A circular cross-section resist the forces exerted on the structure more during an earthquake because a circular column section can distribute external force as well as axial load to all the direction where the rectangle section can distribute only two sides at a time. So by this way it can withstand more forces during earthquack.

Circular cross-section steel columns are more earthquake-resistant because their shape provides equal strength and stiffness in all directions, reducing weak points and stress concentrations. This symmetry allows them to transfer seismic forces evenly, minimizing bending and torsional effects. Their smooth surface also reduces stress risers, making them more resistant to buckling and failure under dynamic loads.

Hamed Ahmadi

This is due to their inherent geometric and material advantages. The symmetrical shape of circular columns ensures uniform resistance to multidirectional forces, which is critical during seismic events where ground motions generate complex, oscillating stresses. Unlike rectangular or H-shaped sections, circular columns lack weak axes, allowing them to distribute stress evenly in all directions. This symmetry minimizes localized stress concentrations, reducing the risk of buckling or plastic deformation under cyclic loading. Additionally, the absence of sharp edges or corners in circular sections prevents stress accumulation at specific points, further enhancing their ability to absorb and dissipate energy.This is due to their inherent geometric and material advantages. The symmetrical shape of circular columns ensures uniform resistance to multidirectional forces, which is critical during seismic events where ground motions generate complex, oscillating stresses. Unlike rectangular or H-shaped sections, circular columns lack weak axes, allowing them to distribute stress evenly in all directions. This symmetry minimizes localized stress concentrations, reducing the risk of buckling or plastic deformation under cyclic loading. Additionally, the absence of sharp edges or corners in circular sections prevents stress accumulation at specific points, further enhancing their ability to absorb and dissipate energy. Another key factor is the torsional resistance provided by circular cross-sections. Earthquakes often induce twisting forces in structural members, and the uniform distribution of material around the central axis of circular columns improves their capacity to resist such torsional effects. This contrasts with prismatic shapes, which may experience uneven torsional stiffness depending on the direction of the applied force.

Ductility is also amplified in circular steel columns. The continuous curvature of these sections promotes smoother plastic hinge formation without abrupt failure. Furthermore, circular hollow sections often exhibit higher resistance to local buckling compared to open sections like I-beams, as their closed shape provides additional confinement to the material.

You could also take a look at this research paper: https://doi.org/10.29322/ijsrp.14.10.2024.p15429