By Alva Solomon

AS expansion works at the Cheddi Jagan International Airport (CJIA) moves toward its December 2017 schedule, the contractor foresees completion of the terminal facilities as the major challenging factor which may impact the timeline.At the same time, works to the actual runway expansion are on schedule and the contractor will utilise a new form of technology in compaction works at the two ends of the main runway.

Minister of Public Infrastructure, David Patterson; Minister within the Ministry of Public Infrastructure, Annette Ferguson; Opposition Member of Parliament and Shadow Minister of Finance Juan Edghill and airport officials, as well as officials of the contracting firm China Harbour Engineering Company (CHEC) toured the airport on Friday and members of the media were afforded an opportunity to view the works in progress at the site.
The 32-month project, which commenced in January 2013, two years after the contract was signed between the Government and CHEC, was extended past its original completion date of September 2015 to December next year.
The scope of the project includes the extension of the main runway 06/24 from 2270 metres to 3360 metres, relocation of the Guyana Defence Force Engineering Corps, relocation of residents’ houses, police houses, road diversions and utility works.
The scope also includes construction of parking, taxiway works and installation of ground-lighting facilities, construction of a new arrival terminal building, extension works to the existing terminal facility, construction of a new diesel generation room, a new fire pump station, as well as a new boarding corridor with bridges.
Works were progressing when the team visited the site at both ends of the runway where compaction works were in progress. At the same time, works off the airside where the new fire pump facilities were ongoing while workmen were carrying out construction works to two of 19 houses. The houses will be built over the next few months for residents identified for relocation at the north-eastern end of the runway, where initial works were undertaken when the project commenced.

At the south-western end of the runway, sand works were impeded on Friday by rainy weather while several trucks , of a total of 125 who were sub-contracted by the Chinese to ferry sand to the worksite, awaited changes in the weather pattern.
At this end, the elevated works are expected to climb past the halfway level by year-end, according to CHEC, and Government engineer Walter Willis noted that works of such height and magnitude have never been undertaken in Guyana.
A CHALLENGE
According to Project Manager Keliang Liu of CHEC, while the runway extension works are on stream and within a controllable schedule, renovation works to the terminal building and works to the new terminal building will be challenging.
“Because of the terminal building, we know that we can only finish it part by part,” Liu said.
The company will be implementing an engineering method, known as vibro-flotation, to speed up the compaction works at both ends of the runway before it is paved.
Vibro-flotation is a Specialist Deep Foundation Technique used for Ground improvement to considerable depth, up to 75 metres. It uses a probe called Vibro-flot (which could be powered electrically or hydraulically) to strengthen the soil by deep compaction to make the soil suitable to support proposed imposed load.
According to online definitions, the process involves the introduction of backfill granular material, in this case sand, to form stone columns interlocking with surrounding soil.
Treatment is to provide adequate bearing capacity, restrict total and differential settlements to acceptable magnitudes under the proposed loading and provide acceptable long-term performance of the treated ground.

The technique was proposed by the contractor, and according to Liu, it differs from the layer-by-layer compaction method which requires a waiting period after compacting material.
“From timing, we get settlement out of the sand, whatever we gain in the process, we get to the true level of embankment before we pave it,” he said.
NEW
According to Patterson, the technique is new to these shores, but “It is very common outside of Guyana.”
Amid queries which may draw concern about the method, including the settlement of the sand during compaction, Project Manager within the Ministry of Public Infrastructure, Carmichael Thorne, further explained that there is a misconception between what is consolidation and compaction.
He said the method is used to compact the sand and settlement, which will happen overtime as a result of the consolidation of the layers below the sand.
The latter, he noted, is a result of the sand being placed there.
“The Vibro-flotation is a method to compact the sand and after the compaction is done, fill will be done to get back to the desired level,” he said.
He added that the issue of settlement overtime and consolidation of the works is an issue that will happen regardless of the method used.
“That has to do with the ground improvement which is being done presently with sand columns and wick-drains.”
He said the project has ensured that the tolerances (or catered eventualities) have met the requirements for a runway in the long-term.
According to Minister Patterson, the design for the paving of the runway is for a 15 to 20-year period.
“So, at the end of the time irrespective of the method you use, it will have to be repaved,” he added.
RELOCATION
Meanwhile, as regards relocation of residents at the northern end of the runway, two families will be relocated immediately and their homes were being completed on Friday.
Referred to as Relocation Scheme, a total of 19 families will move into the area eventually, on plots of land which caters for 57 house lots. This varies from the relocation plans which the previous administration had embarked on.
Patterson said that lights and water will be provided to the relocated residents, while the cost of the homes being built will equate their existing homes based on valuation processes undertaken by the Valuation Department of the Ministry of Finance.

“The Valuation Department executed valuation of size of the properties and they gave a low and high value to work with,” he said, adding: “I think we went down the middle and explained to those persons.”
Following the tour, Edghill said that for the record, the Opposition welcomes the initiative of the MPI to invite the party to participate in the review of the project.
“It would seem that it is a departure from what would have been our complaint about the lack of consultation and disclosures,” he said.
His queries were based on the sums of monies expended for various aspects of the project, including disbursements and the likelihood of expending the total sums spent thus far.
Some $4B was allocated to be spent on the expansion project in 2016 and Patterson said a payment of $2.8B is due shortly. For the relocation of the GDF compound, the first contact of $254M was budgeted and awarded. Later, an inspection was done by army and MPI officials and shortfalls were cited. An additional $63M was budgeted and the sum is currently being expended to facilitate corrective works.
As works on the ground continue, the project may be impacted by unforeseen ground conditions, maintenance of operations as well as the relocation of utility facilities and operators, including airlines which operate at the CJIA.