The spice of life

Pasha Stevedoring & Terminals LP (PST) is one of the Port of Los Angeles’ most varied cargo handling facilities,dealing in both containers and break bulk.Five of the berths where it operates – 177 to 181 – are currently undergoing preliminary design assessment before repair and rehabilitation.A new wharf extension is also under consideration adjacent to berth 174. Consultant Halcrow HPA has been appointed to provide the necessary engineering analysis and  undertake design work.

Driving the project forward is the desire by Pasha to consolidate several operations that are scattered throughout the port into a single area. The stevedore therefore requires more wharfage. It also needs to know that the wharves it already has are structurally adequate to support upgraded operations. Some existing structures date back to the early 1920s and have limited load-bearing capacity.Many of the timber structural components – including deck, piles and pile-to-deck connections – have experienced varying degrees of degradation and now require repair to restore their intended capacity.

“The wharf extension has been designed to  provide a heavy lift capacity (3,000 pounds per sq foot/14,647 kilos per sq metre) for large dimensional cargo and a rail spur on dock for direct loading of overweight dimensional cargo, such as electrical transformers, which can weigh in excess of 375 tons,” says Halcrow HPA project manager Rob Andrews. 

Halcrow HPA nevertheless eschewed an across-theboard load capacity upgrade, undertaking a detailed capacity analysis of existing structures and subsequently tailoring renovations and upgrades to meet the specific needs of terminal operations. This  allowed significant money to be saved by limiting upgrade and strengthening work to that which only really needed doing.

In terms of major challenges, the presence of soil and groundwater contamination in the terminal area behind the new wharf restricted options vis-à-vis stabilising the embankment to enable dredging of the new berth area to go ahead. The Halcrow HPA design team considered a range of options. The best  solution proved to be the installation of a sheet pile bulkhead approximately halfway up the embankment. This option minimised the amount of  bank excavation, provided a positive cut off for the potential migration of contamination of the back land area and reduced the severity of corrosion of the bulkhead by keeping the sheet piles below the  splash zone.

Asked whether the project was helping to add to our overall knowledge base when upgrading terminals,Mr Andrews was in little doubt, commenting:“The design of the new wharf extension is advancing both the art of seismic design and the analysis of concrete container wharves.” Indeed this project will incorporate new seismic standards as adopted by the port in 2005 as  part of its own Seismic Design Code for Container Wharves.

The overall project cost is $25m, of which Halcrow HPA will get $2m. Andrews concedes that, over recent years, the cost of implementing maritime terminal projects has been increasing.“Construction costs have been escalating considerably over the last few years due to huge increases in the price of concrete and steel. We are also seeing a rise in labour costs as recent construction activity has grown,”he notes.“It is difficult to predict if these costs have now stabilised; however, significant construction activity in China allied to rising energy prices would seem to indicate that materials cost will not be coming down in the foreseeable future.”

Cost overrun also seems to be a fact of life in the construction industry, occurring across a broad spectrum of projects, so Port Strategy asked Mr Andrews what might escalate costs at PST. He reiterated that, because the terminal area behind the wharf was a former liquid bulk facility, there were known to be contamination issues. Any soil or groundwater contamination encountered in the wharf extension area could therefore result in cost hikes, although the port typically includes contingency bid items in cases like this to preclude substantial cost increases and delays.

“The project has been designed to minimise excavation into the embankment for this reason and will include measures for dealing with contamination,” he stresses.

In a second study of consultant projects, PB Tankers Ltd/Tankstore is involved in the development of offshore oil storage terminal facilities near Pulau Busing Island, located on Singapore’s south coast.This is being driven by the rising price of oil. Consultant BMT was appointed to undertake the Total Engineering Design and Project Management Consultancy for the proposed construction of four new jetties (7, 8, 9 and 10) as part of the overall project.The company claims to have an enviable track record in jetty construction.

The Oil Tanker Jetty itself consists of four berths, which cater for vessels ranging from 6,000 dwt to 120,000 dwt. Jetties 7 and 8 were handed over to the client in 2006,while Jetties 9 and 10 are currently under construction, with delivery slated for the end of July. 

BMT’s scope of work encompassed preliminary design, preparation of a tender package, tender evaluation and selection of a marine contractor, detailed design, government submissions, site supervision and inspection during construction and construction management.The company is involved in almost all engineering designs as well as with project management services.

According to BMT managing director,David Wignall, during construction it has been vital to maintain close working relations with the client’s terminal operations team, since existing jetties 1 to 6 have had to remain open and fully functional throughout.Strict safety rules have had to be observed and complied with at all levels, especially when ‘hot works’, such as welding, are in progress.

A particular challenge is to protect government owned undersea cables, which cross the construction area close to the jetties. In order to avoid causing any damages or disturbances to these, the contractor has had to ensure their barge anchors do not encroach into the vicinity during piling works.

“We have had to undertake detailed hydrographical studies and monitor anchor movements with GPS to prevent any damage occurring to the undersea cables,” stresses Mr Wignall,pointing out that these are very real innovations. While he concedes that environmental factors may well inhibit future expansion of the jetty area, he also points out that general environmental conditions in Singapore waters are well understood, with limited variations, so such issues will not significantly influence the overall design.