Best Practices for Assessing Roadway Damages Caused by Flooding

As a result of a changing climate that is believed to produce more frequent extreme events witnessed in the United States, thousands of roadway lane miles had been inundated in recent years during various storms and hurricanes. Flood-induced damage to roadways is well recognized and documented in both local and national media as well as in the literature. However, the damages to pavement structures that remain visually intact during a flooding event are not well understood, nor is there a guideline for selecting an appropriate engineering tool or procedure to evaluate such structural damage, based on flood characteristics and roadway conditions. A comprehensive literature review and a national wide questionnaire survey were conducted to identify the best practices for assessing flood-induced roadway damages. The findings indicate: (1) All types of pavements exhibit flood-induced structural damages; however, flexible pavements, particularly those with thin AC layers, are most vulnerable to flood-induced structural damage, relative to rigid and composite pavements; (2) The infiltrated water to unbound pavement layers causes the most damage to the structural loading capacity of flooded roads; (3) The gradation of aggregate base or subbase layers plays a crucial role in defining the resilience of a roadway to flooding by affecting how much time the infiltrated water takes to drain from the flooded roadway; and (4) FWD (falling weight deflectomer), DCP (dynamic cone penetrometer), and GPR (ground penetrating radar) are commonly used in-situ tools for assessing structural damage caused by flooding, with the first sensor deflection, effective structural number, and subgrade resilient modulus as the quantitative indicators. A holistic framework for evaluating flooding risk is proposed, which considers the degree of hazard (i.e., flooding), vulnerability, and consequence of the flooding of the roadways. A quantitative, composite indicator, risk factor, as a multiplication of hazard factor, vulnerability factor, and consequence factor, can be approximated with storm characteristics, pavement characteristics, and functional class of pavement and traffic volume. A flooding risk map is developed based on the risk fact in a space of criticality factor-consequence factor, which is divided into three different risk zones: high risk zone with a risk factor ranging from 64 to 125; medium risk zone with a risk factor ranging from 27 to 64; and low risk zone with a risk factor smaller than 27. Based on the risk factor, three different levels of engineering procedures are recommended to assess flood-induced damages to roadways: (Level 1) Hydraulic and pavement performance analyses + Nondestructive testing + Field Reconnaissance (visual inspection-data recording-checking) (for the roadways with High Risk); (Level 2) Nondestructive testing + Field Reconnaissance (visual inspection-data recording-checking) (for the roadways with Medium Risk); (Level 3) Field Reconnaissance (visual inspection-data recording-checking) or inferring damage based upon previous engineering studies (for the roadways with Low Risk).


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 76p

Subject/Index Terms

Filing Info

  • Accession Number: 01776576
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/LA.19/615, LTRC Project Number: 18-3P
  • Contract Numbers: SIO Number: DOTLT1000219
  • Created Date: Jul 14 2021 5:10PM