Illinois-Specific LRFR Live-Load Factors Based on Truck Data
Advanced Search
Select up to three search categories and corresponding keywords using the fields to the right. Refer to the Help section for more detailed instructions.

Search our Collections & Repository

All these words:

For very narrow results

This exact word or phrase:

When looking for a specific result

Any of these words:

Best used for discovery & interchangable words

None of these words:

Recommended to be used in conjunction with other fields



Publication Date Range:


Document Data


Document Type:






Clear All

Query Builder

Query box

Clear All

For additional assistance using the Custom Query please check out our Help Page


Illinois-Specific LRFR Live-Load Factors Based on Truck Data

Filetype[PDF-9.94 MB]

Select the Download button to view the document
This document is over 5mb in size and cannot be previewed
  • English

  • Details:

    • Alternative Title:
      Illinois-Specific Live-Load Factors Based on Truck Data
    • Publication/ Report Number:
    • Resource Type:
    • Edition:
      12/1/15 – 2/28/19
    • Abstract:
      This research project has a focus on the load and resistance factored rating (LRFR) live-load factors for load rating bridges in Illinois. The study’s objectives were to examine the adequacy of available Illinois weigh-in-motion (WIM) data and to develop refined live-load factors for Illinois LRFR practice, based on recorded truck loads in Illinois. There are currently 20 operating WIM sites in Illinois, each next to a weigh station. Initially, only one WIM site was providing two lanes of truck-weight data simultaneously recorded, while the remaining 19 were collecting data for the driving lane only. Two-lane WIM data are important for live-load factor refinement because it is the cluster events involving trucks in different lanes that induce maximum load effects in primary bridge components such as girders. Thus, such data are critical to live-load factors. Upon recommendation from this project, the capability of passing-lane recording was promptly added to two more of the 20 sites. An additional effort was made in this study to simulate the passing lane’s data for the remaining 17 sites, to maximize the use of Illinois-relevant WIM data for covering the entire state. This simulation used the probability of multiple trucks in a cluster, based on WIM data from eight states including Illinois. It also used truck-weight-demography information and headway distances of trucks in cluster from all available Illinois sites. This simulation method was tested and proven in the present project to be reliable for calibration here for Illinois. The resulting truck records of these 17 sites and those recorded at the other 3 sites capable of providing two lanes of truck-weight data from 2013 to 2017 were then used to develop refined live-load factors for LRFR in Illinois. Illinois trucks are seen in these WIM data to be less severe than those weighed in Canada, which were used in calibrating the current AASHTO LRFD Bridge Design Specifications (BDS) (2017). Illinois trucks recorded in the WIM data were also found to have behaved with little or no influence from the nearby weigh station. Four load-rating cases are addressed in this project in calibrating LRFR live-load factors for Illinois: design load, legal load, routine-permit load, and special-permit load. Based on calibration using Illinois truck-weight records, no change for the design load rating is recommended. Lower live-load factors are recommended for the other three cases for Illinois than those prescribed in the current MBE, by about 8% to 14%, depending on average daily truck traffic (ADTT). Illustrative examples using the recommended live-load factors have been prepared and presented in this report. It is also recommended that Illinois Department of Transportation (IDOT) continue to keep the WIM stations well-maintained, including periodical calibration of the weight sensors and systems; gather more truck-weight-data; review them at least biennially; and focus on possible growth of truck load in both magnitude and volume. When funding becomes available, passing-lane recording is recommended to be added to those WIM sites that currently do not have this capability. Truck-data gathering is also recommended for sites where congested truck traffic is often observed, given adequate funding for such facilities.
    • Format:
    • Funding:
    • Main Document Checksum:
    • File Type:

    Supporting Files

    • No Additional Files

    More +

    You May Also Like

    Checkout today's featured content at

    Version 3.26