About Japan’s earthquake and China’s safety issues

The reason why these "phoenixes" can remain motionless during many extremely strong earthquakes is inseparable from the earthquake-proof technology and measures used in Japanese housing construction.

Foundation and Earthquake Isolation Technique

"There are many high-rise buildings in Japan, which is a small country with a large population. In order to withstand the damage of earthquakes, high-rise buildings in Japan generally use a foundation earthquake isolation technique. Technology." Wang Wei, a registered structural engineer at the China Architectural Research Institute, conducted some research on the seismic performance of Japanese buildings when writing the paper "Seismic reinforcement evaluation standards and reinforcement methods of Japanese buildings."

According to her explanation, this technology is to install elastic rubber pads at the bottom of the building, or friction sliding load-bearing seat buffer devices to resist earthquakes. For example, a 93-meter earthquake-proof structure apartment built by Mitsui Fudosan in Suginami Ward, Tokyo, uses high-strength 16-layer rubber on the outside of the building, and natural rubber system laminated rubber is also used in the central part of the building. When an earthquake of magnitude 6 or above occurs, this protective device can reduce the stress on the building by half.

In addition, Japanese architecture is also particularly particular about the selection of materials. For example, bricks and tiles, which are often used as the main building materials in Europe and China, are now almost nowhere to be found in Japanese architecture. "The Great Kanto Earthquake in 1923 proved that brick-structured buildings are not earthquake-resistant. Since then, brick-structured buildings have almost no longer been used in Japan, and have been replaced by reinforced concrete structures supplemented by lightweight wall materials." Construction industry experts believe that, Buildings with this structure are both safe and earthquake-resistant and energy-saving.

The Kawaguchi Apartment in Saitama Prefecture, with 55 floors above ground and 185 meters high, is known as the tallest apartment building in Japan. It uses the same building material as the World Trade Center in New York, the United States - 168 cft steel pipes. This kind of steel pipe has a diameter of up to 800 mm and a thickness of 40 mm. The core of the pipe is also filled with special concrete that is three times stronger than ordinary concrete.

On the other hand, in order to improve the earthquake resistance of traditional wooden buildings, ordinary Japanese houses adopt a box design - when an earthquake occurs, the house will roll over as a whole and will not be damaged. Professional and technical personnel will also regularly assess the seismic reinforcement levels of private houses, and the government will provide appropriate subsidies and incentives to residents as appropriate.

In the Tohoku region of Japan, where it often snows in winter, in order to cope with the snow, locals often use iron plate materials for the roofs when building houses. Wang Wei’s explanation is: “Using iron plates as roofs is much lighter than buildings using tiles. In addition, in order to keep out the cold, the door and window openings of the houses in this area are smaller, which makes the rooms more earthquake-resistant. . Fewer buildings collapsed, which greatly reduced casualties. ”

Continuously improving construction laws

“After every major earthquake in Japan, the Ministry of Land, Infrastructure, Transport and Tourism will organize efforts. Building seismic investigation, and proposed revisions to the "Building Standards Law" based on the investigation results. "Yuki Terasaki, the architectural producer of the Japanese Industry Pavilion at the Shanghai World Expo, said in an exclusive interview with China Business News during the World Expo that Japanese architects are When designing buildings, the seismic requirements of the Building Standards Act will be strictly followed. And this law is revised every few years.

For example, in the 1970s and 1980s, Japan’s construction laws underwent two major revisions. First, the law denies the seismic performance of the traditional Japanese method of building wooden houses, the shaft-frame method. This construction method uses stone strips to make pillars on the foundation of the house, then puts a wooden frame on it, and uses tiles on the roof. Experts have certified that the wooden axis frame, an inherently unstable parallelogram frame structure, and the heavy tile roof have no resistance to earthquake shaking. Once it collapses, it is likely to cause personal injury. "In 1974, Japan introduced the wooden frame combined wall construction method (two-by-four MEthod) construction technology from Europe and the United States. The revised "Building Standards Act" in 1982 gave support to this construction method. Subsequent earthquakes proved that at that time This support bill is correct because none of the houses built according to the new method collapsed.

The revised Building Standards Act in 1995 stipulates that high-rise buildings must be able to withstand a force of 7 or more on the Richter scale. Severe earthquake. Terasaki Yuki said: "For a construction project, in order to obtain a construction permit from the government department, in addition to submitting design drawings, construction drawings and other documents, a building earthquake resistance report must also be submitted. "The content of the seismic report includes calculating the stress of different building structures in the earthquake according to the different intensities of the earthquake, and then determining the position of the beams and columns of the building, the load-bearing, and the specifications and proportions of steel bars and concrete during construction. Thereafter. This law has been revised three times in 1992, 2000 and 2006.