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Step 1: Obtain Deflected Shape
Based on the lane discretization, the program creates lane loading points along the width and length of each lane in the model. Then it places unit load in gravity direction at each lane loading point to determine the deflected shape. The unit load applied to the lane loading point is proportionally distributed to the tributary joints in the model. Using "Display > Show Lanes > Show Structural Connection For Selected Point" you can display the connections between the lane loading point and the joints in the model. So if our model contains 1000 lane loading points, the program would calculate 1000 deflected shapes, each corresponding to a unit load at each lane loading point. These deflected shapes are then used to determine all response quantities.
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Based on the deflected shapes calculated in the previous step, the program determines influence surface for each desired response quantity (such as reaction or axial force in a member). The value of the influence surface is exact at the lane loading points and linear interpolation is used to obtain values on the influence surface between the lane loading points.
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Moving Load