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Axles/day Axle Load (kip) No. Accumulated 18-kip Equivalent Single Axle Loads ESAL or ESALD The Accumulated 18-kip Equivalent Single Axle Loads (ESAL) is the traffic load information used for pavement thickness design. The normal live load distribution factor (as in Table 3.6) shall be applied to the rest axle . Tables 390 & 395: Equivalent Single Axle Load (ESAL) Factors. single axle load will cause about 16 times the damage as an 18,000 lb. Highway pavement structuresare designed to withstand a specific number of standardized loadings derived from a known mix of truck . The equivalent axle load factors are the basis for determin-ing the design traffic and, as a consequence, for designing of road pavements. ESAL is the acronym for equivalent single axle load. However, the number and types of wheel/axle loads a particular pavement will be subject to over its entire design life become complicated to determine and are subject to uncertainties in traffic growth and changes to the traffic stream composition over time. Due to the relatively low number of buses in comparison to trucks, The design EAL's represent the equivalent num ber of applications of a standard or base axle load anticipated during the design life. The ESAL constants represent the estimated total cumulative traffic loading for each of the four vehicle types by axle classification during the pavement design life. 6.3 A pavement is subjected to the single-axle loads shown in Table P6.3. Compared to a single axle/dual wheel configuration, a tandem axle/dual wheel configuration with the same axle load will reduce N eq by a factor 0.054 (Amorim et al., 2015). single axle load. axle group Table 2: Example to illustrate the impact of the different mass limits for B-double truck 26 m is available to eligible vehicles f) Equivalent Standard Axles (ESA) Equivalent Standard Axle (ESA) is a method of standardizing various axle configurations and loads and their effects on road pavements. Equivalent Axle Load Factors, tandem axles . ESWL = 4048 Kg. 4 log t x t x t tx . Note that EALF = W t18 / W tx log 33 . ESAL factors used in RMS were derived through a composite of data obtained from AASHTO Equivalent Single-Axle Load Values for Flexible Pavements Configuration Total ESALs Single unit 6- and 7-axle respectively 0.7 and 0.9 . eral axle factors can simplify the management of pavement traffic load data and are suitable for routine pavement design purposes. Equivalent Single Axle Load. ESAL calculations are dependent upon the pavement type (flexible or rigid) and the pavement structure (structural number for flexible and slab depth for rigid). W2 = weight in kips of the standard axle or axle group (see Table 6-2) The total ESAL value, i.e., load factor, for that truck is the sum of ESAL values for all axles and axle groups of that truck. ;it is denoted in the literature by the symbol (W18). The design lane load consists of a load of 0.64 klf uniformly distributed in the . be presented in terms of a standard Equivalent Single Axle Load (ESAL).AASHTO defines ESAL as 18,000 lbs. of ESAL is used as the traffic loading input for design of pavement structure. Average estimates obtained at several locations have been used to develop 18-kip Equivalent Single Axle Load (ESAL) constants (see Table 613.3A). Governor's Goals. Most design methods for road pavements require the design traffic, based on the transformation of the traffic spectrum, to be calculated into a number of equivalent passages of a standard axle using the equivalent axle load factors (EALFs). Adopts a load magnitude to the 4 th power. Determine the ESAL for a design period of 20 years using (a) AI's equivalent axle load factors and (b) the equivalent axle load factors from Eq. It should be noted that ESALs as calculated by the ESAL equations are dependent upon the pavement type (flexible or rigid) and the pavement structure ( structural . It was found that the impact of axle configuration on the pavement is significant, i.e. Equivalent Single Axle Load (ESAL) tables are used to calculate pavement loadings (rigid and flexible types) to produce a common parameter for design and planning purposes. W2 = weight in kips of the