耐震補修を施された鉄筋コンクリート構造物の地震応答と耐震性評価に関する研究

京都大学0048新制・論文博士博士(工学)乙第8165号論工博第2694号新制||工||911(附属図書館)UT51-93-F265(主査)教授 山田 善一, 教授 藤井 學, 教授 渡邊 英一学位規則第4条第2項該当Doctor of EngineeringKyoto UniversityDFA

Three-Dimensional Response Spectra for Multiple-Support Input Motions

New response spectra for multiple-support input motions are presented to study the seismic responses of long-span bridges. Three-dimensional response spectra are defined using the response of simple beams with various natural periods. These spectra clearly verify the dominant vibration mode and the critical location of the maximum response. Numerical examples using the earthquake records observed by a newly-installed array at the Akashi Kaikyo bridge construction site in Japan show that the different input motions to each support produce different predominant vibration modes compared with the identical excitation case. It has also been observed that response usually decreases when multiple-support input motions with phase lags are considered. The ordinary response spectra method is also examined and it has been found that the approximated values using the RMS method overestimated the maximum response

Seismic Damage Assessment of RC Structures using Different Hysteretic Models

Estimation of seismic damage of a structure varies depending on the assumed hysteretic rules and input excitations due to indices being calculated from earthquake response time histories. In this study, effects of the different hysteretic models on damage indices were studied. First, the response of RC bridge piers during earthquakes was calculated using different hysteretic models and input motions. Then, seismic damage was evaluated by 1) a damage index based on a linear combination of the maximum deformation ratio and the energy dissipation during cyclic loadings, and 2) damage spectra of damage index, ductility and absorbed hysteretic energy for structures with various natural periods. Results showed that the non-degrading maximum value directed model was accurate enough for seismic damage analysis while the bilinear model underestimated damage because of its linear response to the low intensity cyclic loadings. The maximum value directed model was also needed to predict the damage index from the maximum velocity or the spectral intensity of the input motions