Apool of expertise from around the globe has gone into a major bridge expansion project aimed at ensuring the safety and comfort of pilgrims performing one of the main Haj rituals.

Work was completed at the end of last year on the SR100 million ($26.6 million) expansion of the Jamarat Bridge, aimed at facilitating the stoning ritual, increasing the capacity of the Jamarat site to 500,000 pilgrims per hour and easing the movement of the pilgrims in Mina.
The project has involved the demolition of parts of the existing bridge to provide space for a new, larger structure. The new structure has an electronic system to direct and control the movement of pilgrims over the bridge. It also has a warning system for pilgrims in the tents across the plain if crowds at the site or on the access roads reach critical levels.
The project has entailed the expansion of the three Jamarat basins where stones thrown by pilgrims should fall, and the bridge leading to the site. Posts and concrete barriers provide greater safety to pilgrims.
The basins have been expanded from their previous circular shape to an oval shape, having been designed to enable better access for completing the stone-throwing ritual. 
The project was tackled by Almabani General Contractors Company, which won the contract against stiff competition.
Tracing the history of the project, Almabani’s projects director Joseph Daher says: “To overcome stampedes and unfortunate accidents at the Jamarat Bridge, the Saudi authorities initiated a project to develop ways and means to avoid such tragedies and offer safer circulation for pilgrims. Major modifications to the existing bridge were envisaged by a panel of experts on crowd dynamics and the contract went out to tender.
“Three companies were invited to bid: Saudi Binladin Group, Saudi Oger and Almabani General Contractors. Almabani, which was chosen to carry out this task, accepted the challenge and the privilege of this venture to execute this important project in a record time. It mobilised all the resources necessary to implement the project.  

Scope of work
“A dynamic design and construction team was formed – reaching 1,000 men at peak – from all the different specialisations including a team from Vinci Construction Grands Projets of France to design and value-engineer the structure to meet the crowd movement requirements, and Freyssinet Gulf to carry out the post-tensioning works for the main structure around the three Jamarats as well as the cross-heads at the bridge extension.” Work on the project required the demolition of the existing circular stoning basins and their surrounds to make way for the construction of oval ponds with a long oval ‘shakhes’ (stoning marker wall). It also entailed removal of any intervening columns and creating an expanse of uninterrupted space, which necessitated massive post-tensioned beams up to 44 m in span carried over four enormous columns, giving greater clearance around each Jamarah, he explains.
“A full-scale mock-up of the modified stoning basin and wall was erected for the evaluation of the authorities,” Daher points out.
The western end of the bridge has been widened and, subsequently, the emergency evacuation building was demolished and rebuilt at a new location adjacent to the north and south of the extension.
At the eastern side – which has seen some overcrowding accidents in past seasons – two new emergency escape stairs have been introduced.
“In spite of the overwhelming logistical and design problems involved in making extensive changes to the existing bridge structure in the very tight time frame, the project was completed on schedule, thanks to the strong cooperation and goodwill of all those involved in the project,” he says.
In addition, new signage systems comprising large elevated video screens were positioned strategically to inform pilgrims of the crowding conditions in various locations and crowd-density-sensing cameras that alert the control tower to take appropriate actions to alleviate overcrowding in any specific area.
Stesa (a sister company to Almabani), in association with Thales, a leading international electronics conglomerate, undertook this work and developed the software to count the crowds and measure the rate of flow.  This is the first time that the system has been used for such a scale, Daher points out.

Overview
“Of all the projects that Almabani General Contractors has undertaken over its 30-year history, none compares in international significance with the improvement of the Jamarat Bridge for the impact it has in facilitating a safer and more secure environment for millions of pilgrims from all over the world,” Daher stresses.“This project – though modest in its scale compared to the forthcoming grand development programme – is nevertheless a landmark development in the application of crowd management and engineering concepts and technologies. Years of studies, both in the field and in the analysis of computer-simulated models, have culminated in generic concepts that have now been applied to the existing bridge in a novel and a practical way,” he concludes.