Week 9 Challenge

Aim: To calculate the wave load to be applied to the staad model of the bridge and do the analysis.

Given data:

Base slab width = 9 m

Bridge span=12 m

The maximum crest elevation(η,max) = 3 m.

The deck of the slab is supported by three I Girders.

Each I Girder is 1.7 m in height with a top and bottom flange width of 2.5m. The thickness of the flange and web is 500 mm.

The thickness of the deck slab=2m

Cva=3, Cr =0.4,N = no of girder =3

Solution:

Δz,h = η,max - Centroid of I-Girder= 3 -(1.7/2) = 2.15 m

Δz,v = η,max - depth of I-Girder= 3 -1.7 = 1.3 m

Horizontal load,Fh =γw x Δz,h x Ah = 10 x2.15 x(12x2)=516 kN

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

Vertical load,Fv = γw x Δz,v x Av = 10 x 1.3 x(9x1.7/2)=99.45 kN

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

Maximum Horizontal load = (1+Cr(N-1))Cva x Fh=(1+0.4x(3-1))x3x516 =2787 kN

Maximum Vertical load =Cva x Fv = 3 x 99.45 = 298.35 kN

Analysis in Staad Pro.

The bridge is modeled in staad pro as shown below.

The properties assigned to I-girder beam and deck as given below.

Load application is done as shown below.

Result & Analysis:

Girder beam:

(Bending Moment Diagram)

(Shear Force Diagram)

Maximum bending moment encountered: 113.309 kN.m

Maximum shear force encountered: 53.536 kN

Bridge Deck:

Maximum bending moment encountered: 79.3 kN.m/m