- مبلغ: ۸۶,۰۰۰ تومان
- مبلغ: ۹۱,۰۰۰ تومان
Embedded Column Base (ECB) connections are commonly used in mid- and high-rise steel moment frames, to connect the steel column to the concrete footing. Although recent research has shown these connections to be highly ductile, they are typically designed to be stronger than the adjoining column, resulting in significant cost. To enable assessment of strong-column-weak-base systems that leverage the inherent ductility of these connections, an approach is presented to simulate their hysteretic and dissipative response. The proposed approach simulates ECB connections as an arrangement of two springs in parallel, to reflect moment contributions due to horizontal and vertical bearing stresses. This is informed by recent work that provides physical insight into the internal force transfer within these connections. The springs’ response is defined by the pinched Ibarra-Medina Krawinkler (IMK) hysteretic model, which is able to capture both in-cycle and cyclic degradation in strength and stiffness. The model is shown to reproduce the response of ECB connections with reasonable accuracy. Guidelines to calibrate model parameters are presented; these include physics-based estimation of selected parameters such as strength and stiffness, accompanied by empirical calibration of ancillary parameters associated with cyclic deterioration. Limitations are discussed.
Summary, recommendations, and limitations
This paper presents an approach to simulate the hysteretic response of embedded column base (ECB) connections that are commonly used to connect columns in Steel Moment Frames to concrete footings. Conventionally, these are designed to remain elastic during seismic shaking – this is because as connections, they are implicitly assumed to be less ductile than the adjoining column. As a consequence, previous research has focused mainly on their elastic stiffness and yield strength. However, recent work indicates that these connections may be highly ductile and disregarding their deformation capacity in design results in expensive detailing, which is required to make them stronger than the column. However, no modeling approaches are available to simulate the post-yield dissipative or hysteretic response. As a result, the response of frames with dissipative ECB connections cannot be investigated with confidence. This hinders performance assessment of such frames, ultimately precluding the development of design guidance. Motivated by this, the paper presents a method to simulate the hysteretic response of ECB connections, along with guidelines to calibrate the requisite parameters.