Challenge

Week 8 Challenge

NNikhil Agnihotri9 Dec 2022

Aim of The Challenge : To Model & Analyse the Bridge Section which is having span of 12.0m length for Centrifigual Forces acting on the bridge having Width of Carriageway 7.0 m, Bridge is subjected to 70 R Tracked Vehicle Loading which is having a design speed of 75 km/hr also radius of curvature in the bridge is 3m, in Staad Pro and Brielfy Identify The Displacement, Bending Moments, Shear Forces & Plate Stresses Developed on the Structure while subjecting to Centrifigual Forces.

Introduction : As we Know Staad Pro is Designed and Maintained by Bentley Systems Software Company, Staad Pro is used for Structural Analysis and Design Purposes, As the Given Structure is a Bridge of 12m span, we have to analyse the structure for Centrifigual Forces and briefly describe the analysis results.

Procedure :

Calculations :

Calculation of Centrifugal Force:

C = W*(V)^2/127R

According to IRC 6 2017 70 R Tracked Vehicle is having a total load of 35T + 35T = 70T

Therefore W = 70

Design Speed of Vehicle V = 75 km/hr (Given)

Radius of Curvature R = 3 m (Given)

Hence, C = (70 x 75 x 75) / 127 x 3 = 1033.464 KN.

Modeling :

1. Open Staad Pro and Create a new Project and select Metric in Unit, this will allow us to model the structure in metres as shown in the given diagram and get results in Kn.
2. Input the origin node as 0,0,0 Select the node press CTRL C+ CTRL V input -10 in Y and press ok, create beam between two nodes now select the top node and press CTRL C+ CTRL V input -3.5 in Z and press ok again press CTRL C+ CTRL V input 3.5 in Z and press ok Join all the nodes at top with beams, now select both the node and beam and perform translational repeat number of steps 1 and distance is 12 in X direction, Join top nodes to create a longitudinal girders.
3. Create a Deck Slab Select the corner node press CTRL C+ CTRL V input 0.5 in X and press ok, Select both the nodes press CTRL C+ CTRL V input 0.5 in Z and press ok. Create a Plate Inside these nodes select the plate and perform translational repeat number of steps 47 and distance is 0.5 in X direction, again select all the plates and perform translational repeat number of steps 5 and distance is 0.5 in Z direction which creates our Deck Slab.Which is Shown in the Image Below.
4. Now we can have to Provide Supports in Pier Bottom Select all the bottom Nodes Click on Specification in Upper Tab Create a Fixed Support and Assign the Bottom Nodes to Fixed end Support.

Assingning Specifications :

1. Click on Specification Tab click on Define click on Rectangle Add a Pier Size of YD - 1, ZD - 7 m. Click Add, Again Click on Define Click on Rectange Assign the Cross Girders as YD - 0.676, ZD - 0.3 m. Again Click on Thickness and add a plate of 0.340m click ok. Again Click on Define Click on Tee Assign the Longitudinal Girders as shown in the image below.

2. Select Both the Piers and Assign the Specification having YD - 1, ZD - 7 m Configuration, Similarly Click on Select click on Parallel under Beams click on parallel to X Which selects all the Vertical Girders and Assign the Specification having Tee Section Configuration, Similarly Click on Select click on Parallel under Beams click on parallel to Z Which selects all the Cross Girders and Assign the Specification having YD - 0.676, ZD - 0.3 m Configuration, Also Select all the plates and assign the Specification having plate 0.340m Configuration.After assigning all the properties the model should look like the image provided below.

Adding Centrifigual Force:

1. Click on Loadings click on Vehicle Definitions, click add and give properties as given in the image below.

2. Click on Load Cases Details Click add Click on Load Generation Enter 25 in No. of Loads to be generated click ok. Again click add and give properties as given in the image below.