Week 4 Challenge

Aim and Introduction:-

• The aim of this challenge is to calculate the effect of earth pressure on the abutment of a structure.
• So the earth pressure is to be calculated first as per the given data and section dimenesion.
• Then the model will be created in Staad pro. and the reactions due to the loading is being analyzed for the given section.

Data Given :-

Length of abutment =5 m

Ht. of back fill = 7m

GL. Level = 3m

Water Level at = 3m

Abutment Width =1.0 m

Unit Wt. of Soil = 18 KN/m³

Unit Wt. of Concrete = 25 KN/m³

^{Consider ϕ= 30}

Earth Pressure Calculation :

Calculation of Earth load for the abutment

As ^{ϕ= 30}

^{SO Ka=1/3}

^{Considering the GL side soil at rest.}

^{i.e, K1=Ko x (Ysat - Yw) x h}

^{= (0.5) x (19-10)x 3}

^{= 13.5 KN/m2}

^{Considering the backfill soil as active earth pressure.}

^{K2=Ka x (Ysat - Yw) x h1 + Ka x (Ysat - Yw) x h2}

^{= (1/3) x (19-10)x 4 + (1/3) x (19)x 3}

^{= 30.69 KN/m2}

Soil Loads on Foundation :

P1= Y x h

= (18-10) x 3 = 24 KN/m2

P2= Y x h

= (18-10) x 7 = 56 KN/m2

Uplift Pressure:

Pu = Yw x hw

= 10 x 3

= 30 KN/m2

ANALYSIS IN Staad. Pro.

• The model of the abutment is created in STAAD Pro.
• The height of the abutment is considcered as 10m and the foundation width is considered as 5 m and the length is considered as 8m.

• The material property for the plate and beam has been assigned.

• The 3D rendering view of the structure.

• The foundation has been considered as plate mat with 18 KN/m2/m as subgrade modulus.

• The earth pressure loading has been given as input to the structure as linearly varring and as hydrostatic forces for ouer and inner side of the abutment.

• The soil loads of P1 and P2 on the foundation of the abutment has been applied to the sturcture.

• After applying the load, the structure is being analysed and 0 error , 0 warnings have came as result.

ANALYSIS AND RESULTS

• The base foundation plate pressure has been shown.

• The earth pressure variation and effect on the structre.

• The support reaction report for the structure.

• The displacement diagram with detail report for the earth pressure loading.

• The base pressure variation for the earth pressure analysis.