On 18 June 2025, Autobahn GmbH des Bundes awarded the contract for the first construction phase of the new Riederwald Tunnel in Frankfurt am Main to a bidding consortium consisting of Wayss & Freytag Ingenieurbau AG, Bickhardt Bau SE and Implenia Civil Engineering GmbH.
The Riederwald Tunnel is Autobahn GmbH's largest inner-city construction project in Hesse. It is the centrepiece of the closure of the gap between the A66 and the Frankfurt A661 eastern bypass. The planned route has a length of 2.2 kilometres and comprises both above-ground and underground sections. Around 1.1 kilometres run as a tunnel under the Riederwald district. The planned completion of the gap closure by 2033 will create an efficient connection between the eastern outskirts and the city of Frankfurt and significantly reduce traffic density in the Riederwald district.
The contract for the first construction phase (VE 4.1.1) comprises the first trough and tunnel sections east of the Erlenbruch motorway junction. The tunnel is being constructed using the cut-and-cover method under the protection of a watertight construction pit enclosure. The tunnel structure consists of a closed "two-cell" reinforced concrete frame with staggered tunnel portals in each direction of travel. A filter is installed between the excavation shoring and the structure as well as below the base of the structure to allow groundwater flow in the final state.
Photo: © Die Autobahn GmbH, The future Erlenbruch motorway junction with the western tunnel portal in the background, www.tunnelriederwald.de
