Project 2

Aim-: calculate water current forces ,centrifugal forces, wave forces, snow loads, temperature loads, Barge Impact load and apply it in staddpro

Given Data:

maximum crest = 3 m, N=4 I Girders(1.6 m in height), top and bottom flange width of 2m, The thickness of the flange and web is 0.3m.The span of the bridge is 10 m

constant r = 5. Assume Cva = 3. The Storm elevation = 8.5m.Cr = 0.4.

high flood level is=4 m, mean velocity of the river is 2.5 m/s., width of the carriageway is 9 m.

live load of Class 70R tracked vehicle and the radius of curvature = 2 m.

The design speed of the vehicles is 50 km/hr.

The size of the Pier is 1.2 x 1.2 m.

deck slab width= 10.5m, the thickness =1.5 m. The deck of the bridge is flat with B <30 degrees. The depth of accumulation of snow is 1250 mm.

The Deadweight tonnage of the Panamax vessel is 25000 DWT. The Ship can accommodate a maximum of 1500 containers. Each container is of standard 6.1 TEU.

Solution:

Water Current Load Calculation:

Maximum Velocity = SQRT(2) X Mean velocity of the river

=SQRT(2) X 2 =2.83 m/s

Water Current Force = 52 x K x V^2

Pier is of square shape, K=1.5

Water current force = 52 x 1.5 x 2.83 ^2 = 624.69 kg/m2 = 6.246kN/m2

As the size of the pier is 1.2 m, the UVL to be applied = 6.246 x1.2 =7.49 kN/m

Centrifugal force calculation:

For class 70R tracked vehicle,

Weight of 70R tracked vehicle (W) = 700 kN.

Centrifugal load (C) = WV^2/127R = 700 x (50)^2/(127*2)= 6889.76 kN

The above-calculated load will be applied as a double axle moving load with each axle load as (6889.76/2=3444kN)

Wave force calculation:

Zh= N,max - Centroid of I-Girder= 3 -(1.6/2) = 2.2 m

Zv= N,max - depth of I-Girder= 3 -1.6 = 1.4 m

Horizontal load,Fh =γw x Δz,h x Ah = 10 x2.2 x(10x1.5)=330 kN

(Ah= Bridge span x (thickness of deck))

Vertical load,Fv = γw x Δz,v x Av = 10 x 1.4 x(9x1.6/2)=100.8 kN

(Av= Bridge deck width x (depth of I girder/2))

Maximum Hz load = (1+Cr(N-1))Cva x Fh=(1+0.4x(4-1))x3x330 =2178 kN

Maximum Vt load =Cva x Fv = 3 x 100.8 = 302.4 kN

Snow load calculation:

Consider the density of snow as 9 kN/m3.

As the slope of the deck is less than 30 degrees, so shape coefficient is 0.8 m.

Total snow load = (depth of accumulation of snow)x(density of snow)x(shape coefficient)=1.25 x 9 x 0.8 =9 kN/m2

Temperature loads calculation:

Consider the location as Delhi,

the Maximum and minimum temperatures at Delhi are 48 & 2degrees celcius.

Effective temperature differnece = (48.4-(-2.2))/2 + 10=25.3 + 10 =35.3 degree celcius

Thermal expansion coefficient for concrete= 11.27 x 10^(-6)

Modulus of Elasticity of Concrete = 5000 x (40)^1/2

Stress due to Temperature = α x △T x E = 11.27 x 10^(-6) x 35.3 x 5000 x sqrt(40) =12.58 kN/m2

Maximum Permissible stress = (2/3) x Modulus of rupture of concrete =(2/3)* 0.7 * sqrt(40) =2.95 kN/m2

So it will be ensured that the stress to be encountered in the bridge deck shall not exceed 2.95 kN/m2.

Temperature to be applied in Staad pro as a load case:

The temperature at the Top =48.4 degree

The temperature at the Bottom =(2.1/17.8)*48.4 =5.71 degree (The ratio is taken from IRC 6,Figure 16A)

Temperature difference from top to bottom = 48.4 -5.71 =42.69 degree.

Barge Impact load calculation:

Consider the barge speed as 60 km/h.(16.67 m/s)

Barge Collision Energy = KE = 500 x CH x W x V^2

= 500 x 1.25 x 25000 x 16.67 ^2 =4342014063 N .m

Barge Impact Depth,

aB= 3100 x ( [1 + 1.3 x 10(-7) x KE]^0.5 - 1)

=70616 mm

Which is more than 100 mm,

So Barge Collision Impact Force (PB) = 6.0 x 10^6 + 1600 x (aB) = 118985600 N =118985.6 kN

MODEL ANALYSIS IN STADDPRO

Create the model as per given specification in question and assign the properties to each member

Add each load in load case details and add the calculated values and show the loading diagram for each load

The result and values are as follows for each load by chansging the load case