Slab mein sariya ki spacing kaise decide karte hain?

IS 456:2000 Cl. 26.3.3 ke anusar: Main steel spacing ≤ min(3d, 300mm). Distribution steel spacing ≤ min(5d, 450mm). Jahan d = effective depth. Spacing = (1000 × Abar) / Ast_req formula se nikalte hain.

Slab ki thickness kaise decide karte hain?

IS 456:2000 ke anusar simply supported one-way slab ke liye minimum overall depth D ≥ L/25. Continuous slab ke liye D ≥ L/30. Two-way slab ke liye shorter span/30 se shuru karein. Practically 100mm se 200mm common residential slabs mein.

Distribution steel kya hoti hai aur kyun deni padti hai?

Distribution steel (transverse steel) main steel ke perpendicular dali jaati hai. Yeh shrinkage, temperature change se hone wali cracks ko rokti hai aur load distribution mein madad karti hai. IS 456:2000 Cl. 26.5.2.1 ke anusar minimum Ast = 0.12% of gross area (Fe415) = 0.0012 × b × D.

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RCC Slab Design Calculator One-Way & Two-Way Slab — Sariya Spacing + BBS | IS 456:2000

Poori detail ek jagah: Factored moment (Mu), Ast main + distribution, bar dia, spacing, cutting length, complete BBS table, shuttering area, concrete volume — sab IS 456:2000 ke mutabiq. One-way ya two-way — dono design karo.

✓ One-Way & Two-Way ✓ Main + Distribution Steel ✓ Spacing Calculation ✓ Concrete Volume & Shuttering ✓ Complete BBS Table ✓ AI Drawing Generator ✓ 100% Free

Slab Type Select Karo

ℹ️ One-Way: ly/lx > 2 | Sirf shorter span mein main steel

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Slab Input Parameters

IS 456:2000 ke anusar design

Shorter Span (lx) *

Slab ki shorter direction

Live Load (LL) *

Residential: 2–3 kN/m², Commercial: 4–5 kN/m²

kN/m²

Floor Finish / Other DL

Floor finish + partitions (typical: 1–2 kN/m²)

kN/m²

Concrete

Steel

Slab Overall Thickness (D)

Rule: lx/25 (simply supported). Common: 100–200mm

Clear Cover

Bar Diameter

Support / End Condition

Simply Supported Continuous Cantilever Fixed Both Ends

Slab Width / Longer Side

BBS quantity aur volume ke liye (one-way slab ke liye longer side)

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AI Se Slab Reinforcement Drawing Banao

Values enter karne ke baad drawing generate karo — plan + section view sariya detail ke saath.

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Slab se related kuch bhi poocho:

📊 Slab Bar Bending Schedule (BBS) — Example

3.5m × 4.5m Two-Way Slab, 150mm thick, M25 Fe415, 2 kN/m² LL

Bar Mark	Dia	Nos	Spacing	Cut Length	Total Length	Weight (kg)	Position
MS-X	10 mm	23	150 mm	4.95 m	113.85 m	70.2 kg	Main steel lx direction (bottom)
MS-Y	10 mm	18	175 mm	3.95 m	71.10 m	43.8 kg	Main steel ly direction (bottom)
DS-X	8 mm	14	300 mm	3.95 m	55.30 m	21.8 kg	Distribution steel (top)
DS-Y	8 mm	18	300 mm	4.95 m	89.10 m	35.1 kg	Distribution steel (top)
EB	10 mm	8	—	1.17 m	9.40 m	5.8 kg	Edge / corner bars
🏗️ Total Steel — 3.5m × 4.5m Two-Way Slab						176.7 kg	≈ 11.2 kg/m²

📐 Spacing Formula

s = (1000 × Abar) / Ast
Max: 3d or 300mm (main)
Max: 5d or 450mm (dist.)

🔢 Cutting Length

L = clear span + 2×Ld
Ld = 47d (Fe415, M25)
+ hooks if required

⚖️ Min Distribution

Ast,dist = 0.12% × b × D
(Fe415 — IS 456 Cl.26.5.2)
= 0.0012 × 1000 × D

🔬 Slab Design — IS 456:2000 Theory & Formulas

STEP 1 Slab Type Decide Karo

ly / lx > 2 → One-Way Slab

ly / lx ≤ 2 → Two-Way Slab

lx = shorter span, ly = longer span

One-way mein load sirf lx direction mein transfer hota hai. Two-way mein dono directions mein.

