Product | Fixings Eurocode ‘should be welcomed’

Walton says the adaption of Eurocode 2 to include a standard on concrete fastenings will help the sector’s own journey towards safer, more reliable and more efficient fixings.

It will represent the latest step in a long journey to improve understanding of different types of steel-to-concrete anchors.

A survey jointly carried out by NCE and Hilti in 2015 found that more than one in five respondents had some doubts about the way chemical fixings were being installed on sites.

The findings were taken seriously; a roundtable event organised for the following year was attended by key figures from Balfour Beatty, Arup and WSP Parsons Brinckerhoff among others.

There were calls at the event for a recognised qualification to identify competent fixings installers.

“We found that there were some calls from the market to look at training for installers,” says Walton.

Our field engineers will be out and about in the industry making sure people understand how this affects them

Hilti head of engineering Kirsty Walton

“Designing engineers are qualified to specify fixings, but on the contractor side there is no requirement to be qualified in the same way. We trust that installers understand why certain fixings are specified – but there is no-one who ensures that is the case.”

British Standard BS8539 came into effect back in 2012 to give a code of practice for the selection and installation of post-installed anchors in concrete and masonry.

However, many in the industry believe more needs to be done to clarify matters and ensure contractors on sites understand exactly what they are doing with fixings – and why.

Walton believes the creation by the end of this year of a new regulatory framework for fixings across EU member states will be part of the answer.

A draft version of EN1992-4  is available on the German standards website DIN. “This document describes the general principles and requirements for safety, serviceability and durability of fasteners for use in concrete, together with specific requirements for structures serving as base material for the fasteners,” says the website.

Walton says the full regulation, which moves the anchor qualification / design topic to the same level as steel / concrete design and is incorporated into the well-used Eurocode 2, will aid understanding.

There are clear safety benefits in terms of getting the right product but there are also health benefits at installation in terms of reducing the time operatives spend drilling

Hilti head of engineering Kirsty Walton

“It will give designers more confidence,” she says. “If we say something is approved, that will become more valid.

“It will level the playing field so if you select a product with a European approval then you will know all anchors on the market have been up against the same testing procedure. Also, if design changes are needed when you get to site then you will know whether you have selected a product that will work in the new scenario.

“It should give confidence that designs will work in real life, which was the major concern from the questionnaire and round table.

“A key change is that in the past fatigue was missing in the allowances for European approvals,” says Walton. “In cases of fixing back machinery for example, dynamic loading on an anchor should be considered. At present, we can only refer to the German DIBt Dynamic approval and design concept. Within the new EN1992-4 framework, dynamic design will be possible, with an approval process under preparation, so it again gives the specifier confidence in the product they select.”

Hilti will continue the awareness campaign it has been running with the survey, the roundtable, trade magazine articles and work with the Construction Fixing Association (CFA) and others.

“Our field engineers will be out and about in the industry making sure people understand how this affects them. The key thing is that the designer will have an easier understanding of what the product will do.”

People will over specify if they don’t have confidence

Hilti head of engineering Kirsty Walton

Health and safety benefits go beyond the obvious, and critical, aspect of preventing catastrophic collapses, according to Hilti.

“There are clear safety benefits in terms of getting the right product but there are also health benefits at installation in terms of reducing the time operatives spend drilling,” says Walton.

Project programmes and budgets can also be reduced.

“People will over specify if they don’t have confidence. They may request a deeper pour of concrete or change a base plate design. Over a large site you can add a lot of time and cost.

“Designers can end up putting more fixings in than they need, thinking they need a back-up; but they may reduce the concrete available to each one, which can actually be damaging.”

As part of awareness measures, software is widely available now helping engineers specify the best fixing for their project.

Many UK designers also do work in Europe so it makes sense to continue with this legislation or something very similar.

Hilti head of engineering Kirsty Walton

“Our PROFIS Anchor design software helps design anchor fasteners,” says Walton. You can input your requirements and get the right fixing specified. By saying what materials you are using and other variables, you can be sure you’ll get the right product.”

Alongside standards and awareness, such software is another way of speeding up projects, by allowing quicker decisions and less rework.

Hilti also has its SafeSet range of components designed to work together as elements of a safe installation. This includes the HIT-HY 200 chemical anchor, which, when used with other parts from the Safeset range, removes the need to clean a hole before chemical fixing.

“This removed a step that sometimes didn’t happen and, with chemicals, traditionally this was a key step because if you glue to dust then there is no bond.”

Although greater knowledge and confidence could reduce doubts about chemical fixings, Walton insists there always be a place for mechanical anchors as well.

“We will have a product range allowing choices. We don’t have a preference.”

She adds that the European standards should remain relevant however the UK eventually leaves the EU.

“We don’t know the impact of Brexit. But I would be surprised if the UK would pull away from these standards; the Eurocode has been used for a decade for steel and concrete design so I can’t see us being quick to revert back to the old ways.

“Many UK designers also do work in Europe so it makes sense to continue with this legislation or something very similar.”