MHB recently carried out a soil nailing design for a site at Ballybracken in Northern Ireland. An existing road cutting 4.5m high constructed a few years ago was found to be over steep (31 degrees) and was required to be strengthened to meet current design standards. Due to the site layout it was not possible to cut the slope back to a shallower angle, as this would have involved land purchase. Instead a design was developed using soil nails to increase the factor of safety of the slope. Following analysis using Slope/ W software, 32mm diameter self drilling soil nails from Dywidag were adopted as these permitted installation in the mixed ground without the use of temporary casings. A grid of soil nails at spacings varying from 1.5 to 1.75m was adopted, with nail lengths from 4-5m long and galvanised for the last 2m closest to the ground surface to ensure durability over the 60 year design life. The surface of the slope was faced with Macafferi rockfall netting to span between nail heads. Sub-horizontal slope drains were installed along the toe of the slope to reduce water pressures. Our client was Albion Drilling who also installed the soil nails on behalf of Lagan Construction. The works were successfully completed on site in July 2017.
Photos Courtesy of Lagan Construction
Tom Podger has joined us for a 4-6 month secondment from Network Rail. Tom has a BSc in Civil Engineering from Abertay University and an MSc in Civil Engineering from the University of Dundee and has worked with Network Rail in Glasgow since graduation in 2016.
He will be working as a design engineer in our civils and geotechnical department.
MHB were appointed by Taziker Industrial, on behalf of Network Rail, to carry out design works for the refurbishment of a steel railway underbridge at Ayr Road in Mauchline. The works are currently underway on site – for an update on progress see the NR Scotland Twitter feed #Mauchline
UB240/159 Station Road is a single span, simply supported, wrought iron half-through type underbridge, carrying the twin electrified track of the Bathgate to Helensburgh Line over a public road in Kilpatrick, West Dumbartonshire.
The structure comprises three longitudinal built-up plate girders. The central girder is a hogback girder and the edge girders are constant depth which support fish-bellied transverse built-up cross girders and a longitudinally spanning timber deck. The abutment and wingwalls are of stone masonry construction.
In order to increase the RA rating of the structure in line with that required for the route, shear strengthening was carried out on the central main girder.
MHB Consultants were commissioned by AMCO to carry out the GRIP 4 and 5 design for the superstructure strengthening, condition led repairs, timber deck replacement and repainting.
During a disruptive possession of the line, web plating to central main girder was completed and a new transverse spanning hardwood deck with loose laid waterproofing system installed.
The structure was blast cleaned and received a new corrosion protection system capable of providing a 25 year service life.
Description of Services carried out by MHB Consultants
• Topographical survey
• Paint survey
• Structural condition survey of exiting metalwork and masonry
• Single option development and technical approvals
• Detailed design of structural strengthening
• Site support during implementation
• Design and scheduling of condition-led repairs
• Temporary works design
MHB recently made charitable donations to three good causes, as part of an initiative led by one of our main clients, CPMS. To celebrate their 21st birthday, a Family Fun Day was held on 29 July at Cartha Rugby Club in Glasgow with all proceeds going to St Vincent’s Hospice, Recovery Across Mental Health, and Hazelwood School. Our donation went towards an incredible total of £30,000.
See some of the great work done by these charities at the links below:
St Vincent’s Hospice
Recovery Across Mental Health