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3.6. Structural and Load Associated Distress Analysis <br />As mentioned in section 2, pavement distresses may be categorized into two classifications — load <br />associated distresses (LAD) and non -load associated distresses (NLAD). Load associated distresses, such <br />as rutting and alligator cracking, are those that are directly caused by traffic loading and lead to <br />decreased structural capacity. Non -load associated distresses are those that result from material or <br />environmental issues, including shrinkage (transverse) cracking, bleeding, and raveling. Generally, load <br />associated distresses affect the overall condition score more than non -load associated distresses due to <br />their implications of structural failure. The roadways were classified as Weak, Moderate, or Strong <br />depending on the type of distresses found on their surfaces. The strength rating then translated to a <br />Structural Index (30, 60, or 80 for weak, moderate, and strong respectively). <br />Weak pavements are those with a high ratio of load associated distresses compared to their PCI score <br />and generally require increased pavement thickness to achieve long-term pavement life. Strong <br />pavements are those that have a low load associated distress to PCI ratio and have suitable structural <br />capacity. Surface treatments are acceptable rehabilitation solutions. Moderate pavements are those <br />that require localized rehabilitation and/or increased thickness to achieve full pavement life. These are <br />pavements that are starting to display structural failures, such as rutting or alligator cracking. <br />The following Figure 13 shows the comparison between the sum of LAD on a segment and the PCI of the <br />segment. It is important to note that the large majority of the City pavements can be classified as <br />moderate based off the amount of LAD recorded on the street. There are also several segments that <br />show weaker than expected structural strength based on their PCI. These pavements may require <br />heavier rehabilitation efforts than what would typically be associated with their PCI category. <br />100 <br />m <br />m <br />a 70 <br />a <br />J <br />IA <br />ti 60 <br />v <br />50 <br />a <br />L <br />0 40 <br />0 <br />E 30 <br />Qs] <br />10 <br />N <br />Very Poor <br />Poor <br />Marginal <br />Fair <br />Good <br />Very Good <br />Excellent <br />'v/ <br />iOot'e <br />14 . <br />Weak <br />Pavements <br />is <br />s <br />�♦ <br />.• ; <br />. <br />. <br />Strong <br />Pavements <br />-14 <br />' <br />�. <br />• Nei �. <br />• ♦ <br />♦-- <br />♦♦ , , <br />,♦t <br />0 10 20 30 40 50 60 70 80 90 100 <br />Pavement Condition Index (PCI) <br />Figure 13 - LAD compared to PCI <br />IMS Pavement Management Report Louisville, CO 2022 Page 1 26 <br />