Ouse Bridge Safety Mock Up
We’re currently underway with a major bearing replacement scheme on Ouse Bridge which carries the M62 over River Ouse at Goole. The original structure was built over three years starting in January 1973, spans 1.6km, carries a maximum height at mid-span of 30m and is the final part of the M62 opened in 1976.
Ouse Bridge at Goole
As an ageing structure, maintenance is required, and we’re replacing 208 original bridge bearings. New jacking points are being created by fabricating and lifting 832 steel outstands, weighing half a tonne each and bolting these onto the existing bridge beams 25m above ground level, allowing the structure to be jacked off the sub-structure at each of the 26 piers in-turn providing temporary support to the bridge during bearing replacement.
Bearings at end of life
With the many repetitive lifting operations and working at height issues identified as major risks, our objective was creating and embedding a safe operational environment with the potential to increase productivity to reduce the total number of working-hours and exposure to risks.
We designed a full-size mock-up constructed on site at our partner In-spec Manufacturing’s Middlesbrough steel fabrication plant, replicating every detail of the working area.
Against usual construction procedure, the fabricators and welders from In-spec alongside bearing fitters from supply partner Freyssinet UK worked through the installation and working at height risks together with us, developing a bespoke fit-for-purpose process and methodology and assessing fabrication measurements.
Life size mock up
While it is standard practice to use mock models or off-site training in large-scale projects to develop cutting edge techniques it is not usually considered for routine maintenance works to develop safe systems of work and increase quality control.
The mock up made it easy to train operators, develop methodology and unite the delivery team with safety and productivity goals. As a result, the design phase produced detailed fabrication drawings and an agreed set of defined objectives which results in no waste or rework, saving time, resource and carbon footprint. Another sustainable benefit is that the outstands will remain in situ following this scheme for any future maintenance, saving valuable resource and exposure to risk in years to come.
Developing the methodology on the mock-up up for such a high-risk, long lasting and repetitive scheme has provided an opportunity for operatives to develop safe working methods that work, as well as a training area for future installers and providing a jig to assess fit of fabricated steelwork.
The mock-up was also used to promote concepts to reduce vehicle movements for material deliveries and fabricators and provide much need protection against the elements during the development of ideas and practices. Last minute changes were easily accommodated due to its location and no lost time was incurred during the fabrication.
Feedback on the initiative has been positive throughout. Our front-line delivery team are fully bought into the methodology that they developed. Sub-contractors’ value safe working practices being discussed and developed during pricing. Our client is pleased, as early completion secures safer journeys for road users and parent companies have been impressed with the concept and the obvious benefits it offers with similar initiative being explored in other areas of engineering.
Since then we have used the mock-up to train all our steel erectors before they are permitted to work on the bridge, we have also undertaken trial erections of six different outstands to check fit prior to painting and identified improvements to drilling and hydrodemolition operations prior to commencement on site.
The mock-up will be available throughout the entirety of the scheme allowing the team to collaboratively improve methods and practices so that continuous workplace health and safety improvements are realised.
Scaffold in place at start of work
The success of the trial has in no small part attributed to the excellent safety statistics being recorded by the scheme at zero AFR, an overall reduction in exposure to high-risk lifting operations by 50% and a 3-week reduction in the overall programme duration.
For an initial outlay of £140K to construct and develop the mock-up, the 5-weeks programme period set aside for the erection of the steelwork was reduced to 2-weeks because of the methodology we developed, saving the scheme £270K in preliminary costs. In addition, the hire costs of each of the 26 scaffolds reduced by 1-week resulting in a further saving of £75K. The mock-up provided the opportunity to trial-fit fabricated steelwork prior to painting and delivery, minor design problems found at this stage prevented 4-weeks delay to the programme avoiding costs in the region of £360K. In summary the mock-up has saved the scheme £565K so far as well as providing critical training and safety improvements.
Steel outstands installed
The concept of a mock-up is unusual within highway maintenance schemes but not difficult or impossible to adapt and implement. We would recommend that this approach be considered to all future high-risk activities. The benefits so far have been tangible and identifiable in a way that would be meaningful throughout our industry. For example, our goal of maintaining safety and increasing productivity is being realised.
Using this mock-up proves that safety, if planned and implemented correctly can truly deliver; it is transferrable, adds value and reduces disruption: keeping our people and customers safe and our economy moving.