Moving Load Analysis of Arch Bridge | Midas Civil Tutorial

Hello and welcome to this tutorial for Midas Civil. Today I will show you how to model this bridge in Midas Civil and how to apply the moving load on it. So this is the plan of the bridge. The main deck is 50 meter by 14 meter and the height of the arch is of 10 meters. I will apply three types of load cases on this bridge. Dead load, sidewalk load and vehicle load. And finally you can see here the material and the section properties. So two types of material. All are steel materials. One for the cross beam and the bracings and one for the main garden, the arch rib and the hangar. And six different sections for this bridge. Okay let's go back into Midas Civil. We'll first close this project and create a new project. In this new project the first things to change is the unit. So I will use the kilonewton and the millimeters. And I will add the properties for the material. So the first one will be to add the two different steel materials I will use in this project. So just for the standard use ASTMS and A36 for the first one. Click on apply and your first material has been added. For the second material again go into the DB and select the material A57250 and click on ok. Now your two material has been added. Now select the section tab and we'll begin to add the sections to the project. So click on add and the first section is the section for the main girder. So we'll enter main girder in the name and choose the box type of section. Now this is a user defined section so check user and enter the right properties for this section. So 2000, 600, 10 and 10. Now click and apply and this section has been added. Now we'll add the other sections. So we'll enter in the name cross beam and the values corresponding to this cross beam. Yes first this is an eye section so select eye section into the box and for the parameters we will use 1540, 500, 14 and 27. Now click on apply again. The third section is the arch rib. Enter arch rib. Again it is a box section so select box enter the values 600, 600, 16 and 14. Click on apply. Next section is hanger. It is an eye section and the parameters are 600, 400, 12 and 16. Click on apply. The section struts is the following one. Again use box section. The parameters are 600, 500, 10 and 14. Now click on apply. Finally the last section is the one called bracings and stringer. So enter the name here. This is an eye section and this time we'll use DB section. So select AISC and in the section name choose the section W16 by 100 and click on ok to add. Now you have added all the sections to the project. We can begin the Before modeling the arch rib don't forget to come back to the metal unit by clicking on the button in this part of the screen. Now we will use the wizard in order to create the arch rib. Go into structure and into the wizard tab here you have base structures. Choose arch. So we'll first use the first type parabola1. The number of segments will be 10. Here you have to enter the span of the bridge which is 50 and the height which is 10 meters. Now we have to choose the material. So I will use the second one and for the section choose the arch rib section. Now you have to click on the insert tab and the insert points will be the 0.000 so it's okay. Now just click on okay in order to create the arch rib. Now we will generate the hangers. So for that I will use the extrude function. So use the extrude type node line element in order to transform the nodes to project these nodes on a line and to create the hangers. So first of all you have to select the nodes to be projected. So use this function select by window and select these nodes. Not the first node so we will do again. Select the front view it will be easier for the selection. Now for the material types use the second material and the hanger property for the section. After that I have to save it. In the generation type choose project. Project on a line and here you have to choose the projection line so you can directly select on the screen these two nodes which will define the projection line and just click on apply in order to create the hangers. Now to change the beta angle of these hangers after creation you have to go into change parameter option here. You have to select these hangers so to select that click here on select recent entity so it will select automatically an entity which has been created recently. Then choose element local access and you can change the beta angle. Click apply and the beta angle of all these elements will automatically be changed. To view a bit better I will use the shrink option so now you can see better the sections assigned to your elements. And now I will generate the main girder and duplicate the arch frame. For that choose create element, general beam, tapered beam. In the material section select the second material, choose main girder for the section, zero for the beta angle and don't forget to activate the intersect node option. Now click in the nodal connectivity field and you just have to select on the screen the first node and the last node of the girder and it will be automatically created. Now I will translate this main arch. For that choose translate comment. So now in the tree menu you have the translate element window which appears here. Choose the copy mode, select all the elements on the window and in the distance field choose equal distance and in the y direction choose 14. Now 1 for the number of time. Just click on apply in order to create the second arch strip. Let's use the extrude function to create the cross beams. So first of all you have to select the nodes to extrude. So for that use the select by polygon and by doing like that you can select these elements and nodes. Choose node line elements, beam type, the first material A36. The type of the section will be cross beam. Click on projects on the line and choose the two nodes of the line on which you want to project and just click on apply to create your cross beam. To view better we can hide the sections and activate again the shrink. Now I will generate the bracings. So to generate the bracings you have to choose create element