Case Study - Eastham Bridge Replacement
Collapsed but not lost!
The fine detail of the bridge structure has been saved with high resolution 3D modelling using UAV photogrammetry.
In 2016, the dramatic collapse and then clearance of an historic bridge in Worcestershire was the end to its 223 year history… but its final phase before demolition was recorded for posterity by SUMO Aerial Surveys.
An urgently needed replacement had to be built on the same site as the collapsed bridge. A detailed survey was required of the surviving structure in a hazardous and difficult position in the River Teme.
What were the challenges...
- The collapsed structure was unsafe and inaccessible from the road and embankment.
- It was in need of urgent attention for clearance and replacement.
- Before imminent demolition, a highly accurate and detailed record was urgently needed so original elements of the bridge could be incorporated in the replacement design.
- There was very restricted access to the structure for conventional surveying technology.
How were they overcome.
- SUMO Aerial Surveys carried out an initial reconnaissance of the site to determine what cost efficient and practical survey methodology could be conducted in the quickest time.
- A remotely controlled photogrammetric survey of the surviving structure was recommended which could be operated from a safe distance on the embankment.
- SUMO was instructed to carry out the survey and were on site within 2 days.
Costs and benefits...
The survey cost was less than £1,000. It avoided the incumbent cost of the H&S requirements and planning for a survey from the river.
High resolution data survey data was delivered in 3 days. Structural engineers were then able to design a replacement bridge including elements of the old structure and to begin its demolition.
A 3D model of the data enabled a varied audience to visualise the site.
“Thanks for your quick response with the point cloud data. Your aerial survey was invaluable to safely survey the remains of the original listed bridge both for the historic record and to design the repair and replacement works to the rebuilt bridge. Your system reached areas of the structure that we just couldn’t have achieved with conventional survey techniques, and picked up levels of detail down to individual bricks. The real-colour 3D rotatable output of the survey was very useful to show the planners and interested parties.”
Mark Gorry, Associate Director – Burroughs (Engineering Consultant)
Historical Note: The Grade II-listed Eastham Bridge over the River Teme in Tenbury Wells was built in 1793 and was a private toll bridge until 1907 when it was bought by the County Council. It crosses the river in three spans and the arches are semi-circular, the central arch is higher than the others gave the bridge a considerable rise in the centre. The piers and starlings are stone and the arches and parapet are brickwork. The surrounding area is a Site of Special Scientific Interest.
Survey technology used in this case study...