Tutorial #3: Permit Vehicle with HL-93

Problem Overview

This Tutorial problem will provide an overview of entering and designing a box single cell precast box culvert with both an HL-93 truck and a typical permit vehicle. In the previous tutorials, the dialog box fields were already filled out for you. In this tutorial, you will have to do some data entry to see the final results.

Start Eriksson Culvert as before and begin a new job by opening the Initialize New Design dialog box.

Double-click on the “Four-sided” button to start the project.

For this tutorial we will check both HL-93 and a permit vehicle. While we are using typical assumptions with our permit vehicle, the user is reminded that not all permit vehicles are treated the same. Please check with your governing authority for the proper design assumptions to use with specific permit vehicles.

A full design can easily be accomplished with just a single run of Eriksson Culvert. To start with, make sure you are in Design Mode.

Open the Culvert Properties dialog box and change the clear span, clear height and length to match the input below.

Then access the Moving Loads Dialog Box. The default problem only has one truck, the HL-93.

To add a permit vehicle, click the Add Truck to List button. The truck library screen will be displayed.

Select the NYSDOTPermit vehicle and then press OK. You will be returned to the Moving Loads Dialog Box.

Back on the Moving Loads window, we must now configure the trucks.

Configure each truck as needed by selecting that truck in the list, and then making any needed corrections in the parameters to the right. For this design, we only need to configure the permit vehicle. Highlight the permit vehicle in the list, and then change the vehicle type to Permit Vehicle, and the load combination to Strength II. You may also need to change the rating load factor, but we will leave it at 1.35. Note that this load factor will only be applied to the rating calculations. There is a separate design load factor that will be applied to the flexure and shear calculations (which can be accessed through the load and resistance factors dialog box).

We also need to remove the lane load. Note that parameters at the bottom of this dialog box are not specific to an individual truck but will be applied to all trucks.

Press OK and look at the text report

The thicknesses and the critical section summary tables will display the controlling truck

To save space we use key values for the truck names, in this case, the HL-93 is displayed as AA and the permit truck is displayed as AB in the critical section tables.

Change the operating mode to Analysis Mode.

Switching to Analysis Mode will freeze the reinforcement based on the controlling truck.

Pressing OK will again complete the analysis. Scan the critical section table of the text report to make sure that there are no design deficiencies. Note that the program does this for you automatically, and posts the results in the design deficiency list next to the text report. If there are no deficiencies detected, then the deficiency list will not be present. If there are any deficiencies, then upgrade any of the reinforcement steel as necessary.

That completes this tutorial on mixing permit vehicles with the HL-93 truck to produce an adequate structure.