Is shear deformation considered in Force-Based Beam-Column Element ?

[chenwangNigel]

Hello all,

I am wondering if the shear deformation is considered when I use Force (or Displacement) -Based Beam-Column Element with fiber sections?

If shear deformation is considered, how the shear modulus is calculated?

A more general question is, for such questions, where can I find the mathematical formulation for an element ? Any recommendation of related books?

Thank you for your kind reply in advance.

[mhscott]

https://portwooddigital.com/2022/07/03/ ... -opensees/

[chenwangNigel]

https://portwooddigital.com/2022/07/03/ ... -opensees/

Thank you so much for your reply. Your blogs are really informative and helpful.

I understand that if I define an elastic section in which the shear modulus is given, then assign the section to a force-based beam-column element, the shear deformation will be accounted for.

My follow-up question is: what if I assign a fiber section? The corresponding code is:

Code: Select all

fiber(yloc, zloc, A, matTag)

How can I define the shear property to consider the shear deformation in this case?

[mhscott]

https://portwooddigital.com/2021/07/04/ ... ggregated/

[Prafullamalla]

Code: Select all

# Caltrans column shear capacity in English units (Chapter 3 of Caltrans SDC)
inch=1;ksi=1
mm=1/25.4*inch; MPa  = 0.145038*ksi;
mm2=mm*mm
poisson = 0.20
G = Ec/2.0/(1.0+poisson)
Ag=colDepth*colWidth
Ae=0.8*Ag
mud=3
Pc= 0; # Here Axial load is zero in kips

F1 = Rhos*fyh*MPa/0.15+3.67-mud
if F1 < 0.3 :
    F1 = 0.3
if F1 > 3 :
    F1 = 3

F2 = 1.0+Pc/(2000*Ag*mm2)
if F2 > 1.5 :
    F2 = 1.5

vc = F1*F2*np.sqrt(-fc*MPa*1000)
if vc > 4.*np.sqrt(-fc*MPa*1000) :
		vc = 3*F2*sqrt(-fc*MPa*1000)

Vc = vc*Ae*mm2/1000
 
Vs = Av*mm2*fyh*MPa*hP/sh
Vn = Vc+Vs
Vst = 3.0/4.0*G*MPa*Ag*mm2
gam_y = Vn/Vst
rosfyh=Ros*fyh*MPa 


# Convert to unit mm, N
#define shear force-deformation relationship    
#                                matTag         Fy     E0     b

ops.uniaxialMaterial('Steel01', 6, Vn*4448.22162,   Vst*4448.22162 , 1.0e-3 ) 
# Aggregate shear to the RC section
secTag = secnTag+1

ops.section('Aggregator',secTag,  6,  'Vy',   '-section', secnTag)