![aashto 93 pavement design software download aashto 93 pavement design software download](https://images.squarespace-cdn.com/content/v1/60ca368fc52b04302dc016da/1624558038883-8WZQG5YIHG7J3SUQGQQW/Recycling.png)
If no compressive strength data are available (or cannot be assumed), assume E c = 27,500 MPa (4,000,000 psi), which corresponds to a compressive strength of 34.5 MPa (5000 psi). If no value is known, the PCC elastic modulus (E c) can be estimated from relationships such as the following: The Z R and S o variables account for reliability. In other words, there must be some assurance that a pavement will perform as intended given variability in such things as construction, environment and materials. The reliability of the pavement design-performance process is the probability that a pavement section designed using the process will perform satisfactorily over the traffic and environmental conditions for the design period (AASHTO, 1993 ). The predicted loading is simply the predicted number of 80 kN (18,000 lb.) ESALs that the pavement will experience over its design lifetime. The 1993 AASHTO Guide equation requires a number of inputs related to loads, pavement structure and subgrade support. This can lead to invalid results at the least and incorrect results at the worst. Otherwise, it is quite easy to use an equation with conditions and materials for which it was never intended. When using the 1993 AASHTO Guide empirical equation or any other empirical equation, it is extremely important to know the equation’s limitations and basic assumptions. The accelerated testing done at the AASHO Road Test (2-year period) can be extended to a longer design period.Material characterizations may be applied to other surfaces, bases, and subbases by assigning appropriate values.Loading can be applied to mixed traffic by use of ESALs.The characterization of subgrade support may be extended to other subgrade soils by an abstract soil support scale.In order to apply the equations developed as a result of the AASHO Road Test, some basic assumptions are needed: All PCC was of the same mix design and used the same aggregate and portland cement.JPCP was 4.6 m (15 ft) and JRCP was 12.2 m (40 ft). For JPCP and JRCP, all transverse joints were the same spacing.The loads used to develop the equations were operating vehicles with identical axle loads and configurations, as opposed to mixed traffic.Therefore, environmental factors were difficult if not impossible to extrapolate out to a longer period. The equations are based on an accelerated two-year testing period rather than a longer, more typical 20+ year pavement life.The equations were developed based on the environment at the AASHO Road Test only.
![aashto 93 pavement design software download aashto 93 pavement design software download](https://image.slidesharecdn.com/aashtodesign-131123130543-phpapp01/95/aashto-design-12-638.jpg)
![aashto 93 pavement design software download aashto 93 pavement design software download](https://slideplayer.com/slide/11979460/68/images/13/Functional+Classification+Recommended+Level+of+Reliability.jpg)
The equations were developed based on the specific pavement materials and roadbed soil present at the AASHO Road Test.These equations were developed for the specific conditions of the AASHO Road Test and therefore involved some significant limitations: The following subsections discuss:įrom the AASHO Road Test, equations were developed which related loss in serviceability, traffic, and pavement thickness. The rest of this section will discuss the specific assumptions, inputs and outputs associated with the 1993 AASHTO Guide flexible pavement empirical design equation. This equation is not the only empirical equation available but it does give a good sense of what an empirical equation looks like, what factors it considers and how empirical observations are incorporated into an equation. Load transfer coefficient (value depends upon the load transfer efficiency)
![aashto 93 pavement design software download aashto 93 pavement design software download](https://images.squarespace-cdn.com/content/v1/5e70c7ccdc975f39a6d7b95f/1589394472468-MW18C4DV14U7N2PQS3R3/ICP%2BStructural%2BDesign%2BUS%2BCustomary%2B2011.jpg)
Modulus of rupture of PCC (flexural strength) Predicted number of 80 kN (18,000 lb.) ESALsĬombined standard error of the traffic prediction and performance predictionĭifference between the initial design serviceability index, p o, and the design terminal serviceability index, p t