Behzad Rafezy, PhD, PE
Director of Research & Development, SidePlate Systems, Inc. USA
Title: Seismic Lessons from the Full-Scale Testing of SidePlate, an Innovative Steel Moment Frame Connection
Biography
Biography: Behzad Rafezy, PhD, PE
Abstract
An innovative special moment frame connection using the SidePlate moment connection technology was developed and tested at the Powel Laboratories at the University of California, San Diego (UCSD). This connection uses two interconnecting parallel plates that sandwich and connect the beam(s) to the column and features a physical separation, or gap, between the face of the column flange and the end of the beam, as shown in Figure 1. The load is transferred from the beam to the column through a series of connecting plates and angles all of which are welded in the shop and then bolted in the field. The tested connections comprised of Wide-flange, Built-up Box and HSS (Tube) Columns and rolled and built-up wide-flange beams with three different configurations, namely Standard, Narrow and Tuck. The test specimens were loaded in a displacement control mode using hydraulic actuators in accordance with the Chapter K of the AISC 341-16, Seismic Provisions for Structural Steel Buildings. Tested connections exhibited predictable, ductile behavior and met the established AISC’s requirements for special moment frame (SMF) connections with average 50% additional deformation capacity.
The following techniques were employed and lessons were learned in the development of the connection and the successful conduction of the tests:
1. The panel zone regions are substantially strengthened to force plastic hinging into the beam.
2. The additional side plate extensions cause the beam to hinge further out from the column face, which acts to effectively dissipate more energy without increasing the beam size.
3. The configuration requires only welds parallel to the direction of load providing maximum possible ductility in the welds.
4. Substantial finite element analyses were conducted to optimize weld hold-backs and weld-end profiles to reduce stress concentration at the points of load transfer from the beam to the connection. This results in a balanced and smooth load transfer according to the test results.
5. Only fillet welds are used in the configuration, ensuring that there is no notch effect in the root of the welds.
6. Every detail in every part of the connection was thoroughly studied to make sure that there is neither a high triaxial stress state nor notch effects.
Thorough finite element analysis is conducted if there are any changes or new features to the specification/construction of the connection.