Declutching affected 30% of sheet piles at new Kingstown port

The declutching of the sheet piles created gaps in the quay wall and was observed on approximately 30% of the total installed sheet piles at the port under construction in Kingstown, Prime Minister Ralph Gonsalves has said.

Citing a report from Lenski Douglas, an engineer at the Project Implementation Management Unit Gonsalves told a press conference that the declutching has compromised the overall soil retention capability of the quay wall.

“However, the global geotechnical and structural stability of the quay wall has not been compromised,” Gonsalves said, adding, “by design, the global stability of the quay wall is dependent on the stability of the king piles”.

He said these king piles were properly installed to their design depth and have not been compromised by the declutching of the sheet piles.

The EC$600 million port project has come under scrutiny after images began appearing on social media in February showing large pools of water and reclamation material washed out from inside the quay wall.

The main opposition New Democratic Party (NDP) held a press conference on the matter on April 2, during which West Kingstown MP Daniel Cummings, an engineer, said there was a catastrophic failure at the project.

Gonsalves, citing Douglas, denied this was the case.

The prime minister, who is a lawyer, said the sheet piles “serve the primary function as lagging elements for backfill retention, and only contribute to 3% of the overall lateral stiffness of the quay wall structure.

“… the quay wall stability analysis and design checks for static and seismic conditions were conducted, and the results show that the overall structural stability is maintained,” the prime said as he read from what he said was Douglas’s report.

He said the report also contained “a lot of technical stuff … about demand and capacity ratios less than 1 and the maximum shares and bending moment envelopes and so forth.

“I’d leave that if Agamemnon wants to have a conversation with Lenski Douglas,” he said, referring to former Southern Grenadines MP, Glanford Stewart, a former minister of works, who also spoke at the NDP’s press conference.

“… but the results show overall structural stability is maintained.”

The prime minister said the rectification of the sheet pile will proceed in two phases.

“First the declutched sheet piles will be rectified. Second, along the quay wall will be recompacted to design standard.”

He said the design to reinstate the backfill retention ability of the quay wall comprises “welding of EX 26-700 steel plates, the same material as the original sheet piles, to the outside face of the sheet piles and king piles”.

Gonsalves said that once welded, “the closure plates will be back-filled with concrete — something called tremie concrete — … which will seal the space and prevent any further loss of backfill material. Corrosion allowances are considered as per the project specification.”

He said the model results show, “demand/capacity ratios is less than one for the various loading plate condition and weld length.

“This is why they can tell you that the overall structural stability is being maintained.”

He cited the report as saying that a “2D steady state seepage analysis was performed to analyse the groundwater conditions.

“Based on the results, the factor of safety at the base of the declutch repair is in the order of 20. Recommended factor of safety are between 4 or 5. Hence, the model suggests/shows that future soil loss is not possible once the repairs are performed as designed.”

The report said that the government was awaiting the submission of the work method for the compaction.

Gonsalves commented:

“Because remember, you know, what we said here, first, the declutched sheet piles will be rectified, and there’s a plan for that, which is what I had said long ago. And secondly, along the quay wall will be recompacted to design standards.

“But the actual work method for this recompacting, our technical people have not received the work method as yet, but they will get it.”

The prime minister cited the report as saying that while the contractual end date is Aug. 31, the government was working closely with the contractor and supervision consultants in this regard to ensure that the rectification works are executed safely and efficiently.

The report said, “resource mobilisation will be adjusted subject to the pace of the rectification works and other factors such as weather conditions, especially given that we are entering into the 2025 hurricane season”.

He said the contractor was pursuing the remedial works as part of his contractual obligation and pursuing recovery of cost through his insurance.

“The cost of the rectification works will not be the responsibility of the state,” Gonsalves said, adding, “There may be other things for which we are responsible for, but not this.”

He said the report said four teams were executing the welding of the plates to close the gap.

“This work is being done on a 24-hour schedule with a day shift and a night shift. To date, plates have been installed and completed between sheet piles, S87 and S112, or approximately 70 meters of the quay wall.

“I want you to hear this sentence. An above surface manifestation of the rectification work would not be visible until the compaction phase commences on around the first half of June 2025.”

Gonsalves said he had asked Douglas to give him some comments on the NDP press conference

The prime minister quoted Douglas as saying:

“In general, the statements made at the press conference were not based on any data. Assumptions were flawed and predictions outlandish, somewhat unbecoming of engineering professional standards.”

Gonsalves said he had heard that when a member of the press asked Stewart how he had come to his conclusions, he said, “calculations”.

The prime minister said this was also Stewart’s response when he was “confronted” about his statements during the construction of Argyle International Airport.

Gonsalves continued:

“They said at the press conference the NDP, the spokesperson said, the clutching of sheet piles is a catastrophic failure.

“The answer to that statement is simple: the global stability of the quay wall is not compromised by the declutching of the sheet piles. The loss of reclamation material through the gaps resulting from the sheet piles declutching from the king piles only compromised soil retention ability of the quay wall. The rectification works being executed is to address this issue.

“So how could the declutching of the sheet piles be a catastrophic failure? This is not water engineering, you know,” Gonsalves said.

At the press conference, Stewart had said that the sheet piles were driven 40 feet too short.

Gonsalves said:

“This is what I’ve been advised: ‘If one cannot say how deep the current piles are, how can one be confident they are 40 feet too short?’”

“This pronouncement also illustrates a total misunderstanding of what occurs when sheet piles declutch,” Gonsalves said, adding, “This is what I’ve been advised.”

“Material is escaping through gaps between the king piles and sheet piles where declutching occurred. Both the sheet piles and the king piles were installed to their correct design depth.

“Of course, there’s the ‘port will be destroyed by August/September.’ Well, we will see what would happen to that.

“Just two words were given to me on that: The advice: ‘outlandish prediction’.”

The prime minister said the statement at the NDP press conference that the government had an EC$30 million variation because of damage to the port caused by Hurricane Beryl was “incorrect.

“Claims resulting from Hurricane Beryl are pursued by the contractor through the relevant insurance.

“There may be other things which we are responsible for, but none of those things,” Gonsalves said.

The prime minister accused the opposition of engaging in “hysteria, same hysteria which they had when we were constructing the Argyle International Airport”