Twenty-five years on...What next for the Demerara Harbour Bridge?
By Oscar P. Clarke
July 22, 2003
|Related Links:||Articles on bridges|
|Letters Menu||Archival Menu|
Consideration, some say, is now being given to having it replaced with a permanent concrete structure while components of the bridge could possibly be used to span the Berbice river.
The floating steel structure, measuring 6074 ft (1851.4 metres), spans the Demerara river from the village of Peter’s Hall on the Eastern side to Pln. Meer-Zorgen on the west and was originally envisaged as a temporary structure with a life span of 10 years.
But fifteen years past its expiry date, it is still being used albeit with modifications and constant maintenance.
Stabroek News, in a recent interview with the DHB’s acting Project Manager, Nazarudeen Aziz, examined the past, present and future of the bridge.
Stabroek News also spoke to Civil Engineer, Joseph Holder who played an integral part in the bridge’s procurement, construction and maintenance over the years.
The bridge consists of 61 spans of varying lengths and floats on 122 steel pontoons. It was acquired and constructed during the period 1976-1978, finally opening to the public on July 2, 1978.
Holder recalled that the idea of a bridge across the Demerara River was a dream of the late sea captain John Cogland who as a member of the colonial legislative council had passed a motion for the bridging of the two land masses.
The idea was the focus of two pre-feasibility foreign studies which looked at the transport sector in the country.
The studies, which had been financed by the United States Agency for International Development (USAID), were the last to be done as relations between it and Guyana turned cold following the Cubana Air disaster in 1976.
It was not until the government in 1975 acquired 120 ft of acrow panel from the UK company to use in its sea defence maintenance work that the company in the hope of further penetrating the local market held a training programme to showcase the value of its products.
It was at this two-week training programme held at the Guyana Defence Force central base at Camp Ayanganna that the idea of building a steel bridge was advanced.
Holder, along with colleagues from the Works ministry’s hydraulics and roads division and personnel from the GDF, took part in the training session at which the company’s general manager and another engineer took turns in providing theory and practical sessions.
It was after this session that the question was put to the visiting team who promptly began exploring the idea.
On their return to the UK they arranged for maps of the mouth of the river to be sent to them and later designed a structure with a retractor span and even arranged financing for the project.
The plan was better suited to an earlier preferred site closer to Banks DIH and an offer was formally made to the Ministry of Economic Development headed by the late Hugh Desmond Hoyte.
They further offered to host a local engineer whom they could acquaint with an example of the technology, which at the time was new to countries like Guyana.
Holder was chosen and recalled spending ten days in the UK examining floating supports with trusses along with the mechanism involved in functioning the retractor span. It was on his return that he attested to the soundness of the material and approved the project as worth proceeding with.
However a further hitch developed with the harbour master, who had earlier verbally agreed to the bridge’s siting near Rahaman’s Park, now refusing to put his approval in writing.
His refusal, Holder recalled, was because he felt that the wharf at the Demerara Sugar terminal would be too close to the proposed structure and would be a navigational nightmare when ships arrived at the port.
Once a new site between Bagotstown and Peter’s Hall had been chosen a new arrangement had to be worked out with the UK Company for the supply of more components and additional financing since the river was 770 ft wider than the earlier proposed site.
Once this hurdle was overcome, along with that of acquiring part of the cane fields at Vieira’s Versailles estate on the West Bank, the contract was finally tied up in the UK in March 1976.
In May 1976 the turning of the sod signalled the start of the project...
After acquiring the site preparations were made to accommodate shipments of components, which began arriving shortly after and which could not be accommodated at the Guyana National Engineering Corporation wharf.
Unloading involved three days of non- stop work to remove all the steel which was stacked around the vicinity of the project site.
As components began arriving the area set aside to accommodate them was quickly used up resulting in additional space having to be sourced.
Another setback was the non-availability of a hydraulic crane to facilitate the positioning of the components on the river.
This was however remedied after the government, through Guyana Stores Ltd (GSL), arranged a deal to acquire it from another British company which finally had it delivered by September 1976.
Recruitment of Staff
Most of the staff attached to the project received government wages of about $550 per day Holder said, as it was done by local labourers hired by the Ministry of Works.
He recalled that Taylor Woodrow which was noted for its contracting prowess had asked to be contracted but due to the tight budget constraints it was only feasible to hire locals.
This situation was made even more difficult due to the fact that at that time there were several large contracts ongoing and the only labourers they could obtain were primary school dropouts and Bagotstown bad boys!
Additionally the other technical persons attached to the project were a group of University of Guyana graduates who had only obtained diplomas and as such were not recognised as engineers in government circulars.
Although being employed as technical engineers, the officers were not paid wages nor were they entitled to the benefits enjoyed by fully qualified engineers although being classified as such.
Holder recalled that members of this group who were members of the Public Service Union (PSU) including himself took up the grievance.
After four years of representation and five months before the bridge finally opened the government was persuaded to accept their qualifications as equivalent to that of engineers or as an alternative.
