Subject : Design of Tie Beam
Doc. No.:JI-180-007-ECV-097, Rev.A
Design of Tie Beam TB1 for foundation mkd. F1 & F2 : Reference 1 : BS 8110:1997 Part-1 Reference 2 : BS 8110:1997 Part-2 Y
Design Forces from staad output:
h
Z b
Beam
L/C
Node
409
128
12
Axial Force kN 80
Shear-Y kN 150
Shear-Z kN 10
Torsion kNm 10
Mom-Y kNm 40
Ultimate moment Mu=
200 kN-m
(Mz)
Shear Force V=
150 Kn
(Fy)
Max. torsion,T=
10 kN-m
Mom-Z kNm 200
Remark
(Torsion)
Design Parameter: Characteristic strength of reinforcement bar,fy= Characteristic strength of concrete fcu=
2 360 N/mm 2 30 N/mm
Ratio b b =
1.00
gc =
1.00
gs =
1.00
Depth of section,h=
400 mm
Width of section,b =
400 mm
Top concrete Cover (upto main reinf) =
40 mm
Bot. concrete cover,d' (upto main reinf) =
40 mm
Side concrete Cover (Upto main reinf) =
40 mm
Diameter of reinforcement bar=
25 mm
Actual cover should be 65 mm as the beam is exposed.
Subject : Design of Tie Beam
Doc. No.:JI-180-007-ECV-097, Rev.A
Design for Bending : (Ref.1, CL.3.4.4.4) Effective depth of member,d=
347.5 mm 0.156
K' = Mu bd 2 fcu
K
0.138 < K'
Compression reinforcement not required Z d 0 .5
K 0 .25 0 .9
Hence Z = X
d
Tension steel required Ast = Nos of bar required = Compression steel required Asc = Nos of bar required =
Z 0 . 45
281.78
mm <
330.13 mm
281.78 mm 146.04 mm 2
2075 mm 5 nos
2 0 mm 1 nos
Number of Tension reinf. bar provided = Area of tension reinf. provided = Number of compression reinf bar provided = Area of compression reinf. provided =
5 2454 5 2454
Total reinforcement provided for bending Asp=
2 4909 mm
2
Min Ast =
181 mm
Min Asc =
2 181 mm
nos. mm2 nos. 2 mm
Design for Shear & Torsion :
y1
h
x1 b
(Reinforcements are Indicative Only) Diameter of link or stirrup bar=
10 mm
y1 = x1 =
310 mm 310 mm
hmax =
400 mm
hmin =
400 mm
Shear stress developed v =V/bd=
2 1.079 N/mm
< .8 fcu or 5 N/mm2 (Ref.1,CL.3.4.5.2)
Subject : Design of Tie Beam
Doc. No.:JI-180-007-ECV-097, Rev.A
ptt provided=
1.766 %
Permissible shear stress,vc=
2 0.764 N/mm
Hence shear reinforcement is required Shear resistance required by link Vu = For shear links
Asv1
Shear stress due to torsion,
Vu * sv (0.95* fyv * d )
vt
2T 2 hmin (hmax hmin / 3)
(Ref 1, Table 3.8)
Provide at a spacing of sv =
150
mm
43.84 kN 2 55.33 mm
2
0.47 N/mm
2
So, v+vt=
1.55 N/mm
vtu =
2 4.38 N/mm
vtmin=
0.37 N/mm
2
(Ref.2,CL.2.4.4,Eq-2) < vtu Hence ok (Ref 2, Table 2.3) < vt
(Ref 2, Table 2.3)
Hence reinforcement for torsion is required. For torsional links
Asv2
T * sv 0.8x1 y1 * (0.95* fyv)
Asv = Asv1+Asv2 =
2
57.05 mm
2 112.38 mm
Link bar dia for resisting torsion= No of legs along the width of beam= Total area of peripherial link bars=
10 mm 2 2 157 mm
Provide additional vertical leg dia = No of legs = Additional area to cater shear = Total available area for shear and torsion =
10 mm 2 2 157 mm 2 314 mm
Hence Provide vertical link bar (2-legs) of 10 mm dia @ both way. '+ additional leg of 10mm dia@
150 mm c/c
Additional longitudinal reinf for Asv f yv ( x1 y1) As resisting torsion, sv f y Reinforcement distributed at each top and bottom = Reinforcement distributed at each sides =
o.k.>Asv2
o.k.>Asv1+Asv2 (Ref 2 Table 2.4)
150 mm c/c
2 649 mm
(Ref.2,CL.2.4.7)
2
320
162.3 162.29
mm mm2 320
Total longitudinal reinforcement reqd. due to moment and torsion Asr (at top and bottom) = Total longitudinal reinforcement provide Asp =
320 320
2 2238 mm 2 2454 mm Hence ok
Subject : Design of Tie Beam
Doc. No.:JI-180-007-ECV-097, Rev.A
Check for bending and shear about other axis : Ultimate moment Mu= Shear Force V= Max. torsion,T=
40.00 kN-m
(My)
10 Kn
(Fz)
0 kN-m (Torsion) (Torsion check same as earlier)
Design Parameter: 2
360 N/mm
Characteristic strength of reinforcement bar,fy=
2 30 N/mm
Characteristic strength of concrete fcu= Ratio b b =
1.00
gc =
1.00
gs =
1.00
Depth of section,h=
400 mm
Width of section,b =
400 mm
Top concrete Cover=
40 mm
Bot. concrete cover,d' =
40 mm
Side concrete Cover =
40 mm
Diameter of reinforcement bar=
25 mm
Actual cover should be 65 mm as the beam is exposed.
