Proceedings of ICE Civil Engineering 162 November 2009 Pages 34–41 Paper 09-00024

doi: 10.1680/cien.2009.162.6.34 Keywords bridges; geotechnical engineering; project management Replacement of bridges: a mega- project for

Mostafa Hassanain PhD, PEng, PMP The Sitra bridges are part of a busy 3.2 km causeway linking is head of bridge and flyover projects at the Ministry of Works, , the main island of Bahrain to the island of Sitra, one of the most Bahrain strategic road links in the kingdom. However, after just 30 years the structures have succumbed to the aggressive marine environment and are being replaced at cost of US$280 million, along with construction of a new causeway alongside the old one and a major new grade-separated intersection. This paper describes the design, construction and management challenges of delivering the country’s biggest ever road project in a sensitive marine environment and highly congested urban area.

The Sitra bridges project in Bahrain involves 1976, the structural condition of its two marine the replacement of a 3.2 km causeway linking bridges has deteriorated so significantly that it the main island of Bahrain to the island of Sitra is no longer economically feasible to maintain across the environmentally and politically sensi- or repair them. In addition, the causeway can- tive (Figure 1). The causeway is one not accommodate the ever-increasing traffic of the most strategic road links in the kingdom’s volumes it must carry. This has led to long highway network. traffic queues that are frustrating to road users Since the causeway opened to traffic in and have a negative impact on the movement

Figure 1. in February 2007 (looking north)

CIVIL ENGINEERING Replacement of Sitra bridges: a mega-project for Bahrain

of goods and services, and consequently a detri- in length. The northern bridge has four spans mental effect on the local economy. The cause- (45.4, 54.6, 54.6 and 45.4 m), while the south- way is currently being replaced. ern bridge has seven spans (50, 60, 60, 60, The project, which commenced in November 60, 60 and 50 m). Each bridge consists of two 2006, also involves the transformation of the separate and similar structures carrying one northern approach to the causeway from an direction of traffic. The superstructures consist at-grade, signalised junction into a three-level, of cast-in-place, post-tensioned, voided concrete grade-separated interchange. This will be box girders with a maximum depth of 3 m the first such interchange in Bahrain. Umm (Figure 3). The substructures consist of cast-in- Al-Hassam junction is the main road junc- place, reinforced concrete piers (Figure 4) car- tion leading to the causeway from the capital, ried on reinforced concrete pile cap crosshead Manama, and is one of the most traffic-congest- beams over bored, steel-encased reinforced ed junctions in Bahrain. concrete piles embedded in bedrock. The abut- The approximately US$280 million project ments comprise cast-in-place reinforced con- Figure 2. Existing marine bridges have 12 m spans is the largest and most complex single road crete bank seats on similar piled foundations. and only 1.9 m navigational headroom project ever undertaken in Bahrain. The king- dom is investing heavily in this road segment because most of the passenger and heavy traffic to and from passes through it. In addition, following completion of the pro- posed Qatar–Bahrain causeway, this segment of the road network will be the main access to Manama from Qatar. Enhancement will bring significant benefits to the economy of the kingdom by easing the move- ment of people, goods and services not only on a local scale but also a regional one. The client is the Ministry of Works of the Kingdom of Bahrain, the designer and construc- tion supervision engineer is Cowi of Denmark and the main contractor is Gamuda Berhad of Malaysia. Sitra causeway

The existing Sitra causeway is a dual, two- lane carriageway with two marine bridges – a Figure 3. New marine bridges span 45–50m and provide navigational clearance of 5.2 m northern bridge 216 m in length and a southern bridge 576 m in length. The remainder is on embankments. The existing bridges are charac- terised by simply-supported spans of 12 m each (Figure 2). They carry several utility lines includ- ing high- and low-voltage cables, water pipe- lines, telecommunications cables and a natural gas pipeline. These are located beneath the deck and in the central median on an independent service deck. Some of the utility lines provide vital links in the overall services grid of the whole country. The existing bridges have low navigational headroom of 1.9 m above mean high-water level. Due to the strategic importance of the causeway to the overall roads network, traffic movement and the utilities had to be maintained during its replacement. The new crossing is cur- rently being constructed approximately 50 m to the west of the existing one and mostly parallel to it. The new causeway will be a dual, three- lane carriageway. In addition, in each direction there will be a hard shoulder that could be converted into a fourth lane in the future when increased traffic volumes require it. Figure 4. Piers of the northern bridge at various stages of construction – three temporary piled access platforms allow tidal flows to continue around the works The two new bridges are 200 and 400 m issn 0965 089 X ProCeedings of the Institution of Civil Engineers – CIVIL ENGINEERING, 2009, 162, No. CE6 35 Hassanain

