The Largest Carbon Fiber Civil Structure in the World

The Largest Carbon Fiber Civil Structure in the World

An elevated walkway surrounding the holiest place in Islam was, briefly, the largest carbon-fiber civil structure in the world.  Here is a brief history of the Mataf Bridge.

In Islam, the holiest site in the world is the Kaaba, the cube-shaped building at the center of the Masjid Al-Haram, generally known in English as the Grand Mosque or the Holy Mosque, in Mecca, Saudi Arabia. Every able-bodied Muslim who can afford it is required to visit the site at least once in his or her lifetime, a pilgrimage known as the Haj. The Kaaba is also the focus of another, non-obligatory pilgrimage, the Umrah. One of the rituals performed by pilgrims during both Haj and Umrah is tawaf, the circumambulation of the Kaaba seven times in the counter-clockwise direction. The area surrounding the Kaaba, where pilgrims perform tawaf, is called the mataf. It is the central courtyard of the mosque.

Over the centuries, the mosque has been expanded several times, and it is the largest mosque in the world. The number of pilgrims and visitors has continued to increase greatly. The mataf, in its pre-2013 configuration, could accommodate approximately 50,000 pilgrims performing tawaf per hour. Nonetheless, during the Haj season, at peak traffic, performing tawaf had become difficult, and even physically hazardous. There were incidents of stampedes where pilgrims were injured or killed, such as one in 2006.

The Saudi government commissioned a study of the problem in 2011, and a multiphase plan was developed to expand the mataf as part of a larger general expansion of the mosque complex. (When this expansion is complete, Masjid Al-Haram will be able to welcome 2.5 million worshippers and visitors at a time.)

The mataf is completely surrounded by the building of the mosque, three floors of space for worshippers, including a vast open roof. To expand the mataf horizontally required removing parts of the structure, construction which would, temporarily, reduce the available space for tawaf and cause even greater crowding. It as estimated that traffic would be reduced to 22,000 per hour.

To relieve some of this pressure, the plan included expansion vertically. It consisted of an elevated walkway, made largely of carbon fiber composite, which would encircle the Kaaba. It was connected to the two upper floors of the mosque by approach walkways. The entire structure became known as the Mataf Bridge

A video by the contractor, The Saudi Binlanden Group, posted to Youtube in November, 2012, entitled “Mataf Expansion Project Simulation,” describes this walkway as a “mobile floor” with an outer diameter of approximately 94m, inner diameter of approximately 70m, and a deck 12m wide. It gives the total surface area as 3000m2, and a dead load of approximately 60kg/m2.

The video also details the method of erecting the bridge. Bridge elements would be stored in a basement area, and moved onto the mataf for erection using a temporary elevated rail system that would pass over the over the heads of worshippers so as not to interfere with foot traffic on the mataf. The video shows columns, beams, and decking being placed by cranes while worshippers are still able to perform tawaf within the inner circumference of elevated walkway. Deck sections are keyed with a slot and groove system for rapid construction. It could be assembled in less than three days.

In 2013, islam.in.ua reported the July 25 opening of the new Mataf Bridge. Use of the walkway was to be reserved for disabled and elderly pilgrims, which was said to accommodate 7,000 wheelchair-borne pilgrims per hour.

Haj Ministry spokesman Hatim Qadi said, “Since the bridge would be set apart for weak, infirm and disabled pilgrims, the movement of able-bodied pilgrims below on the ground floor will become easier as that area will be free from wheelchairs that used to clutter in an already crowded area.”

The maker of the walkway, Premier Composite Technologies, describes it on their website as the largest carbon fiber civil structure in the world:

The floor panels for each ring are manufactured from a carbon epoxy laminate with a structural foam core. The surfaces are then covered with sintered glass. The beams that structurally support the floor panels are also carbon epoxy reinforced parts.

The ceiling panels of each ring are moulded into decorative patterned panels using the same epoxy foam sandwich/carbon reinforcement construction. Each panel is also embedded with LED lighting.

All panel moulds are milled to the greatest degree of accuracy using the Premier Composite Technologies 5 and 6 Axis milling machines to ensure all design joints are 100% accurate to the nearest millimetre for optimum load resilience.

Overall the two rings are structurally supported by a total of 72 carbon tubular pillars. Built entirely out of carbon fibre using a filament winding process, the epoxy/carbon structures are up to 13metres tall, with the largest weighing only 1.5 tonnes.

All the structural elements including the columns are manufactured from carbon fibre composite materials.

A total of 400 tons of carbon fibre composites has been used, which makes it the largest carbon fibre reinforced civil structure in the world.

The structure is designed to accommodate up to 35,000 people.

It was deployed in two phases. The first deck, 4 meters (13 feet) high, was erected in the spring of 2013. After the season of Umrah pilgrimage was over, the second deck of the bridge was erected at 13 meters (43 feet) high.

The Saudi Binladen Group’s video includes animation of foot-traffic simulation software, showing the space or congestion created by different rates of worshippers entering the floor. At 12 per minute, the expanded space is greatly under-utilized. At 180 worshippers per minute, crowding slows down the completion of the tawaf, and danger of injury rises significantly. A rate of 155 worshippers entering (and leaving) per minute is found to be optimal. With an average time for completion of tawaf at 25 minutes, the two decks of the bridge could provide space for almost 19,000 additional pilgrims per hour.

In May, 2014, there was a stampede which was initially, falsely, reported as a collapse of part of the Mataf Bridge.

On Sept 11, 2015, Al Jazeera reported on the collapse of a construction crane on the third floor of the mosque, which killed 107 people

On April 4, 2016, The Saudi Gazette reported:

MAKKAH — Work on demolition of the suspended mataf (makeshift bridge facilitating circumambulation of Holy Kaba) began on Sunday. The whole process will be completed by May 27.

The temporary bridge was erected in August 2013 to reduce congestion in the Grand Mosque due to the implementation of the third phase of its expansion.

The demolition has begun on the western side of King Fahd Expansion Project as the area is ready to receive pilgrims and visitors.

Faisal Wafa, a staff member of Umm Al-Qura University, who is the chairman of the technical committee of the mataf, said the purpose behind the construction of the temporary bridge has been served. “It is time it should be demolished,” he said.

He said the contractor of the expansion project is carrying out the demolition process in collaboration with the security forces of the Grand Mosque, the Civil Defense and the technical committee to ensure the highest degree of safety for the pilgrims.

Wafa said trucks to remove the debris will enter the mataf area through Al-Shabakiyah area.

He said the the first floor of the mataf has been dedicated for pilgrims using hand-pushed wheelchairs while the mezzanine floor will be used by pilgrims on electric chairs.

Wafa said the entire third phase of the expansion project from Al-Shamiyah area, all mataf floors and the ceiling will be ready for use during Ramadan.

He said the new mataf area will allow about 107,000 pilgrims circumambulate the Kaba in an hour.”

 

In May, 2016, Arab News reported:

MAKKAH: The temporary mataf has been completely dismantled and removed, providing much more space for worshippers to perform the congregational prayers near the Kaaba on Friday.

“A total of 10,489 pieces of the mataf and connecting bridges were removed within 35 days, Wael Al-Halabi, a member of the technical committee for projects of the Two Holy Mosques, was quoted as saying by local media.

More than 580 individuals from the group participated in the removal of the bridge in addition to 80 engineers from the technical committee, he said.

He appreciated the efforts of the committee’s employees in removing the temporary mataf quickly, and also thanked the Ministry of Finance, Special Command Force of the Grand Mosque, Presidency of the Two Holy Mosques, Makkah Civil Defense and the Binladen Group.

Images sourced as noted.