Lenght Equivalent Diagonal Strut (Equivalent Masonry infilled wall) to Sap and Etabs
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Author: Veggeta
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Lenght Equivalent Diagonal Strut (Equivalent Masonry infilled wall) to Sap and Etabs
#1
Lenght Equivalent Diagonal Strut (Equivalent Masonry infilled wall) to Sap and Etabs

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This spreadsheet calculate depth frame, inputs to Sap and Etabs, this as alternative method to simulate masonry infilled wall using Equivalent Diagonal Strut, only frame model.

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For bibliography, you can refers...

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Note: for evaluation purposes only, Is your responsability check the calculus
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#2
Dear vegeta
as you represent the Lenght Equivalent Diagonal Strut , when the forces in the same plane but in opposite directions (positive and negative)
Greetings
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#3
Hi,
Its not stated as per which code this sheet has been prepared.
1) It does not take into account the material properties say E for the frame material and masonry, and the I's for the columns and beams that are in contact with the masonry, hence arising in a more conservative approach.

Is it as per codal requirement that these do not have to be taken into account when deciding the width of the strut?

A STRUCTURAL ENGINEER has the ART OF USING MATERIALS That Have Properties Which Can Only Be Estimated TO BUILD REAL STRUCTURES That Can Only Be Approximately Analyzed TO WITHSTAND FORCES That Are Not Accurately Known SO THAT HIS/HER RESPONSIBILITY WITH RESPECT TO PUBLIC SAFETY IS SATISFIED.
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#4
For Pana 2, the model Diagonal Strut works only compresion, not tension. (Its alternative method)

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For hmwere

The spreadshets only calculates the geometric properties of the diagonal and it assumes his behavior, The user must dominate the method of the equivalent diagonal, using Etabs and or Sap, this method is a simplification in order to compute the global structural capacity.

The properties of the material are input in the program in the respective options (walls only, columns works normal properties). I summarize the following thing for the properties of the materials.

Em = E masonry
Gm = G masonry
I = (Area colum of the confining frame) * b*b
δ= b/h
Ashear= (0.37 – 0.12 (B/h) + 0.023λ)(Awall masonry + 2Accol).
inputs in properties materials and section in Etabs addionally realeases options...

The calculation of the reinforcement depends on every user, since the method only gives the efforts. The leaf only is the auxiliary one to facilitate the calculation of the thickness of the diagonal. Each one can use the code of design of reinforcement that wants.

Sorry bad english

Regards...
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#5
@ Veggeta, I agree with you. I just needed to know as per which code of practice your spreadsheet was prepared.
You will believe me that this method(used in the spreadsheet) is not just out of simple statics but a codal requirement.
I am not against it(of course it holds for its code provisions) but just want us to share some of its draw backs in regards to calculation of the width of the strut. Its similar to the New Zealand code requirement.
1) Calculation of the width, w of the strut is an ex- ETABS or ex-SAP piece of work.
2) ETABS will need, correct me if i am wrong, w,t, Em for calculation of the stiffness of the strut( what would be an equivalent of the stiffness of masonry).
3) The New Zealand code estimates w=D/4 ( just an empirical value). D is the length of the diagonal strut.
4) As per Hendry (1998), w=f(Ef,Em,Ic,Ib,t,h,L,@)
where Ef=Youngs modulus of frame material
Em=Youngs modulus of masonry
w= width of strut
Ic=moment of inertia of column
Ib= moment of inertia of beam
h= height of masonry
L = length of masonry
@=angle of inclination of strut
5) Holmes (1963) estimates w=D/3
If you try to calculate w using any of the above methods, Hendry comes out to be more economical than the rest ( it takes a lot of factors into considerations).
ETABS/SAP will take the w we give them so if its conservative, results will be definitely conservative because w will affect the stiffness of the strut.
@ Veggeta, please try mentioning the code for which your spreadsheet is based. This will refrain us from conflicting code requirements.

Regards.


A STRUCTURAL ENGINEER has the ART OF USING MATERIALS That Have Properties Which Can Only Be Estimated TO BUILD REAL STRUCTURES That Can Only Be Approximately Analyzed TO WITHSTAND FORCES That Are Not Accurately Known SO THAT HIS/HER RESPONSIBILITY WITH RESPECT TO PUBLIC SAFETY IS SATISFIED.
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#6
Dear Hmwere

I don't know New Zeland code, but a try explain something,

1) Both, taking the necessary considerations.
2, 3, 4, 5) I understand his point, on the used model (considerations), I agree whit you, but D/4 if not necesary empirical value, also his characteristics of the model are calculated on the basis of the observed failure mechanism on the infill. In this case is taken most practical, but the model is chequed for laboratories and many countries (including Fema), but I insist in And since you know several failure mechanisms exist, including the one that does not model itself in the nude, and yes w = f (Elements Boundary properties, Em, etc)....

and finally, my problem (obvious) is the language...

Regards...

PD ( I´m looking for the paper about this...... , but I don't find it, ....)
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