Bespoke fixings for challenging projects 18 Oct 2018

Sandrine Ordener, Engineering Director at Optimas Solutions Tunnel Division

Standard connection and alignment systems are not always the suitable solution for connecting tunnel sections, depending on differing ground environments. Tunnel lining fixings need to match the conditions to appropriately connect segments and rings. They should help seal the tunnel from water ingress as well as preventing tunnel rings from opening or the tunnel ovalizing.

Optimas produces a variety of fixing solutions
Optimas produces a variety of fixing solutions

When there are local conditions with corrosive environments or the likelihood of seismic events, otherwise reliable standard tunnel fixing solutions may not last, so will compromise the service life of the entire tunnel. Standard connectors may not be able to withstand corrosion, balance strength and flexibility during earthquakes or bear high loads.

Reengineering existing solutions or the development of a new product is where Optimas Solutions Tunnel Division specialises.

For each customer enquiry, Optimas will decide whether a standard fixing is appropriate, or whether a modification or a new design is required. For example, to address the challenges of tunnel construction in corrosive environments such as in the Inner Doha Resewage Implementation Strategy (IDRIS) project in Qatar, Optimas Tunnel Division redesigned a standard grouting system, accommodating high-density polyethylene (HDPE) in-liners, to increase the lining resistance and service life.

Bespoke fixings in situ
Bespoke fixings in situ

After initial assessment a design concept is produced, tested theoretically, and then a prototype is created using 3D-printing. Laboratory and real-life tests follow to evaluate the effectiveness.

In developing products, Optimas adheres to ISO 9001 quality standards and its own Quality Control-Quality Assurance (QCQA) system which involves extensive documentation and reference to previous projects. Having completed more than 400 projects Optimas now has more than 500 standard products in the Sofrasar range and in North America Optimas is now partnered with David Klug and Associates.

Modifications may take one to two months to produce, and an entirely new product eight to 24 months.


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