Semi-penetration type steel truss girder bridge

The invention discloses a semi-penetration type steel truss girder bridge which comprises a first middle chord, a second middle chord and a third middle chord which are oppositely arranged on the samehorizontal plane in parallel, the first middle chord, the second middle chord and the third middle chord are connected through a plurality of cross beams, and a bridge deck slab is laid above the first middle chord, the second middle chord and the third middle chord; a group of upper chords is arranged right above each of the first middle chord and the third middle chord; each group of upper chords comprises two linear first upper chord units and a concave arc-shaped second upper chord unit; two ends of the second upper chord unit above the first middle chord are respectively connected with two ends of the first middle chord through one first upper chord unit; two ends of the second upper chord unit above the third middle chord are respectively connected with two ends of the third middlechord through one first up