Experimental study on axial compressive capacity of oil-filled steel pipe

Research on steel pipe reinforced concrete has advanced significantly, yet its role in construction still requires more exploration. This study examines a new type of structure similar to steel pipe concrete columns, known as Oil-Filled Steel Pipe (OFST), which consist of circular steel tubes filled with anti-wear hydraulic oil. Despite being a derivative of steel, there is limited global research on these columns, with most studies focusing on their use in mechanical devices rather than as structural elements in buildings. Therefore, investigating OFST is highly relevant. This paper evaluates their axial compressive load capacity and analyzes steel pipe concrete structures to enhance understanding. Findings show that both the length and slenderness ratio of the columns significantly affect their load-bearing capacity, with increases in either reducing capacity. Additionally, a higher diameter-to-thickness ratio decreases axial pressure-bearing capacity, indicating that thicker walls enhance the load-bearing capacity. Notably, OFST have a higher load-bearing capacity than empty steel pipes when there is no internal pressure, but internal pressure reduces this capacity.