Long Spans

M

muhendis_gokhan

New Member
Greetings to everyone, In normal reinforced concrete structures, our project is hollow block, that is, our beam height is 30 cm. According to my observations in several projects that I have heard and seen, men crossed 13 meters with a beam of 30 cm in height. They used beam dimensions of 30 cm and 120-130 cm or something. But even if the width is 120, as the beam height is 30 cm, shouldn't our length be 1/15 in the inner beams according to the regulation, since the beam height is 30 cm? I mean, I have projects where I exceed 7-8 meters with 30 cm, but 13 meters is a very large span... How can we operate such a beam without any problems, and on the basis of which directive is a project with such beams approved? I would like to thank you in advance for your help, especially if there is a friend who uses this type of beam and has his project approved... :?: :?:
 
When my friend is no longer a room control, it is left to the knowledge of the controlling friends. Even if the programmers keep this job tight enough, they can't do the job. after that it becomes the work of an ignorant engineer.
 
Hello, the limit values given in TS 500 Article 13.2.1, Table 13.1 determine the height/span ratios that do not require deflection calculation. If the deflection is calculated, the conditions in the chart are not binding. Good work
 
Okay, that's exactly what I'm saying, brother. You said that if the deflection calculation is made according to this item in TS500, this item is not binding. How is this done by adjusting the brogram or do you mean if I do the deflection calculation manually?
 
In the program, when the beam height/span ratio exceeds the limit values given in Table 13.1, deflection verification is made automatically. In addition, in the case that does not require deflection verification, the user can have the deflection inspected under any condition by ticking the Always check deflection condition option in the beam settings.
 
Something came to life in my head, thank you, Mr. Levent. As you exemplify, I used 7.60 beams a lot, but I think these 13-meter beams I saw are troublesome and impose a great responsibility on us :)
 
The amount of deflection allowed at 13m is 5.42 cm and it is excessive for a 30 cm beam, and for such a beam, the deflection value will be around 10 cm even if there is no load on it... So it is not possible to prove it by calculation... It is not quite right to cross those openings with that height, except for pre-stressing.
 
yes, you're right, almost twice the deflection value. By the way, let me ask you something else, if the sudden deflection is calculated according to ln/180 rather than ln/360, what's wrong with it? then there will be more deflection amount and we will be able to pass a longer distance without changing the beam height, right? Or am I confused? :) (By the way, the place where I'm doing the project is not the earthquake zone, it's the 5th zone, that is zero, but of course we take it as the 4th zone in the program)
 
sudden deflection is not a problem, the problem is the total deflection... Deflection does not have much connection with the earthquake zone, the combination that will cause deflection problems in the calculation is mostly 1.4g + 1.6q
 
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