Figure 5. Gridlocked Umm Al-Hassam junction in December 2005 Figure 6. Rendering of the proposed grade-separated interchange

The new bridges have navigational headroom of Following the opening of the new causeway The junction is located at the intersection of 5.2 m above mean high-water level. to traffic, the two old bridge structures will be Shaikh Isa Bin Salman highway – the main road Aesthetics of the marine bridges was a demolished, while the existing causeway will be artery from Saudi Arabia to the new Shaikh major criterion set out by the client. This has retained and converted into a landscaped public Khalifa Bin Salman port in the east–west direc- resulted in a decision to eliminate the cluttered recreational area. tion – and Kuwait Avenue to the north and appearance of utilities on and beneath the Shaikh Jaber Al Ahmed Al Sabah (which is bridge deck and to provide instead chambers Umm Al-Hassam junction carried by the Sitra causeway) to the south. It for the numerous existing and future utilities is physically constrained due to severe space inside the cross-section of the superstructures For years, the signalised Umm Al-Hassam limitations in the surrounding areas and the of the marine bridges. road junction has held the undesirable distinc- presence of a large number of significant under- The causeway embankment comprises a bund tion as one of the most traffic gridlocked areas ground utilities. constructed out of quarry run protected by rock in Bahrain (Figure 5). It was determined that The solution adopted was to transform the armour towards the sea. The bund serves as most of the traffic capacity benefits which would junction from an at-grade, signalised junction retainer of the dredged-sand filling forming the accrue from replacement of the causeway would into a three-level, grade-separated interchange final embankment and also acts as temporary not be realised if the junction was not completely (Figure 6). This involved the construction of a access road during construction. overhauled. 560 m long underpass for east–west traffic, a 26 m long at-grade bridge for north–south traf- fic over the underpass, a 379 m long flyover for east–south traffic and a 183 m long ramp for east–north traffic. The underpass consists of a watertight open- trough structure with a reinforced concrete bot- tom slab of thickness 0.5–1.2 m tied down with 942 vertical ground anchors to resist buoyancy. The side walls comprise permanent steel sheet piles tied back in the ground with inclined ground anchors to resist horizontal forces, and covered by cast-in-place, reinforced concrete cladding on the traffic side (Figure 7). The total width of the underpass is approximately 26 m and it carries three lanes plus a verge in each direction. The at-grade north–south bridge comprises a two-span, continuous, reinforced concrete deck slab that is supported at each end by the top of the underpass walls and by a central reinforced concrete wall. The central wall, in turn, is sup- ported by bored, steel-encased reinforced con- crete piles. The bridge has an overall length of approximately 26 m and a total width of about Figure 7. Underpass trough during reinforcement placement for bottom slab – showing vertical anchor 73 m. It accommodates eight traffic lanes in a sleeves, under-slab waterproofing and permanent sheet piling variety of through and turning movements, in

36 ProCeedings of the Institution of Civil Engineers – CIVIL ENGINEERING, 2009, 162, No. CE6 issn 0965 089 X Replacement of Sitra bridges: a mega-project for Bahrain

