Sanghyun Choi

Seismic Repair of Damaged RC columns with Steel and CFRP Jackets

In this paper, the comparative performance of repaired RC columns using steel and CFRP is presented. Also, the effect of transverse reinforcement ratio on the behavior of the steel and the CFRP repairing is investigated. Monotonic and cyclic load tests are conducted on nine RC column specimens with different repairing strategies and transverse reinforcement ratios to compare the load-displacement curves and the hysteretic behaviors. From the tests, it is observed that both steel and CFRP jacket repairings can significantly increase the displacement ductility and the ultimate load capacity of damaged columns.ࠀĀࠀ會Āࠀぅ?⨀꣈Ā᐀會Ā᐀衅?⨀჈ༀĀ저會Ā저?⨀鎝Ā᐀會Ā᐀㡆?⨀衬鎝Ā᐀會Ā᐀遆?⨀偮鎝瀀ꀏ會Ā?⨀꣈Ā᐀會Ā᐀䁇?⨀偒悗Ā㰀會Ā㰀顇?⨀悗Ā㈀會Ā㈀?⨀聓悗଀Ā᐀會Ā᐀䡈?⨀ᡔ悗Ā᐀會Ā᐀ꁈ?⨀끔悗ကĀ저會Ā저?⨀䣆Ā저會Ā저偉?⨀Ā저會Ā저ꡉ?⨀磇

Parameter Identification Using Static Compliance Dominant Frequencies

This paper presents an improved system identification methodology for structural systems by applying static compliance dominant (SCD) frequencies. The existing sensitivity-based system identification technique is extended to adopt the static compliance dominant frequencies, and the performance of the additional spectral information, i.e., SCD frequencies, is compared with that of the natural frequencies only via a numerical example of a mechanical system. The results of the numerical study indicate that the additional use of the SCD frequencies improves accuracy in system identification problems.

Nondestructive Damage Identification in a Truss Structure Using Time Domain Responses

In this paper, an algorithm to locate and size damage in a complex truss structure using the time domain response is presented. Sampled response data for specific time interval is spatially expanded over the structure to obtain the mean train energy for each element of the structure. The mean strain energy for each element is, in turn, used to build a damage index that represents the ratio of the stiffness parameter of the pre-damaged to the post-damaged structure. The validity of the methodology is demonstrated using data from a numerical example of a space truss structure with simulated damage. Also in the example, the effects of noisy data on the proposed algorithm are examined by adding random noised to the response data.