What is balanced cantilever method in bridge construction?

Balanced cantilever method is also called hanging basket method. It uses movable suspended scaffolding (hanging basket) to pour concrete symmetrically from two ends to their respective middle span at the same time and impose pre-stressing force.

It demands balanced temporary loads at both ends, construction at the same time (generally the difference shall be not more than the weight of 1/4 section) and concreting at the same time. Steel wire rope can be pulled from the cantilever end to the pile cap as concreting the single bridge.

If there is a heavy wind (wind level >6), construction shall be stopped. Some temporary measures can be taken with a wind level <6, such as temporarily connecting two bridges to lateral direction.

Construction technology process: hanging basket moves forward to proper position—level the formwork—install steel bars for bottom and web plate—install inner formwork—bind steel bars for top plate—install pre-stressed pipe—inspect and accept—concreting-maintain the concrete, remove the formwork and treat the joint—penetrate the pre-stressed tendon—tension the pre-stressed tendon—seal anchor and grouting—hanging basket moves forward to proper position.