Experts defend compaction method for extending CJI Airport runway

Last Updated on Friday, 8 July 2016, 16:55 by Denis Chabrol

At the southern end, the area has to be filled and compacted with huge amounts of sand to the height of the vegetated area.

Despite lingering concerns about the vibroflotation method of compaction to extend the runway of the Cheddi Jagan International Airport (CJIA),   the Guyana government and China Harbour Engineering (CHEC) on Friday assured that aviation safety would not be compromised.

CHEC Project Manager,  Keliang Liu told a news briefing after an extensive tour of the project site that vibroflotation was chosen as the best option for compaction because doing it by layer would be too expensive. “If we do one layer y layer compaction, it’s very high cost,” he said.

The project provides for the extension of the  2,270 metre-long runway by another 1,090 metres, the construction of a new arrivals building and the rehabilitation of the existing terminal for use by departing passengers only. There will also be a new boarding corridor and boarding bridges to prevent passengers from exiting  and entering planes by the air-stairs and the tarmac.

Shadow Public Infrastructure Minister, Juan Edghill (left) speaking with Chief Executive Officer of the Cheddi Jagan International Airport, Ramesh Ghir and Ministry of Public Infrastructure’s Project Manager, Carmichael Thorne during a tour of runway extension works.

Demerara Waves Online News was told that top decision-makers at the CJIA were still mulling their next move because they were not entirely confident in the future integrity of the extended runway using the vibroflotation method to compact the north and south ends with millions of tons of sand. There are concerns about whether vibroflotation has been used often to compact soils and whether runway undulations negatively resulting from that process could lead to high recurring costs to take corrective measures annually.

Public Infrastructure Minister, David Patterson acknowledged that vibroflotation has not been used in Guyana unlike other countries where it is being widely used. Asked whether he was convinced that extended area of the runway would be safe for use by aircraft over the long term, Patterson said “yes” and movements would be calculated over a 20-year period.

“At the end of the  twenty years, irrespective of whatever method would have been used , existing and the new would have been repaired,” he said.

The Ministry of Public Infrastructure’s Project Manager, Carmichael Thorne explained that  settlement would occur over a period of time as a result of consolidation of the layers below the sand. He said filling would be done to get back to the desired level. “The issue with the settlement over time or the consolidation is an issue that will happen regardless of the method of compaction that is used and that has to do with the ground improvement that we are doing presently with the sand column,” he said.

Thorne said himself and other experts have made every effort to ensure that the tolerances would meet the requirements for the airstrip “for the long term.”  He said no additional cost would be incurred as that has been built into the design.

Technical Adviser at the Ministry of Public Works, Walter Willis said the consultants have hired Golder Associates as a sub-consultant to examine concerns about long-term settlement, spacing of the sand columns and the number of drains to extract moisture quicker.

The CJIA expansion project alone is budgeted to cost US$138 million and conclude by December 1, 2017. The overall cost, which includes consultancies and the relocation of several facilities, would bring the total figure to US$150 million.

Government has allocated land, constructed roads and is constructing houses for the relocation of several squatters who are currently living very close to the expansion works.

The Public Works Minister also said the Environmental Protection Agency (EPA) has approved the diversion of a number of creeks allow for the expansion of the runway and buffer zones.

Junior Minister, Annette Fergusion; Shadow Minister of Public Infrastructure, Juan Edghill, top officials of the Guyana Defence Force, CHEC, government and the CJIA participated in the tour.