As part of Network Rail’s 2017/18 programme to carry out repairs and refurbishment of existing structures, MHB Consultants were appointed as designer by Taziker Industrial to undertake the engineering design of the works on Underbridge 090/243 at Letham Mill, north of Arbroath.
The works included strengthening of the West Main Girder to carry the required RA rating by installation of a section of top flange plate, metalwork repairs, particularly to deck troughing units, to address defects identified during Condition Surveys undertaken by MHB and masonry repairs to a wingwall of the bridge, which was found to be bulging during the Condition Survey. Additionally, a new paint system was applied to the structure with warning chevrons also being applied.
The works were carried out during “Rules of the Route” possessions, with no requirement for disruptive track closures. Site works were completed by main contractor TI in April 2017, with the retaining wall anchors being installed by Albion Drilling.
MHB Workscope included:
· Condition Survey – On & Off-Track
· Assessment Verification
· Structural Re-assessment of failing items to justify increased capacity
· Structural Design of strengthening
· Development of condition led metalwork repairs
· Geotechnical Design of anchors for wingwall of structure
· Temporary Works Design for anchor installation