"Is My Home a Bomb?"... Terrace Collapses Entirely After a Year and a Half

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

Entering the complex, the accident site where an exterior terrace had completely detached just a year and a half after completion immediately caught the eye.

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

Out of concern for additional accidents, steel pillar-style supports (jack supports) were noticeably installed on other terraces along the exterior wall of the building in question.

Workers deployed everywhere continued safety reinforcement measures while riding truck-mounted aerial platforms.

A resident who requested anonymity said, "It is a absolute relief that there was no one living in that unit," adding, "Now that an unexpected accident has happened once, I am scared that 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 persists.

The accident occurred on the morning of the 7th at 6:2 AM on the second floor of one building at the Lux Ocean SK View apartment in Songdo-dong, Yeonsu-gu, Incheon.

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

Although the unit had been sold, no one had moved in yet, and no passersby were around, resulting in no casualties.

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

The collapsed terrace is 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 that a defect occurred during the post-installation process of joining the protruding terrace structure afterward, once the building construction was fully completed.

Such cantilever structures carry the risk of collapsing under the weight if the joint construction is shoddy.

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 rebar design for the joint was 190 mm, but it explained that it was actually constructed about 50 mm shorter at 140 mm.

It also added that an insufficient injection amount of chemical anchor adhesive at the accident site was a construction problem.

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

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

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

He continued, "Since Korea uses formwork when constructing apartments, the system involves building the walls first and constructing protruding structures later," explaining, "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 president of the Korea Association of Architectural Structural Engineers, said, "When constructing protruding parts like balconies with chemical anchors, if they are not designed so that the adhesive strength is precisely exerted, risk factors exist," adding, "Thorough detail review is necessary, but this part does not seem to have been done properly."

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

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

There are a total of 24 units within the complex featuring such protruding terraces.

However, as a collapse accident instead occurred in a space they moved into after paying expensive sales prices, residents' complaints regarding fears of additional accidents are growing.

At the briefing session held by the builder, placards made directly by residents appeared, carrying messages such as "Is my home a bomb?" and "Classmates say they won't come over because the house might collapse," reflecting 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," adding, "Since the accident, there is great confusion as Jeonse and monthly renters are demanding contract cancellations due to the fear that it might collapse at any moment."

In this apartment, 57,296 defect complaints have been filed from the start of move-ins in March of last year until recently, continuing concerns over the overall construction.

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

Regarding the precision structural safety diagnosis to be promoted in the future, an agreement has been reached in the direction that the emergency committee will directly select the company, while SK ecoplant will bear the cost.

It is reported that the companying side is also reviewing plans to file a criminal complaint against the supervisory firm.

Amidst this situation, administrative authorities have also embarked on full-scale aftermath handling and cause identification.

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

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

An Incheon City official said, "Safety measures are currently underway at the site for the terrace units," 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.