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Concrete Framed Buildings
Published in Roy Chudley, Roger Greeno, Karl Kovac, Chudley and Greeno’s Building Construction Handbook, 2020
Roy Chudley, Roger Greeno, Karl Kovac
When first mixed, concrete is a fluid and, therefore, to form any concrete member the wet concrete must be placed in a mould or formwork to retain its shape, size and position as it sets. Falsework is the term used for the temporary structure which supports the formwork.
Working at height – hazards and risk control
Published in Phil Hughes, Ed Ferrett, Introduction to Health and Safety in Construction, 2015
One particular form of such activity which can be particularly hazardous is the use of false-work. False-work is a temporary structure used to support a nonself-supporting structure during its construction or refurbishment. An example is the wooden structure to support a brickwork arch which is being built. Only competent persons should plan, erect, load or dismantle false-work. The collapse of false-work structures is common and, when occurring at height, can cause serious injury. Most accidents caused by the collapse of false-work result from the lack of liaison between the various trades using it and its suppliers or erectors.
Concrete Bridge Construction
Published in Wai-Fah Chen, Lian Duan, Bridge Engineering, 2003
Simon A. Blank, Michael M. Blank, Luis R. Luberas
Falsework may be defined as a temporary framework on which the permanent structure is supported during its construction. The term falsework is universally associated with the construction of cast-in-place concrete structures, particularly bridge superstructures. The falsework provides a stable platform upon which the forms may be built and furnish support for the bridge superstructure.
Design of Haunched Single Span Bridges
Published in Structural Engineering International, 2020
The construction sequence consists of casting the end segments on falsework and then activating the tie-downs. Form travelers are then used to cantilever out segment by segment until midspan is reached, whereupon the closure segment is cast. The form traveler has been assumed to weigh 45 tonnes (50 tons). Top cantilever tendons are stressed as each segment is erected, while bottom continuity tendons are stressed after continuity is established. The articulation is such that the pot bearings at both abutments are locked against longitudinal movement during construction, and one of the bearings is freed after closure, so as not to lock-in stresses in the main span. (An alternative design might be to have the superstructure monolithic with the abutments—this may be a more efficient design—but many of the generalizations made here would be difficult to describe as this design would be more site specific).
The combination of tile vaults with reinforcement and concrete
Published in International Journal of Architectural Heritage, 2019
David López López, Tom Van Mele, Philippe Block
The construction of concrete shells requires formwork with rigid shuttering onto which concrete can be poured and allowed to harden. These formworks are typically complex and unique, and most times not reused. Furthermore, their construction is labour and material intensive, and often even requires a separate foundation. Therefore, formworks for concrete shells are expensive and wasteful. Tile vaults can be used as permanent formwork for concrete shells to reduce construction waste and cost (of the formwork itself but also of the foundation to support the falsework), and thereby provide an interesting solution for the efficient construction of vaulted structures. Concrete would be applied onto a tile-vaulted formwork, afterward forming a composite structure. On the one hand, as compared to a typical tile vault with multiple (more than two) layers, the addition of a top layer of concrete to, for example, a two-layered tile vault, reduces time and labor because of the easier applicability of the concrete in comparison with the placing of the bricks. A higher weight for the same thickness should be expected though, due to the concrete´s higher specific weight. On the other hand, as compared to a typical concrete vault, this system reduces costs by allowing the construction without a formwork. Besides, it provides an exceptional finishing to the intrados. As drawback, the new composite structure presents a more complex structural behaviour, in which the bonding between the two materials plays an important role.
Innovative Design and Construction Process for a Self-Anchored Suspension and Cable-Stayed Cooperation Bridge in China
Published in Structural Engineering International, 2018
Xiaoming Wang, Chengshu Wang, Minfang Zhang, Yuanxiao Xu, Xiaoming Lei
Using the aesthetic design of the cable and self-balance systems presented in this paper, the Dongtiao River Bridge was finished in July 2015. Since then, it has achieved the status of becoming an urban landmark in Huzhou. With the increasing expansion of the highway network in China, new lines inevitably cross existing lines or channels. The proposed non-falsework construction method for the self-anchored suspension bridge innovatively minimises the construction risk and the impact on the existing channel. The proposed configuration transformation control method for spatial cable suspension bridges effectively prevents buckling damage occurring to the hangers during installation. The Dongtiao River Bridge serves as a useful reference for the design and construction of cables to support new bridges.