Week 12 Challenge

Aim : to calculate the barge impact on the bridge superstructure

Procedure :

Given

Span of the bridges is 12m

Width of the bridge is 7m

rise of bridge truss is 5m

deck slab thickness is 0.5m

cross girders 0.75 X 1.8 m

Ch = 1.25

DWT of empty vessel = 52500 t

Length of Vessel = 296m

width of vessel = 32m

Depth of draft = 12m

Barge collision Energy = 500 x ch x W x V^2 = 500 x 1.25 x 52500 x 16.7^2 = 9151078125 N-m

Barge damage depth = aB = 3100 x ([1+1.3 x 10^(-7) x KE] - 1 ) = 103867.52 mm

Since aB > 100 mm

Barge collision impact force = PB = 6.0 x 10^6 + 1600 x aB = 172188043 N = 1.72 * 10^5 KN

let us assume a Beam of ISMB 500

then the impact of barge will be on the area of 12 x 0.5 = 6 m^2

Pressure due to impact on the girder = 1.72 x10^5 /6 = 0.29 x 10^5 KN/ m^2 = 29000 KN /m^2

Staad model

with the above mentioned specifications the following model is generated

the following properties are assigned to the structure

the loading of the impact is converted as pressure and acted in the horizontal direction as shown below

The analysis shows there is no error