

Title of Thesis
Study Of Energy Dissipation Capacity Of RC Bridge Columns Under
Seismic Demand 
Author(s)
SYED MOHAMMAD
ALI 
Institute/University/Department
Details Department of Civil Engineering / N.W.F.P.
University of Engineering and Technology, Peshawar 
Session 2009 
Subject Civil Engineering 
Number of Pages 275 
Keywords (Extracted from title, table of contents and
abstract of thesis) Study, Energy, Dissipation,
Capacity, RC Bridge, Columns, Seismic, Demand, concrete piers, quasistatic tests 
Abstract Field studies were
carried out to investigate various parameters of bridges found in
northern part of Pakistan. After the large Kashmir earthquake of
Mw7.6 in 2005, detailed field investigations to study the seismic
performance of bridges was also undertaken. A mathematical function
to define the functionality of bridges was developed which is
helpful for quantifying the seismic resilience of bridges. Criterion
for minimum required functionality for different bridges and limit
states were defined for extremely large rare earthquake and for
moderate occasional earthquakes. From the field data, typical
parameters of reinforced concrete bridges were established. A series
of experimental studies were undertaken in the laboratory on four
scaled models of a typical bridge that consists of pier having
single column. The pier column was of low strength concrete with
solid circular cross section. The objective of the study was to
experimentally determine the energy dissipation capacity of low
strength concrete piers. Two types of tests were done on the four
bridge piers: quasistatic cyclic tests and free vibration tests
before, during and after the quasistatic tests. From the
experimental results on four scaled low strength bridge piers
damping was seen to decrease with increase in damage, natural period
of piers doubled near failure, energy degradation was seen to be
more in low strength piers. Energy based strength degradation and
pinching is predominant in low strength concrete piers along with
large permanent deformations. Response modification (R) factors
based on natural period of bridge are found to better represent the
energy dissipation and are accordingly proposed. The values of
Rfactor calculated for low strength concrete piers are lower than
AASHTO LRFD 2007 thus more conservative. The fragility curves
plotted for the bridge columns indicate that for peak ground
accelerations (PGA) of seismic Zone 3 and above of the seismic
hazard map of Pakistan (for 475years return period) pushes the
bridge in to damage state that is allowed for large earthquakes only
(with return period of 2,500 years) Mathematical function for the
quantification of seismic resilience of bridges is proposed for the
first time. It is demonstrated that using the general guidelines of
AASHTO LRFD 2007 quantification of seismic resilience is possible.

