Analysis of Dangerously Rushed Apartment Construction (1): Expert Warns '90 Years Behind Japan, Durability at Most 10-15 Years' - Severely Lacking Materials, Zero Power Sources...

◆ Far Too Little Reinforcement... Clear Material Shortage

-- Material shortages are also serious in North Korea.

Imamoto: Material shortages can be seen in various aspects. As mentioned earlier about the forms, all temporary materials like scaffolding and support structures are wooden. No steel is used at all.

While bamboo and such are often used as temporary materials in Asia where wood is abundant, steel is still used for elements that must bear concrete weight or need secure fixing.

-- How about the amount of reinforcement used in the building?

Imamoto: The amount of reinforcement is very low. One indicator of building safety is 'structural safety,' which measures resistance to external forces like earthquakes and is determined by concrete strength and reinforcement amount.

The vertical reinforcement bars in columns called 'main bars' (② red circle) only number four, the minimum. In Japan, typically 12-20 are used.

The parts wrapping these main bars in a band shape are called 'shear reinforcement.' The closer the spacing, the higher the seismic resistance. Earthquake-prone Japan requires spacing under 15cm. However, here in North Korea, judging from the size of nearby workers' helmets, spacing appears to be about 30cm.

Also, walls typically have reinforcement at minimum 20cm spacing both vertically and horizontally. In this photo (③), while vertical reinforcement is visible, spacing appears to be over 1m apart.

◆ Total Collapse in Great Kanto Earthquake Scale, Safe Habitability Only 10-15 Years

-- Overall, how would you evaluate the level of North Korea’s construction capabilities ?

Imamoto: Judging from construction conditions and methods, it's close to Japan's construction competency in the 1920s-40s. That’s about 90 years ago. When we investigated the concrete strength of 5-6 story reinforced concrete apartment buildings built in Japan during that period, it was about half to two-thirds the strength of recently built buildings under similar conditions.

-- What's a concrete image of that strength level?

Imamoto: If an earthquake of the Great Kanto Earthquake (in 1923) occurred in North Korea, it wouldn't be surprising to see damage similar to Japanese buildings of that time - meaning many buildings could totally collapse.

-- North Korea has very few earthquakes. In that case, how long might the buildings last?

Imamoto: Along with 'structural safety,' another important indicator is 'durability' - or in other words, 'how long can it be safely inhabited'? The durability of these North Korean apartments would likely be at most 10-15 years.

For example, when reinforcement inside concrete rusts and expands, causing concrete to crack and fall off, that's not a safe living situation. Considering the removal of the form too early, unfortunately, these cannot be seen as buildings that can be safely inhabited for a long time. (to be continued)

※ All construction site photos are from Sinuiju, North Pyongan Province. Photographed by ASIAPRESS in October 2024.

Analysis of Dangerously Rushed Apartment Construction (2): Expert Says 'Only Completion Matters, Life is Being Disregarded' - Past 23-Story Building Collapse in Pyongyang...