Damage Detection in Concret Filled Tube Column Based on Exper-imentally Modal Data and Wavelet Technique

Document Type: Research Paper


1 Semnan University

2 Ph.D. Student, Department of Civil Engineering, Semnan University, Semnan, Iran

3 Department of Civil Engineering of semnan University, Semnan, Iran

4 Department of Maritime Engineering



Damage detection in Concrete-Filled Tubes (CFST) and its application in special structures such as high rise buildings, towers and bridges is important. CFST columns are widely considered by researchers and engineers due to the simultaneous utilization of steel and concrete proper-ties. Hence, any damage to this structural element may result in more serious and irreparable damages. Accordingly, identification of a particular type of damage that may be due to the buck-ling of a steel tube plate has been performed in this study. Since the buckled part in the column goes out of the system or its bearing capacity significantly decreases, in order to simulate the damage in this study, a part of the CFST column steel wall was cut off and since it's more likely to occur in the middle of the column, damage has been located in the middle of the column. After making the specimen and performing the test, the modal data has been extracted and has been called in MATLAB software and analyzed with the aid of the wavelet transform tool. The results show that the frequency is reduced and the mode shape of the specimens does not match com-pletely before and after the damage (Modal Assurance Criteria(MAC)), which indicates the dam-age in the specimen. To identify the location of the damage, the mode shape obtained from the modal experimentally has been given to the wavelet transform as the input signal and Daubechies (Db) wavelet has been applied that correctly identifies the location of the damage.