A 26-story apartment building in Xiangyin county, Hunan province, began as a line of factory-made steel units arriving by truck. Each module was 12 meters long, 3 meters high and 2.4 meters wide, giving the pieces the compact proportions of a shipping container before they were lifted into place.
Five days later, the Jingdu Holon Building was standing. China Daily reported that Broad Group Holon built the 14,000-square-meter apartment structure from Jan. 7 to Jan. 11, 2024, using a modular system designed to move much of the work from the construction site into a factory.
The project drew attention because it turned a high-rise build into a tightly managed assembly process. The Modular Building Institute reported that the Jindu residential tower represents the 16th generation of Broad’s Holon Building concept, a system the company has been developing for nearly 15 years.
Factory-Built Rooms Arrived Ready to Connect
Broad’s method starts before the modules reach the site. Instead of building each floor piece by piece outdoors, the company prefabricates apartment units in a factory, where parts such as wiring, ductwork and other installed systems can be prepared before transport.
Once the stainless-steel modules arrive, crews stack them and bolt them together. Jeremy Zimman, marketing director for Holon modular building systems at Broad USA, told the Modular Building Institute that the current process requires no site welding. In his description, cranes pick and place the modules, workers tighten bolts, and utilities are connected after the pieces are in position.
China Daily reported that once the units are assembled, electricity and water can be turned on. The completed building includes staircases, four elevators, and eight 68-square-meter apartments on each floor, according to Zhang Yanwei, a manager at Broad Group Holon Jianan Co.
The apartments were designed as more than empty rooms. Zhang said the company was furnishing the units, while Zimman described the Holon system as a turnkey modular building product that includes air conditioning, ventilation, water tanks and other building systems. Mobile appliances, including refrigerators, washing machines, dryers, dishwashers and microwaves, are not included.
Stainless Steel Carries the Structure
The building relies on stainless-steel modules rather than conventional concrete construction. Zimman said Broad Sustainable Building was founded in 2009 after a major earthquake in China in 2008, when many concrete buildings collapsed. He said the company first moved toward steel as a stronger alternative, then later shifted to stainless steel.
That choice is central to Broad’s claims about the system. Stainless steel resists corrosion, but Zimman also pointed to ductility, which means a material can bend or stretch under force instead of breaking suddenly. Broad uses stainless steel for the load-bearing parts of the Holon system.
A patented floor system called B-CORE forms part of that structure. The Modular Building Institute described B-CORE as a stainless-steel sandwich structure brazed in a special furnace at 2,000 degrees. Sunny Wang, president of Broad USA, said it is made from two stainless-steel plates with stainless-steel tubes fused between them, with copper involved in the brazing process.
The Jindu tower used 264 modules. Zimman said those pieces fall into two main categories: room modules and elevator modules. Because the building’s walls are not load-bearing, the rooms can be configured more flexibly while the company still manufactures a limited number of module types at high volume.
Two Cranes and 100 Workers Assembled the Tower
The on-site build in Xiangyin used 100 builders working in shifts, along with one mobile crane and one tower crane. The Modular Building Institute said Broad livestreamed the full assembly on YouTube, allowing viewers to watch the tower rise as the modules were stacked.
The site’s closeness to Broad’s factory helped the logistics, according to Zimman. But the modules were also designed around the dimensions of a 40-foot shipping container, which means they can move by flatbed truck or container transport. That shape is part of the company’s broader effort to make the system easier to ship by land or sea.
Broad also claims a fast factory production process behind the short site schedule. Zimman told the Modular Building Institute that each module can be produced in 21 minutes, while the same report said a 40-by-8 B-CORE slab can be produced every two minutes. Those are company-reported production figures.
The building is intended to house people brought to Xiangyin through a special talent introduction program. China Daily reported that residents will not have to pay rent for the first two years, making the project not only a construction demonstration but also part of a local housing plan.
The Company Says the Building Can Be Moved
Broad Group Holon has made several performance claims about the Jingdu Holon Building. Li Shun, general manager of Broad Group Holon, told China Daily the apartment building is earthquake resistant because its stainless-steel structure is more durable than concrete. That is presented as a company claim, not as an independent test result in the source material.
Li also said the apartments are well insulated and can reduce air-conditioning costs by as much as 90 percent. The exterior walls are designed to reduce noise and retain heat, while four-paned windows are intended to keep solar heat out on sunny days.
China Daily reported that, according to the company, the building should last for more than 1,000 years. The same report said the entire building can be dismantled and rebuilt somewhere else when necessary, a claim that fits the prefabricated construction design but remains a company-stated expectation.
Tony Frost, a modular building expert from New Zealand, stayed for a week in an earlier 11-story Holon building in Changsha. He told China Daily the building felt strong and clean, with high-tech systems including water filtration that made the tap water enjoyable to drink. He said it felt “sturdy, almost like a concrete structure,” while adding that small changes to interior color and texture would improve it.
