In the aftermath of the 1994 Northridge earthquake, extensive field in
vestigations revealed damage in wood frame construction in the form of
splitting of the 2 x 4 or 2 x 6 wood sill plates along the line of an
chor bolts that typically connect shear walls to the masonry or concre
te foundation. Due to the severity of such brittle failures, the city
of Los Angeles has recently restricted the use of 2X dimension lumber
in sill plates and requires the use of 3X dimension lumber. This paper
presents an experimental investigation of the performance of 2X dimen
sion lumber sill plate connections at the yield and ultimate Limit sta
tes during incremental quasi-static reversed cyclic loading and sugges
ts possible cost-effective retrofit strategies for their improved seis
mic performance without having to increase the sill plate thickness. P
roposed retrofit strategies are based on providing confinement to the
sill plate using metal reinforcing straps and reinforcing clamps to in
crease the deformation capability and energy dissipation capacity of t
he connection, while maintaining substantial levels of connection stre
ngths.