What it took to rebuild Portland Port in six months – and who did it

A major port expansion in Dorset has come in under a rigorous six-month programme deadline.  

Knights Brown has finished construction of a 250m deep-water berth at Portland Port, having been appointed as managing contractor last year. 

Inside the deal: The privately-owned commercial operation received between £25 million to £26 million backing from HSBC, it is understood. 

The scheme, started in October, involved rebuilding a deep-water berth to enable accommodation of up to two 350m ocean liners simultaneously.  

Works also included construction of a 75m extension to the Outer Coaling Pier and creation of an additional 15,000 sqm of quay space, extending the total available area to 21,000 sqm. 

The expansion will help Portland “keep pace” with increasing demands from its cruise and cargo customers.   

Design and build team  

• Knights Brown (Managing Contractor)  
• Ramboll (Principal Designer)  
• Red 7 Marine (Piling works) 
• Van Den Herik (Dredging)   

Local contractors Barrett Electrical, D&M Groundworks, ESG Trading, Pipefix and Quest Marine were also involved in supporting the works.    

With Knights Brown adopting appropriate mitigation methods to minimise the port’s exposure, Portland Port agreed to carry the major project risks and directly procure high-value materials and subcontract packages. 

Collectively, this allowed the project to be brought in line with the budgetary restraints without compromising the scope of works. 

What were the principal operations? 

• Demolition of the original deep-water berth and dolphin. 
• Construction of a 410m combi pile wall comprising 136, 1.4m-diameter, 24m-long tubular steel piles separated by sheet piles. 
• Anchoring each tubular pile with 32m-long tie rods to a sheet pile anchor wall. 
• Installation of 25-tonne precast concrete units on top of the piles to act as permanent formwork for the in-situ capping beam, itself comprising more than 2,000 m3 of structural concrete. 
• Crushing and transporting (off road) 400,000 tonnes of locally sourced quarry waste to create a granular fill material to bring the extended quay area to level. 

Challenges and solutions 

Knights Brown worked closely with Ramboll on value engineering and rapid construction opportunities, including off-site fabrication and limiting works that had to be carried out over water and avoiding tidal activity. 

The precast capping beam aspect eliminated the need for shuttering and was designed to allow prefabrication of the steel reinforcement.  

Another productivity gain by Red 7 Marine and specialist engineers involved designing a pair of bespoke piling gates to speed installation of the combi pile wall through improved accuracy and tolerance.  

Portland Port was acquired from the Royal Navy in 1996.   

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