The Reason Behind the Gape Formed during the Match Casting of Bridge Precast Segments

To ensure a perfect matching between bridge precast segments, match casting is used as shown in figure 1, the segments cast using this method will perfectly be joined at the field, shear keys, and dimension of segments will be identical and this, in turn, will help in enhancing severability and load bearing of the bridge.

In match casting, the face of the old segment used as a formwork for the new segment, due to concrete hydration, temperature of old segment will increase and the old segment will temporarily bow due to temperature gradient, new segment will stick to the old segment and bow.

The shape of new segment will be similar to old segment, after the completion of casting the old segment will restore the original shape and the new segment will maintain the bow shape and this will result in the gape, the effect of temperature gradient will increase for slender and deep segments.  match2bcasting-1255756gap-is-formed-between-adjacent-bridge-segments-8480479