SangHoon Oh's scientific contributions

The quantitative damage index considering structural types are essential for the effective post-earuthquake safety evaluation. This paper is the fundamental research in order to present the quantitative damage index for reinforced concrete members with non-seismic details. The crack width changes related with seismic response were studied based on the static test results of one-span and -story specimen with non-seismic details. According to the test result, cracks mostly occurred on the beam-column joints and the upper- and lower- part of columns. The flexural crack width on the column end section and shear crack width on the upper column were widely opened by loading. The residual crack widths were also getting larger since yielding of reinforcements. Meanwhile, the maximum residual crack width was lower than the 1/2-fold of the maximum crack width before yielding, and got the 1/6- and 1-fold of the maximum crack width after yielding.

In this paper, the novel retrofitting method using metal laths and steel plates for unreinforced masonry(URM) walls was presented, and the seismic retrofitting effects of URM walls were evaluated by the static test. The main variables were the presence of openings, and the application of the novel retrofitting method. The test results showed that the strengths of the retrofitted specimens became 1.27~2.51 times higher than those of the non-retrofitted specimens irrespective of whether there were openings or not. The ductilities of the retrofitted specimens were also 1.21~2.28 times higher than those of the non-retrofitted specimens. In the case that the steel plate for retrofitting located at the upper and lower end of a specimen was additionally fixed to the loading frame, the strength and ductility were even higher. Meanwhile, the specimens retrofitted by the novel method showed the highest energy dissipation capacities, and the metal lathes were considered to be very effective on dissipating energy.