Design for Bending : (Ref.1, CL.3.4.4.4) Effective depth of member,d=
347.5 mm 0.156
K' = K
Mu bd 2 fcu
0.028 < K'
Compression reinforcement not required Z d 0 .5
K 0 .25 0 .9
Hence Z = X
d
Z 0 . 45
336.49
mm >
330.13 mm 38.61 mm
330.13 mm
Subject : Design of Tie Beam
Doc. No.:JI-180-007-ECV-097, Rev.A
Tension steel required Ast = Nos of bar required = Compression steel required Asc = Nos of bar required =
Number of Tension reinf. bar provided = Area of tension reinf. provided = Number of compression reinf bar provided = Area of compression reinf. provided = Total reinforcement provided for bending Asp=
2
354 mm 1 nos
2 0 mm 1 nos
2 982 2 982
2
Min Ast =
181 mm
Min Asc =
2 181 mm
nos. mm2 nos. 2 mm 2
1963 mm
Design for Shear & Torsion :
y1
h
x1 b
(Reinforcements are Indicative Only) Diameter of link or stirrup bar=
10 mm
Shear stress developed v =V/bd=
2 0.072 N/mm
ptt provided=
0.706 %
Permissible shear stress,vc=
2 0.563 N/mm
Hence no shear reinforcement is required Shear resistance required by link Vu = For shear links
Asv1
Vu * sv (0.95* fyv * d )
Total longitudinal reinforcement reqd. due to moment and torsion Asr (at sides) = Total longitudinal reinforcement provide Asp =
< .8 fcu or 5 N/mm2 (Ref.1,CL.3.4.5.2)
>v
Provide at a spacing of sv =
(Ref 1, Table 3.8) 0
0.00 kN 2 0.00 mm
2
517 mm
2 982 mm Hence ok
Design Summary : Tension reinforcement 5 nos T25 bar Each side face reinforcement 2 nos T25 bar Compression reinforcement 5 nos T25 bar Shear reinforcement T10 bar @150c/c outer & T10 bar @150c/c inner
mm
Max Fx Min Fx Max Fy Min Fy Max Fz Min Fz Max Mx Min Mx Max My Min My Max Mz Min Mz
Beam 5011 5012 5012 5011 5009 5011 5010 5015 5016 5013 5011 5013
L/C Node Fx kN Fy kN Fz kN 205 DSW + PLE 103 + PLO 142.606 +0.50 FL +AT -216.931 + AL + TI-48.939 203 DSW + PLE 106 + PLO +-44.46 FT + AT +132.404 AL + TD 16.66 210 DSW+PLE+PLO 106 - AT+AL74.604WT+TI 172.678 19.812 211 DSW+PLE+PLO 103 + AT+AL+ 43.438 WT+TD -245.828 -42.874 215 DSW+PLE+PLO 102 + AT+AL+ -14.323 WL+TD 117.502 52.598 215 DSW+PLE+PLO 103 + AT+AL+ 44.518 WL+TD -215.912 -53.933 214 DSW+PLE+PLO 120 + AT-AL90.022WL+TI -44.341 16.874 214 DSW+PLE+PLO 120 + AT-AL89.363WL+TI -72.157 -18.21 213 DSW+PLE+PLO 121 + AT+ 70.937 AL+ WL+TI -32.789 -18.549 216 DSW+PLE+PLO 121 + AT-AL-3.665 WL+TD -20.198 -18.552 209 DSW+PLE+PLO 103 + AT+AL+ 140.964 WT+TI -245.791 -42.533 215 DSW+PLE+PLO 121 + AT+AL+ -27.175 WL+TD -6.215 16.871
Mx kNm -13.511 -5.943 -10.999 -16.22 9.791 -5.488 28.556 -24.253 22.631 17.072 -20.897 -13.47
My kNm -46.489 -26.284 -34.932 -36.833 -43.77 -47.798 -30.874 -29.225 59.569 -59.504 -36.469 56.832
Mz kNm 280.993 124.741 374.169 312.647 109.05 194.912 -172.515 -173.134 -196.975 -247.245 396.91 -281.844
