Look for the YR bridge series by Wawasoo.
These are the kind you are looking for but are bendy. Use with caution because they can "twist up".
<kuid2:430547:101713:1> YR Bridge Plate Girder Bendy
<kuid2:430547:101717:1> YR Bridge Plate Girder Super Bendy
There's a bunch of styles including bendy ones.
There are also some spline bridges like his from BlackDiamond1964 with one without railings.
<kuid2:405066:32:1> BDW Deck Girder Bridge #1 Spline
and some by Jack (JJSlll54)
<kuid2:46819:38129:2> JJS Deck Girder
<kuid2:46819:38130:1> JJS_Deck_Girder_4_Meter_Dbl
<kuid2:46819:38162:1> JJS Deck Girder 2
<kuid2:46819:38131:1> JJS_Deck_Girder_5_Meter_Dbl
Hope this helps. All are similar, but the one in the picture looks closest to those by Wawasoo and JJS