A proposal for the evaluation and design method of butt joint structure segment

Abstract

Recently, rapid assembling of segments and elimination of secondary tunnel lining are recommended. To satisfy these requirements, we have developed a new type reinforced concrete segment called “QB segment” which is bolt less type and flat shape inner section.
The longitudinal joints of QB segment are not connected. The joints are simply butted; therefore erection time can be reduced.
We intended to adapt the design method of segment using beam-spring model tosimplify the calculation. The studies are executed by comparing tests results, theories and analyses, based on axial force parameter, using a full-scale flat segment.
The study reached to the proposal that beam-spring model functions inaccordance with axial compression stress, reducing the rotation spring ratio calculated by Betongelenke formula.