【Life on the Construction Site】Civil Engineering Department University Curriculum Connection Construction Work Series-Material Mechanics, Structural Science

Mechanics of materials and structural science, to be honest, they are not very useful on the construction site. The on-site emphasis is on the quality management of construction according to the drawings, the progress management of completion on schedule, and the teaching of people, machines, materials, methods, and environment. Mechanics, what is the use?

When you enter the construction industry, you will find that there are many experienced seniors, not necessarily those who graduated from the Department of Civil Engineering, or even colleagues who have changed careers from the Department of Philosophy. It seems that these academic principles are not important at all, and anyone can do it. Yes, even some very powerful seniors have only graduated from high school when they have become directors and managers. It makes me think what the hell am I going to do after studying for so long?

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What is material structure?

Mechanics of materials is an extension of applied mechanics. For applied mechanics, you can read this [Construction Life] Department of Civil Engineering and Civil Engineering University Curriculum Connection Construction Work Series - Applied Mechanics . Applied mechanics is more biased towards the state of force after two objects are in contact. Mechanics of materials, on the other hand, is about the distribution of forces inside materials. Structural science and mechanics of materials have a complementary relationship. The discipline of mechanics is a complete set of systems.

Internal force distribution of components

The basic knowledge for constructing the internal force distribution is Shear force diagram and Bending moment diagram , The shape of these pictures is a bit like the Guandu Bridge. It is composed of several arches. In the past, professors would say that bridges are very mechanically beautiful structures, which should be one of the few artistic senses of our civil engineers. Show it.

The more commonly used concept is probably that a beam is stressed in the center, the largest part of the shear force will be at the left and right supports, and the largest bending moment will be in the center of the beam, which has a lot to do with how the beam bars are tied. The structure diagram is designed based on these basic arguments.

As for cutting a beam, the upper half is under pressure, the lower half is under tension, and the middle part is not under stress, which is super suspended, but this is what the mechanics of materials are learning. It is very important where the beam casing can be placed, and the rules are not set casually.

I remember chatting with a fire pipe master before. He mentioned that because of poor planning and design in the early stage of a certain builder, the fire pipes were casually passing through the beams, and they were also drilling close to the bottom of the beam, and drilling multiple holes in one beam. Drill, let it finish naturally, I think it may be because I don't understand the reason behind it.

So learn the mechanics of materials, you can more or less know why it doesn't work, you don't have to explain so much on the construction site, but at least you will know better what you are insisting on.

member deformation

Knowing the force distribution inside the material, you can also know how the material deforms, which side is deformed the most and which side is the most stressed. This will be taught in the course of material mechanics, but, although it is said to be deformation, the naked eye can't see it at all. It can only be said that the predecessors who invented the mechanics of materials are really powerful.

The most important structural units for stress and deformation are beams and columns in buildings, so the mechanics of materials also has a large part in explaining the relationship between the stress and deformation of beams and columns.

How the upper part of the beam section is under pressure and the lower part under tension, you explain it to someone who has never learned any mechanics, no one can understand what you are doing, how can it be under pressure and tension, it's too strange Well, in fact, there is no need to explain it to anyone. I have never explained such a thing on the construction site.

The beams and columns of buildings are usually rectangular solid components, but in the mechanics of materials, you will also learn some thin tube circular components, force analysis of spherical steel grooves, etc., which may be encountered in the case of chemical plants, Building a house is almost impossible.

Regarding the deformation of components, the bicycle and automobile industries may be much more professional than us. Whether the frame is rigid or not, how much deformation will be caused by turning or pedaling, how much energy can be absorbed, and how much energy consumption can be saved, which is comparable to our cover. The house is more professional, for them, our mechanics may be pediatrics.

The role of material structure on the construction site

In fact, as long as you can construct according to the drawings, you don't need to use the knowledge of material mechanics, but you will know why the lower layer of the beams and bars cannot be overlapped, and the sensitivity of looking at the construction drawings of the steel bars will become higher, and you will know why he is wrong, not Can only answer: "It's the same as the structural drawing department."

There is a concept in the structural design, to design "Strong Pillars Weak Beams" , what does this have to do with it? Sometimes the rebar workers would put more rebars in the beams when they were tying up. If they were going to ask them to take them out, the master would say, "Sir, it doesn't matter if you put more steel than less."

If you remember the above principles, you will insist on asking them to take them out. Although the influence of a beam and reinforcement may not be large, the construction according to the drawings is the basic responsibility of the construction site, not too much but good quality.

As for why strong columns and weak beams? This is because the regulations do not require that the house must not collapse. After all, there is a big earthquake that occurs once in a thousand years, and any building may be cracked. If the beam is weaker than the column, we can see the beam crack first, so that we can There is a chance to escape.

The damage of the beam is a crack, but the column is different. The damage of the column is a direct fracture. If the column is broken, the house will collapse, and there is no chance to escape. So why should the column be strong and the beam weak? This is the reason.

However, this is a bit involved in the scope of structural design, not only in the mechanics of materials, but also in the mechanics series courses of the Department of Civil Engineering, which are all related before and after. knowledge comes.

Epilogue

In fact, I have not repaired the material structure very well. I can only think of these in the application of the construction site. If the seniors who read this article have any other opinions, please leave a message and let me know.

In addition, I was also asked if there are any recommended books to read if I didn’t graduate from the undergraduate department. I listed them below. If you are interested, you can refer to them again:

• Introduction to Graphical RC Construction: Master the basic knowledge, structure, construction method and application of reinforced concrete construction at one time
• Introduction to Graphical RC Building: Master the basic knowledge, design, construction and application of reinforced concrete buildings at one time
• Introduction to Graphical Building Construction: Master the basic knowledge, construction methods and applications of building construction at one time

The engineering-related articles I wrote are all organized in this " Engineering Series Articles ", and will continue to be updated in the future, I hope to be helpful to you.