the technique can be widely adopted in design practice. The proposed design approach is based on results from segmental analyses of slender SSTT-confined circular columns subjected to eccentric loads. The results obtained from the analyses are used to determine the variables governing the design of such columns. The use of the proposed design parameters predicts conservatively the capacity of small-scale slender HSC circular columns confined using the SSTT, and can be thus used in the practical design of reinforced concrete (RC) structures.

5. Conclusions

This article proposed new parameters for the practical design of circular high-strength concrete (HSC) columns confined with an innovative Steel Strapping Tensioning Technique (SSTT) using a nominal curvature approach. The new parameters were obtained from segmental analyses of slender SSTT-confined columns subjected to eccentric loads. The results obtained from the analyses were used to determine the basic parameters that influence the design of such columns. A new equivalent stress block and block depth factor equation were proposed for the design of circular SSTT-confined sections. It was found that the block depth factor can be considered as constant and equal to β1 = 0.90, whereas the mean stress factor is variable and depends on the strap confining volumetric ratio. The use of the new proposed parameters for the design of SSTT-confined HSC columns using the nominal curvature method leads to conservative predictions of the maximum axial load and flexural strength of small-scale columns. However, future research should verify the accuracy of the approach at predicting the results of full-scale specimens. Besides, the current adopted stress–strain model was developed based on circular cylinders and hence no stress concentration at corners have been considered. The proposed design procedure can be used for rectangular or square sections columns provided that the correct stress–strain model for sections other than circular columns are used.