A box girder bridge, an evolution of the plate girder bridge, is fabricated from either post-stressed concrete or sheet steel plate and is commonly built for roadway flyovers and light rail transport. Some modern steel trestles, for example, are composed of a number of girder bridge segments. Concrete girder bridges are typically cast in place (using falsework supports that can be removed later), while the steel-plate type may be preassembled at a fabrication yard and then placed using cranes. The latter method is often used in situations where access for construction is limited due to traffic, which may be detoured around the work area, utilizing a limited number of lanes.

The passage is primarily concerned with

(A) the construction of modern steel bridges called box girder bridges.
(B) box girder bridge construction methods where access to construction is limited.
(C) how the box girder bridge is related to segmental bridges, such as trestles.
(D) why the plate girder bridge is considered the ancestor of the box girder bridge.
(E) the fabrication and construction methods of the box girder bridge.



According to the author, the girder bridge construction method employed where access for construction is limited to periods of light traffic is the

(A) cast-in-place method.
(B) post-stressed method.
(C) preassembled method.
(D) method using falsework supports.
(E) steel-plate method.