The advantages of incremental launching in bridge construction

There are numerous different bridge launching methods used within the world of construction, applicable for different types of bridges and sizes. When it comes to building bridge decks greater than 250 meter in length however, one reigns supreme: the method of incremental launching. The convenience and efficiency of the incremental launching method is something that most bridge construction finds valuable.

Now, why would they vouch for this construction method? 

That’s what this article intends to answer.

Why the incremental launching method reigns supreme

With incremental launching, the bridge deck is built in sections by pushing the structure outwards from an abutment towards the pier. The superstructure segments are constructed in casting yard behind the bridge abutment. Each bridge segment is matchcast against the previous one and then prestressed onto the section of the superstructure that’s already been built. The superstructure is then hoisted forward equal to the length of the specific segment. You repeat this process until you reach the other side and the bridge is complete. 

Building a bridge as per this method provides a plethora of advantages including:

• Faster construction: As most bridge sections and the advancement of the bridge happen in fixed instalments with repetitions in both design and the process itself of fixing the segments, the construction is sped up considerably. There won’t be any need for unique adjustments for each bridge segment.

• Easier access: Valley, steep slopes, streams, and other similar hard to handle terrains provide a real challenge for many bridge building projects. Transporting precast bridge segments to these areas can be difficult, at times even impossible. As such, one of the biggest advantages of incremental launching is that the majority of the construction work can take place from the prefabrication areas.

• Increased safety: As all construction and assembly processes are done on-site with the incremental launching method, the risks are reduced considerably. The lower elevation levels and not having to work around bridge pillars or half-constructed platforms play a huge role in increasing the safety for the workers.

• Less and smaller equipment: As the bridge segments are constructed on-site, a bridge project using the incremental launching method requires both less and smaller equipment, tools, and machines to deliver materials since all the construction and assembly takes place in the prefabrication area. 
• Minimal disturbance to surrounding area: Last but not least, incremental launching has a minimal impact on surrounding areas, once again due to the fact that the launching process takes place from the prefabrication area.