The primary advantage of the box girder construction lies in its high torsional stiffness , a necessary quality for large span bridges where a heavily loaded main traffic lane produces a non-uniformly distributed live loading in the transverse direction of the bridge , further torsional loads are experienced by bridges having curved plan forms . In general , box girder bridge sections are more streamlined than those of other types of bridge and are often selected over other possible solutions for aesthetic reasons . An additional advantage of the box-section is that its geometry allows a larger cross-sectional area of steel to be accommodated in the bottom plate than is possible in the bottom flange of a normal plate girder . Thus box girders posses lower constructional depths . Due to the major need to engineering applications incorporating box girders in our life , studies like current research are necessary .