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The Problem Of Ageing Concrete In Bridge Structures

By April 23, 2020 No Comments

We all remember the disastrous Morandi bridge collapse in Genoa in Italy that happened in August 2018, an incident that killed 43 people and left hundreds homeless, a tragedy that highlighted the need for regular maintenance of concrete structures, particularly when the effects of climate and pollution on corrosion are taken into account.

In the UK, approximately 70 per cent of Highways England and 30 per cent of Network Rail bridge inventory is made up of reinforced concrete bridges – and ageing concrete can deteriorate for all sorts of reasons, ranging from freeze-thaw and sulfate attack to alkali-silica reactions.

In order to maintain the safety of these structures, regular work must be carried out to ensure that bridges and other infrastructures continue to be fit for purpose now and well into the future.

Issues such as surface erosion, chloride ingress, cracking and corrosion can all rear their heads because of exposure to the elements over the long term, as well as the load from traffic causing wear and tear. And, as evidenced by the Morandi incident, prioritising bridge repair and maintenance is a must or it could pose significant risks to life.

In 2016, bridge engineering experts expressed their concern about the viability and safety of thousands of bridges around the country at a symposium organised by the Civil Engineering Research Centre.

Director of civil engineering and convenor of the meeting Jonathan Haynes explained at the time: “The challenges to keep UK plc moving are enormous. Most masonry (brick) bridges are over 150 years old and well past their design life expectancy, and to make matters worse the EU keeps increasing the allowable wheel loads on trucks and trains keep going faster.”

And over at the University of Bath, researchers have been working closely with industry to develop strength tests to increase the work life of bridges – since maintaining these structures costs millions of pounds annually.

As a result, a strengthening method was developed for structures with inadequate capacity, known as deep embedment strengthening.

This involves glueing fibre reinforced polymer rods into holes drilled through beams to serve as extra shear reinforcement, a more efficient and ductile technique than alternative methods and one that can be applied to both slabs and beams.

Carbon fibre strengthening is another option to address structural deficiencies or demands in existing structures. This can enhance the structural capacity of elements that need additional rehabilitation, strengthening and repair, including pipe rehabilitation, seismic retrofit, structural preservation, blast mitigation, corrosion-related repair and more.

This is what we here at CCUK specialise in, adopting an engineered approach to the restoration of concrete, masonry and timber structures. Repairs require quality materials and experienced and skilled tradesmen to ensure the work is undertaken correctly. If you’d like to find out more, get in touch with us today.