Week 12 Challenge

AIM :

• To calculate the barge impact load of the Panamax vessel, design the bridge for given specifications and apply the calculated load on the bridge using staadpro.
• Barge refers to the ships or vessels crossing the bridges constructed in rivers, canals, sea causes collision on the bridge structure.]

> span arrangement

> Horizontal clearance between the inner piers.

> vertical clearance above aircraft of the bridge to the soffit of the deck.

> minimum depth of water in the channel.

• IRC 6 2017 gives the details for barge impact loads.
• Barge collision energy is given by KE = 500 * ch * w * v2
• CH is a hydrodynamic coefficient.
• W is barge displacement is tonnage.
• V is barge impact speed.

PROCEDURE :

The step by step procedure for the design of the bridge is

• First, enter the coordinates for nodes, give coordinates as (0,0,0) and (0,7,0) for the pier, after node creation connect the two nodes by beam, using add beam command.

• The pier has been added for the bridge, the next step is to copy the pier for the other three corners.

• select and copy the pier in z-direction for 1 step at a spacing of 7m, the 7m shows the width, hence the two piers will be created at distance of 7m width of the bridge.

• select and copy the two piers in z-direction for a step at a spacing of 12m using translational repeat command, hence another two piers will be created along the span of the bridge at a distance of 12m.

• Next, we need to add nodes for creating a truss-like section above the deck slab in y-direction, select the longitudinal beams and insert nodes by using insert node button in the geometry section.

• using translational repeat command select the end nodes on both side of the longitudinal beam and repeat them in y direction for 1m height, likewise repeat the other nodes in y direction for height of 1m additionally from the previous nodes.

• The node is raised in y-direction on either side of the central node, the central node will repeat in y-direction for a height of 5m using translational repeat command.

• The nodes are copied in y-direction for required height, connect the members using add beam command, thus the structure above the deck slab will be like a truss structure.

• add a midpoint node in the above members and connect the them using add beam command, after creating the truss structure we need to assign sectional properties to the bridge.

• Add a rectangular section of size 2.5 * 2.5 of concrete material, select the piers and assign the property to selected piers.

• Add a rectangular section of dimension 1.5 * 1.5 of concrete material, select the longitudinal beam and assign the property to selected beams.

• Add channel section ISMC 100, select the truss structure raised above deck slab, assign the selected property to the truss structure.

• Add fixed support, select the piers and assign the support to selected piers.

• The next step is to form a deck to the designed bridge structure, select the corner to repeat them in the x and z direction of spacing 0.5m, create a plate using add plate command, repeat the plate in the x-direction for 23 steps and 13 steps in the z-direction.
• Add a plate thickness of 550m and assign the thickness to deck plates.

RESULT :

• The next step is to give loading to the structure, add a new load in load case details and give title as barge impact load, add a calculated load as a member load.

• After adding load, click on global z-direction and select the piers to apply the calculated load, after loading click on the run analysis command for analysis of the structure, then enter into post-processing mode.

• Click on the plate stress and select my for given loading, the stress diagram will be displayed in contour image, showing the stress values at the plate.

• The above table shows the stress values of the beam, for the barge impact load.
• Hence the bridge is designed and analyzed for the given loading.