21 APRIL 2025 WorldWide Drilling Resource® Refurbishing One of London’s Iconic Structures Adapted from Information by Fugro In 2023, Fugro began ground investigations for refurbishing the Hammersmith Bridge, an iconic structure spanning the River Thames in London, UK. Experts assessed ground conditions surround i ng the bridge's abutments and piers, hoping to identify and mi t i ga t e potential risks. The busy site location meant working and collaborating with a range of stakeholders, including engineering firm FM Conway; the London Borough of Hammersmith and Fulham; Port of London Authority; and the public. With the bridge and surrounding roads remaining open to pedestrians and traffic, and the river being used by water vehicles, operations had to be planned meticulously. The Hammersmith Bridge structure posed unique challenges, especially for the nearshore element, where the ground investigation had to be conducted over water in a tidal river. To address the challenges, jack-up barges were used with the ship Skate 2D due to its adaptability in the confined space and the ultra-low sulfur diesel powering the barge. One of the borehole locations was very close to the bridge and multiple Thames Water assets, which posed a significant challenge to gathering the essential data. Working with FM Conway, the deck plan of the ship was rearranged to allow the crew to position the jack-up to avoid damaging both the bridge and Thames Water assets. The onshore scope of works, carried out on the riverbank around the bridge posed its own set of hurdles as the bridge abutments had weight restrictions and ongoing structural works taking place. A Fraste piling and limited-access rig was chosen as it could achieve the required depth of drilling while remaining below the weight limits. The compact size of the rig also allowed the company to work within the confines of the existing structural works. Due to the geology of the site, all vertical positions were initially carried out using cable percussive drilling to progress the borehole through any overlying gravels. The inclined boreholes and some of the deeper vertical holes were carried out using a Comacchio 602 rig which was able to drill to depths more than 160 feet allowing the company to sample the Lambeth Group soil below the London Clay. During the works, the Skate 2D operated one of two purposebuilt CPT (cone penetration test) innovations developed specifically for the project. One borehole required a new CPT deck mount to ensure efficient switches between boreholes and CPTs. The second CPT innovation was a purpose-built CPT rig, which was developed in-house and attached to a floating barge which was used to access the seismic CPT hole under the bridge deck. The jack-up barge provided access to the bridge foundations. GEOTECH
RkJQdWJsaXNoZXIy NDk4Mzk=