standard axle or axle group (see Table 6-1) The total ESAL value, i.e., load factor, for that particular truck is the sum of ESAL values for all axles and axle groups of that truck. of ESAL is used as the traffic loading input for design of pavement structure. The equivalent load most commonly used in pavement design in the U.S. is the 18,000 lb (80 kN) equivalent single axle load (ESAL). (Table ), It is the AASHTO way to characterize the material properties = f ( CBR, E ) m2 , m3 -drainage coefficient for layer i (Table ) D1 , D2 , D3 -actual thickness for layer . The estimated or projected magnitude and occurrence of the various traffic loading are converted to the total number of passes of equivalent standard axle loading ( ESAL ), usually the equivalent 80KN (18kips) single axle load. 10 Six or More Axle Single Trailer Trucks 0.93 9 Five-Axle Single Trailer Trucks 1.20 8 Four or Less Axle Single Trailer Trucks 0.30 7 Four or More Axle Single Unit Trucks 0.42 6 Three-Axle Single Unit Trucks 0.42 5 Two-Axle, Six-Tire, Single Unit Trucks 0.26 4 Buses 0.57 3 Other Two-Axle, Four-Tire Single Unit Vehicles negligible Axles/day 2 1250 10 1252 6 5125 16 1565 10. HL-93 live load vehicle. So, we must check if the final SN 3 . LEFs multiplied by the number of axle loads within a given weight category and axle configuration (single, dual, tridem) give the number of 18-kip single-axle load applications that will have an equivalent effect on the performance of the pavement structures. The ESAL calculations in the reports are based on periodic turning movement counts and annual average daily traffic determinations. Generally, these factors only consider the type of axle (single, tandem . The LEF of any axle is defined as the ratio of the damage per pass of the axle in question versus the damage per pass of a standard load (usually the 18,000-lb single axle). 18.0 Faulting at joints 0.7 Table 2: Power law exponents for different modes of deterioration (Atkinson et al., 2006) Little (1993) had a research on plastic deformations of unpaved granular pavement . fad = dynamic axial factor Fa = Ka Equivalent bearing load P The equivalent bearing load to be used for the L10 basic rating life calculation either as described before or based on specific customer load . The equation is somewhat complex and . 8.2.4 Repetitions of Axle Loads. A model for equivalent axle load factors. A "load equivalency factor" represents the equivalent number of ESALs for the given weight-axle combination. The EALF depends on various parameters, but in existing design methods, only the axle. The total no. . The existing axle load equivalency factors depend on, among other variables, pavement type and thickness. . Vehicle loads are expressed in 18-kip Equivalent Single . Answer: The reference ESAL is an 18,000 pound single axle with dual tires. A model for equivalent axle load factors. This problem has been solved! For (1.1 for flexible pavement). bChain or belt factor (Table 4.4) 4.2 Bearing load distribution For shafting, the static tension is considered to be supported by the bearings, and any loads acting on the . The guide, however, requires the development of truck axle load spectra, which are expressed by the number of load A model for equivalent axle load factors. Table 380: Axle Correction Factors. Equivalent Single Axle Load (ESAL) Design Factors 2020 . S is the centre to centre distance between the two wheels = 30 cm. 8000 kg (18 kip) Equivalent Single Axle Loads (ESALs) can be estimated for the design period, which in turn are used to calculate the Traffic Index. An ESAL is defined as an 18,000 pound load on a single axle with dual tires. Tables 390 and 395 . By convention, an 18,000- We prepare the Highway Equivalent Single Axle Loading (ESAL) Reports for consultants undertaking pavement designs for Alberta Transportation. 4.4 Equivalent load 4.4.1 Dynamic equivalent load When both dynamic radial loads and dynamic axial loads act on a bearing at the same time, the hypothetical . The "traffic" term is determined by Equivalent Standard Axle Load (ESAL) repetitions which is often admitted as 80 kN single axle load. Equivalent Single Axle Load Factors . 