again. So the first things to do will be to select the entities. So it will automatically select the cross beam I just created and I will go into view tab to activate only these elements. Now click on elements number so you can view the number of each element and in the window here element type general beam. The material will be A36 and the section will be the section bracing and stringer. Zero for the beta angle. Don't forget to check this option elements. If you don't check it you will have some problems after that. Now click in these nodal connectivity and I can create my bracings. So first click on these two middle elements to create the main bracings here. Create directly by clicking on screen like that and now I will translate elements again. So go in the node elements translate choose select single to select these two bracings and choose copy equal distance 5 over dx four times and click on apply. Now I created this range of bracings. Now I will mirror these elements on the other side. So click on mirror function. Select previous and recent entities. So it will ask you append to current selection. Click on yes. Choose the plan yz for the reflection and enter 25 which is the middle of the bridge and just click on ok to create the others the other bracings. Now I will create the bracings on the arch ribs. So go into the view and choose inverse active so you will see only the two arch ribs. Now click on create elements with elements general beam choose A36 for the material and choose the section number five strut. Enter zero for the beta angle. Don't forget to check the intersect node. Click on the nodal connectivity field and select directly click on screen to connect these nodes together. Now click on select single to select these five elements which I just created and activate them here. Now we'll use the create element function here. Use the section bracing and stringer zero for the beta angle and connect the middle of these elements and now click on these nodes to create the bracings. Click on activate all and we completed the modeling of the bridge. Now we'll assign the beam and release condition to the hangers. So again in the boundary tab select beam and release. Click on add replace and to see better I will inactivate the section. To select very quickly these hangers you can go in this part of the screen and select z in the filters. Now if you select select all it will only select the hangers. For the condition of the and release select my and mz and just click on apply. So you will see there is a small symbol green which is now here on each end of these hangers. To assign the other condition unselect the z-axis in the filter and click on select element by identifying. Here choose section and select bracing and stringer add. So this is a very quick way to select all the bracing and stringers in your model. Again fix my and mz and click on apply. Now again click again here section and this time select the closed beam. Click on add and here we will again we'll activate only these elements. So go in the view activate only. What we will do is to select only these parts elements. So for that click on here and intersect line and if you click here only these elements will be selected. Now in the condition select pinned fixed and click on apply. Now select the other elements here and this time select fixed pinned and click on apply. Now you can activate all the elements and we finish to add to apply all the boundary conditions. I will then create a cross beam group. So this is necessary in order to enter the moving load. So click on select entity section. Select the cross beam section and add. Activate only these elements and choose the top view. Now right you can close this. Right click on click on group and right click on structure group. Click new and here you can enter the name cross beam 1. Enter. Select the elements here so you can use this and if you drag and drop the cross beam all these elements will be assigned to your cross beam group. So I repeat this is necessary to do that in order to apply the moving load on these cross beams. Next step is the definition of the load cases and the definition of these loads. So click on static load case. Here in the name you can enter the name of the first load case which will be dead load. The type you can choose dead load. Click on add. You can enter now side walk load. Click on add and close this window. Now we will create this tool. Go into the load tab. Click on elements beam load element here. Select the dead load for the load case. Click on add. Select uniform load. Global z for the direction and here actually you only have to add the value of this dead load which is minus 90. Then click. You have to select also the main girder. So to select the main girder you have to go in here elements. So section main girder add. Now you can click on apply to create this dead load. For the side walk load this is the same. So you can select again previous. You just have to change the load case for side walk load. Uniform load global z and it will be minus 6 for the value of the load. Click again on apply to create the side walk load. Now we'll see how to define the moving traffic load. So in load you have moving load here. For the code you can choose the code you want to use. So in this case I will use the AASHTO code LRFD. You have first to define the traffic lanes. So click on traffic lanes. Click on add and we have to define the four lanes. So you have to define the eccentricity of the lane. So for the lane one use... So before entering the values I will change the unit to the British unit. I'll use K-I-P-S and the foot. Now for the eccentricity enter minus 11.5. The wheel spacing will be 6 feet. The cross beam... Click on cross beam. So here you see that the cross beam group defined previously is here. Now you have to select the two points for the traffic lane and you see it has been added here. So click on ok to create this traffic lane. You can see it here. Now we'll create the second traffic lane and lane two. Eccentricity this time will be minus 35. Select cross beam both for the moving direction and again select these two points and click