After being struck by a HGV vehicle travelling along the B800, the River Almond Bridge which supports the M9 required significant steelwork, concrete and painting repairs. The first beam had been struck with such force that an 8.4-metre section had to be removed and replaced with new steelwork.
Closing the M9 to allow this work to be carried out would cause traffic delays and inconvenience to the general public. Millar Callaghan presented the client with designs and calculations for a temporary supporting structure that allowed the M9 to stay open to traffic throughout the works.
After a survey of the damage was carried out, our workshop fabricated the new steel beam. The beam was then 100% NDT tested before going off for shot blasting and painting.
Before any repairs could be carried out the temporary support structure would need to be in place. The twenty 100 tonne jacks positioned under the bridge would need to be loaded to support both the dead and live loads from the M9 motorway above. With the jacks set and the M9 fully supported the repair works could now start. The damaged section of the first beam was removed and the new section tacked in position. The new section was fully welded and after a 48-hour cooling period all welds were ultrasonically tested.
Concrete repairs and resin injection was carried out to several damaged areas of the bridge structure. Finally, the damaged areas of the bridge were dressed back and painted with a full highways approved paint system.
