[단독] When I went up to the 39th floor, there was no ‘barrier’ to support the concrete load.

It wasn’t just high-rise structures that collapsed. Hwajeong-dong, Seo-gu, Gwangju Metropolitan City More than a week has passed since the collapse of Hyundai I’Park, and the situation in which the construction management system itself of HDC Hyundai Development Company, the builder, was poor is being revealed in various places.

As the experts directly checked the high-rise part of the building where the accident occurred, there were no scaffolding pillars that must be installed to secure the supporting capacity of the lower slab (concrete structure) during concrete pouring. In addition, specimens made and stored in the form of lumps of concrete for quality inspection of the concrete poured on each floor were not produced on the 39th floor, the source of the collapse.

Critics from the construction industry say, “If at least one of the construction officials, such as the supervisor, had been awake, this would not have happened.” This is the reason why some are pointed out that this accident is a total human resource that has led to defective materials, poor construction, and neglect of follow-up management.

According to the Hankook Ilbo report on the 18th, it was confirmed that at the time of concrete pouring on the 39th floor of Building 201, where the collapse occurred, the support that would support the concrete load had already been removed from all places except the PIT floor (the floor through which facilities and pipes pass). done.

The advisory group of experts from the Accident Management Response Headquarters, who inspected the entire building from the basement of Building 201 to the rooftop of the 39th floor for over an hour the previous day, said in common, “There were no supports that supported the building on all floors where people could walk.” Park Hong-geun, a professor of architecture at Seoul National University, who is the head of the advisory group, said, “There were no copper bars on the PIT floor just below the 39th floor, but there were no copper bars on all floors below the 38th floor, where the weight of concrete poured heavily was concentrated.” Song Chang-young, professor of architecture at Gwangju University, said, “The height of the PIT floor is only about 1.5 m, which is enough for pipes to pass through. There were no companions,” he explained.

According to the construction regulations for formwork and copper bars in the standard specification for concrete construction by the Ministry of Land, Infrastructure and Transport, when constructing a high-rise building, the copper bars must be installed over at least three floors. If this regulation was observed at the site of the accident, the 36th to 38th floors should have been maintained when pouring the 39th floor. According to experts, the concrete load applied to the 38th floor, where Dongbari was dismantled, is estimated to have reached 400 tons. Moreover, it is pointed out that the site managers and supervisory companies have neglected the follow-up management of the site managers and supervisory companies, such as the reinforcement of the ridges did not follow even though there were several abnormal signs such as dents in the flat floor prior to the collapse.

On the 14th, the police seized and searched field offices and secured 27 specimens used for the concrete compressive strength test, but failed to secure the 39th floor specimens that had been poured on the day of the accident. At that time, the specimens confiscated by the police were only for casting on the 22nd, 37th, and 38th floors. It was also confirmed that there were no specimens made on the day of the accident in the test room near the site office where the search and seizure were conducted at the same time.

Normally, when ready-mixed concrete is delivered to the construction site, the quality manager of the construction company checks the concrete dough temperature and the climate on the day of construction while watching the ready-mixed concrete company staff and supervisor, then collects samples, makes a specimen, and records them. Specimens manufactured in this way are stored in the construction site test room and the pouring site, respectively, and quality changes such as compressive strength according to climate are continuously checked. In light of this, the absence of a concrete specimen at the time of the accident is interpreted as evidence of poor quality control and inspection by the contractor and supervisor.

Gwangju = Ahn Kyung-ho reporter khan@hankookilbo.com

Gwangju = Najuye reporter juye@hankookilbo.com

Gwangju = Park Jun-gyu reporter ssangkkal@hankookilbo.com