Three dimensional non-linear dynamic response of reinforced concrete columns under multi-directional seismic actions | |
| Author | Tuladhar, Roshan |
| Call Number | AIT Thesis no.ST-98-09 |
| Subject(s) | Columns, Concrete Structural dynamics Earthquake hazard analysis |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | The arbitrary orientations of the cross-section of a column impart different base motions even under the same earthquake. The input principal directions of base motion are altered. Is the effect significant for seismic performance design? To answer the question three-dimensional nonlinear analytical tool named COM3, which is capable of simulating the reinforced concrete behavior under reverse cyclic loading, is used. The 1995 Kobe earthquake record of 3D ground accelerations recorded at the Kobe Observatory is used for the simulation of the ground motions. This study is done basically with a cantilever column, 30cm * 60 cm * 220-cm. Multi-directional ground motion is achieved by rotating the cross section at 15° intervals: 0° through 90° both in clockwise and counterclockwise directions with respect to the recorded East-West axis. The material constants and the control parameters governing the computational mode are kept constant throughout the study. Basically two types of analysis is performed. namely Compression failure analysis based on the compressive strain of the extreme compression fiber and the Deflection ratio analysis based on the concept of ratio of maximum introduced deflection and the defined yielding deflection, both considered along the same direction. Analyzes were performed at the constant axial stress level. Out of the twelve different directions, under high axial stress level, the two directions corresponding to the 30° and 45° clockwise rotations could not attain the compressive strain level of 1 %, whereas the others could. Appreciably higher deformation along the weak axis is found to induce appreciably higher down deflection along with compression failure. The time average of vector norm of deflection vector was used to quantify the directional severity. The failure analysis is also performed for the square section with the same amount of reinforcement. The marked directional effect, as in the case of rectangular section, is not available in the symmetrical square section. Deflection ratio of .the rectangular column was found to vary between 2.5 and 9.0 that indicates the wide extremes of the multi-directional effect. The deflection ratio analysis agrees quite well with the compression failure analysis. |
| Year | 1998 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Kishi, Toshiharu; |
| Examination Committee(s) | Worsak Kanok-Nukulchai;Gupta, Satyendra P.;Pennung Warnitchai;Wijeyewickrema, Anil C.; |
| Scholarship Donor(s) | Government of Japan; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1998 |