addition to a built-up reinforced concrete serv- It is worth noting that, according to the ment steel is specified as 80 mm, except ices corridor having a width of approximately literature, the Sitra causeway is the first for piles where it is 100 mm. This may be 10 m to accommodate several utilities. project where such extensive use of stainless reduced to 45 mm in locations where stain- The east–south flyover has six spans (49, steel reinforcement has been adopted. Other less steel only is used. The tolerance on the 68.61, 80, 66.39, 60 and 55 m), while the east– examples for its use for bridge construction in cover layer measured at any point before and north ramp has five spans (31.823, 40, 40, 40 North America, Europe and Asia have been after concreting is set at ± 10 mm applied to and 31 m). The superstructures’ consist of cast- recently reported, although the use of such the specified nominal cover. in-place, post-tensioned, voided concrete box reinforcement in each particular case was not girders. The substructures structural system is this extensive and was constrained to certain Geotechnical conditions similar to that of the marine bridges. structural elements. Concrete is specified in six different classes Difficult ground conditions have been Durability design for reinforced and prestressed concrete encountered in the project. In general, the according to the structure exposure condi- bearing strata for the foundations consist of The Middle East region is characterised tions and possible concrete deterioration carbonate siltstone and mudstone deposits with by aggressive environmental and climatic mechanisms. Cement type Cem I (with minor a minimum thickness of about 15 m. These conditions which make structural concrete changes and additions) in accordance with are underlaid by limestone deposits which are vulnerable to chloride attack and rapid dete- BS EN 197-13 and fly ash are used as binder. generally located at depths 25–35 m below rioration. The Sitra causeway is located in a The fly ash content is 30% of the total binder seabed or ground level, and which are known severe marine environment exposed to high content by weight. The most important ben- to be very competent bearing strata. Compared water salinity and temperatures, airborne efit of using fly ash in concrete is reduced to these limestone deposits, the strength of the chloride salt sprays and salt-laden dust, high permeability to water and aggressive chemi- carbonate deposits is more modest. temperatures and temperature gradients, and cals by creating a denser product, and thus Ground investigations at Umm Al-Hassam high humidity. improving the resistance of reinforcement to junction and in Tubli Bay for the northern To ensure the structures would resist the corrosion. The maximum water/binder ratio bridge showed that the carbonate siltstone adverse conditions and meet the client’s is 0.4. The gradation, type and source as well and mudstone deposits were so weak that they requirement for durability, a criterion was as conformity procedures of fine and course could not be core drilled; they behaved more set by the client for the design life of the aggregates are diligently specified to avoid like slightly cemented soil than weak rock. For structures at 120 years in accordance with the problems exhibited by aggregates used in design purposes, these deposits were treated British Standard BS 5400-4, Steel, concrete Bahrain. as slightly cemented very dense sand instead and composite bridges.1 This was the bridge Compressive strength of all reinforced and of very weak rock – an assumption considered design standard adopted by Bahrain until prestressed concrete is specified at C40/50 in to be on the safe side. A geological section March 2006, when it was replaced with the accordance with BS EN 206-14 meaning the along the causeway alignment is illustrated in American Association of State Highway and 28-day characteristic 150/300 mm cylinder Figure 8. Transportation Officials AASHTO LRFD strength of 40 MPa or 150 mm cube strength Assigning characteristic values for the relevant bridge design specifications.2 of 50 MPa. geotechnical parameters to be used in the design A rational probabilistic, performance-based, The nominal concrete cover to reinforce- of the foundations was challenging due to the service-life design methodology was used by the designer to model the transport of aggres- Length along causeway: m sive substances into concrete and the corre- 0500 1000 1500 2000 2500 3000 3500 sponding deterioration mechanisms. Life-cycle 7 costing studies were carried out to compare 6 the performance of different alternate materi- 5 4

als with respect to the design life requirement. m Northern bridge Southern bridge

The approach adopted was to use stainless m: 3 steel reinforcement in those areas of the struc- 2 tures most exposed to chlorides, combined with Datu 1 carbon steel reinforcement in other locations. ey rv 0 Su

The reinforcement is distributed as follows –1 al

on –2 n piles – carbon steel only ti –3 n pile caps – carbon steel mostly with a few Na n n stainless steel dowel bars for the piers –4 n piers – stainless steel in the outermost –5 Bahrai layers with carbon steel in inner layers –6

n superstructures – stainless steel in the rom –7 l f l

outermost layers of exposed outer and ve –8 Top of upper caprock inner surfaces with carbon steel in dia- Le –9 Top of marine sand phragms and as bursting reinforcement –10 Top of lower caprock n base slab in underpass – carbon steel only –11 Top of carbonate siltstone and mudstone n cladding walls covering sheet piling – –12 stainless steel in the outermost layers of exposed surfaces with carbon steel in Figure 8. Geological section along the causeway alignment inner layers. issn 0965 089 X ProCeedings of the Institution of Civil Engineers – CIVIL ENGINEERING, 2009, 162, No. CE6 37 Hassanain

variability and relative incompetency of most of and the abutments of the southern bridge. Some Rock socket the underlying ground strata. This was accom- of the piles were raked at 4:1 (Figure 9) to help plished using the available ground investigation resist the horizontal earth and surcharge pres- lengths varied data in conjunction with experience with similar sures more efficiently. . ground conditions in the region. Pile lengths in limestone (rock socket lengths) from 16 5 to 37 m The presence of relatively competent bearing varied due to the competency variability of strata of carbonate siltstone and mudstone at ground strata. The derivation of ultimate end depending on the variable depths below seabed or ground level bearing capacity and skin friction of the bored called for pile foundations. Pile diameters varied piles was based on the design principles outlined characteristics of between 1 m for the east–north ramp to 1.2 m in AASHTO LRFD bridge design specifications.2 for the piers of the southern bridge, and 1.5 m Rock socket lengths varied from 16.5 to 37 m the bearing strata for the east–south flyover, the northern bridge depending on the characteristics of the bear- ing strata; the longest were for the piers of the northern bridge. Pouring mass concrete