STEP 2 Factored Load & Moment

Self weight = 25 × D (kN/m²)

wu = 1.5 × (SW + SDL + LL)

SS: Mu = wu × lx² / 8

Cont: Mu = wu × lx² / 10

Cant: Mu = wu × lx² / 2

STEP 3 Ast Main Steel

R = Mu / (b × d²)

pt = (0.5fck/fy)[1 − √(1 − 4.6R/fck)]

Ast = pt × b × d

Ast,min = 0.12% × b × D (Fe415)

📌 Spacing = (1000 × Abar) / Ast ≤ min(3d, 300mm)

STEP 4 Two-Way Slab Moment Coefficients

Mux = αx × wu × lx² (lx direction)

Muy = αy × wu × lx² (ly direction)

αx, αy = IS 456 Table 26 coefficients

(depend on ly/lx ratio & edge condition)

✅ Two-way slab mein dono directions mein Ast alag-alag calculate hoti hai

QUANTITY Concrete Volume & Shuttering Area

Concrete Volume

V = lx × ly × D (m³)
+ 5–10% wastage

Shuttering Area

Soffit = lx × ly (m²)
Sides = 2×(lx+ly)×D

Curing Period

Minimum 7 days (OPC)
14 days better practice
Shuttering: 7–14 days

❓ Aksar Pooche Jaane Wale Sawaal — RCC Slab

One-way slab aur two-way slab mein kya fark hai? ▾

Jab slab ka ly/lx ratio 2 se zyada ho to ise one-way slab kehte hain — load sirf shorter span (lx) mein transfer hota hai, longer direction mein sirf distribution steel dali jaati hai. Jab ly/lx ≤ 2 ho to yeh two-way slab hai — load dono directions mein distribute hota hai aur dono directions mein main steel dalni padti hai. Two-way slab zyada economical hota hai kyunki load dono taraf share hoti hai.

Slab mein sariya ki spacing kaise nikalte hain? ▾

Spacing = (1000 × Area of one bar) / Ast required formula se milti hai. Area of bar = π×d²/4 mm². IS 456:2000 Cl.26.3.3 ke anusar main steel ki maximum spacing = min(3×effective depth, 300mm). Distribution steel ki maximum spacing = min(5×effective depth, 450mm). Example: 10mm bar, Ast=500mm² → Spacing = (1000 × 78.54)/500 = 157mm, provide 150mm c/c.

Slab ki minimum thickness kya honi chahiye? ▾

IS 456:2000 Cl. 23.2.1 ke anusar deflection control ke liye: Simply supported one-way slab: d ≥ lx/28 (Fe415). Continuous slab: d ≥ lx/32. Cantilever: d ≥ lx/7. Overall depth D = d + cover + half bar dia. Practically residential slabs mein 120–150mm common hai, terrace slabs mein 150–175mm.

Two-way slab mein IS 456 Table 26 ka kya use hai? ▾

IS 456:2000 Table 26 mein two-way slab ke liye bending moment coefficients αx aur αy diye hain — yeh ly/lx ratio aur edge condition (all edges simply supported, two adjacent edges continuous, etc.) par depend karte hain. Formula: Mux = αx × wu × lx² aur Muy = αy × wu × lx². Isse dono directions mein alag-alag Ast calculate ki jaati hai.

Slab concrete mein kitna cement, sand, aggregate lagega? ▾

M25 concrete (1:1:2 mix) ke liye approximately: Cement = 450 kg/m³, Sand = 0.45 m³/m³, Aggregate = 0.90 m³/m³. Ek 150mm thick 3.5×4.5m slab ka volume = 3.5×4.5×0.15 = 2.36 m³. Cement = 2.36×450 = 1062 kg ≈ 21.2 bags. 10% extra add karein wastage ke liye. Market grade concrete (RMC) use karna better option hai site par quality control ke liye.