Application of steel deck in bridge structure

With the large-scale application of steel deck, bridge structure for how to apply the steel deck has gained the favor of bridge experts. Whether it is a concrete bridge or a steel bridge, the choice of steel deck composite floor slab has become a form of bridge deck slab.

Steel Deck Bridge Deck slab Concerns

Possible pitfalls in the already existing bridge deck system include two:

1. fatigue cracks can occur in bridge decks under the repeated action of cyclic heavy traffic loads;

2. insufficient composite action between the concrete and the steel bridge deck.

Problems Addressed by Composite Bridge Decks

Composite Bridge Decks made of steel deck composite floor slabs solve the above two problems to a certain extent, ensuring the safety and durability of the bridge deck.

Advantages of composite floor slabs

Through the depth of interaction between high strength concrete and steel deck, the composite bridge slabs is formed, avoiding the separation phenomenon of concrete bridge deck and steel girder, arranging calculated steel reinforcement in the upper part of the bridge deck, so that the composite bridge deck forms a whole structure, and also does not cause fatigue cracks in the bridge deck. In addition, in the bridge deck steel beams through the steel deck welding studs, increase the stiffness of the bridge deck, so that the concrete bridge deck and steel beams to form a sufficient composite effect.

Design Concept

1. When designing the steel deck, it should be designed in accordance with the template, with the force reinforcement laid at the bottom and the steel deck as the force reserve;

2. not only consider the bottom stress reinforcement, but also can consider the bottom distribution of reinforcement, in order to ensure the integrity of the whole bridge deck plate and the composite role with the bridge deck steel beams, the distribution of the upper part of the reinforcement and the negative moment reinforcement need to be calculated to ensure that to eliminate the generation of cracks in the bridge deck.

3. welding studs on the steel deck, need to be considered in accordance with the way of non-composite beams to increase the composite role of concrete and steel beams.

4. high strength crack resistant concrete should be used for the concrete to ensure compression resistance of the bridge deck.

5. using steel deck on concrete bridge columns, try to use pre-buried connectors and eliminate field installation of connectors.

Requirements for steel deck selection

Types of steel decks

Choose high ribbed steel deck to enhance the stiffness of the steel deck of the bridge deck itself, the use of open plate and closed plate can be used, the steel deck must be used steel floor deck instead of form deck.

Materials of steel decks

Shall conform to ASTMA 875, Grade 50, with a minimum yield strength of 50 Ksi.

Thickness of steel decks

According to the mixed calculation of the construction phase and the use phase, the thickness should not be less than 1.2 mm, and can use thicker steel deck, such as: 1.5 mm or 2.0 mm.

The application of steel decks on bridge structures is the trend of the future, and more and more bridges will use steel decks.