4 1 18 log 79 . For Z = 20 cm. Requests will only be considered for students who have successfully completed a previous DL course. The table on GVW and maximum allowable axle load prescribed under RA 8794 as shown will be used in calculating the EF of each truck type. Title: AASHTO Flexible Pavement Design Method Load equivalency factor (abbreviated further as LEF) express the ratio of vehicle number to the number of 100kN equivalent standard axle. The CivilWeb Equivalent Single Wheel Load Calculation Spreadsheet includes tools to calculate the equivalent single wheel loads for these vehicle types and calculates the proximity values for the other wheels to give a load and a repetition value which can be used to model each pass of the vehicle. . The existing axle load equivalency factors depend on, among other variables, pavement type and thickness. 6.23. a 36,000 lb. Conversion factors are available to express axle loads other than 18,000 lbs. Normally the turning movement studies performed to determine . The load factor for each truck category is determined by averaging the total ESAL values for all trucks in that category. For problem P6.3, you need to find the total equivalent single axle loads (EASL) for the 20-year period using two ways of computing the equivalent axle load factor (EALF): a) use the AI load (EALF) factor values shown in Table 6.4 for each axle load, and b) use Equation 6.23 to compute the EALF for each axle load. PER RA 8794 GVW k 16880 27,250 30380 a) In a 2 - axle truck, the load distribution . Description. In the analysis load equivalency factors were calculated for each vehicle separately. (39) Where, P is the wheel load (single wheel load) = 5500/2 = 2750 Kg. However, since vehicle configurations and axle loads vary, AASHTO has established a method to convert different axle loads and configurations to ESALs. 0 .201/0.47 + 0 .201/0.5 = 0.067 , or , W tx / W t 18 = 1 .167 , or W t18 / W tx = 0.857 From Table 6.4 of Huang , EALF = 0 .857 . Equivalent Single Axle Load (ESAL) and Equivalent Axle Load Factors Traffic Input in AASHTO 1986/1993 Pavement Design Approach . Determine the ESALs for a design period of 20 years assuming a growth factor of 4% using the Al's equivalent axle load factors (Table 6.4) Single Axle Tandem Axle Axle Load (kip) No. Axle load projections were developed for all in-service years up to 1998 for 558 LTPP traffic sites that had adequate traffic monitoring data in the IMS database. The combinations are shown on Table 1. a 36,000 lb. . In most road pavements design methods, a solution is required to transform the traffic spectrum to standard axle load with using equivalent axle load factor (EALF). Table 1 shows some typical load equivalencies (note that spreading a load out over two closely spaced axles reduces the number . 1. ESAL is a concept developed from data collected at the American Association of State Highway Officials (AASHO) Road Test to establish a damage relationship for comparing the effects of axles carrying different loads. Description. Figure 2. Determiantion of axle load equivalency factors on the basis of fatigue criteria for flexible and semi-rigid pavements. Axle Load (tonnes) 5.14 6.00 3.20 EALs Equivalency (ESALs) 2.45 NOTES: Equivalent axle loads for cars and tandem axle groups from 1993 AASHTO Guide for Design of Pavement Structure (SN=5, p t = 2.0) Axle factors are provided for each axle type, axle load (2 ton increments), and pavement structural number (SN). Z is the thickness of the pavement. These values can then be used with the BPA . Baltic Journal of Road and Bridge Engineering, 6 (4 . . Equation 6.23: EALF= (Lx/18)^2 8 Thickness design governed by number of traffic repetitions of a standard vehicle or axle load, usually the 18-kips (80-kN) Single Axle Load If the axle load is not 18-kips or consists of tandem, it must be converted to an 18-kips SAL by using an Equivalent Axle Load Factor (EALF) The number of repetitions under each single - or multiple - axle load must be multiplied by its EALF to . single axle load. equivalent 18-kip (80-kN) axleloads (EAL's). Equivalent single axle load (ESAL) Equivalent Single Axle Loads (ESALS) are used to measure the decrease in roadway quality over time. A summation of the equivalent effects of all axle loads during the design period. Figure 4 compares damage factors for the axle assemblies using single flotation or dual tires. single axle with dual tires. This factor relates various axle load combinations to the standard 80 kN (18,000 lbs) single axle load. Summing the different ESAL values for each axle combination on a vehicle provides a vehicle's Load Equivalency Factor (LEF). International Journal of Pavement Engineering, v. 16, n. 10, p. 881-893, 2015. conducted a study to define the LEFs for flexible pavements by considering the type of axle (single, tandem or tridem), the type of wheels (single and dual) and the constitution of the pavement. 