clarification diagonal beams chevron i beam

[odisseo 18]

If it were possible, I would like to make more clear on the supporting element that in American is called beam chevron and in Italian should be an oblique shackle countervent, which would discard weight tensions and stresses on the supporting columns of the structure, I am clearly referring to heavy metal carpentry structures. Thank you.
chevron effect and chevron beam analysis:
" from source to network
beam designers and connection designers have a different standard of care in the analysis of beams in v- and v-converted frames subject to side loads. when the sum of the vertical components of the counter-winding forces is different from zero, (1) the beam designers evaluate the cut and the moment of the required beam, treating the vertical unbalanced load as a concentrated force that acts at the counter-effects point ignoring any local effect resulting from the geometry of the connection of the counter-wind and (2) the connection designer assesses the cut of the beam required based only on the moment that acts on the interface between the beam. This document proposes a new method to evaluate the cut and time of the required beam that includes the consideration of beam light, the position of the working point and the local effects of the connection, a method that can be used both by the beam designer and the connection designer. shows that the scale of the unbalanced vertical load affects the impact of the local connection effects; when the sum of the components of the vertical wind force is nothing or relatively small, the local connection effects dominate the overall effect. on the contrary, when the unbalanced vertical load is relatively large, global effects prevail; In this case, including the local connection effects it will be possible to predict a smaller required beam moment, possibly allowing lighter beams.

the system of chevron countervents provides the highest level of rigidity and average ductility using the yielding or instability of the countervents. This system shows weak post-instability behavior while other structural elements such as beams, columns and joints show elastic behavior. as a result of the instability of the convent on a plane, the unbalanced force acts perpendicularly at the center of the beam's field and translates into the concentration of the damage on that plane. Consequently, the interested story becomes prone to the mechanism of soft history and the structure eventually collapses. to avoid this problem, it is possible to place vertical elements (cerniere) between the beams so that the head of the countervents is connected at altitude and the consequent debalancing force in the plane is transferred to the upper floors. such frame is known as the hinge frame. with proper hinge configuration, you can face the problems and weaknesses of the chevron reinforcement frame. Therefore, frames for hinges can become real substitutes of this type of reinforcement systems. using the chevron element in the chevron counterwind and turning it into a hinge frame, it is possible to increase the strength, ductility and energy absorption capacity of such frames.

An Overview of Pros and Cons of Zipper Braced Frames

An Overview of Pros and Cons of Zipper Braced Frames

www.cwejournal.org

 

[odisseo 18]

a friend of mine told me that in his opinion this type of beam could be assimilated to a "dot" or to a counterventure to counteract the lateral thrusts

according to his intuition:
from the structural point of view is called a working element, as it is understood from the term, simple compression, unlike the pull that instead works with simple traction.

the dot is also called "biella compressessa" or "asta compressessa". the rod and the dot represent the simplest finite element: rod element or biella.
the dot and the pull are the components of isostatic reticulation beams.
a last question if I can without a further question
What difference would there be between trave np,trave ipe and trave inp? thanks greetings and greetings to all of you.

 

[biz]

What a difference would be between beam np,trave ipe and beam inp

vary geometric characteristics and static values.

 

[odisseo 18]

Basically, I think ipe is more robust right?
the np if I have not understood badly they are used as contrafixes to realize the frames in metal carpentry "skid ", right?

 

[biz]

ipn and inp were more common in the past, while ipe is much more common nowadays. I can't justify the answers. I don't want to say nonsense, but I think ipe is more "young" than ipn. between ipe and ipn or inp there is no substantial difference as regards static values, tables at hand.
Well different with he obviously.
then if you go to see Indian standards, for example, with which I have been dealing lately, there are other normalized profiles that are very close to our ipe, for example. This is my opinion.

 

[meccanicamg]

a friend of mine told me that in his opinion this type of beam could be assimilated to a "dot" or to a counterventure to counteract the lateral thrusts

according to his intuition:
from the structural point of view is called a working element, as it is understood from the term, simple compression, unlike the pull that instead works with simple traction.

the dot is also called "biella compressessa" or "asta compressessa". the rod and the dot represent the simplest finite element: rod element or biella.
the dot and the pull are the components of isostatic reticulation beams.
a last question if I can without a further question
What difference would there be between trave np,trave ipe and trave inp? thanks greetings and greetings to all of you.
View attachment 67234

each profile has a bit of its history and its application. then clearly that if at calculations it is verified, you can use what you want.
normally heb and hem are used to make pillars you shed or to hold very stressed parts of floor.
with ipe you make all horizontal traversines of loft floors.
the hypn is born to drive to small lamps (for the self-centering and more inertial tilted wings) or to drown in the concrete to anchor us over machines that have traction loads.
upn is born for the use of countervents or to be drowned and used to weld rails from rails.
angles l to equal and unequal sides are used single or coupled to make countervents. singles are used to make crowning on the ground around concrete holes.
even with the t you make small countervents, beams of connection with little load.

 

[Legs]

As regards the chevron system, I recommend reading ntc18 in the section on concentric v-downs.
In practice, under horizontal loads, one of the two diagonals enters the band (the diagonals are deliberately very slender) while the tense one catches all, or almost, the force (then, in the worst case, has a double traction compared to the one with the diagonals both working).
as it says how much you reported in the translated text (I went to look for the original text but it was written wrong also in English) actually creates an asymmetry that in fact leads to having a concentrated force applied to the center of the traverse. It is evident that a plastic hinge will be formed in the traverse where much of the energy supplied by horizontal loads will be dissipated. normally the energy should be dissipated in the diagonals thesis but with this system it deliberately moves the dissipation in the traverse.

I think I understand that the method chevron does nothing but calibrate the sizing of the diagonals to still have a contribution of the compressed diagonal (from formulas it seems that it considers at least 30% capacity). from the photos it seems to me to note that the sizing of the transverses takes correctly account also of the need for dissipation required.

However if you want to try to calculate the convent cell you can do it with any calculation program (just to say I often hear about ftool. I use frame2d of ice creams).
extreme cases are the one with 100% working diagonals and the other only with the tense diagonal (the compressed one can eliminate it directly from the model).
The chevron system is between these two cases. you can simply assign to the diagonal
compressed a reduced module or a reduced area of 70% i.e. it is enough to multiply the area by 0.3.
You can then check how much the flender moment affects the traverse in various cases (with this analysis you can get the static limit multiplier).
If you want to build a mechanism to determine the cinematic limit multiplier of the convent cell. do not take into account the dissipation of the diagonals which is negligible compared to that of the transverse.

 

[Legs]

@meccanicamg I would just like to add some other information about using profiles.
heb and hem are used in particularly important structures (high buildings, structures with wagons carrying several dozen tons). in the classic sheds of the small Italian productive reality it is easier to find hea for the columns and ipe or still hea for the beams.
commercially for small supplies are easier to availability hea than heb and especially hem.
reticolars often build with l. profiles use them in pairs for lower and upper bridles and single for diagonals and uprights. wanting you can also use upns (but it is less frequent). you can also use reticolar columns.
if it may interest you use l to strengthen the reinforced concrete pillars or masonry males.
l are then connected with a series of welded dishes (calastrelli).
ipe and hea are used so much in the renovations because they are sufficiently read to be handled manually or with winches or with other small lifting machines (imagined of wanting to make a hole in a loft of an apartment. You can't carry reinforcement beams with the bedbed. It is important that beams be read).

 

[odisseo 18]

thanks for your comprehensive answers.