Are Elastomers a Solution?

As I have written before, I preferred to start my professional life as a project engineer.

Although I have practiced my profession in many branches that can be done almost in this profession, including the construction site environment, the Izmir- Aydın highway bridges and viaducts, the highway bridges and viaducts between Gaziantep and Birecik, and the bridge crossings on the Batıkent branch of the Ankara metro are projects that I am proud of and value very much in my professional life, especially during my years as a project engineer.

I must say that I am very pleased that the bridges and viaducts on the Gaziantep-Birecik highway were not damaged in the recent earthquake. 

When I read in the report of the on-site inspection that there was no problem, to tell you a lie, I felt really relieved. 

I wasn't worried about anything, but still, when it is a project for which you have done the calculations and you have your signature on it, after such a big earthquake, you are a little bit worried if something has happened.

The earthquake effects of bridges and viaducts are much higher than those of building-type structures. 

Both their calculations and the construction phase require great care and especially ground investigations should be carried out very carefully. Because these are serious engineering structures.

These art structures (we call such structures art structures) should have a certain flexibility especially under heavy traffic load.

For this purpose, flexible bearings, which we call elastomers, are foreseen under the bridge girders in the project.

Although these bearings have many different solutions today, in the years when I was a project engineer, they were special flexible bearings produced with rubber-based elastomer filling material between steel plates and produced in layers in sizes suitable for their calculation.

Although the lateral displacement of these bearings during the earthquake is also taken into account, in fact, the elements that ensure that the bridge elements remain stable under the influence of these lateral earthquake forces are the earthquake wedges made and equipped with appropriate calculation on the head beam.

In these days when we realize once again that the earthquake has turned into a disaster because of the mistakes made, there are a lot of broadcasts on seismic isolators on the screens. 

Everyone is asking very curious questions about what this magic solution is.

Yes, seismic isolators are a magical solution that can minimize the effects of earthquakes on the building superstructure.

In fact, although they have recently been used in new hospital constructions in a certain environment, not many people know about them. 

However, even in my years as a project engineer, these isolators are not much different from the elastomers we used in bridge bearings.

In other words, even if we start the calculation from the years when I was a project engineer, let's say 1993, it is a solution that has been known for 30 years. 

If you take into account that there are companies in our country that started producing these bearings in 1973, these materials have already been produced in our country for 50 years. 

Their use in the world dates back much earlier. 

For the first time in the early 1800s, steel plates that allow horizontal movement in the direction of the bridge length were used in bridge bearings.

In the early 1900s, sliding bearings were used as a new solution in the form of round section steel material, or ball-style steel bearings.

In the 1950s, rubber-based flexible bearings were introduced.

These bearings are actually used to transfer the vertical load from the bridge beams to the foundations in a more flexible way, or they are thought to be a remedy for the lengthening and shortening of the bridge due to the heat, especially in countries with hot climatic conditions. 

But elastomers, which came into use especially after 1950, also provide a certain benefit during earthquakes, as they provide a certain flexibility to the bridge in lateral movements.

Of course, these bearings need to be replaced after a certain period of time due to the deformation of the rubber material.

For this purpose, we specially design the reinforcement calculation of the tie beams cast in place between the beams so that the beams can be lifted a certain amount by means of high tonnage jacks placed under the beams. All that load, can you imagine, has to be lifted so that the elastomer can be replaced.

Now, of course, it is a question mark why these systems, which have such a long history, have not been used in buildings until today. 

I am not talking about their sporadic use in some private buildings, I am asking why they have not been used in general.

I think this is because the vertical loads of buildings are quite high.  

In buildings, especially when they are multi-storey, the vertical loads on columns are much higher than on bridge beams. 

However, I think these systems could have been developed for heavy loads if desired.

Nevertheless, I would like to remind you that these and similar systems require special engineering calculations and need a good construction phase.

I think that if we gave this much importance to engineering and control mechanisms, we would not have had such a disaster without the need for these systems.

So the problem is not in the fact that something can be done better technically. It is that we as a country do not attach importance to this issue. We have poor memories, or we are careless.

The problem is that everyone, especially those who have a little money in their pockets or who have special relations in certain places, always do construction work to make money, and especially because the construction of buildings is seen as a source of rent, we collectively build bad constructions for the sake of rent sharing. 

So the problem is immorality!

As I have written before, if you are looking for a culprit, it is all of us. 

Everyone is to blame, including those who watch this rent-seeking scheme go on in front of their eyes and still vote for those who run it!

Since our topic is seismic isolators, let me return to our subject.

Can these materials be a solution to our problems?

Yes, I think they can. 

Although it is not technically possible to apply them to all kinds of buildings, I can even say that they should be made compulsory in buildings whose calculations are made in accordance with these systems from the beginning.

There are other solutions for high-rise buildings, but for low-rise buildings, yes, it can be a solution.

Because it really absorbs the earthquake effects and ensures that the buildings are minimized during the earthquake, you may not even feel the earthquake in buildings with seismic isolators.

In existing buildings, if the structure of the building is technically suitable for this, it is possible to place them on the columns on the ground floor with a special process.

I think the cost is actually not that frightening. 

If it is put into use nationwide, its cost will decrease considerably with the principles of competition.

However, the necessary arrangements in the legislation should be made as soon as possible to prevent construction by anyone and everyone. I think this is even more important than seismic isolators.

Only in this case, I think we can build strong and safe buildings in which we can live in peace.

Construction work should be done by staff who have studied and been trained in this field.

Since this will put an axe on rent sharing, I don't know if a valiant man who can do what I am saying will one day start to govern this country.

Nevertheless, let me say that I have hope.

If this nation wants, it can force those in power to make these arrangements, and I think it should!

Because I hope this nation has realized in this earthquake that these low-quality buildings can turn into coffin buildings at the most unexpected moment.

Yes, seismic isolators or elastomers are a solution for earthquakes!

Love and respect to everyone from Moscow