Eccentric compression behavior of steel reinforced UHPC columns: Experiments and analysis

To study the eccentric compression performance of steel reinforced ultra-high performance concrete (UHPC) columns, static tests were conducted on six specimens under vertical loading. The tests compared the effects of factors such as eccentricity, steel ratio, slenderness ratio and longitudinal reinforcement ratio on the eccentric compression performance of specimens The results indicate that due to different eccentricities, five specimens exhibited large eccentric compression failure while one specimen experienced a small eccentric compression failure. An increase in the steel ratio and longitudinal reinforcement ratio enhances the peak load-carrying capacity of the specimens. However, an increase in eccentricity and slenderness ratio resulted in a reduction of the peak load-carrying capacity. Based on the experimental results, a finite element model for the eccentric compression of the specimens was established. A parameter analysis was conducted to extend the analysis of influencing parameters such as UHPC strength, steel strength, eccentricity, steel ratio, longitudinal reinforcement ratio and slenderness ratio. One factor at a time method was used to expand the number of parameter analysis results. Considering the effects of the steel ratio and UHPC strength, the eccentricity increase coefficient was established using the results from the expanded parameter analysis. Furthermore, based on reasonable assumptions, a calculation formula for the bearing capacity of steel reinforced UHPC columns under large eccentric compression was proposed. The predicted results showed good agreement with experimental and FE simulation values. The findings of this study provide theoretical guidance for the design and application of steel reinforced UHPC columns. • Tests were carried out on six steel reinforced UHPC columns under vertical eccentric loading. • Five steel reinforced UHPC columns suffered large eccentric compression damage and one experienced small eccentric compression damage. • Based on the FE analysis, the calculation formula of the eccentricity increase coefficient was proposed. • The calculation method of the normal section bearing capacity of steel reinforced UHPC columns with large eccentricity compression was established.