Impact case study database

Impact 1 – New design guidance: Our research has led to the introduction of guidance documents which are used by designers to underpin their assessment, retrofit designs and interventions. Our work has underpinned the 2012 edition of the UK guidance document, TR55 [A]; specifically, the findings of the University of Bath’s strengthening research is incorporated into the TR55 guidance, forming essential clauses associated with maintaining structural integrity, which must be complied with when considering any FRP strengthening scheme, whether axial, shear of flexural strengthening. This edition is recognised as a leading document in the field and its reach has been Worldwide, particularly in countries where structural design guidance is based upon Eurocodes (EU, Africa, Asia, Middle East). This has led to the saving of at least many 100s of buildings and structures from being demolished or requiring more costly and invasive interventions over the census period, both within the UK and internationally.

| | | --- | | Fig.2 Hawley Bridge |

Our work has also been incorporated into the new Highways England Design Manual for Roads and Bridges, CS455 [B], in March 2020, but was used prior to this for ongoing bridge assessment since 2017. In both cases, this has resulted in major savings to cost of interventions and reduced environmental impact to both construction and infrastructure users (e.g. maintained or increased traffic flow, providing societal benefit). As a direct example of the impact, within the census period, Highways England alone has commissioned four major structural strengthening schemes, all designed to TR55, using methodology informed by our research [C]:

1) Hawley Lane South Bridge (Fig. 2), carrying the M3 Motorway over a county road (2014). The flexural strengthening design of RC solid slabs.

2) Ashridge Farm Bridge, carrying the A34 Trunk road over a farm access (2015). The strengthening of RC abutments.

3) Peover Eye Bridge, carrying the M6 Motorway over the Peover stream (2016). The flexural strengthening design of RC voided slabs.

4) Tickeridge Farm Accommodation Bridges (originally constructed between 1958 and 1962), carrying a farming road over the M5 (2017). NSM flexural strengthening design of RC abutments.

As an example of scale, the Hawley Bridge strengthening scheme cost GBP5,000,000 (using 1,000m of FRP rods and 5,000m FRP plate) [D]. As part of the tendering for these works, whole life cost analysis is always carried out. The capital cost of the Tickeridge Farm bridge strengthening works [E] was GBP796,759. Compared to the alternative conventional steel plate strengthening approach (which was also costed) the whole life cost saving was GBP554,807. The approach enabled construction time to be decreased from 17 to 10 days, greatly reducing impact of diversions and associated carbon footprint. The resulting work extended the existing design life by another 40 years. What’s more, compared to conventional steel retrofit solutions, FRP strengthening schemes result in a decrease of 70% CO₂e emissions, require 80% less energy and use 95% less water. [F]

Impact 2 – New design software: The new retrofit and assessment methods developed by the Bath team have been adopted by Sika AG in their design software [G] and others, globally. The scale of the reach and breadth of impact is best indicated via Sika AG’s strengthening materials business: Sika AG are an international company with a GBP6,700,000,000 turnover in 2019 [H]. 20% of this is related to refurbishment, which includes strengthening using composites, supported by the software based on TR55. As they state in their letter [I]:

“*This has had global reach, with over 6,000 downloads and activations of our software across Europe alone and another 8,000 across the rest of the world; Africa, Asia, the Middle East and North America, where Sika also operate, having active users in more than 100 countries”. “ Since introducing the software, we have seen a very dynamic growth in our business based on the wider understanding of the system within engineers community; this reflects in a > 30% increased total turnover in CFRP systems for structural strengthening since 2015 in EMEA [Europe, Middle East and Africa] countries”.

Sika added that [I]:

*“…implementation of this strengthening technique using our products has saved countless buildings, bridges and structures across the world from being demolished or requiring extensive structural interventions, the cost of which would run into many millions of pounds each year”.

Examples includes the Rialto Bridge structural restoration in 2017 and structural strengthening of the world’s largest archaeological museum, the Grand Egyptian museum, Giza, in 2019 [J].

Impact 3 - Bridge half-joint assessment impact:

The results of the research into assessment of bridge half-joints with reduced concrete cover to prestressing tendons due to corrosion has already found its way into design standards. In 2017, Highways England approved the rules for assessment, informed by our research, to be used in all the prestressed concrete bridges with half joints due for assessment in Area 10 and 13 in the UK (a total of almost 100 bridges of which 15 have already been assessed as of January 2020) [B]. As stated by the Highways England Structures Manager [C]:

“As a direct result of the research described in the paper [5] , which has provided the appropriate technical background based on rigorous and verifiable procedures to define the required level of safety, a number of bridges located in Cheshire, Greater Manchester, Merseyside, Lancashire and Cumbria on Highways England’s Strategic Road Network have had their service lives extended by avoiding unnecessary assessment failures. This led to substantial operational and cost savings, as it ensured that measures such as road closures, monitoring, strengthening or replacement, ranging in cost from a few hundred thousand to a few million pounds for each bridge, are only implemented when really necessary, also minimizing the associated environmental impact of the works”.