deflection condition

[yakubu]

The cantilever beam span shown in the picture is 200 cm. While checking the deflection condition in the program, the opening is taken as ln=160 cm, (beam h=160/5=32 cm). That is, the width of the butt beam at the end of the console decreases from the actual length. Is this true?

 

[HakanŞahin]

Hello, according to TS 500, the ln value is taken as a clean opening. The cantilever beam cassette combines with the forehead beams. Therefore, the value received is correct. Good work

 

[yakubu]

HELLO HAKAN; I understood your answer, but this situation got a little weird for me. That is, the program considers the clean opening as the ln value as per ts500. I also increased the width of my forehead beam to a value of 175 cm. When I look at the results, the deflection calculation value saves the limit value. When we increase the load of the console so much, this is an extremely strange thing, we need to provide the deflection calculation in this way, how do we explain this to the control engineers? good work...

 

[HakanŞahin]

HELLO HAKAN BEY; I understood your answer, but this situation made me feel a bit strange. The program takes into account the clean span as the ln value as per the ts500. I also increased the width of my forehead beam to a value of 175 cm. The calculation value saves the limit value.

When you reduce the beam span, you make the beam more rigid and the displacement value of the beam decreases. You can see this by looking at the deflection values in the pictures you added. When you make Ln=0.25 meters, the sudden deflection is 0.39 mm. The total deflection is 1.02 mm. Ln= When you do 1.70 meters, the sudden deflection is 5.09 mm. The total deflection is 13.38 mm. Accordingly, the deflection conditions are saved.

When we increase the load of the console that much, it is an extremely strange thing, we need to calculate the deflection in this way. How are we going to explain this to the control engineers?

What do you mean when we increase the load carried by the console? The system is completely solved and the elements are displaced as much as they can, depending on their static size. Already, the displacement values of the cantilever beam seem to have decreased considerably compared to the first. You need to provide the deflection condition by making system changes in the most appropriate way for your architectural project. A change you make may cause another result to be revealed in other elements. good work...

 

[yakubu]

Thank you for your answer. I stated that the console load will be increased by the self-weight of the 175 cm beam. Although, as you said, we can say that the system is mathematically rigid. I think that the console will behave like this after manufacturing: the outer edge of the 175 cm beam I made makes more displacement than the inner edge, that is, this beam leans outwards from the end of the 25 cm console beam. I don't know if I think wrong. The program calculates the displacement at the end of the 25 cm console, in reality, I think there would be more displacement at the 200 cm end. Thank you for your interest.

 

[HakanŞahin]

Thank you for your answer. I stated that the load of the console will be increased by the self-weight of the 175 cm beam. Although as you said, we can say that the system has become rigid mathematically. I think the console will behave like this after manufacturing: this is the 175 cm beam I made. The outermost edge of the .square beam makes more displacement than the inner edge, that is, this beam leans outward from the end of the 25 cm cantilever beam. I don't know if I am wrong. The program calculates the displacement at the end of the 25 cm cantilever, in reality, there is more displacement at the end of the 200 cm cantilever. Thank you for your interest.

The displacement is not calculated at the end of the 25 cm console. The lengths of the element rods (theoretical points of the beam-beam connections) are taken from the middle axes of the element. The concept we call clean opening refers to the part remaining after the rigid arms (3 dimensional frame) The rigid arm represents the length of the support region and represents the element forming the support. It has a stiffness that depends on the stiffness n. The displacements found as a result of the analysis, on the other hand, are the displacements found with the remaining distance value between the middle axes of the element, not the clear opening value. (More theoretically, the clear span is calculated by the total length of the rigid arms). The deflection value also depends on the solution of this system. If you change the brace width of a member supported by a beam, you change the width of the rigid arm (and therefore its stiffness), not the total span value of the member. The total clearance is still the same. The change of displacements in the example you gave depends on this reason. Examine the attached picture: In the 3D frame, the beam K01 is formed with the joint number N5 and N6. The theoretical length of the beam is the distance between the nodes N5 - N6. A green line appears to the right of the beam. This green line depends on the width of the K03 beam to the right of the K01 beam. (rigid zone length) Now the same system is done for the K02 beam immediately on the right. The only difference is that the support width (the width of K04) has been increased to 100 cm. The theoretical length of the beam is the distance between N15-N14. Note that the total length value of beam K01 has not changed. The only thing that changes is the length of the green line. (rigid zone length). If we sum up; The clear clearance value mentioned here is related to the evaluation of the deflection limit values depending on the TS 500. However, the displacement values are calculated with the distances between the theoretical points. Good work

 

[yakubu]

Your explanation was quite understandable. Thank you so much. Good work...