Variable Depth Bridges
Product Description
- An advanced solution for box girders, achieving longer spans and improved slenderness.
- Imitates the aesthetics of traditional on-site solutions.
- 1990s: development of the first single-girder continuous decks with variable depth.
- 2003: implementation for curved viaducts (radius 200 m).
Main Characteristics
- This means breaking the span down into sections, with half lap joints and wing-shaped elements on piers.
- Linear or parabolic variations in depth, with a difference of around 1 m between the pier and the centre of the span (maximum 1.6 m for a pier depth of 3 m).
- Central span length of over 40 m (up to 60 m).
Types Of Structures Where It Can Be Used
- Highway viaducts with deck widths of around 12 m, based on a statically indeterminate set-up and large span lengths.
- Large beams for special building structures (pavilions, for example).
Advantages
- Reduced weight in transport due to sectioning of central spans.
- Facilitates the negative moment of the end restraints on piers by increasing the depth in this section.
- Reduces the shear force by facilitating the arch effect of the pier concrete.
- As a result of the above, maximum span lengths using prefabricated components.
- Highly characteristic aesthetic affect, coming close to the appearance of an arch bridge.
Construction Details
- Typical continuous span set-up, minimum depth between 1.2 m and 1.5 m and a maximum of around 2 m on pier.
- Two transverse supports on piers and abutments, with half lap joints in the area where the theoretical moment is zero.
- Centre span lengths of over 40 m with end spans of around 30 m.
- Possibility to attach a wing-shaped beam to the side to avoid temporary pier supports.