Allowable stress calculation and seismic resistance grade 3

Let's take a closer look at allowable stress calculations and seismic resistance grade 3.

In particular, understanding allowable stress calculations and seismic resistance level 3 is the first step to creating safer buildings.

Importance of allowable stress calculations and seismic design based on seismic grade 3

Whether it's wood, steel frame, or other construction methods, earthquake resistance grade 3 is the pass mark.

The probability of a magnitude 8 to 9 earthquake occurring in the Nankai Trough is"50% or more within 90 years, 30-70% within 80 years."How to get through this safelyEarthquake resistance grade 3 is requiredThis is common knowledge among construction professionals.

Most people believe that steel-framed buildings are strong, while wooden buildings are not, but there are steel-framed buildings with Class 1 (same level as the Building Standards Act) and wooden buildings with Class 3 seismic resistance. Naturally, in this case, regardless of the type of structure, Class 3 seismic resistance is overwhelmingly stronger.

No matter which company you go to, they will give you a catalog and sales pitch saying, "It's strong because of this construction method." That's why the general public doesn't understand, but anywayIf the structure has a seismic resistance rating of 3 or higher, it passes the test.Thinking like this can save you a lot of unnecessary headaches.

Simulation for each seismic resistance grade

In fact, there is a video that shows a simulation in which 1 houses built with strengths ranging from 3 (very weak) to 1.5 (extremely high earthquake resistance) are shaken by the seismic waves of the Great Hanshin Earthquake, assuming that the strength defined by the Building Standards Act is 0.5 and seismic resistance grade 2 is 16. If you watch this, you will see the results clearly.

It can be seen that the only houses that survived the earthquake waves were the last four buildings in the row and the two buildings on the right side of the second row from the back, that is, houses with a seismic resistance rating of 4 (= 2 or higher).

Seismic dampers: They don't just withstand vibrations, they control it

However, for those with more stringent requirements, such as "I want to reduce the shaking itself when a major earthquake hits," or "I want to maintain the initial strength as much as possible even if there are hundreds of aftershocks," or in areas where microtremor surveys show that the shaking during an earthquake is expected to be particularly intense, it is also possible to install "seismic dampers."

There are many seismic dampers available. Most of them use the frictional heat of rubber, but their characteristics vary greatly depending on the temperature, and many of them have the risk of deterioration over time. Ours is the only seismic damper that does not have such concerns, and is recommended by Mr. Sato of the Structural Engineering School.MudamWe recommend a vibration damper.

Here too there is something you must not make mistaken about."There is little point in installing seismic dampers in a building with a seismic rating of 1 or 2."That is what any reputable seismic damper manufacturer would say. However, in reality, after the Kumamoto earthquake, there was a steady stream of companies in neighboring areas that were installing only seismic dampers in houses with low seismic resistance ratings and then loudly announcing that the houses were "highly seismically resistant." This is similar to companies that rush to install underfloor air conditioners without improving insulation or airtightness.

"Basic performance trumps equipment!!"Remember, this is the starting point.