Análise do limite do IRI para pistas de pouso e decolagem brasileiras a partir da aceleração vertical percebida pelas aeronaves

Abstract

In Brazil, the roughness of runways must be monitored by the International Roughness Index (IRI), which should reach a maximum of 2.50m/km. However, this index was developed to evaluate the effect of pavement roughness on a mass-spring-damper system of an automobile. As there are numerous differences between automobiles and aircraft, the way these vehicles respond to pavement roughness is distinct, which makes the adoption of this index in airports inadequate and its use can lead to mistaken decisions regarding pavement maintenance. In order to minimize these mistakes, it is necessary to analyze the suitability of the maximum value allowed for IRI. The objective of this research is, therefore, to carry out this analysis from a parameter that takes into account aspects not predicted by IRI, such as the operating speed and the physical characteristics of the aircraft, as well as all the wavelengths of the pavement roughness. Then, the vertical acceleration perceived by aircraft due to the pavement roughness was adopted, whose acceptability limit is equal to 0.4g, where “g” represents the acceleration of gravity. Therefore, the roughness of six runways was analyzed by these two parameters with the ProFAA software, which simulated the movement of two aircraft models at different speed levels while traversing the runway profile. The values obtained were compared with their respective limit. It was observed the occurrence of cases in which one parameter classified the roughness of the section as acceptable, while the other did not, representing situations in which the operational safety related to the pavement roughness would be compromised or situations in which there would be inappropriate application of material and financial resources. In order to minimize these occurrences, it was evaluated what would happen if the limit established for IRI were changed to 2.00 and 3.00m/km. It was concluded that a possible change in the IRI limit would not make maintenance activities more effective, suggesting, therefore, that the present value should be maintained. Additionally and the purpose of comparing indexes, the roughness of the runways was also analyzed by Boeing Bump Index (BBI).