Improved Surface Drainage of Pavements Final Report (1998) / Chapter Skim
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Chapter 5 Summary, Findings, and Recommendations
Chapter 5 Summary, Findings, and Recommendations
Pages 117-130
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From page 117... ...
The guidelines support an interactive computer program, PAVDRN, that can be used by practicing engineers In the process of designing new pavements or rehabilitating old pavements' is outlined In figure 39. The intended audience for the guidelines is practicing highway design engineers that work for transportation agencies or consulting firms.
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From page 118... ...
10 Equation No.'s. 16-19 1 Hvdroolanino Analvsis Hydroplaning speed Equation No.'s 21-24 Rainfall Intensity Equation No.
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From page 119... ...
minimize the longest drainage path length of the section under design by altering the pavement geometry and (2) reduce the resultant water film thickness that will develop along that drainage path length by increasing the mean texture depth, choosing a surface that maximizes texture, or using permeable pavements, grooving, and appurtenances to remove water from the surface.
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From page 120... ...
The designer has no real control over these environmental factors but needs to select appropriate values when analyzing the effect of flow over the pavement surface and hydroplaning potential. Five section types, one for each of the basic geometric configurations used In highway design, are examined.
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From page 121... ...
A more complete description of the design process, the parameters used in the design process, and typical values for the parameters is presented In the "Proposed Design Guidelines for Improving Pavement Surface Drainage" (2) alla in Appendix A
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From page 122... ...
= Point of Tangency PCC = Portland cement concrete WAC = Dense graded asphalt concrete 0GAC = 0pcn~raded asphalt concrete where OGAC includes all types of intentally draining asphalt surfaces GPCC = Grooved Ponland cement concrete Taneent Pavement Type Mean Texture Depth 1)
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From page 123... ...
KINW (Calculates Minning's n, Water Film Thickness (WEIR) , and Hydroplaning Speed UPS)
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From page 124... ...
There are no simple means for controlling water John thickness, but a number of methods can effectively reduce water film thickness and consequently hydroplaning potential. These include: Optimizing pavement geometry, especially cross-slope.
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From page 125... ...
of k is not warranted. Based on the previous discussion, no new test procedures are needed to adopt the design guidelines developed during this project.
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From page 126... ...
These fixtures, when installed between travel lanes, offer perhaps the most effective means of controlling water film thickness from a hydraulics standpoint. They have not been used extensively In the traveled lanes and questions remain unanswered with respect to their installation (especially in rehabilitation situations)
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From page 127... ...
for different pavement surfaces to include toned Portland cement concrete surfaces. A series of photographs of typical pavement sections and their associated texture depths should be considered as an addition to the design guide (21.
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From page 128... ...
These Include: 1. Full-scale skid resistance studies to validate PAVDRN in general and the relationship between water film thickness and hydroplaning potential in particular are needed in light of the unexpectedly low hvdronlanin~ speeds predicted during 128 , .
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From page 129... ...
These include porous Portland cement concrete surfaces, porous asphalt concrete, and various asphalt m~cro-surfaces.
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