Thus Holder recalled that the project not only involved a battle against the forces of nature but also against industrial disputes.
As a tribute to his success in securing the completion and smooth functioning of the DHB he was in 1980 awarded a Medal of Service.
The spans are numbered from the east to the west with span one and 61 sitting on reinforced concrete abutments at each end of the bridge. Span 34 consists of the high span which has a horizontal clearance of 105 ft (32m) and a vertical clearance of 26 ft (7.9m) to allow small craft to pass under.
Unfortunately after ten years there was a lot of erosion due to a lack of maintenance, primarily as a result of the constantly changing management structure employed to run its affairs.
During those early years the bridge was managed by several entities including the Ministry of Public Works with part of the Transport and Harbour Department, then known as Guybridge, being merged to form the Guybridge Civil Engineering Company Ltd (GCECL). GCECL along with HRCCL and Ayanganna Consultants were brought under the umbrella of the holding company, Construction Management Combine Ltd (CMCL).
After CMCL’s dissolution in 1990, GCECL was merged with HRCCL to form General Construction Company Ltd (GCCL) which managed operations and maintenance of the bridge until 1998. During this period various individuals were responsible for the structure’s management but lack of adequate funding and general neglect led to eventual problems.
It was during this 1988-1993 period, according to Aziz, that the bridge suffered its more spectacular failures including the collapse of spans 13 and 14, which sunk to the bed of the river resulting in its closure for about two months.
It was not until European Union grants in excess of US$10M were secured to facilitate rehabilitative works that stability was restored to what is a lifeline for the West Coast communities.
At the same time the government was required to find in excess of $800M as counterpart finding to aid in the remedial work.
Holder by this time had returned to help in rehabilitative works and viewed his second coming as one for reflection and modernisation where he recognised that supporting such a structure in salt water led to high maintenance costs.
At the time of the rehabilitation, Holder appealed for such work to be done paying attention to past experiences including that of the unsuitability of steel to the salt-water surroundings.
Although questions were raised about the replacement of the pontoons with other structures including pre-stressed piles and concrete slabs these were overlooked and the steel piers were retained.
According to Holder, an idea previously suggested would have seen the high span rising to some 140-ft over the main channel occupied currently by the retractor span.
He said the floating structure could have been maintained albeit with modifications with the fly over starting in the region where the current high span is positioned and touching down east of the Republic Park housing scheme.
The cost of the entire project in 1990 was valued at US$15M which was a mere US$5M more than that eventually acquired from the EU for the rehabilitation.
This proposal, Holder said, had been the focus of a cabinet discussion during the presidency of Desmond Hoyte who later mandated a small sub-committee to look at the paper.
But Holder said the idea was later overtaken by the preparation for national elections in 1991 subsequently held in 1992 and the change in government.
No effort was later made to gain the expertise of knowledgeable professionals when bids were put out to source replacement parts under the EU-funded rehab phase, Holder said. Thus the replacement of the steel pontoons with more steel structures although a bid to supply concrete pontoons was received from a German firm.
A contract was eventually awarded to Damen Shipyards of the Netherlands for the complete rehabilitation of the pontoons and anchorage systems. It was at this time that Damen replaced 106 of the 122 pontoons, with fabrication being done by Linden Mining Enterprises (LINMINE). E C Vieira Investment Ltd was charged with the responsibility of facilitating their installation and that of anchorage components.
As part of this rehabilitation, improvements to the general surroundings including construction of new offices, a workshop, public conveniences at both sides of the river and bus stops were carried out. At the same time, a revamping of the toll system saw the installation of computers to enhance collecting, lighting for the approaching roadway and the bridge itself as well as marine and navigational aids.
Also financed under the project was the rehabilitation of the sensitive retractor span at a cost of $235M by another Dutch firm, EBR Techniek, with the local company IEL Engineering functioning in the role of subcontractor. As part of the work the winches used to open and close the bridge were replaced as well as the electrical system. The entire operation, according to Aziz, is now done by fully computerised hydraulic winches.
With the completion of the rehabilitation works in 1998 the management and Monitoring Unit responsible for that task, was assigned responsibility for the entire operations and maintenance of the bridge, a task which it continues to carry out as a semi-autonomous agency within the Ministry of Public Works and Communications.
Aziz said this arrangement was reached as a result of the financing agreement with the EU, which advised that the DHB should function as a semi autonomous body with toll revenues being at such a level to offset operational costs with reserves to facilitate future maintenance.
However although toll prices, having been kept artificially low for several years, were hiked, they are not viewed as adequate to provide for the operations as outlined in the EU agreement.
Current revenue from use of the bridge by both marine and road traffic stands at approximately $180M per year, which just about covers the cost of operations and maintenance, barring any accidents. There is little or no surplus remaining for further developmental works.
