Adjusting system for reaction force introduced in a girder under `push-out´ erection method based on the fuzzy theory

In the push-out erection, the bridge girders are pushed out in sequence, to the predetermined positions with accuracy so as to keep the specified longitudinal alignment and cross section profile and certify that no imbalance occurs in the reaction force at the supports. The girder reaction force is adjusted by means of a jack, and very often, the amount of correction is decided empirically or by trial and error. It was indispensable to establish an accurate jack reaction force adjusting method for reaction force errors, specially in erection of curved or multi-supported girders, and also to set up an efficient erection control system. Therefore, in the first phase of the present study an adjusting system for the reaction force, using the least squares method to minimize the jack adjusting amount of the reaction force was elaborated on a trial basis. In the second phase, profile errors were added to the control parameters and fuzzy theory was applied to make up a reaction force adjusting system for the sequential control of the jack adjusting amount due to reaction force and profile errors