DYNAMIC STABILITY IDENTIFICATION OF A FULL-SCALE TAINTER-GATE AND EXTENSION OF GATE-OPENING RANGE FOR OPERATION

摘要

To assure the complete stability and long-term safe operation of the large number of Tainter gates used worldwide, an effective method of distinguishing those gates susceptible to instability from unsusceptible gates is essential. This paper presents a case study of the dynamic stability identification of an operational Tainter gate in Japan, based on field vibration testing using steel-rod breaking excitation. First, an overview of the field vibration test and the in-water natural vibration characteristics of the gate is presented. The dynamic stability of the gate was identified from the test results in conjunction with our previously developed theoretical analysis. From the specific test data for a limited number of operating conditions, our theoretical analysis permits assessment of the dynamic stability of the gate for all operating conditions. In particular, the dynamic stability of the gate for small gate openings was confirmed, and subsequently validated by long-duration ambient excitation tests with very small gate openings. This study was the first attempt at operating the gate at openings smaller than the conventional minimum recommended opening. As a result, not only did the field test validate the gate's reliability for long-term operation, but it also permitted an extension of the gate-opening range for operation.