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J u n e 0 6 - 0 7 , 2 0 1 9
P a r i s , F r a n c e
Page 27 Research & Reviews: Journal of Engineering and Technology
ISSN: 2319-9873 Civil engineering 2019
International Conference on
Structural and
Civil Engineering Research
O ver the years, many methods have been proposed to strengthen reinforced
concrete beam-column joints (“BCJs”), e.g. by jacketing using different
materials. In buildings, strengthening will provide to have sufficient fire
resistance, minimum alteration to building plans, and minimum impact to the
environment, like dust and noise. It is the objective of this study to develop
a strengthening strategy for BCJs with the above in mind. It comprises
experimental studies to be completed in December 2018 and numerical
studies which will still be on-going. In this study, unsymmetrical chamfers are
proposed to enhance the joint shear capacity of BCJs. Chamfers are installed
on the soffit of beams and concealed by the false ceilings, i.e. no alteration
to building plans. Further, they can be constructed easily within one hour by
unskilled labours and are especially attractive for hospitals and fire-station
requiring minimum interruption of service. In the experimental studies, 17
BCJ specimens are tested to failure under progressive increase in cyclic
deformation. Structural configurations are based on typical BCJs commonly
found in Hong Kong. The specimens are at 2/3-scale and include interior BCJs,
exterior BCJs and BCJs with unequal column sections. It is well demonstrated
that, by developing compression chords in chamfers to resist the joint shear
force, joint shear strength is increased. Mode of failure is shifted from joint
shear failure to flexural failure in columns or beams. Numerical studies have
also been carried out using finite element models and micro-truss elements.
The former implements WCOMD, a non-linear finite element package for
reinforced concrete and the latter is based on a 4-node truss element developed
in this study. Performance of BCJs with chamfers is predicted numerically to
understand the load transfer mechanism. Parametric studies will be applied to
develop simple strut-and-tie model for the design of chamfers.
Biography
Siu-shu Eddie Lam has received his PhD in 1989 from the
University of Southampton, UK. He is an Associate Professor
in the Department of Civil and Environmental Engineering,
The Hong Kong Polytechnic University. He is a Fellow of
the Institution of Structural Engineers and the Hong Kong
Institution of Engineers, Registered Structural Engineer in both
Hong Kong and China, Member of the Institution of Mechanical
Engineers and a Barrister. His research interest is in Structural
Engineering and Earthquake Engineering.
An approach to strengthen reinforced concrete beam-column
joints by unsymmetrical chamfers
Siu-shu Eddie Lam, Zhihang Xue, Sohail Maqsood
The Hong Kong Polytechnic University, Hong Kong
Siu-shu Eddie Lam et al., JET 2019, Volume:8