Experimental Evaluation of a Rocking Damage-Free Steel Column Base with Friction Devices

Abstract

The paper presents the experimental evaluation of an earthquake-resilient rocking damage-free steel column base, previously proposed and numerically investigated by the authors. The column base uses post-tensioned high-strength steel bars to control its rocking behavior and friction devices to dissipate seismic energy. It is equipped with a circular steel plate with rounded edges, which is used as a rocking base. The rounded edges prevent stress concentration and damage of the contact surfaces, while the circular shape allows rocking towards all plan directions. Contrary to conventional steel column bases, the proposed column base exhibits monotonic and cyclic moment-rotation behaviors that are easily described by analytical equations. The latter allow the definition of a step-by-step design procedure, which ensures damage-free behavior, selfcentering capability and energy dissipation capacity for a target design base rotation. The experimental tests are conducted under monotonic and cyclic loads demonstrating the damage-free behavior even under large rotations. Then, the experimental results are used to validate the design procedure and to calibrate refined 3D nonlinear finite element models in ABAQUS that will allow further investigations.

Design and analysis of a seismic resilient steel moment resisting frame equipped with damage-free self-centering column bases

“…These configurations allowed the achievement of superior behaviour under loading in the column strong-axis direction, while damage and stiffness degradation were observed under loading of the column in the weak-axis direction. [32] presented and experimentally investigated [33] a rocking damage-free steel CB equipped with FDs and high-strength steel PT bars. Non-linear dynamic analyses were carried out showing the potential of the CB in preventing the first-floor column yielding and in eliminating residual deformations in steel MRFs.…”

Seismic Performance of Steel MRFS Retrofitted With Brbs: Influence of the Design Decisions for the Devices

“…Finally, the third retrofit scheme (R-C) aims at avoiding damage in the MRF; therefore, the roof displacement is limited to the step at which any of the MRF elements overpasses the IO PL, based on the AC defined by the ASCE 41-17 [14]. Nowadays, there is considerable interest in the definition of seismic-resilient structures (e.g., [11,21,22]) and this third retrofit option aims at limiting the damage to the BRBs only at the CP PL hence allowing an easy and quick repairability of the structure. Table 1 The design process is carried out by considering an equivalent Single-Degree-of-Freedom (SDoF) system approximation [23], based on the bi-linearised (system base shear vs. roof displacement) capacity curves from the original bare frame, with an initial stiffness (k0) equivalent to the ratio between the 60% of the maximum base shear (Fu), and its corresponding roof displacement.…”

Effective placement of self‐centering damage‐free connections for seismic‐resilient steel moment resisting frames

“…Furthermore, it has been shown that protecting column bases (CBs) from damage is an essential requirement for seismic‐resilient structures. To this scope, several research studies proposed and investigated the use of SCDF connections in CBs 27–30 . Freddi et al 27,28 .…”