Des piles de pont remarquables

The goal

Building a new motorway interchange and a new bridge with the least possible impact on road traffic
The A1 road located in the north of England will be transformed into a motorway to improve traffic flow in this region. In the Leeds area, several bypasses are being built, including the Holmfield Cross. This new motorway junction has a bridge with exceptional and original piers.

The project

Summary : The bridge piers had to meet facing concrete requirements and the work had to be carried out without impacting the traffic conditions of the neighboring roads.

Challenge :
The biggest difficulty of this project was to manage to maintain traffic on the border lane, the M62, during the construction of the bridge. In addition, the facings of the twenty-two piers of the bridge had to meet particular architectural specifications.

Solution

1. Specific requirements
   The new motorway interchange is made up of several ramps, which rise to different levels. It is because of this that the heights of the twenty-two piles were located between 5 and 17 m. Specific shape and facing quality requirements had to be met for these unusual champagne flute-shaped piers. For each pile, it was necessary to create a vertical linear structure as well as a flat facing in architectonic concrete. The ideal solution was to use a formwork system that was easily adjustable in height (in view of the mass production of the piers) and capable of absorbing the different pressures exerted by the concrete, a formwork that complied with safety standards and was able to to carry out the widening and rounding of the piers in a high quality concrete facing.

   The choice therefore fell on Mammut formwork from MEVA. This large-scale modular was combined with custom-made steel formwork and fitted with pre-curved Alkus skins. The standard sections, which could reach 11.5 m high on some piles, were carried out during the first rotation. The Y-shaped pile heads were cast in a second rotation. The vertical lines at the level of each pile were obtained by screwing specific strips onto the skin of the formwork.
    
   

2. Easily adaptable climbing brackets
   
   

   

   
   
   KLK230 climbing brackets supported the formwork and acted as secure working platforms. These platforms could be adapted on the pile heads, although the inclination of the heads varies greatly. The two end forms were installed differently from one pier to the other, over the entire height. Thanks to the implementation of the KLK platforms , the bordering roadways were able to remain fully open to traffic.
    
3. Innovative solutions whatever the situation

   For the piles that had to be erected on the strip of greenery wedged between the two tracks of the A1, a special solution had to be found for the shoring of the formwork. The installation of a traditional type of shoring would have led to a significant reduction in the carriageway or led to a temporary closure of the motorway.

   For this, MEVA had a ready-made solution, made from systems available for hire: the loads due to the wind could be taken up by two  » Space  » scaffolding towers, which were installed on the strip of greenery at the same time time as the formwork piles. The formwork and bracing, mainly made up of standard parts and supplemented by custom-made elements as well as essential safety accessories, created a solution perfectly suited to the situation, a system that was simple and quick to install.

The result

The commissioned company was more than satisfied with the formwork systems and the quality of the concrete facings. This project, which was well planned, now makes it possible to facilitate traffic between the south and the north of England as well as to Scotland.

Featured Products

• Mammut Wall formwork 
• KLK Climbing systems 
• Space Tower Shoring 

Entreprise de construction:
RMG Joint Venture (AMEC, Alfred McAlpine, Dragados, Kellog Brown et Root)

Projet:
A1M Holmfield Pont de l’échangeur

Lieu du chantier:
Leeds, UK

Planification du coffrage:
MEVA Formwork Systems, Colnbrook, UK