Nonlinear FE Investigation of HSS Column Base Plate Connection: Fid-Bau Portal

Nonlinear FE Investigation of HSS Column Base Plate Connection

Mahbub, Haisam Bin / Amanat, Khan Mahmud

The column base plate is a vital component in steel structures as it is responsible for transferring and distributing the entire load from the superstructure to the foundation. This connection plays a critical role in transferring both lateral and axial loads to the underlying foundation system. Any failure in this connection can cause the entire structure to collapse. However, the current design guidelines provided by AISC Steel Design Guide One have some limitations such as the provided formulations compute an average value of tensile forces for all the tension bolts and do not provide methods to determine the tension bolts in an inner row of bolts. To overcome these limitations, this research aims to investigate the response of base plate connections with hollow steel section (HSS) columns under lateral loading with the aid of finite element analysis. The objective is to address the limitations of the design guideline and to observe the actual tension distribution in the bolts. A Nonlinear Finite Element Model has been developed in ANSYS and validated using previous experimental data, demonstrating its accuracy and reliability. Comparative studies have been conducted, comparing base plates with different thicknesses and two anchor rod layout patterns. The numerical findings from the model are compared with the experimental evaluations proposed in previous studies. Additionally, the role of anchor rods in resisting tension is examined. Studies conclude that for thicker base plates, a linear relationship can be established between numerical and experimental findings. In base plates with low thickness, an increase in column deflection results in a higher contribution of anchor rods in resisting tension. In addition, it is observed that for a given base plate thickness, the ratio of tension force resisted by inner rods to outer ones is higher for an eight-rod layout compared to a twelve-rod layout. Overall, this research provides insights into the behavior of base plate connection with HSS column and discusses methods to address the limitations of existing guidelines. The findings contribute to enhancing the safety and reliability of steel structures by improving the understanding of base plate behavior and optimizing their design.