Head wall
Short Description
Reinforced concrete Head wall design as per BS codes...
Description
Reference
Description 5.5.1 Design for Critical BM ULS Design Inner face of wall Design ULS Bending (BM ULS) Width of the section (b) Section Height Concrete Cover Main R.F Bar Diameter spacing Shear/ Secondary R.F Bar Diameter Concrete Strength ( fcu) R.F Strength (fy)
Results
38 1000 400 50 12 150 10 30 460
cl .5.8.4.1, Check for Minimm area of R.F Part 4 , BS Effective Depth (d) 5400 Provided R.F (As) Min. R.F percentage Min. Area of R.F
eq.5, Part 4, BS 5400
cl.5.3.2.2
eq. 1 eq. 2 cl.5.3.2.3
344 mm 754 mm2 0.15% 516 mm2
As> Min. R.F, Hence Satisfactory Lever Arm (z) calculation The lever Arm of 1- 1.1 fy As the Section (z) = fcu bd
{
cl.5.3.2.2
z 0.95 d
= =
}d
331.28 326.8
value z is greater than 0.95d Hence z = 326.80 Ultimate Resistant (Mu ) calculation
mm
mm mm
mm
Mu = ( 0.87fy) Asz = 98.61 Mu= 0.15fcubd2 = 532.51 Mu is taken as the lesser of eqn 1 and eqn2 Hence Mu = 98.61 Check for ULS bending Moment Mu > BM ULS , Hence provided R.F adequate SLS DESIGN Servicible Moment Moment ,Permanent loads, Mg Moment , Live loads , Mq
kNm/m mm mm mm mm mm mm N/mm2 N/mm2
=
22 kNm
=
19 kNm
=
3 kNm
kNm kNm kNm
Section Height Concrete Cover Dist com. face to crack point ,a' Dia of Main Bar E steel E concrete,short term (Table 3, part 4) A steel,provided Max Bar Spacing fy f cu
= =
400 mm 50 mm
= = = =
300 12 200 28
mm mm kNmm2 kNmm2
= = = =
754 150 460 30
mm2 mm Nmm2 Nmm2
Limitations Allowable crack width = Stress Limitation Factor, Concrete = Stress Limitation Factor, Steel =
0.25 mm 0.38 0.75
Effective depth d = 344 mm cl.4.3.2.1.b, Econcrete,long term = 14 kNmm2 part 4 Modular ratio (α) = 14.29 Taking first moment of area about neutral axis :
x z
= =
75.98 mm 318.67 mm
x =depth to N/A z=lever arm
cl.4.1.1.3. & Table 2
Max steel stress ,fs
cl.4.1.1.3. & Table 2
Max Con. Stress, fcb = 1.82 N/mm2 0.38 fcu = 11.4 N/mm2 fcb BM ULS , Hence provided R.F adequate SLS DESIGN
kNm/m mm mm mm mm mm mm N/mm2 N/mm2
mm
mm mm
mm
kNm kNm kNm
Servicible Moment Moment ,Permanent loads, Mg Moment , Live loads , Mq Section Height Concrete Cover Dist com. face to crack point ,a' Dia of Main Bar E steel E concrete,short term (Table 3, part 4) A steel,provided Max Bar Spacing fy f cu
=
8 kNm
=
7 kNm
= = =
1 kNm 400 mm 50 mm
= = = =
300 12 200 28
mm mm kNmm2 kNmm2
= = = =
754 150 460 30
mm2 mm Nmm2 Nmm2
Limitations Allowable crack width = Stress Limitation Factor, Concrete = Stress Limitation Factor, Steel =
0.25 mm 0.38 0.75
Effective depth d = 333 mm cl.4.3.2.1.b, Econcrete,long term = 14 kNmm2 part 4 Modular ratio (α) = 14.29 Taking first moment of area about neutral axis :
x z
= =
74.61 mm 308.13 mm
x =depth to N/A z=lever arm
cl.4.1.1.3. & Table 2
Max steel stress ,fs
cl.4.1.1.3. & Table 2
Max Con. Stress, fcb = 0.70 N/mm2 0.38 fcu = 11.4 N/mm2 fcb
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