The Riyadh metro will be about 180km long with six lines and 85 stations, including underground, elevated and at-grade sections. Line 3 will be the longest line of the metro, at 42km, running east-west and includes 22 stations.

BT work consisted in designing both temporary works and permanent works for the ramps necessary to access the transfer stations 3J1, 3J2 and 3K1.

The excavation is carried out by using a bottom-up method. For the shallow stretches of the ramp, an open excavation is possible without requiring temporary works and for deeper stretches, temporary works are needed.

The retaining system is constituted by pile walls or micropile walls. The maximum excavation level is reached by supporting the retaining walls with temporary steel struts and anchors. Then, the permanent structures (bottom slab, permanent walls, roof slab) are built starting from the bottom.