on ok to create the lane two. Now that we've created the traffic lanes we can close this window and we have to define the type of vehicles. So click on add standout and here select the code AASHTO LRFD load. For the load name you can just use this one. Vehicle load type ok and for the dynamic load allowance use 33. Click on ok and we'll click again on add standart. Okay same standart but this time we'll use the 93 TDM standart and use again 33 for the dynamic load allowance. Now click on ok. We'll close the window and we'll see how you can add the moving load cases. Click on moving load cases. Click on add. Enter the name MVL for moving load. You can use the default scale factors and you can add here. First vehicle class use this one. Scale factor one. One for the minimum number of lanes and two for the maximum number of lanes. Select these two lanes and put them into the selection lane window. Click on ok. Now click on add again to add the other vehicle class. Scale factor one. One and two for the maximum number of lanes. Again add these two lanes. Now you can click on ok and you have defined your moving load case. Now it's the time to define the analysis control options for the moving load. So go in the analysis tab. Click on moving load and here you can define all the analysis options. So we'll use exact all points for the line point selection and we'll use five for the number of line elements. For the frame we'll use normal and all for the reaction displacement and force moment. Click on ok. Launch the analysis. So click on perform analysis here. And you see that in less than three seconds the analysis has been performed. Before looking at the results we'll create some load combinations. So go into result tab. Load combination. So this type of load combination is created in the first process so you don't have to do the calculation again. Enter name. So load combination one. Load cases. Enter dead load, sidewalk load and moving load. And click on close. Now let's verify the deform shape. Click here on deformation. Deform shape. Use the cb combination minimum lcb1. Dxyz for the component. Check undeformed and legend. Deformation value you can set that to real deformation. And you will have the deform shape here. So if you activate the section this is what you get for this load combination. Now it's time to let's look at the shear force and the beam diagram. So hide again the section and come back to the initial view by clicking here on initial view. Now we'll select only this face in order to see the beam diagram in this section only. So in the view section here the selection tool choose plane selection. XZ plane. Select the first mode and click on close. And activate only these elements. Now you can go in the front view and click on beam in the results tab. Beam diagram. So it is in result forces. Beam force and moment. I will select beam diagram. For the load case select moving load mbl. Now enter my for the component. You can choose five point for the display option and line field. Now enter one in the scale field. Check contour and legend and click on apply. And now you have a view of this beam diagram. Lastly we'll check the influence lines results. So for the moving load. So all the moving load results are in this tab. Click on influence lines reaction. We'll check the line the lane one only. Before doing that I will activate again all the mesh and come back to initial view. Okay. Result influence line reactions. Lane one. One for the key nodes. And one for scale factor. Check legend and click on apply. And now you can see the influence line. So if you want to see it for another node. You can check the number of the nodes for example. And if you want to see it for the node 19. You can like that until 19. Okay. Let's go to the front view to see that there. This influence line. Now you can animate all that by clicking on animate. Apply. Check on record and you have small animation of your load. Moving load and your bridge. Now let's check the displacement. Always for the lane one. Close this animation. The key node enter 15. Enter two for scale factor. Make it a bit bigger and see better what is happening. Legend. Check the legend and click on apply. You can get a front view. Now you see at this node the displacement influence line. You can check also the B force moment. For the lane key element 23. Use two for scale factor. My. Add the part I of the beam. Check legend. Click on apply. And this is the influence line for the beam and force moment. Now the last visualization option for the result is the moving load tracer. So click on moving load tracer. Then you can go into reactions again. For the case just use mdmax, mdl. One for the key node. One for scale factor. Check control. Apply force on legend and click on apply. And you have another view of this moving load tracer. To do better I will only activate this part of the beam. Okay. Now let's look at the beam force moment for the moving load tracer. You can enter 28 here. Scale factor one. My. Now you see what is happening on this part of the bridge. Having determined the moving load location by the moving load tracer, we will now examine the method of converting the live load into static load. If we click right min max load to file button of the moving load tracer function, the converted static load is saved in a mct file. When we execute the mct file using the mct command shell in the model file already generated, the static load will be entered in the model. So click here. Click on ok. And now you see the results in the text file. Click on file. Exit. And in the main menu click go in the tools menu. Mct command. Shell. And here you can open this file that you just imported. Select a load. Static load case. And in the name confirm that this load has been generated. Click on close. And click on analysis again. Now if you go into the results and check again the diagram, you have the load case here which appeared. You can check for my or activate the legend with y. You can use solid form. View better. And now you can see the influence of this load on static load. And this is all for this tutorial. Thank you very much for watching.