Ultimate Bearing Capacity of Pile Caps Comprising Concrete‐Filled Dual Steel Tubes

ABSTRACT The construction of building foundations requires substantial time and effort, particularly in fabricating reinforced concrete footings and foundation beams. To address these challenges, this paper proposes a novel structural system that utilizes steel structures for the foundation beams and reinforces pile heads with double steel tubes. Loading tests were conducted to assess the influence of various factors. The applicability of existing evaluation equations is examined to highlight the need for a new prediction formula. As a result, this paper proposes an evaluation equation for the ultimate bearing capacity and a constitutive law to predict the behavior under compression forces.