The manufacturing method for a 90-degree horizontal bend in a glass-fiber reinforced plastic (GFRP) bridge beam involves cutting the bottom plate of a central section of the beam into an equilateral trapezoid. The two sides of the GFRP bridge beam connected to the equilateral trapezoid bottom plate form rectangles. Then, swap the GFRP bridge beams at the ends and connect them to the central section, followed by welding and securing. The middle section features an isosceles trapezoid bottom plate for the GFRP bridge beam, with an angle of 67.5 degrees between the waist and bottom edge. No cutting of the GFRP bridge beam is required, saving materials and simplifying the operation, making it suitable for constructing GFRP bridge beams.

The bottom edge length (diagonal) of the fiberglass bridge tray after bending is equal to the width of the tray, which can be controlled within the range of 100~400mm. Select two points of this length on the side plate of the fiberglass bridge tray, draw two perpendicular lines relative to the bottom edge. Choose the bending direction of the bridge tray as the side for the cutting opening. The fiberglass bridge tray is selected with the opening side as the bottom edge, and the two drawn perpendicular lines serve as the bisectors of two isosceles triangles. The calculation formula for the bottom edge length of this isosceles triangle is L=2×(bridge height×22.5°).