Cars pay $50, minibuses pay $100 and other vehicles, depending on the tonnage, pay stipulated sums to cross the bridge. This only occurs at the eastern end. Marine vessels of the coastal type pay $15,000 while ocean going vessels are charged $50,000 to proceed southbound. Trawlers, according to Aziz, are exempted from charges.
Statistics show that an average of 3,500 vehicles cross the bridge each way daily and on average one ocean-going vessel and eight trawlers use the bridge daily.
This situation, Aziz said, requires government to continue to provide a subvention to the entity as was the case prior to the corporation having control of its revenue stream during its early years of operation. The previous arrangement had seen all revenue earned by the bridge’s operations being passed on to the treasury and an allocation being made annually from the national budget. The government last year provided $35M in subventions to the entity for developmental works.
It is his view that despite the current economic situation, users should pay a competitive price for passage across the bridge.
Roughly 98 persons are directly employed by the DHB including maintenance and a 24-hour traffic management section whose duty it is to pay keen attention to the structure.
The traffic management section has responsibility for toll collection, bridge operations, the retractor span and security checks.
Other departments include permanent maintenance, electrical, mechanical and structural personnel.
There are also persons responsible for the maintenance of the buildings and cleaning of the surroundings.
During its life span the DHB has experienced several disruptions especially after its first ten years of existence when a lack of effective maintenance caused sections to collapse and other parts to break away in periods of heavy tidal movement.
The first incident occurred during the afternoon of March 1988 when span 13 and 14 sank to the bed due to what Aziz said was anchorage problems and lack of maintenance.
This was the first of several other operational failures which saw the bridge breaking into segments due to strong tidal action on January 28, 1991, a situation rectified on February 19 some 22 days later. On April 4, only two months later, the bridge was again forced to cease operations when a section sank, leading to over a month’s closure. It was eventually reopened on May 17. The structure broke up on January 20 of the following year. The last of the structural mishaps occurred on August 18, 1998.
Since that period several accidents involving vessels have caused disruptions, the last major one being on October 25, 2002 when a Barama tug and barge collided with the stanchion of the high span damaging two entire sections.
Damage valued at $18M is still to be paid, Aziz said. Prior to that on May 25, 2002, a barge and tug owned by Unamco broke its mooring at a nearby wharf aided by falling tides and drifted into the retractor span dislodging the entire section and damaging electrical components. Repairs costing $9.9M, according to Aziz, are yet to be paid by the company.
He viewed the collision at the high span as the costliest of all and the one at the retractor as the most technically challenging. But these were rectified within a matter of hours rather than the length of time taken when the bridge suffered earlier breakdowns.
This he attributed to the highly skilled personal employed at the DHB. This was demonstrated with the July 1 accident involving two Noble House trawlers, which caused traffic to be debarred from crossing the structure.
He said it was vital to keep the bridge’s anchorage sturdy as a means of holding the structure steady and pointed to the protection offered by buffer piles positioned around both the high span and retractor area.
There are also certain guidelines that vessels are expected to follow when using the retractor and high span including proceeding against the tide, which allows them to drift away from the bridge if they develop problems.
Additionally vessels are required to notify the bridge’s personnel when they are about to proceed, particularly when under the high span.
According to Aziz, plans are expected to include the replacement of 16 pontoons not completed under the EU project with the phasing out of the cluster pattern and installation of the new single-line pontoon in keeping with the new standard.
There are also plans to continue routine maintenance of the structure, which would see pontoons periodically being taken out, cleaned and painted to ensure that they last. To aid in this exercise, management hopes to establish a slipway of its own to undertake future maintenance. Damaged decking, which Aziz said was a frequent occurrence, is expected to receive constant attention including being coated with an asphalted surface to prevent skidding as part of the road-resurfacing project.
Other work planned includes the constant changing of wire ropes and anchorage as well as frequent checks particularly on the retractor span.
Aziz was particularly keen on stressing the importance of routine maintenance as the structure is constantly exposed to wear and tear by traffic.
He is also keen to see the government, over the next five years, give serious thought to construction of a fixed level concrete bridge to replace the aqua-panel structure already years past its original life span.
The construction of a concrete structure, similar to that erected in neighbouring Suriname, would, he said, eliminate the need for closure to road traffic on a daily basis.
He suggested components from the current structure could be used elsewhere in less salty water such as the Essequibo or across the Berbice River as an interim measure.
He would also like to see the bridge effectively being operated as a viable autonomous agency with an independent minded team of administrators who have the structure’s future at heart.
Holder is of the view that ways would have to be examined to facilitate the modernisation of the existing structure especially with the proposed siting of the deepwater harbour off the west shore of the Demerara River.
The current weight limit of 20 tonnes would be inadequate to accommodate shipments from Brazil once such a venture became a reality.
The bridge would have to be able to meet new demands or face being declared obsolete.
He suggested a similar stance be adapted as that taken towards the Berbice Bridge, which is expected to have a capacity of 63 tons in keeping with limits in Suriname.
He says most of these ideas are outlined in the National Development Strategy touted as the guide to future development.