Abstract
Many of the concrete utility poles used for the Shinkansen broke and collapsed by the Tohoku Region Pacific Coast Earthquake. The major factor of the critical damage that led to the collapse of these concrete utility poles was compressive failure of concrete resulting in brittle fracture. Based on clarification of past damage to concrete poles and the evolution of concrete pole design, a seismic reinforcement method was developed to prevent brittle failure of concrete utility poles by changing their structure from that of a PC utility pole structure to a steel enveloped RC pole structure with improved deformation performance. Toward practical application, the performance of the proposed design was evaluated with cyclic alternating positive-negative loading test, bending tests and shaking table tests using full-size concrete poles, and upon satisfactory results, seismic reinforcement work was conducted.
