Movable Scaffolding Systems (MSS): Introduction

Span-by-span casting with Movable Scaffolding Systems (MSS) is a high-quality alternative to precast segmental construction in large-scale bridge projects, and definitely a more affordable technology in medium-length bridges. Less post-tensioning, simpler deck design, much simpler geometry control, only one construction joint per span, and continuous reinforcement in that only joint lead to high-quality, durable bridges with long service life and low maintenance costs. MSS technology also avoids investments for precasting facilities and segment transportation means, minimizes the demand for labor and auxiliary equipment, and can be integrated with multiple production support systems. In 41 pages, the eManual introduces span-by-span casting with MSS through comparisons with alternate construction methods for medium-span prestressed-concrete bridges. It explores one-phase casting of box girders and ribbed slabs and two-phase casting with and without first-phase post-tensioning. It also discusses multi-phase casting of wide box girders by combining in-place precasting of pier tables, two-phase MSS casting of the central box core, and segmental casting of the side wings with forming carriages rolling over the central core. For each span casting method, the eManual explores cage prefabrication and its impacts on the span cycle time, the filling sequences for the casting cell, the design of deck post-tensioning, and staged application of post-tensioning to control structure-equipment interaction. Introduction In-place casting on falsework Movable scaffolding systems One-phase casting Multi-phase casting Casting procedures Choice of the most appropriate type of MSS Bridge design recommendations for effective use of MSS References With extensive illustrations, the eManual introduces the different types of MSS and provides exhaustive guidance on the choice of the most appropriate type. It also explains how to design bridge piers, abutments and superstructures for effective use of MSS in relation to the selected staged casting process.