Several structural elements required pouring massive quantities of concrete. The casting of elements such as the base slab of the underpass, as well as the pile caps (some of which have dimensions of 19 × 7.5 × 3 m for the northern bridge) can generate significant heat from hydra- tion of the cement, leading to thermal cracking. This is even more challenging during the hot summer months. The specifications limited the maximum concrete temperature to 65ºC. Additionally, the maximum temperature difference between the mean temperature of any structural element and the temperature at the surface of the element was limited to 15ºC. To reduce the temperature of mass concrete pours, the contractor used small-diameter steel pipes embedded in the Figure 9. Abutment piles for the marine bridges – some were raked at 4:1 concrete to circulate cool water (Figure 10). This decreased the core-to-surface temperature gradient. It also controlled the subsequent heat removal and accompanying concrete volume changes during the early stages of hardening in the first several days following placement. Water with a temperature of 15ºC was cir- culated in pipes fitted with control valves that allowed small adjustments to the rate of water flow. The water then returned to the cooling machine at a temperature of about 18ºC, where its temperature was brought down to about 15ºC and recirculated in the pipes within the mass concrete. Concrete temperatures were continuously monitored for 14 days after placement, after which the embedded cooling pipes were pres- sure grouted. Silt treatment and removal

Deep silt deposits on the seabed in Tubli Bay proved problematic for the construction of the causeway as they are highly compressible and not suitable as a foundation base. North of the northern bridge, the silt layer thickness was about 1.5 m and had to be removed. A simple method was utilised by the contrac- Figure 10. Cooling pipes within the reinforcement of the underpass bottom slab tor, involving building a temporary rock bund

38 ProCeedings of the Institution of Civil Engineers – CIVIL ENGINEERING, 2009, 162, No. CE6 issn 0965 089 X Replacement of Sitra bridges: a mega-project for Bahrain

3 m away from the toe of the proposed per- from intensive reclamation, and the discharge of tidal levels and therefore flushing of the bay. manent quarry run bund. The temporary bund partially treated sewage and industrial effluents. The contractor thus erected three temporary fully enclosed the area to be cleared from silt Government and community bodies are now platforms supported on driven steel piles across (Figure 11). Water pumps were used to dewater voicing the urgency of restoring Tubli Bay. The each marine channel to provide access for the bunded area and the silty material was left matter has also been a source of much political construction activities (see Figure 4). These to dry. Excavators then removed it for disposal wrangling in the country’s parliament as well as platforms allow largely unrestricted water in an area approved by the environment authori- in the local media. movement into and out of the bay. ties. Over 15 200 m3 of silt was removed from The environmental and political sensitivity Temporary cofferdams are installed to provide this location. After removal of the silt, construc- of Tubli Bay precluded any significant blocking safe working platforms for the construction of tion of the permanent rock bund and embank- with temporary backfilling of the northern and the bored piling, pile caps and piers. Each coffer- ment filling followed. southern marine channels during construc- dam has dimensions of 24.7 × 24.7 m, and con- A similar method was used at the southern tion of the new bridges, in order to maintain sists of steel sheet piles, walers and cross-braces approach to the southern bridge, where silt deposits 3–3.2 m thick were present. However, this was a larger area and even after it had been dewatered, access for the removal of the silt was not as easy. Temporary rock access roads were therefore constructed within the bunded area; there was a central spinal access with ‘fingers’ leading off on both sides. These access roads overlaid the silt and were approximately 1.5 m thick. They were removed on completion of the work. About 40 000 m3 of silt was removed from this location. The presence of much deeper deposits of silt than was expected in other areas of the project necessitated the adoption of a more complex and expensive approach. Some areas south of the causeway, where a permanent road was to be constructed, had deposits with depths exceeding 6 m. At the toe of the south abutment of the southern bridge, a ‘valley’ with an average thick- ness of silt of approximately 10 m was identified. At the north abutment of the southern bridge, silt layers approximately 2 m in depth were present. Dredging was utilised at these three locations to remove the silt. Figure 11. Treatment of silt north of the northern bridge A cutter-suction dredger pumped the silt to a separation and water purification area (Figure 12). The material was then allowed to settle. Clean water was later discharged into the sea and the remaining silt was removed by excava- tors to a stockpile area, where it was left to dry and then disposed of. A total of about 287 000 m3 of silt was removed using this method. Since construction of the southern bridge was a critical-path activity, removal of these unexpect- edly large quantities of silt caused a delay to the contractor’s schedule. This was the main reason for granting the contractor a 211 day extension of time. Working within Tubli Bay

