Editing Box girder bridge (section)

==Construction==
[[File:0197Barangays Burol Balagtas, Bulacan 22.jpg|thumb|Construction of a box girder viaduct on the [[North–South Commuter Railway]], [[Philippines]]]]
If made of concrete, box girder bridges may be cast in place using [[falsework]] supports, removed after completion, or in sections if a [[segmental bridge]]. Box girders may also be prefabricated in a fabrication yard, then transported and emplaced using [[crane (machine)|crane]]s.

For steel box girders, the girders are normally fabricated off site and lifted into place by crane, with sections connected by bolting or welding. If a composite concrete bridge deck is used, it is often cast in-place using temporary falsework supported by the steel girder.

Either form of bridge may also be installed using the technique of [[incremental launching]].  Under this method, [[gantry crane]]s are often used to place new segments onto the completed portions of the bridge until the bridge superstructure is completed.

=== Advantages and disadvantages ===
====Advantages====
* Reduces the slab thickness and self-weight of bridge
* Cost effective 
* Greater strength per unit area of concrete
* Quality assurance, as precast girders are made off-site

====Disadvantages====
(Mainly non-modular designs)
* Structural steel girders are costly
* Logistical inefficiencies and transportation cost