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Estimating Sheet

Step-by-step Guide to Slab Bridge Design

Construction Software

Reinforced Slab Bridges is mostly suitable for short distances, a solid reinforced concrete slab, normally cast in-situ instead of precast, is the simplest design to about 25m distance, such voided slabs are less expensive as compared to pre-stressed slabs.

Slab bridges stand for the structures where the deck slab also functions as the main load-bearing element. The span-to-width ratios remain in such a manner that these bridges are designed for simple 1-way bending rather than 2-way plate bending.

This design guide presents an elementary procedural outline for the design of slab bridges with the LRFD Code and also comprises of a worked example.

The LRFD design process for slab bridges is equivalent to the LFD design process. According to both codes, the main reinforcement should be designed for Strength, Fatigue, Control of Cracking, and Limits of Reinforcement.

All reinforcement should be completely developed at the point of necessity. The minimum slab depth guidelines indicated in Table should not be abided by if the reinforcement satisfies these requirements.

For design, the Approximate Elastic or “Strip” Method for slab bridges is available in Article should be utilized.

Also Read: How to design bridges through excel sheets

With adherence to Article, edges of slabs should either be reinforced or be supported with an edge beam that is integrated with the slab. As demonstrated in Figure 3.2.11-1 of the Bridge Manual, the #5 d1 bars which expand from the 34 in. F-Shape barrier into the slab meets the criteria since shear reinforcement (strengthening) for the exterior edges of slabs.

When a 34 in. or 42 in. F-Shape barrier (with equivalent d1 bars) is applied on a slab bridge, its structural capacity as an edge beam should have been checked normally. The barrier should not be considered structural. Edge beam design is essential for bridges having open joints and probably at stage construction lines. If the out-to-out width of a slab bridge goes beyond 45 ft., an open longitudinal joint is necessary.

Click on the following link to download the spreadsheet

Download Bridge Slab Spreadsheet