London Banter - Cracks found in key Olympic Road Network bridge

Cracks found in key Olympic Road Network bridge - NCE

Urgent inspections were taking place this week to work out how to
repair cracks on a crucial M4 motorway structure in London in time for
the Olympic Games.

The 15mm long hairline cracks were discovered by chance in welds on
the Boston Manor Viaduct just west of junction 2 near Hounslow last
week.

The Highways Agency has not confirmed the exact location of the weld
cracks, but their discovery has forced it to impose weight
restrictions on the damaged stretch, diverting coaches and lorries
onto busy local roads.

The Highways Agency said the 1.03km long, 1960s, steel structure
comprises 14 spans of plate girder construction and three spans of
lattice girder construction with box girder chords. The elements are
attached using a combination of bolts and welds.

The problems were first discovered on 24 March during a special
investigation of the structure’s electroslag welds.

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The affected section is on the Olympic Route Network (ORN) and will be
used to carry coaches travelling to and from Heathrow airport and the
Olympic Park in East London.

It would be a major embarrassment for Games organisers if the
restrictions cannot be lifted.

Transport for London (TfL) is in charge of the ORN. Following the
discovery of structural problems on the nearby Hammersmith viaduct
last February, TfL roads director Dana Skelley told NCE that “no other
structures” were at risk.

She said Hammersmith Flyover was a unique case because of its mode of
failure.

Skelley also insisted that all of TfL’s structures had been fully
checked and it had a “robust regime in place” for assessing
structures.

The Highways Agency, TfL and the London 2012 Organising Committee are
looking into contingency plans but they are likely to rely on the
current diversions for the time being.