Abstract:The (35+70+35) m variable cross-section continuous steel-concrete composite beam is used for Yinzhou Avenue across Nantang River. Due to the bridge deck easily cracked in the hogging moment area near the central bearing point of this bridge, the construction process of fulcrum jacking synchronously first and then falling back is adopted to make the bridge deck obtain the sufficient compressive stress reserve and improve the anti-crack performance of bridge deck. In order to ensure the engineering quality and construction safety, a finite element model of the bridge is established by using MIDAS Civil finite element software to simulate the construction process of the central bearing point jacking first and then falling back. And through the comparison, the reasonable jacking height of the central bearing point is determined. The calculation results show that the reasonable jacking height of central bearing point is 40 cm. The concrete bridge deck in the hogging moment area is compressed without the cracks under the frequent conditions. The minimum reaction force of the end support is 188.1 kN (without the support separation), which can meet the anti-crack requirements of variable cross-section continuous steel-concrete composite beam bridge deck.
