"Is My Home a Bomb?"... Entire Terrace Collapses After 1.5 Years

On the morning of the 20th, at Songdo Luxe Ocean SK View apartment in Songdo International City, Yeonsu-gu, Incheon.

Entering the complex, the accident site where an exterior wall terrace had completely collapsed just a year and a half after completion was immediately noticeable.

Beyond the safety control line, a temporary barrier was set up in the empty space on the second-floor exterior wall where the terrace should have been.

To prevent additional accidents, steel column-type supports (jack supports) were visible installed on other terraces along the exterior wall of the building.

Workers deployed everywhere continued safety reinforcement work while riding aerial work platforms.

A resident who requested anonymity said, "It is a immense relief that there was no one living in that unit," adding, "Now that an unexpected accident has happened once, I am afraid another accident might occur."

Administrative authorities have launched a full-scale investigation into the recent terrace collapse accident at this apartment.

However, as it is expected to take a long time for the investigation results to come out, residents' anxiety continues.

The accident occurred on the second floor of one building at the Luxe Ocean SK View apartment in Songdo-dong, Yeonsu-gu, Incheon, at 6:02 AM on the 7th.

At that time, the terrace structure and stone finishing materials on the exterior wall of the second-floor unit fell to the ground together.

Fortunately, there were no casualties as although the unit was sold, move-in had not taken place, and no residents were passing by the area.

SK ecoplant, the builder, cited "insufficient performance of the post-installed terrace joint" as the most likely cause of the accident during a residents' briefing session held on the 10th.

The collapsed terrace features a so-called "cantilever" structure where only one end of the structure is fixed to the building slab (reinforced concrete floor plate) while the other end protrudes and floats.

This means a defect occurred during the post-installation process of connecting the protruding terrace structure later after the building was fully constructed.

Such cantilever structures risk collapsing under loads if the joint construction is substandard.

SK ecoplant estimated that the rebar "anchorage length" (the embedded length of rebar inside the concrete to support the structure) in the terrace doorway section was insufficient.

The joint rebar design was 190 mm, but it explained that it was actually built about 50 mm shorter at 140 mm.

It also added that a shortage of chemical anchor adhesive injected into the accident site was a construction problem.

This is a method of fixing by drilling a hole in the concrete, inserting rebar, and hardening it with a chemical adhesive.

Experts pointed out that in the case of this construction method, high-level caution is required during the process, yet supervision and oversight may not have been properly carried out.

Jung Kwang-ryang, former chairman of the Korea Institute of Structural Engineers, diagnosed, "The method of drilling holes in the concrete, injecting epoxy, and inserting rebar is the method that requires the most thorough caution even among post-construction methods, and I suspect that the supervision and oversight for this were lax."

He continued, "Since Korea uses formwork when building apartments, it is a system where walls are built first and protruding structures are constructed later," adding, "The part where the balcony is joined to the existing structure is the most critical point, and the vulnerability there was missed."

Seo Gyu-seok, former chairman of the Korea Institute of Structural Engineers, said, "When constructing protruding parts like balconies with chemical anchors, there are risk factors if they are not designed so that the adhesive strength is accurately expressed," adding, "Thorough detail review is necessary, and this part does not seem to have been done properly."

He further pointed out, "For such protruding parts, there are also methods such as constructing them integrally when pouring the main body slab," and noted, "It leaves some regret that a part with large shear force (force acting on the structure) and high risk was handled using a post-construction method with chemical anchors."

The terrace unit where the accident occurred heavily promoted a specialized design boasting a "West Sea ocean view" at the time of sale.

There are a total of 24 households in the complex to which such protruding terraces are applied.

However, with the collapse accident occurring in a space they moved into after paying expensive sale prices, complaints among residents fearing additional accidents are growing.

At the briefing session held by the builder, placards made directly by residents such as "Is our home a bomb?" and "Classmates say they won't come over because the house might collapse" appeared, voicing their anger toward this accident.

An official from the residents' emergency committee emphasized, "Because many terraces are designed, it could have easily led to a major disaster," and added, "Following the accident, confusion is severe as chonse and monthly rent tenants demand contract cancellations due to the fear that it might collapse at any moment."

In this apartment, 57,296 defect complaints have been received from the start of move-ins in March of last year until recently, leading to ongoing concerns about construction overall.

The residents' emergency committee is urging SK ecoplant to refund the sale prices for households wishing to move out and to completely reconstruct the exterior walls and terraces for households wishing to stay.

An agreement has been reached regarding the precision structural safety diagnosis to be promoted later, in which the emergency committee will directly select the company while SK ecoplant bears the cost.

The management is also reported to be reviewing plans to file a criminal complaint against the supervision company.

Amidst these circumstances, administrative authorities have also entered into full-scale situation handling and cause determination.

Incheon Metropolitan City has formed a Facility Accident Investigation Committee (Investigation Committee) together with the Ministry of Land, Infrastructure and Transport to conduct a detailed cause investigation.

The committee plans to intensively examine the entire construction process including design, construction, supervision, and licensing for three months until November 20.

An official from Incheon City said, "Safety measures for the terrace units are currently underway at the site," and added, "We will uncover the cause of the accident through future on-site investigations and prepare safety measures for similar protruding structures as well."

(Photo: Yonhap News)
※ Please note: This article was translated by AI and may contain errors.