Cutting edge

Savings from pre-purchase of materials, alternative methods of construction, temporary holding solutions for dredged material… global port consultants can bring much-needed original thought to port projects.

When Jacksonville Port Authority (JAXPORT) signed a lease agreement in 2005 with Mitsui OSK Lines (MOL) to develop a new $230m container terminal on Dames Point in Jacksonville, the contract to undertake the planning and development work was awarded to Halcrow.

Despite a demanding schedule of 42 months for permitting, design and construction, the Halcrow/JAXPORT team, which was later joined by general contractors Yates Construction and Tower Group, delivered the project on time and within budget, with the first ships arriving in January 2009.

Jack Belt, chief construction manager for Halcrow, explains that the company's role as Agency Construction Manager began during the design phase of the project.

"In 2006, China was booming, and there was a world-wide construction material shortage. In particular, steel was in very high demand. We advised JAXPORT to directly purchase steel sheet piles, H-piles, pipe piles, and tie rods required for construction of the bulkhead.

"The pre-purchase of these items saved the project approximately $1.5m in steel price escalation and contractor mark-up costs. The pre-purchase also avoided the delivery lead time of four to six months from impacting on the construction schedule."

After Yates was selected as contractor, alternative methods of construction were evaluated and available materials identified, in the process reducing the cost of the project by a further $30m.

"During construction, we had to make sure that there was no negative impact on shipping activities in the port or on operations at adjacent terminals. In addition, we had to protect the surrounding environment and wildlife through the strict compliance with environmental regulations, something which required diligent monitoring of the contractor," says Mr Belt.

Construction of the terminal's pavement was novel. The 7-inch thick asphalt paving was laid over 8-inches of "easy base" on compacted sub-grade. "Easy base" is a mixture of limestone, sand and fly ash, with the latter, a waste product from coal fired power plants, supplied by the local electric company. This low cost sub-base material increased the compressive strength of the sub-base of the pavement section by 35% and ultimately resulted in nearly $9m being saved on the asphalt paving on the project.

Mr Belt adds that Halcrow was fortunate that the nearest disposal sites for dredged material were on the opposite banks of the channel of the St Johns River. However, delivering the material by road would have had a major impact on traffic and taken months to complete. It was therefore planned to dredge the material directly on to the project site, but that would have meant dredging could not commence until the bulkhead was in place, which in turn would mean the project would not be completed on schedule.

Halcrow therefore devised a solution to dredge from the channel towards the shoreline into temporary holding cells erected during the construction of the bulkhead, thus enabling dredging to commence at the beginning of the project and savings of $15m to accrue.

Meanwhile, David Byrne, of international consultancy Noble Denton, discusses the company's work with Jebel Ali. Having recently undertaken work for an oil products shipper based in the port of Jebel Ali, Dubai, Noble Denton's team on the ground in Dubai initially carried out a feasibility study and Port Marine Risk Assessment for a proposed new berth at the port.

However, it was then asked to assume responsibility for the project management, working with Noble Denton's Newcastle (England) office to execute the bulk of the risk assessment and associated ship manoeuvring simulations, which under-pinned the work. The simulation activity, which was carried out in the north-east of England at the South Tyneside College (STC) Ship Simulator, used naval architecture and nautical input together with a full bridge team, including pilots.

"Following the successful outcome of this project, the port authority for Jebel Ali, DP World, who were observers in the original work, directly commissioned us to carry out similar ship manoeuvring simulations for Jebel Ali, again using the STC simulator.

"The objective in this case was to better understand the behaviour of the largest container ships currently trading (about 14,000 teu) in their approach to Jebel Ali and during berthing alongside with tugs," recalls Mr Byrne.

The manoeuvring simulation of such very large vessels with highly limited under keel clearances is particularly challenging and raised difficult technical problems, he adds. In order to fully understand the practicalities of handling these ships at such deep drafts and in difficult or limiting weather conditions, the team was required to push the simulation system to the limits.

"The insights gained in carrying out the work, together with the associated technical report, were helpful to the port in formulating its risk management strategy for these important vessels, which have since successfully started to visit the new container berths at Jebel Ali without incident," says Mr Byrne.

Probed about the use of simulation in developing port projects, he says that, in the past, the use of full bridge simulation was unusual, usually because of cost considerations. However, the availability of relatively cheap, higher-powered computers and the establishment of world class facilities in various centres has made this approach more readily available and at reduced cost.

"Without such tools, the port developer has to rely on either heuristic nautical experience or much less sophisticated computer-based simulations," he observes. "Furthermore, the ability to engage a full bridge team in highly realistic simulations provides the nearest thing to 'real life' experience and credible measures of ship controllability, thereby resulting in the best possible input to the port risk assessment process."

He adds that, in the future, this use of advanced simulation techniques could be expected to become more or less standard practice in any significant port development, given that the benefits are potentially huge and the costs relatively trivial in the context of overall project costs.