The use of balanced lowering method technology for bridge construction in cramped urban environments

Abstract

The main trends in bridge building are: the implementation of new materials, the assimilation of novel technologies, and the construction time reduction. The new technologies assimilation is often associated with the need to build bridge structures in cramped conditions. Considered by the author balanced lowering method technology corresponds to these trends. The technology was developed at the Vienna Technical University, the main idea is to assemble the supporting elements in a vertical position with subsequent deployment to the design horizontal position. To reduce the weight of the mounted elements, this technology uses thin-walled prestressed precast concrete units. After installing it in the design position, they perform the function of leave-in-place form and are cast in place directly on the construction site. This technology was invented for high pier bridges to eliminate the erection and dismantling of temporary support but has recently been shown to be cost-effective for low pier bridges. The advantage of this method is not only the construction time reduction and the free underbridge clearance presence but also the fact that the braces are not only a mechanism for turning the span into a horizontal position but also allow to reduce the estimated span length. The article discusses the bridge projects across the Lafnitz and Lahnbach rivers in Austria, as well as previous options for bridge projects. Particular emphasis in the work is placed on the bridge construction technology consideration, the main technological stages identification, as well as the performance features of certain works. The author presents recommendations on the application of this construction method.

Keywords

• umbrella bridge
• balanced lifting method
• construction stages
• thin-walled prefabricated elements
• cramped conditions
• fixed formwork