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Vehicle 2 Impact Factor:
Vehicle 2 Direction:
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Vehicle 3:
Vehicle 3 Impact Factor:
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Lane Load
Lane Load Magnitude (kip/ft)Lane Load Width (ft):: The design lane load, as defined in AASHTO LRFD, is typically 0.64 klf and expressed as force per unit length. It is used in conjunction with the design truck or tandem. OpenBrIM applies the lane load in both transverse and longitudinal directions on a design lane only if it increases the critical force effect. As indicated in the screenshot below, the red and yellow regions show the areas that can be loaded with the lane load for negative force effects, whereas the green and blue regions show the areas that can be loaded with the lane load for positive force effects.
Lane Load Width: According to AASHTO standards, the typical width for a lane load is 10 ft. Entered value is utilized convert lane load to the pressure per square foot. For instance, if the entered value for lane load magnitude is 0.64 klf and the lane load width is 10 feet, the pressure per square foot can be computed as follows:
0.64 klf ÷ 10 feet = 0.064 kips/ft
Thus, the pressure per square foot would be 0.064 kips/ft².
Afterwards, this value is multiplied by the areas (i.e., red and yellow regions, as shown in the screenshot below) that contribute to maximizing the lane load force for negative force effect.
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Vehicle Placement Settings
Min. Vehicle Spacing [Back to Front]: If there are multiple vehicles defined for the design lane, the spacing between them in the longitudinal direction cannot be less than the entered value. For example, in the case of two trucks for HL93, the typical value for this spacing is 50 ft per AASHTO.
Max Vehicle Spacing [Back to Front]: If there are multiple vehicles defined for the design lane, the spacing between them in the longitudinal direction cannot exceed the entered value. Typically, a value larger than the length of the bridge is entered because AASHTO does not impose any limitation on this value. However, some DOT loading requirements may limit this distance as well.
Adjacent Span Placement:
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Adjacent Span Placement[Yes/No]: The placement of the two-truck vehicle shown below is not compliant with AASHTO standards because both trucks are located on the same span. To prevent this type of placement, the user should select adjacent span placement as “Yes”.
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Lane Placement Settings
Apply Lane Constraint[Yes/No]: Lane placement constraints are implemented to prevent the placement of lanes in a specific section of the roadway perpendicular to the direction of travel. If "yes" is selected, and the start and end parameters for the constraint are entered, the placement of lanes will only be prevented in that section. For instance, if the region.
Lane Constraint Start-End: Specify the starting and ending transverse station range along the roadway where you want to place the lanes.Suppose a roadway has a width of 48 feet, and no lane placement is permitted between 20 and 28 feetfeet, and the PGL location is assumed to be 0. The left width is 38 feet, and the right width is 10 feet when looking upstation from the alignment. In this case, the lane placement will occur within the range of -38 to 10 feet in the transverse direction. If there are restrictions on lane placement between 5 and 10 feet, as well as between -38 and -28 feet in the transverse direction, the lanes will only be placed between 0 -20 feet and 28-48 feet.
Lane Constraint Start [ft]:need screenshots - and don’t how it really works
Lane Constraint End [ft]:28 and 5 feet in the transverse direction. Therefore, the user needs to enter the lane constraint start value as -28 and the lane constraint end value as 5.