DAR GROUP

Project

QFJob Ref.

Q09074

Section Sheet no./rev.

1

Calc. by

MSDate

04-May-06Chk'd by Date App'd by

AEDate

RC ONE-WAY SLAB DESIGN TO ACI 318-05175

mm

150 mm

142 m

m

Slab definition

Slab type; One-way simply supported

Overall thickness of slab; h = 175 mm

Clear shorter span of slab; ln = 4000 mm

Trial tension reinforcement (resisting sagging); Bar No. 4 - 13 mm dia

Clear cover to tension reinforcement; cc = 25 mm

Depth to tension steel (resisting sagging); d = h - cc - Dtry / 2 = 144 mm

Materials

Specified compressive strength of concrete; f’c = 35 MPa

Specified yield strength of reinforcement; fy = 415 MPa

Modulus of elasticity; ESACI = 199948 MPa

PASS - span/depth ratio is within permissible limit

Maximum design moment and shear in span (per 1 m width of slab)

Maximum ultimate sagging moment; Mus = 65.00 kNm/m

Maximum ultimate shear force; Vu = 32.00 kN/m

Check slab in bending - SAGGING

Required nominal flexural strength; Mns = abs(Mus) / 0.9 = 72.22 kNm/m

Stress block depth factor; 1 = max(0.65, (0.85 - 0.05 (f'c - 28 MPa) / 7 MPa)) = 0.80

Reinforcement ratio at strain of 0.004; b = 0.85 1 f’c / fy (0.003 / (0.003 + 0.004)) = 0.025

Maximum reinforcement ratio; max = b = 0.025

Flexural resistance factor; Ru = Mns / d2 = 3.51 MPa

Reinforcement required; req = 0.85 f’c / fy × [1 -(1 - 2 × Ru / (0.85 × f’c))] = 0.009

Outer compression (sagging) steel not required

Steel calculation - SAGGING

Area of tension steel required; As_req = req × d = 1294 mm2/m

Minimum area of tension steel required; As_min = max(1.4 MPa × d / fy, (f’c / 1 MPa) × d 1 MPa / (4 fy))

As_min = 511 mm2/m

Maximum area of tension steel; As_max = max × d = 3527 mm2/m

Tension steel provided - SAGGING, No. 5 @ 150 mm centers

Area of tension steel provided; As_prov = 1340 mm2/m

PASS - area of steel provided - OK

Maximum allowable spacing; smax = min(3 × h, 450 mm) = 450 mm

Actual tensile bar spacing provided; s = 150 mm

PASS - spacing of bars (sagging steel) less than maximum allowable

DAR GROUP

Project

QFJob Ref.

Q09074

Section Sheet no./rev.

2

Calc. by

MSDate

04-May-06Chk'd by Date App'd by

AEDate

Check for section - SAGGING

Depth of equivalent rectangular stress block; a = (As_prov × fy) / (0.85 × f’c) = 19 mm

Revised depth of tension steel; d = (h - cc - D / 2) = 142 mm

Depth of neutral axis; c = a / 1= 23 mm

Net tensile strain in long. steel at nominal strength; t = 0.003 × [(d - c) / c] = 0.0152

Section is tension controlled, design OK

Strength reduction factor; = 0.9

Revised required nominal flexural strength; Mns = Mus / = 72.22 kNm/m

Actual nominal flexural strength; Mns_prov = As_prov × fy × (d - a / 2) = 73.79 kNm/m

PASS - actual flexural strength exceeds required nominal flexural strength

Transverse inner reinforcement - (for shrinkage and temperature)

Minimum ratio of transverse reinforcement; t = 0.0018

Minimum area of transverse reinforcement required; At_req = t × h = 315 mm2/m

Maximum allowable spacing of bars; smax_t = min(5 × h, 450 mm) = 450 mm

Transverse steel provided , No. 3 @ 200 mm centers

Transverse reinforcement provided; At_prov = 318 mm2/m

PASS - area of inner steel provided (transverse) OK

Actual transverse bar spacing provided; st = 200 mm

PASS - spacing of transverse bars is less than allowable

Check for shear

Nominal shear strength required; Vn = abs(Vu) / 0.75 = 42.67 kN/m

Shear strength provided by concrete; Vc = (f’c / 1 MPa) d 1 MPa / 6 = 140.01 kN/m

Shear strength provided by shear steel (assumed); Vs = 0.00 kN/m

Shear capacity of section; V = Vc + Vs = 140.01 kN/m

PASS - one way shear capacity

Check of clear cover (ACI 7.7.1)

Permissible min nominal cover to all reinforcement; cmin = 20 mm

Clear cover to tension reinforcement (sagging); cc = h - d - D/2 = 25 mm

PASS - cover to steel resisting sagging exceeds allowable minimum cover

Design summary

Slab is 175 mm thick in 35 MPa concrete

Tension steel provided - SAGGING, No. 5 @ 150 mm centers in 415 MPa steel

Transverse steel provided, No. 3 @ 200 mm centers in 415 MPa steel