Ardleigh Green – STIP Bridge Demolition & Replacement

Temporary works design and demolition engineering support including hoardings, service protection, crane positioning, working platforms, tandem crane positions, retaining walls, and a temporary service bridge. 

Andun were contracted by the demolition contractor Clarke Demolition (part of the Tru 7 group) for the demolition works. For the other temporary works on the scheme Andun were employed directly by Hochtief, who were the principal contractor.

The A127 bridge was demolished and replaced with two new dual lane road carriageways and a service bridge as part of the Structures & Tunnels Investment Portfolio (STIP) for TFL. 

The aim of the Ardleigh Green project was to improve traffic flow through the Southend Arterial road choke point. The project was split into two phases to limit the disruption to traffic and rail networks as far as possible. 

First Phase

The first phase of the scheme involved installing a new service bridge to the North of the existing structure. The service bridge was lifted into place with a tandem lift undertaken by a pair of 500Te cranes. The cranes were sited on reinforce earth and concrete abutments. Andun undertook a cat III check on this phase of the works. 

Services in the existing bridges were then diverted onto the new service bridge. This allowed the demolition of the original bridge.  The Northern half of the bridge was then demolished, and the new bridge span carrying the Eastbound traffic was launched in to place. 

Andun undertook design and checking works on various items of temporary works to facilitate this phase.

This included: 

  • Hoardings
  • Service protection 
  • Working platforms
  • Piling platforms
  • Tandem Crane operation
  • Temporary retaining wall 
  • Reinforced earth walls 
  • Temporary service bridge
  • Slope stability checks
  • Gas pipe support
  • Crane positioning
  • Retaining wall design

Second Phase 

Andun were appointed by Clarke demolition company to undertake the demolition engineering and phasing works for the demolition of the remaining structure. This phase was complicated by the constraints, including the new service bridge, new road bridge, and limited access points.

The scheme also had a relatively tight possession plan once times for lowering and raising OLE were taken into account. 

The reach and capacity of plant used on the scheme was critical to making the plan work. A lot of engineering went into justifying the existing structure for the intended sequence. Full 3D demolition sequence drawings were produced, which were used to communicate with all stakeholders.

CDC also found them useful when briefing the machine drivers and operatives. 

Andun were also involved in the Highbury Corner and Upper Holloway STIP projects.

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