Estimation of Optimal Opening Rate of Rahmen Bridge with Open Wall through Moment Analysis of Corner

Abstract

The earth pressure acting on the wall of a Rahmen bridge generates significant bending moments at the corners. These moments create problems in the wall in terms of stability and economy. In this study, a Rahmen bridge with an open wall was adopted to solve the problems highlighted above, and its optimal opening rate was estimated. Structural analysis was performed for 36 analytical cases by applying the limit state design method according to lengths of 20 and 15 m for the closed height ratio (h/H) and closed width ratio (b/B) of the wall. Within the scope of this study, in the Rahmen bridge with a 20 m span, it is desirable to design an open wall to satisfy the 0.4 ≤ h/H ≤ 0.614 and 0.75 ≤ b/B < 1 conditions when adequate reinforcement is provided at the wall end in contact with the haunch. Additionally, an open wall should be designed for the 15 m span Rahmen bridge to satisfy the conditions of 0.229 ≤ h/H ≤ 0.586 and 0.833 ≤ b/B < 1 when suitable reinforcement is provided at the slab end in contact with the haunch. Therefore, the Rahmen bridge with an open wall can be used instead of the conventional Rahmen bridge, considering the economy and on-site applicability factors.