The existing marine bridges allow coastal tidal flows into and out of Tubli Bay to the west and the passage of minor marine vessels mostly for small-scale fishing activities. Tubli Bay is an inshore coastal area of high environmental sensitivity and importance, and was once consid- ered to be one of the richest marine and coastal resources in Bahrain. However, over the past Figure 12. Dredging of silt south of the causeway three decades, the bay has suffered significantly issn 0965 089 X ProCeedings of the Institution of Civil Engineers – CIVIL ENGINEERING, 2009, 162, No. CE6 39 Hassanain

(Figure 13). Installation of the cofferdams is by the construction works and accommodating area. Traffic counts and observations revealed staged in such a way that minimises obstruction them at another location within the project area. that traffic conditions in the junction after the to tidal flows and thus the flushing of the bay. implementation of the ‘tennis racket’, in gener- The cofferdams are dewatered through staged Traffic management plans al, did not get any worse than they were before excavation with progressive installation of sump Mega-projects attract intense pressure to mini- the implementation. pits. Removal of silt and other unsuitable mate- mise, if not to eliminate completely, their adverse Due to the anticipated effect of the traffic rials is carried out until reaching the caprock construction impacts on road users. In addition, management plan on road users, an extensive level. Depending on the particular geotechnical some of the toughest project challenges tend to media campaign was put in place to alert the conditions at each cofferdam, caprock is to be be concentrated in some of the oldest and most public and to guide them to possible alternate broken through to reach the formation level of congested urban areas. The combined effect of routes away from the construction site. An the pile cap. The cofferdams are then filled with these factors presented huge challenges to man- extensive communications plan was implement- dredged sand for construction of the bored piles, aging traffic in and around construction zones. ed to secure the support and cooperation of the following which the infill material is excavated to These factors played a big role in determining traffic planning authorities and the traffic police. the formation level of the pile caps to allow the the optimal traffic management (diversion) plans construction of the pile caps and piers. implemented in the project. Underground services diversions A key requirement by the client was to Bahrain is a small country. As a consequence, Project management challenges maintain traffic without interruption during all all road reserves are usually occupied with phases of construction. A key objective of the numerous underground utilities. At major Mega-projects of such size and complexity traffic management plans developed was to road intersections, such as Umm Al-Hassam require the cooperation of numerous stakehold- minimise construction-related traffic congestion junction, myriad utility crossings exist. Some ers representing a variety of interests, priorities, by providing safe and comfortable detours to of these utilities were laid many years ago and opinions and agendas. There are over 40 primary road users around the work sites. This was not accurate as-built drawings for their alignments stakeholders in addition to numerous other only beneficial to the travelling public but also and depths do not appear to exist. It is not secondary stakeholders involved in the project. to the contractor by ensuring safe and efficient always possible to confirm the locations of all Achieving and maintaining stakeholder and construction activities. utilities crossing major intersections during public support and cooperation throughout the In addition to many minor and short-dura- project planning as this would result in unac- project has proved exceptionally difficult; in fact tion traffic diversions, the contractor has thus ceptable interruptions to road traffic. This has it has been the most challenging aspect of the far successfully implemented one major traffic resulted in situations where complete reliance project thus far. management plan at Umm Al-Hassam junc- on as-built drawings has caused problems dur- Some of the numerous project management tion. This plan was put in place in May 2007 ing construction. challenges encountered on the project are dis- to allow the contractor to start excavating the For example, early site investigation following cussed in more detail below. Other challenges western side of the underpass. The junction was the commencement of the project showed that included relocating 23 tenants of the northern converted from a signalised intersection into an a 900 mm diameter foul sewer pipeline running strip of Mina Salman industrial area to make elongated signalised roundabout, often referred along the northern side of Shaikh Isa Bin Salman possible the widening of the southern side of to by the project team as the ‘tennis racket’ due highway is located further south than anticipated Shaikh Isa Bin Salman highway, and compensat- to the obvious resemblance (Figure 14). Traffic at its western end, and that it encroaches into ing the fishermen of Tubli Bay who were affected was rerouted safely around the underpass work the excavation of the underpass. The contractor was instructed to construct a realignment of the encroaching segment of the pipeline away from the underpass excavation. At the eastern end of the pipeline, the sewer was found to be very close to existing build- ings and the contractor decided to thrust-bore the sewer in the vicinity of these buildings. The sewer relocation was also affected by 11 kV and 66 kV electricity cables, and telecommunications fibre-optic cables, which either cross or run near the revised alignment. Thrust-boring was there- fore extended to overcome these obstructions. The connection of the revised alignment to the existing alignment at the eastern end was affected by water mains, resulting in the instal- lation of a temporary segment of reduced sewer pipe cross-section until the water mains are decommissioned and removed in the future as part of the project. This situation delayed the contractor’s schedule by several months because construction of the underpass is a critical-path activity. The contractor was then granted a 100 day extension of time. Numerous types of utilities other than those already mentioned exist around and across Figure 13. A cofferdam with a completed pile cap and pier Umm Al-Hassam junction: 220kV and low-

