مقاله انگلیسی رایگان در مورد پیش بینی نیروی کوبشی ستون های لوله ای پر شده از بتن – الزویر 2011

This paper describes a series of compression tests of circular hollow steel (CHS) sections and circular concrete-filled tubular (CFT) sections. The diameter to thickness ratios of the test specimens ranged 45–140. This range was set to investigate the effect of local buckling in the circular steel skin on the ultimate strength of CFT columns. The confining effect against filled-in concrete was also studied. A squash load formula for CFT stub columns is proposed to account for the post-local-buckling strength of steel skin. The ultimate strength of steel skin was predicted by a kind of Direct Strength Method (DSM). The proposed DSM does not require the computation of the effective area of the steel skin, but uses the gross area of the steel skin and the design strength formula based on various test results. The compressive strength formula of the filled-in concrete accounting for the strength ratio of steel skin to filled-in concrete is also proposed to consider the increase in compressive strength of the filled-in concrete, due to the confining effect of the steel skin. The design strengths of CFT columns were compared with the test results for verification.

Introduction

The attractive way to solve the local instability and the low ductility of thin hollow steel tubes is filling them with concrete. The concrete-filled tubular (CFT) composite sections are being widely used as columns of high-rise buildings and bridge piers in recent years. Since the steel skin confines the filled-in concrete tri-axially and the concrete resists against the inward deformation of steel skin, both steel and concrete contribute to the strength enhancement of the CFT column.