ABSTRACT
Figure 1(a) shows an SC-MRF with PT-WFD beamto-column connections. The PT strands run parallel to the beams across multiple bays. The WFD, shown in Figure 1(b), includes two channel sections (referred to as friction channels) welded to the column flange. Brass cartridge plates are sandwiched between the webs of the friction channels and beam to enable reliable friction to occur at their interface. The channels are clamped to the beam web by tightening the friction bolts shown in Figure 1(b) to produce the normal force on the friction surface. The friction channels are welded to the column flange after the friction bolts are tightened. The shape of the friction channels is selected to reduce the effect of weld shrinkage on the normal force to the friction surface. The shim plates shown in Figure 1(b) are welded to the column face to provide good contact surfaces for the beam flanges. Slotted holes are used in the beam web to accommodate the travel of the friction bolts during gap opening and closing of the connection that is discussed later. Reinforcing plates welded on the
1 INTRODUCTION
Conventional moment resisting frames (MRFs) are designed to dissipate energy under the design earthquake by developing yielding and associated damage in critical regions of the main structural members. This damage can result in large residual drift after the earthquake. To avoid large residual drift, posttensioned (PT) beam-to-column connections for self-centering moment-resisting frames (SC-MRFs) were developed by Ricles et al., [2001]. These connections are designed to develop a gap opening at the beam-column interface. The PT force enables the connection to self-center upon unloading. Energy dissipation occurs in special devices designed for the beam-column connection regions.
