Assessing the Seismic Performance of Threaded Rebar Coupler System
Currently there are many use of threaded reinforcing
bars in construction fields because those do not need additional screw
processing when connecting reinforcing bar by threaded coupler. In
this study, reinforced concrete bridge piers using threaded rebar
coupler system at the plastic hinge area were tested to evaluate seismic
performance. The test results showed that threads of the threaded rebar
coupler system could be loosened while under tension-compression
cyclic loading because tolerance and rib face angle of a threaded rebar
coupler system are greater than that of a conventional ribbed rebar
coupler system. As a result, cracks were concentrated just outside of
the mechanical coupler and stiffness of reinforced concrete bridge pier
decreased. Therefore, it is recommended that connection ratio of
mechanical couplers in one section shall be below 50% in order that
cracks are not concentrated just outside of the mechanical coupler.
Also, reduced stiffness of the specimen should be considered when
using the threaded rebar coupler system.
Reinforced concrete column, seismic performance,
threaded rebar coupler, threaded reinforcing bar.
Research for Hollow Reinforced Concrete Bridge Piers in Korea
Hollow section for bridge columns has some
advantages. However, current seismic design codes do not provide
design regulations for hollow bridge piers. There have been many
experimental studied for hollow reinforced concrete piers in the world.
But, Study for hollow section for bridge piers in Korea has been begun
with approximately 2000s. There has been conducted experimental
study for hollow piers of flexural controlled sections by Yeungnam
University, Sung kyunkwan University, Korea Expressway
Corporation in 2009. This study concluded that flexural controlled
sections for hollow piers showed the similar behavior to solid sections.
And there have been conducted experimental study for hollow piers of
compression controlled sections by Yeungnam University, Korea
Institute of Construction Technology in 2012. This study concluded
that compression controlled sections for hollow piers showed
compression fracture of concrete in inside wall face. Samsung
Construction & Trading Corporation has been conducted study with
Yeungnam University for reduce the quantity of reinforcement details
about hollow piers. Reduce the quantity of reinforcement details are
triangular cross tie. This study concluded that triangular reinforcement
details showed the similar behavior as compared with existing
Hollow pier, flexural controlled section, compression
controlled section, reduce the quantity of reinforcement details.