How to handle precast girder segments joints in the bridge construction?
With different precast girder segments joints treatment methods, it is divided as dry assembly method and wet joints assembly.
Dry assembly method refers to cohere all segments together by coating epoxy resin in the assembly, then tension them to be one entirety.
Wet joints assembly means to pour cast in situ concrete into joints with about 50cm wide between two segments, the beam launcher could move to next span only after the cast in situ concrete reaches the strength. With the waiting time, the construction time for one span with wet joints assembly will take about 10 days, while the dry method assembly only takes 3-4 days.
Dry assembly method has a lot of advantages comparing with other construction methods:
- Compared with full span cast in situ method: the latter must set support and the ground base must have a higher load bearing capacity, so it will have a big influence on the traffic and environment under the bridge; besides, the construction period takes a long time;
- Compared with full span precast girder installation method: the latter could not transport to a long distance with large dimension, the precast yard must be built nearby, so construction in the city could not meet the demand easily. Transportation in short distance also has higher demands on road, investment and environment.
So more and more urban bridge construction projects use dry assembly method.
