압출가설시 발생하는 상부구조의 휨모멘트 해석식

Abstract

ILM (incremental launching method) has been acknowledged as the pre-stressed concrete bridge engineering method efficient to ensure quality. The superstructure of the bridge constructed by this method is temporarily located on the center of the span and the supporting points under construction. Therefore, the sections are structurally undergone maximum positive moment, maximum negative moment, and maximum shear force arising from self weight. And, a launching nose is generally used to minimize high stress creating temporarily during launching. The magnitude of this temporary stress creating on the upper section is dependent upon the launching nose’s characteristics. This study has proposed an analysis formula simplified on the assumption that the launching nose section is a quasi-equivalent section (rigid; equivalent section, weight; tapered section) in order to ensure the accuracy of the analysis formula and improve its usage with reference to the interaction between the launching nose and the upper section; and a prismatic analysis formula modified by displacing a diaphragm’s weight by a concentrated load in order to improve the accuracy of the existing analysis formula that assumes the launching nose section as the equivalent section. To judge the accuracy and usage of two analysis formulas proposed, we have compared and analyzed computational structural analysis programs and existing analysis formulas based on actual ILM bridge data. As a result, all of two reveal the superior accuracy and also their usage has been improved by the simplification of analysis formulas.