Looking back at the past, there are many vintage technologies that we no longer use - telex machines, analog telephones, cassette tapes and floppy disc. While we may find it amusing that anyone ever found this technology to be cutting-edge, we can’t overlook their place in history. After all, much of today’s technology would not exist without its dinosaur ancestry.
Uncovered coal stockpiles may now become history too.
Freedome® technology moves the task of covering stockpiles into the next generation. Freedomes (Geometrica’s trademark for freestyle domes) allow for versatile and flexible design options for irregular piles with spans up to 300m. This cutting edge, patented, all-terrain building system offers safe, economical, efficient storage with low maintenance.
With 25 years experience providing bulk storage solutions around the globe, the Freedome at Bocamina II is one of Geometrica’s most challenging and successful projects to date. Here’s a lighthearted video (duration 01:44) about how we delivered this exciting project from concept to completion.
Bocamina’s New Coal Storage
Located in the coastal town of Coronel in southern Chile’s Bíobío region, the Bocamina power station is a thermoelectric power plant operated by Endesa, the country’s largest electric utility company.
Covering the coal storage yard was part of Endesa’s overall initiative to bring the plant’s environmental standards to a level amongst the highest in the country, if not the world. Endesa contracted with Echeverria Izquierdo Soluciones Industriales (EISI) for the construction of these improvements for the plant in mid-2015.
Because of the long span and irregular shape required for the storage area, it was concluded that only one global supplier could deliver - Geometrica. Today, Bocamina is the first plant of its kind with such a modern coal storage structure.
Endesa's Bocamina power station near the coastline
Endesa provided the design requirements for the structure. Based upon these requirements, Geometrica designed the storage structure. Due to its proximity to the coast and location near convergent tectonic plates, the design incorporated severe wind and seismic loading conditions.
The coal storage dome installation finished in December 2016.
|Coal Storage - Freedome|
|Storage Capacity (MT)||150,000|
|Plan Shape||Triangular free-form|
|Major Span (m)||206|
|Minor Span (m)||151|
|Structure Material||Galvanized Steel|
|Structure Support||3m high concrete wall|
|Access Openings||1 feed conveyor, 2 personnel, 10 vehicle|
|Ventilation||Gravity and Forced|
|Catwalks and Stairs||781m|
|Material Handling||Slewing Stacker, Front end loaders, Reclaim hoppers|
|Structural Bars (qty)||92,100|
|Covered Area (m2)||22,400|
|Cladding Area (m2)||28,350|
Access openings for vehicles and personnel were incorporated into the design. Galvanized steel stairways and walkways were also provided with OSHA-approved guide rails and non-slip grating. Most of these stairways and walkways hang directly from the Freedome to provide access to the ventilation system, lighting, and to help with coal inspections.
The Freedome is made of galvanized steel tubular bars joined by high-strength cylindrical aluminum connectors. Not only lightweight, galvanized steel provides corrosion resistance for years of worry-free storage with minimal maintenance.
Cladding, made of galvanized and painted corrugated steel panels covers 94% of the surface area; translucent acrylic panels in a matching profile cover the remaining surface area to allow natural light into the structure. At the dome’s apex, a vent cap 20m in diameter was installed.
Construction was carried out entirely with locally-sourced labor and supported with site consultants from Geometrica. No welding was required since all of the structure’s connections were joined with Geometrica’s efficient, mechanical hubs.
Locally-sourced labor with a perfect safety record
The Freedome was divided into two-ton substructures. The substructures to be installed first were made first. All manufacturing was carried out in complete substructure units that were sorted and crated according to the exact installation sequence.
Every structural member received a dot peen mark and sticker with identifying information. Unique marks, part numbers, fabrication parameters, packing parameters and QR coding ensured that all part information was available exactly when and where required.
The coal storage structure was fixed to a reinforced 0.75m wide concrete edge beam. The edge beam rests on a reinforced concrete wall approximately 3.5m high. The wall and beam were built in two concrete casting steps. The first casting, 3.2m high, acts as a support for the structure. The second casting, approximately 0.3m high, was done after the structure was completely assembled, and anchors the base ring of the structure onto the supporting wall.
Bocamina’s Freedome used the “perimeter-up” method of construction. The first layer of nodes and tubes were laid on the supporting concrete wall. Then, every 3 to 5 tubes were joined to one node to form a “spider”. Each spider was then raised to the work front and tapped into place, creating a ring around the entire base. These rings grew, one on top of the other until the whole skeleton was formed.
Cladding installation underway for the new Freedome
Neither scaffolding nor other special equipment was required, and the project was completed with a perfect safety record. After erecting the complete structure, the galvanized steel and acrylic cladding panels were installed.
EISI’s head of engineering, Francisco Sanchez, had this to say about the project: “I was impressed by the professionalism, precision, and respect demonstrated by everyone at Geometrica. It has truly been excellent work.”
The Rest is History
Old ways to cover stockpiles and control fugitive dust just don’t work well anymore. Conventional building systems have limitations and simply cannot accommodate covering large spans on uneven terrain. Sprinklers add moisture and deplete water resources. Chemical treatments are generally expensive to use. As a stopgap measure for a windbreak, walls or fabric barriers can be tried but they are often ineffective.
Geometrica has the solution to cover large volumes of coal. What was once thought impossible, Endesa has a new cover for its coal stockyard at their Bocamina plant. Chile’s largest electricity provider has set a new standard for environmental excellence.
Endesa's new Freedome is now a landmark in the city of Coronel (Chile)
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