Challenge

Week 10 Challenge

AIM and INTRODUCTION :

To calculate the settled snow load accumulated on the bridge of span 10m and to apply the calculated snow on the bridge using staad pro and to perform structural analysis.
snow loads are more common in regions where snowfall occurs and regions where colder climate prevails.
snow load is calculated as per IS 875 part four and also loads are applied as per IRC 6
The minimum load considered should be 900kg/m3 as per clause 224 IRC 6.
The design snow load S = μ * s0.
The density of snow load varies according to its settlement over structure.
New snow = 50 - 70 kg/m

Damp new snow = 100 - 200 kg/m3.

settled snow = 200-300 kg/m3.

depth hoar = 100 - 300 kg/m3.

wind packed snow = 350 -400 kg/m3.

firn = 400 830 kg/m3.

very wet snow = 700 - 800 kg/m3.

Glacier ice = 830 - 917 kg/m3.

>> Positive roof slope.

>> Negative roof slope.

>> Multilevel roof slope.

PROCEDURE :

The staad pro design steps are as follows :

In this challenge the first step we need to enter the coordinates of nodes, give the coordinates for the pier.

The nodes been added, connect the nodes by beam using added beam command, thus a pier has been created for the structure.

After adding pier, copy the beam in the x-direction at a spacing of 10m with steps as 1 using translational repeat command, the 10m indicates the span of the bridge, another pier will be formed, connect the two piers by adding beam.

Then repeat the piers in z-direction for 3 steps at a spacing of 5m each, using translational repeat command, an another 3 sets of piers and beams has been created.

link the piers and beams by using add beam command, next step is to add a deck to the bridge for that we need to add plate elements.

copy the corner node and repeat the node for a step in x-direction at a mesh size of 0.5m using translational repeat command, an another will be created.

copy the two nodes in the z-direction at the same mesh size of 0.5m for one step, connect the four nodes using add plate command, then we need copy the plate in x and y direction.

copy the plate in the x-direction for 19 steps at a spacing of 0.5m, the plates will be added in the x-direction for the entire 10m span of the beam, after the copy the plates in z-direction for creating the deck for the bridge structure.

next step is we need to specify the properties for the beams, piers, and plates, add a rectangular section and assign it to the longitudinal beams, and cross beam on either end of the bridge.

Add a circular section of 1.5 m and select the piers, click on the assign to selected beams button and select the assign button, the property will be assigned to the piers.

Next, specify the thickness of the plates in the deck slab, add a plate thickness of 0.5 m, then assign the property to the plate.

add a rectangular section of required breath and depth, select the cross beam and assign the property to the beams.

The next step is to give loading to the bridge structure, add a load case and give title as snow load, give the load as uniform force, enter the calculated load value with the negative symbol in the global y-direction.

next, we need to apply the minimum design load in the deck slab, select the plates and apply the load in the global y-direction with a minus symbol indicating the load acting downwards.

RESULT:

After loading, we need to analyze the structure, click on analysis and design command select run analysis, the staad pro will check for errors, after that click on post-processing mode for further analysis of the structure

In the post-processing, mode click on the results tab, select mZ for loading load, the bending moments of the structure has shown above.

select the plate stress and select the stress type as mY for load 1, the results will be detailed in contour image form.

Ship work like this
in your own course.