Proceedings of 3rd International Civil Engineering and Architecture Congress, Türkiye, 12 Ekim 2023
Purpose: Reinforced concrete (RC) buildings are significant
engineering structures that must withstand various static and dynamic loads, as
well as environmental effects, over their operational lifespan. These
structures are vulnerable to damage or complete loss of their load-bearing
capacity due to two primary dynamic loads: earthquakes and fires. This study
aimed to explore the combined effects of fire and earthquakes that could
potentially lead to structural damage. In this study, the structural behavior
of a RC plane frame model with a history of fire exposure and subjected to
varying levels of earthquake effects was investigated experimentally.
Study design/methodology/approach: This
study primarily encompasses the construction of the experimental model, subjecting
the model to fire testing and conducting a series of shake table tests on the
fire-damaged model. Throughout the experimental process, following each event
that could lead to alterations in the construction of the model and its structural
behavior, Experimental Modal Analysis (EMA) measurements were conducted to
determine the dynamic
characteristics of the model. The
assessments were made based on the changes observed in the dynamic
characteristics of the model.
Findings: After the fire, the natural frequency values of the
first three modes of the structure significantly decreased. The decrease in
frequency values continued cumulatively with increasing earthquake damage to
the fire-damaged experimental specimen placed on the shaking table. Ultimately,
reductions of 54.48%, 64.73%, and 76.69% were observed in the 1st, 2nd, and 3rd
modes of the model, respectively.
Originality/value: Significant changes in the dynamic characteristics of
a structure indicate potential structural damage. The EMA method yields highly
effective results for the prediction and detection of damage that may occur in
the structure. The study outcomes emphasize the importance of interventions
aimed at preparing a structure, exhibiting weaknesses due to fire-related
factors to be resilient against seismic events.