Axial local compressive behavior of reinforced concrete-filled stainless steel tubular column piers

Abstract

In offshore structures, stainless steel structures are widely used in recent years. This paper presents an experimental and numerical study on carbon steel reinforced concrete-filled stainless steel tubular columns, which is defined as CFSCT (concrete-filled stainless‑carbon tubular) stub columns, under local compression. A total of 25 specimens were tested, the effects of outer tube thickness, concrete strength, local compression ratio and shape of bearing block on the local compression performance were studied. The advantages of CFSCT specimens over conventional design schemes were discussed. FE models were established to verify the experimental results. Parametric study was conducted to consider a wider range of geometric and material properties. The results indicate that with the increase of β, the stiffness of the specimen decreases and the deformation performance increases. When local compression ratio β = 2.25, increasing outer tube thickness and concrete strength results in an improvement in bearing capacity of 21.0% and 9.6%, respectively. When β = 9, increasing the thickness and strength of inner tube proves to be more effective, resulting in the highest increasement of 81.6% and 108.7%, respectively. The shape of bearing block has little impact on the bearing capacity. Under the same steel ratio, SI values of CFSCT specimens are 28.8% and 141.7% higher than those of CFSST specimens at β = 2.25 and 9, respectively. Finally, the bearing capacity results were further compared with current design codes, and equations of evaluating local bearing capacity were proposed, which shows good agreement with experiment results.