Abstract:
Design of seismic resistant structures is based on the assumption that real structures yield when
subjected to design level ground acceleration. Assessment of seismic vulnerability of reinforced
concrete buildings in the earthquake prone regions is a challenging task. The traditional approach
to seismic design of a building is a force-based design. In this approach, there is no measure of the
deformation capability of a member or of a building. Structural failures of soft-storey structures in
recent earthquake have exposed the weakness of current design procedures and shown the need
for new concepts and methodologies for building performance evaluation to enable necessary
retrofit measures.
Pushover-based seismic evaluation is now able to directly calculate the nonlinear seismic demand
and evaluate its consequences on the structures. Applied Technology Council-40 (ATC-40), 1996
and Federal Emergency Management Agency (FEMA), 2002 proposed a simplified nonlinear
static analysis (Pushover Analysis) procedure. The central focus of the simplified nonlinear
procedure is the generation of the “Pushover” or Capacity curve. The nonlinear static (Pushover)
analysis has become increasingly popular in structural applications around the world. Numerical
tools like SAP 2000 developed by Computers and Structures Inc., which can perform the
pushover analysis.
In this thesis the main focus is to evaluate the seismic performance of soft storey structures
retrofitted with FRP wrap in the plastic hinge region. Structural deficiencies of the soft storey
buildings have been determined to demonstrate how their performance can be improved under
seismic action. Eight Soft-Storey Building models located at Dhaka city are studied by pushover
analysis using SAP 2000. The results obtained from analysis show that all the structures contain
seismic deficiencies and require seismic retrofitting.
Fiber reinforced polymer (FRP) composites have found increasingly wide applications in civil
engineering due to their high strength-to-weight ratio and high corrosion resistance. One
important application of FRP composites is as wraps or jackets for the confinement of reinforced
concrete (RC) columns for enhanced strength and ductility.
In this thesis, GFRP (Glass Fiber reinforced polymer) is considered for FRP wraps which is quite
expensive. However, additional cost involvement are estimated as per standard rates and found
within 0.49% to 3.75% of the total project cost for getting desired level of seismic performance as
per ATC 40 and FEMA 356.
