estimasi tulangan perlu balok tinggi berlubang

Tulisan ini melanjutkan sebelumnya, mengenai hasil pembesian tulangan balok tinggi dengan elastic FE program bantu SAP. Keadaan lain yang ditinjau adalah pengaruh adanya lubang.

Elastic FE models

Stress path

Concrete principal stress

Elastic Linear FE

Nonlinear FE (Muttoni etal, 2007)

STM models

(source: Muttoni etal, 2007)

fig.3

(source: Steven etal, 2000)

Reinforce bars arrangement

fig.4

fig.5

Kontur tulangan perlu arah datar (H)

Kontur tulangan perlu arah tegak (V)

Perbedaan hasil ditampilkan dengan bar chart berikut,



Pola retak dan kapasitas beban ultimit pada beberapa jenis model STM dan konfigurasi tulangan hasil penelitian Maxwell, B.S. (1996) dgn scaled down 5.5



Terlihat konfigurasi tulangan orthogonal dgn kombinasi diagonal menghasilkan kapasitas beban ultimit lebih besar dibandingkan konfigurasi tulangan lainnya. Semua model mencapai beban terfaktor yg direncanakan sebesar 22Kips (Maxwell, 1996)

 

calculation pads,

' Horizontal bars Reinforcement
As1=Avg(3.599,1.735,0.719,0,0)*500*0.9/0.75= 726.36
reff1a=2*0.25*Pi*25^2= 981.75
reff1b=2*0.25*Pi*20^2= 628.32
As2=Avg(2.558,0.702,1.267,1.124,0.878)*500*0.9/0.75= 783.48
reff2a=2*0.25*Pi*25^2= 981.75
reff2b=3*0.25*Pi*20^2= 942.48
As3=Avg(3.833,2.095,1.359)*(2338-2000)*0.9/0.75= 985.20
reff3a=2*0.25*Pi*25^2= 981.75
As3=Avg(3.833,2.095,1.359,0.698)*(2675-2000)*0.9/0.75= 1616.96
reff3b=7*0.25*Pi*16^2= 1407.43
As4=Avg(2.775,0.0386,0.0481,0.031,0.005,0.073,0)*(2000-500)*0.9/0.75= 763.89
reff4=6*0.25*Pi*12^2= 678.58
As5=Avg(3.832,0.553,0.153,0.102,0,0.143,0)*(2000-500)*0.9/0.75= 1229.91
reff5=6*0.25*Pi*12^2= 678.58
' Vertical bars Reinforcement
As1=Avg(3.343,1.716,1.165,0.700)*(2625-2000)*0.9/0.75= 1298.25
reff1a=2*0.25*Pi*25^2+2*0.25*Pi*12^2= 1207.94
As1=Avg(3.343,1.716,1.165,0.700,0.456)*(2938-2000)*0.9/0.75= 1661.39
reff1b=7*0.25*Pi*16^2= 1407.43
As2=Avg(0,0.640,0.097,0.153,0.148,0.571,3.343)*(2000-500)*0.9/0.75= 1273.37
reff2a=7*0.25*Pi*12^2= 791.68
reff2b=6*0.25*Pi*12^2= 678.58
As3=Avg(0.049,0.021,0.027,0.025,0.029,0.027,0.027,0.0258,0.027,0.022,0.029,0.018,0.04,0.027,0.06,0.071,0.121,0.258,0.492,2.6180)*(7000-2000)*0.9/0.75= 1204.14
reff3a=16*0.25*Pi*12^2= 1809.56
reff3b= 0.00
' Minimum bars reinforcement
A_smin=0.002*1000*400-50= 750.00