BAHÁ’Í WORLD CENTRE — Construction of the Shrine of ‘Abdu’l-Bahá is moving swiftly ahead with the project team preparing to cast the roof structure—a trellis that will span the central edifice where the sacred remains of ‘Abdu’l-Bahá will be permanently laid to rest.

The project team has been meticulously laying the formwork for the trellis using expanded polystyrene (EPS) blocks that are specially cut to form valleys of negative space into which concrete will be poured, forming the intricate roof structure.

This unique roof structure will be composed of one continuous slab, making it necessary for the concrete to be poured all at once. The project team will need to work continuously over 48 hours to complete the work.

Khosrow Rezai, the project manager, explains that two types of concrete are being poured—standard grey concrete and higher-quality white concrete—and that the sequence in which these are poured needs to be carefully coordinated.

“The pouring areas are sloped in four directions,” says Mr. Rezai. “Four pumps are being used to pour the white concrete from above to the lowest areas at the north and south ends of the trellis up to a pre-determined level before we switch to the regular grey concrete that will cover the remaining areas in three separate sequences.”

It is critical that each stage follows a precise sequence, and this demands detailed planning to ensure that the stages are perfectly synchronized. Mr. Rezai explains that this process is “calculated based on the volume of concrete, the rate of its application and the areas that it covers, to allow for a continuous pour before concrete begins to set.”

The images below provide a view of aspects of the work currently under way, both in preparation for the trellis and on other areas of the site that are advancing simultaneously.

This animated sequence shows the process of building the trellis, including the placement of EPS formwork, the placement of rebar, the pouring of concrete, and finally, the removal of the formwork.

Once the EPS blocks are cut, they are encased in fiberglass to allow workers to safely walk on them without damaging the surface. After the blocks are installed, the surfaces are treated to ensure that they create the precise geometry required for the trellis.

Work to lay rebar in the valleys between the formwork blocks is advancing.

While the final preparations are made for the trellis, work on the east and west berms has continued. On the west berm, a layer of soil has been added, and the paths that will trace a star pattern on the berms are beginning to be formed.

On the east berm, a section of the base layers has been completed, leaving the remaining sections clear as a staging area for the trucks that will pump the concrete for the trellis. The other sections of the east berm will be completed once the trellis concrete has been poured.

Work on the ‘Akká Visitors’ Centre has been rapidly advancing, with the roof and walls nearing completion. Within the next few weeks, work will begin on the interior of the building.

Marble from Italy that will adorn the trellis, once the concrete structure is complete, has arrived and is being stored on the site.

The image above provides an aerial view of the latest developments on the work at the site of the Shrine.