40 ProCeedings of the Institution of Civil Engineers – CIVIL ENGINEERING, 2009, 162, No. CE6 issn 0965 089 X Replacement of Sitra bridges: a mega-project for Bahrain

Figure 14. The ‘tennis-racket’ signalised roundabout at Umm Al-Hassam junction

voltage electricity cables, several sizes of water utilities-related works and also instilled a sense mains, several sizes of stormwater drains, of focus and accountability among the concerned References 1. br i t i s h St a n d a r d s In s t i t u t i o n . Steel, Concrete treated sewage effluent lines and natural gas stakeholders. and Composite Bridges. BSI, London 1990, BS pipelines. Several of these utilities have to be 5400-4. diverted and/or protected during construction. Conclusion 2. am e r i c a n As s o c i a t i o n o f St a t e Hi g h w a y Some will be abandoned, but several will be a n d Transportation Of f i c i a l s . AASHTO laid anew. Mobility of people, goods and services is an LRFD Bridge Design Specifications, 4th edn. To complicate matters even more, the authori- important requirement for the economic growth AASHTO, Washington D.C., USA, 2007. ties in Bahrain ban all construction works on of any country. Economic activities prosper 3. br i t i s h St a n d a r d s In s t i t u t i o n . Cement – Part or near high-voltage electricity cables for about where accessibility is good and mobility is fast. 1: Composition, Specifications and Conformity 6 months every year because there is not enough Thus, transportation infrastructure facilities are Criteria for Common Cements. BSI, London, 2000, BS EN 197-1. redundancy in the system to accommodate among the most important factors for the devel- 4. br i t i s h St a n d a r d s In s t i t u t i o n . Concrete. Part power cuts caused by damaged cables during opment of an economy. 1: Specification, Performance, Production and hot summer months. Although this is gradually Bahrain is investing heavily in the upgrading Conformity. BSI, London, 2000, BS EN 206-1. changing as the government upgrades the electri- of its transportation infrastructure. Currently, cal power infrastructure, it remains an important the cornerstone of this investment is the replace- constraint that must be taken into account in the ment of Sitra bridges. This mega-project, when contractor’s schedule. Any slips in carrying out completed in mid-2010, will introduce a major any required cable diversions and/or protections enhancement to the roads network in the king- What do you think? could delay the schedule by several months. dom, and thereby will provide a significant boost If you would like to comment on this paper, Regular coordination with the various public to the country’s economy. please email up to 200 words to the editor at and private utilities agencies was carried out [email protected]. diligently on this project, sometimes under the Acknowledgement If you would like to write a paper of 2000 to 3500 patronage and with the contribution of the high- words about your own experience in this or any est levels of senior management in the client’s The author thanks the Ministry of Works, related area of civil engineering, the editor will be organisation when needed. This helped over- Kingdom of Bahrain for permission to publish happy to provide any help or advice you need. come impediments to the timely completion of this paper. issn 0965 089 X ProCeedings of the Institution of Civil Engineers – CIVIL ENGINEERING, 2009, 162, No. CE6 41