OFFICE BUILDING 1. ANALYSIS BY YIELD LINE THEORY SLAB (OFFICE ROOM)

OFFICE BUILDING

1. ANALYSIS BY YIELD LINE THEORY

SLAB (OFFICE ROOM)

Size of Room = 6m   6.23m

1. DATA:

L_X                                          =          6m

L_Y                                =          6.23m

Live Load (q)  =          4KN / m²

Floor finish load          =          0.8 KN / m²

Concrete grade            =          M₂₀

2. DESIGN CONSTANT:

F_Y                                =          415 N/mm²

F_CK                                        =          20 N/mm²

Q_U                                          =          2.759

3. DESIGN SLAB:

Longer span (Ly)        =          6m

Short span    (Lx)        =          6.23m

(ie) Design of Two way slab

3. DEPTH OF SLAB:

For simply supported slab using Fe₄₁₅ H_YSD bars for clause 24., of I­s: 456 – 2000 Code.

Span / overall depth                =          35  0.8 = 28

 Overall depth (D)               =   =  = 214mm  = 200mm

Adopt Overall depth (D    =   200 mm     effective depth (d)            =      175 mm

4. LOAD CALCULATION:

Self Weight of Slab                =          0.11  25 =2.75 KN / m²

Live Load                                           =           4 KN/ M²

Floor Finish                                         =            1 KN / m²

Total Service road (w)                        =        7.75 KN / m²

Design ultimate Load (w_U) = 7.75  1.5 ,  W_U = 11.63 KN / m²      

5. ULTIMATE MOMENT & SHEAR FORCE:

                        =

M_U     =          4.359

M_U     =          12.017 KNm/m

V_U     =          0.5 W_UL  =      0.5

V_U     =          17.43 KN /m

6. LIMITING MOMENT CAPACITY OF THE SLAB:

M_U Lim                           =      0.138 fck bd²

                                        =      (0.138

M_U Lim                           =      19.941 KNM

M_U < M_U lim, The Section is under reinforced

7. TO GET AST:

M_U (Short Span) = 0.87 fy AST d

  Ast           =   359.75 mm²

8. SPACING  & MIN. AST:

Use 10mm bars

S_V =

S_V = 218.31 mm , say 210 mm

 Provide 10mm bars @ 210mm centers in the short span

 Ast (Provided)       =  = 373. 99 mm²

 Ast (Long Spom) = = 0.7  210   =     147 mm²                                 

   Ast  (Minimum)     = 0.12 % of 6 D             = 0.12 / 100 =132 mm²

Provide 10mm bars @ 300 mm C/C

9. CHECK FOR SHEAR STRESS:

Permissible shear stress table 19 for Is 456 – 2000

= 0.585 N/mm²

Since  the shear stresses are within safe permissible limits

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I am Thomas Britto here to share my experiences in the civil engineering field to all my readers.Today many students are struggling to buy books at high prices. So I decided to start a blog and share my experience and knowledge with all my readers.

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