Shanghai residents walking through the city’s eastern Huangpu neighborhood in October may have come across an unusual sight: a “walking” building.
An 85-year-old primary school has been lifted off the ground – in its entirety – and relocated using a new technology dubbed the “walking machine”.
In the city’s latest effort to preserve the historic structures, engineers attached nearly 200 movable stands beneath the five-story building, according to Lan Wuji, the project’s chief technical supervisor.
The supports act like robotic legs. They are divided into two groups that rise and fall alternately, imitating the human step. The connected sensors help control how the building progresses, said Lan, whose company Shanghai Evolution Shift developed the new technology in 2018.
“It’s like giving the building crutches so it can stand up and then walk,” he said.
A timelapse shot by the company shows the school trudging forward, one small step at a time.
According to a statement from the Huangpu District Government, Lagena Elementary School was built in 1935 by the municipal council of the former French Concession of Shanghai. It was moved to make room for a new commercial and office complex, which will be completed by 2023.
Workers first had to dig around the building to install the 198 movable supports in the spaces below, Lan said. After the building’s pillars were sheared off, the robotic “legs” were extended upward, lifting the building before moving forward.
Over the course of 18 days, the building was rotated 21 degrees and moved 62 meters (203 feet) away to its new location. The move was completed on October 15, with the old school building set to become a center for heritage protection and cultural education.
The project marks the first time this “walking car” method has been used in Shanghai to relocate a historic building, the government statement said.
In recent decades, China’s rapid modernization has seen many historic buildings razed to clear land for glittering skyscrapers and office buildings. But there is growing concern about architectural heritage lost to demolitions across the country.
Some cities have launched new protection and conservation campaigns including, at times, the use of advanced technologies that allow old buildings to be relocated rather than demolished.
It can be traced back to official indifference towards historic architecture the government of Communist Party leader Mao Zedong. During During the disastrous Cultural Revolution, from 1966 to 1976, countless historic buildings and monuments were destroyed as part of its war against the “Four Olds” (old customs, culture, habits and ideas).
Mao’s death in 1976 re-emerged calls for architectural conservation, with the Chinese government granting protected status to a number of structures before passing a heritage conservation law in the 1980s. In the following years buildings, neighborhoods and even entire cities received state support to maintain their historic appearance.
Nonetheless, relentless urbanization has continued to pose a significant threat to architectural heritage. Land sales are also a key source of revenue for local governments, meaning buildings with architectural value are often sold off to real estate developers for whom preservation is not a priority.
In the capital Beijing, for example, more than 1,000 acres of historic alleys and traditional courtyard houses were destroyed between 1990 and 2010, according to the state-run newspaper China Daily.
In the early 2000s, cities such as Nanjing and Beijing – spurred by critics protesting the loss of old neighborhoods – drew up long-term plans to preserve what remained of their historic sites, with protections introduced to safeguard buildings and limit the builders.
These conservation efforts have taken different forms. In Beijing, a near-ruined temple was transformed into a restaurant and gallery, while in Nanjing a 1930s cinema was restored to resemble its original form, with some additions that adapted it for modern use. In 2019, Shanghai welcomed Tank Shanghai, an arts center built in refurbished oil tanks.
“Relocation is not the first choice, but it is better than demolition,” said Lan, supervisor of the Shanghai elementary school project. “I would rather not touch the historic buildings at all.”
He added that to relocate a monument, companies and developers must go through stringent regulations, such as obtaining government approval at various levels.
Building relocations, he said, however, are “a viable option.” “The central government places more emphasis on the protection of historic buildings. I am happy to see this progress in recent years.”
Shanghai has probably been the most progressive city in China when it comes to heritage conservation. The survival of a number of 1930s buildings in the famous Bund neighborhood and 19th-century “shikumen” (or “stone door”) houses in the renovated Xintiandi neighborhood have offered examples of how to breathe new life into old buildings, despite some criticism of how the renovations were carried out.
The city also has a long tradition of relocating old buildings. In 2003, the Shanghai Concert Hall, built in 1930, was moved 66 meters (217 feet) to make way for an elevated highway. The Zhengguanghe building – a six-storey warehouse, also from the 1930s – was then moved 38 meters as part of a local redevelopment in 2013.
More recently, in 2018, the city relocated a 90-year-old building in the Hongkou district, in what was then considered Shanghai’s most complex relocation project to date, according to state news agency Xinhua.
There are a few ways to move a building: it can slide along a set of tracks or be dragged by vehicles, for example.
But Lagena Elementary School, which weighs 7,600 tons, posed a new challenge: It is T-shaped, while previously relocated structures were square or rectangular, according to Xinhua. The irregular shape meant that traditional pulling or sliding methods may not have worked because it may not have resisted the lateral forces imposed on it, Lan said.
Additionally, the building had to be rotated and follow a curved path for its movement instead of simply moving in a straight line – another challenge that required a new method.
“In my 23 years of working in this industry, I have not seen any other company capable of moving structures on curves,” he added.
Experts and technicians met to discuss the possibilities and test a number of different technologies before deciding on the “walking machine”, Xinhua said.
Lan told CNN he could not share the exact cost of the project and that relocation costs will vary on a case-by-case basis.
“It cannot be used as a reference, because we have to preserve the historic building, no matter what,” he said. “But overall it’s cheaper than tearing down and then rebuilding something in a new location.”