Herrmann-Debroux viaduct closed with uncertain future
The Herrmann-Debroux viaduct is closed since last Friday after an independent assessment company found “weaknesses” in the viaduct’s concrete on a section of 10×2 meters.
The government waits for further analysis to decide on the possible reopening. In the long term, a boulevard would ideally replace the viaduct.
Thursday night, inspectors found that the viaduct was suffering from “delamination of the chamber’s lower slab”. The concrete of one of the four 180 chambers constructing the viaduct’s supporting structure was shearing horizontally, implicating risks in the construction’s stability.
In 2016, a visual inspection reported “infiltration, corrosion, cracks, areas of concrete sounding hollow and part of concrete’s detachment”. Despite that, the report determined the viaduct was “visually correct”.
Wednesday, the Seco Company mandated by Brussels-Mobility will give its first report on the mechanical aspect of the problem. On the result’s base, the government will decide if the second biggest axis into Brussels is to be reopened or not.
Concrete chemical analysis will also enlighten on the problem’s extent. “The Herrmann-Debroux viaduct’s construction is different from others. Where on others we can isolate the section and replace it, on Herrman-Debroux the supporting structure is in one piece”, explains an engineer.
Condemned to destruction
The viaduct built in 1973 will be demolished in the long term, it’s in the Regional sustainability plan: “the penetrating axis will undergo a transformation into urban boulevard by 2025”. This major axis going into the capital presents a saturation rate higher than 85%.
With Brussels authorities wanting to cut down traffic by 20% by 2025, reducing the major axes is one of the solutions. This has to go in pair with the creation of park-and-ride facilities and a public transport offer increase.
“The Reyers viaduct demolition proved it. It is now possible to delete this kind of construction”, explains an expert. Even the Minister-President Rudi Vervoort admits: “viaducts don’t have a place in tomorrow’s city”.
The problem is that removing the Herrman-Debroux viaduct will not have the same impact as Reyers did. Where the second was only used by a limited inner-traffic, the first one is the second most important axis into the capital after the E40. It is used at 95% by commuters and therefore it’s majorly congested at peak hours.
In Reyers’ case, alternatives have to be dealt with by the Region only. For the Herrmann-Debroux case on the other hand, the mobility and public transport alternatives depend on the Federal government (regional train) and the three regions (car-sharing, buses, trams…). The alternative plan will therefore take longer to be put in place.
‘It has to be put back into service’
“We’re not ready”, explains the acting mayor Christophe Magdalijns (Défi), “The signal to our economic operators would be disastrous. Important urban developments are planned especially in the Delta area and numerous workers drive to work everyday on the viaduct. Except if there’s a huge problem, the viaduct has to be put up back into service, just to give us the time to find alternatives and to work on changing commuters behaviours”.
The current plan foresees a replacement of the viaduct by a two-way boulevard. Supposed to start in 2018, the public budgets for this considerable construction works have yet to be determined. “In one way, keeping the viaduct costs less than destroying it”, smiles Magdalijns.
“If the repair costs of the viaduct are too high, it will not be reopened”, concedes a government’s eminence in private, “but it will no be demolished either. This will also have an important cost”.
30 years of neglect
“We all know that the tunnels are at the end of their life”, said Pascal Smet last Monday. The idea is refuted by a certain number of construction expert but they point out that there is a necessity to control and maintain regularly these structures exposed to pollution, water infiltrations, corrosion from the salts, etc.
Obvious, isn’t it? Not for the region’s authorities that neglected to maintain properly these structures for the last 30 years. Tunnels, bridges and viaducts were only inspected after an incident, experts reports were piled up in drawers and budgets were allocated to more electorally sexy objectives. The minister’s auditions point to a collective responsibility from the Brussels Mobility officials.
Where the maintenance budgets were before allocated to other uses, the Vervoort government ensured that it will deploy the necessary means: 5 million each year for the “normal” tunnel maintenance and 4,5 million for bridges. For the other extras, they have to be drawn from the regional budget. “We’re draining the regional budget to repair errors from the past but we don’t have any choice”, says the regional minister, grinding his teeth.