Beam transporter

Last updated: 2013-06-25

Total video time: 64:15

Exercise data: swept-pth-beam-trnsprt-data-c3d12.zip

swept-pth-beam-trnsprt-01.mp4 11:40

In 2007, WisDOT in cooperation with Spancrete performed a study to accurately model beam transport trucks with swept path software. This training package has been assembled to provide guidance to designers on development of proper swept paths for the beam transport trucks. Included with this training package are the following files:

  • 149' Beam (Training Vehicle).vcl
    • This vehicle file can be imported in to AutoTURN and used to practice swept path development. This is the vehicle that was used in the study and should only be used for training purposes. The actual design vehicle is located in the WisDOT OSOW library and is called 165' Beam 1.
  • template.dwg
    • This drawing contains the actual surveyed path of the 149' Beam truck at two intersections (1 left turn, and 1 right turn). There are multiple paths from multiple vehicles/drivers shown at both intersections to represent variability.
      • 16tdq125305_crop.tif, 16tdq125320_crop.tif, 16tdq140320_crop.tif
    • Cropped USGS aerial imagery to provide background reference
  • Beam Transporter Training.dwg
    • This file has the template.dwg and USGS aerial imagery xreferenced into it
    • This file can be used or copied to practice drawing swept paths.
    • This file contains two swept paths that have been drawn for the left turn and the right turn to show what the finished swept paths should looks like.

Import the 149' Beam training vehicle into AutoTURN

  1. Select Vehicles from the AutoTURN menu.
  2. At the bottom of the Vehicles dialogue box, choose Import Vehicle.
  3. Select the 149' Beam (Training Vehicle).vcl file and click Open.
Tip:

Helpful Hints and information for creating beam transporter swept paths:

  • The rear bogie articulation is completely independent of the front steering and is controlled with hydraulics by the driver. A typical articulation rate for the bogie over a given travel distance is dependent on the anticipated vehicle speed. A good starting point for design purposes is to articulate the rear bogie a maximum of 4 degrees for every 17 feet of travel entering and exiting the maneuver. This is roughly the distance between the front axle and the first king pin.
  • The vehicle is capable of articulating the bogie as a stop condition. However, this is highly undesirable and is only done is extreme circumstances. This action places elevated lateral forces on the girder and bogie, especially on dry pavement.
  • When articulating the rear bogie while entering the maneuver, try to get the bogie to follow the path of the tractor as long as you can. This will method will help provide a smooth transition.
  • Avoid articulating the bogie too earlier or too quickly causing it to swing outside of the tractor path.
  • The maximum articulation angle between the jeep and tractor is 45-degrees. The maximum articulation angle between the jeep and the beam is 45-degrees. These angles are preset in the vehicle template. Exceeding these angles increases the risk of tipping the beam. The maximum articulation of the bogie is 20-degrees and is limited by its mechanical capability. This is also preset in the vehicle template.

Animate swept path

From the AutoTURN menu, click Run Animation . The Run Animation button has standard controls for play speed, stop, pause, and a slider to move to a specific position in the swept path. The animation will display best if the aerial imagery is turned off. Watch for erratic or unrealistic movements such as swerves.

swept-pth-beam-trnsprt-02.mp4 2:55

This section contains actual video footage of the beam transport truck's rear bogie and is intended to give the audience a better idea of how the vehicle works.

swept-pth-beam-trnsprt-03.mp4 13:13

This is Step 5 from Accurate swept paths for complex OSOW vehicles. Trace the actual swept path that was surveyed in Step 3. This section demonstrates how to the Beam Transporter vehicle works by creating a swept path over an actual surveyed swept path of the vehicle.

Practice drawing swept paths using the 149' Beam training vehicle:

  1. From the AutoTURN menu, choose vehicles
  2. In the custom vehicle library, select the 149' Beam (Training Vehicle) in the Vehicles dialogue box and click OK.
  3. From the AutoTURN menu, click Generate Arc Path
  4. Place the vehicle on the screen so the front of the tractor roughly lines up with the surveyed point markers
  5. Click a point in front of the vehicle to define the start angle. Set the start angle so the rear bogie roughly lines up with the surveyed paths
  6. In the SmartPath Tools dialogue box, click the Override Angle box. This controls the articulation angle of the rear bogie. To control the angle in Autocad Civil 3D, hold the Ctrl button down while scrolling your mouse wheel. Negative override angles are for left turns and positive override angles are for right turns.

swept-pth-beam-trnsprt-04.mp4 15:08

In this exercise, we will practice maneuvering the beam transport vehicle through a single lane roundabout.

Place the swept path on the proper layer. There are layers available in the wisdot templates for swept paths. They can be located easily by using the RAB layer filter.

  • RAB_EB_TURN_Left
  • RAB_EB_TURN_Right
  • RAB_EB_TURN_Thru
  • RAB_EB_TURN_U

Info: Remember: The 165' Beam vehicle located in the WisDOT OSOW library is to be used for design.

 

Create a swept path without applying an override angle to the rear bogie.

In some cases, minor modifications to the roundabout entry, truck apron, and exit can be made to make this possible. Adding features like a truck apron to roundabout entry, expanding the central island truck apron, and widening the roundabout exit can sometimes be done to make it easier for the vehicle. Be sure to have features like these reviewed by a qualified roundabout designer and get WisDOT approval.

Create the swept path using the rear bogie override angle

The through maneuver on a roundabout is an S-curve. The key is to make the S-curve as flat as possible for this vehicle. Maneuvering an S-curve requires the bogie to articulate left, then right, and then back left again. While doing this, it is important not to exceed the 4-degree/17 ft rule for transitioning the bogie angle. Only articulate the bogie as much as is needed and no more.