Challenge 2

S.No-1

Aim: A structure is subjected to Dead load of 100 kN, Super imposed dead load of 50 kN, Live load of 200 kN, Wind load of +/- 150 kN and Earthquake load of +/- 200 kN.

Determine the design loads on structure per Working Stress Method(WSM) and Limit State Method(LSM) of design.

Explanation:

From Table=18 IS 415:2000

1.5DL+1.5LL=1.5(150+200)=525KN

1.5DL+1.5WL=1.5(150+150)=450KN

1.5DL-1.5WL=1.5(150-150)=0

1.5DL+1.5EL=1.5(150+200)=525KN

1.5DL-1.5EL=1.5(150-200)=-75KN

0.9DL+1.5WL=0.9(150)+1.5(150)=360KN

0.9DL-1.5WL=-90KN

0.9DL+1.5EL=0.9(150)+1.5(200)=435KN

0.9DL-1.5EL=-165KN

1.2DL+1.2LL+1.2WL=1.2(150)+1.2(200)+1.2(150)=600KN

1.2(DL)+1.2(LL)-1.2(WL)=240KN

1.2DL+1.2LL+1.2EL=1.2(150)+1.2(200)+1.2(200)=660KN

1.2DL+1.2LL-1.2EL=1.2(150)+1.2(200)-1.2(200)=180

LIMIT STATE OF SERVICEBILITY

1.0DL+1.0LL=1.0(150+200)=350KN

1.0DL+1.0WL=1.0(150+150)=300KN

1.0DL-1.0WL=1.0(150-150)=0

1.0DL+1.0EL=1.0(150+200)=350KN

1.0DL-1.0EL=1.0(150-200)=-50N

1.0DL+0.8LL+0.8WL=1.0(150)+0.8(200)+0.8(150)=430KN

1.0(DL)+0.8(LL)-0.8(WL)=190KN

1.0DL+0.8LL+0.8EL=1.0(150)+0.8(200)+0.8(200)=470KN

1.0DL+0.8LL-0.8EL=1.0(150)+0.8(200)-0.8(200)=150

Result:

CRTICAL LOAD FOR LIMIT STATE OF COLLAPSE=660KN AND -165KN

CRTICAL LOAD FOR LIMIT STATE OF SERVICEBILITY=470KN AND -50KN

S.No-2

Aim: Consider a 150 mm thick slab with 8mm bottom reinforcement spaced at 125mm. Clear cover to bottom rebar is 20 mm. Grade of concrete is M30 and grade of steel is Fe415. Determine the moment of resistance of the section per m width of slab. Also, classify the section as under-reinforced, over-reinforced or balanced section.

Explanation:

WIDTH=1000m

NO OF BARS=1000/125=8

Ast=8x(3.14/4)8^2=402.1 sq.mm

EFFECTIVE DEPTH(d)=150-20-(8/2)=126mm

MOR=0.87x415x402.1x((126-(1.015x415x402.1)/(1000x30))

=1.74KMm

Xu=(0.87x415x402.1)/(0.36x30x1000)

=13.4mm

Xumax/d=0.48

=0.48x126

Xumax =60.48mm

Result:

Xu< Xumax

SECTION IS UNDER REINFORCED