0000004397 00000 n 18-kip equivalency concept; in addition, the results can facilitate the development of mathematical models for calculating load equivalency factors, if necessary. The average daily traffic has to be converted to a number of 18,000 pound single axle vehicles with dual tires. GROSSVEHICLE WEIGHT GVW Truck T e Code 2 - axle 1- 1 3 - axle 1- 2 4 - axle 11 - 2 Maximum allowable axle load = 13,500 kg. Table: Example 2 Solution : Axle: No.of Load: EALF : Load: Repetition : i (KN) () 1: 120: 1000 = 6.200: 6200: 2: 160: 100 = 22.63: 2263: 3: 40: 10000 = 0.04419: 441.9: Example 3 Let number of load repetition expected by 60kN standard axle is 1000, 120kN is 200 and 40 kN is . In such circumstances, the default values given in Table 2.6 should be used: Table 2-6: Default Values for Axle Load Factors for Gravel and Low Standard Roads Axles per Heavy Vehicle 2.3 ESAs per Heavy Axle 0.20 ESAs per Heavy Vehicle 0.46 The implications of applying the default values for different design periods are shown in Table 2.7. ESAL for the terminal PSI (Table 20.13 for p t = 2.5.) The CivilWeb Equivalent Single Wheel Load Calculation Spreadsheet includes tools to calculate the equivalent single wheel loads for these vehicle types and calculates the proximity values for the other wheels to give a load and a repetition value which can be used to model each pass of the vehicle. The total no. VDOT's current pavement design procedure subdivides truck traffic into two categories, i.e., single-unit trucks and combination trucks, and was based on studies performed in the early 1990s. require the use of an equivalent single axle load (ESAL), 18 kip single axle load, for design traffic input. Because pavements having differing structural capacities respond differently to a given axle load, for a range of structural . The equivalent load commonly used in the U.S. is the 18,000 lb (80 kN) equivalent single axle load (normally designated ESAL). 4 log 79 . Overview. ESAs are assessed by Analysis of errors in prediction of cumulative equivalent axle load applications also suggests that the largest uncertainty is due not to the errors associated with axle load equivalency factors but to other . Equivalent Single Axle Load Factors . The equation outputs are load equivalency factors (LEFs) or ESAL factors. Load equivalency factors have been devised to measure the relative damaging effects of different types of loadings on pavements. single axle load will cause about 16 times the damage as an 18,000 lb. F. j - equivalent axle load factor; s - standard axle . The design tandem, representing two trailers in series attached to one truck, consists of a pair of 25.0-kip axles (50-kip total vehicle weight) spaced 4.0 feet apart, with the transverse spacing of wheels set as 6.0 feet. The equivalent load most commonly used in pavement design in the U.S. is the 18,000 lb (80 kN) equivalent single axle load (ESAL). single axle load. This means that the axle factors and consequently the number of equivalent axle loads change along a highway corridor as the construction of the pavement changes, even when the traffic loads do not change. Lane distribution factor (Table 613.3B HDM) ADT 2 d 935 Number of mixed flow lanes in one direction 2-axle truck LDF d 1 ADT 3 3-axle truck d 550 ADT 4 4-axle truck d 225 ADT 5 5-axle truck d 1025 18-kip equivalent single axle load for the surface (Table 613.3A HDM) 30-year constants ESAL d 2070 # ADT 2 C 5520 # ADT 3 C 8820 # ADT 4 C 20670 . % of Commercial Volume (CADT) Classification Two Axle Five Axle Heavy 30 - 50 25 - 40 Medium 50 - 70 10 - 25 Light 70 - 100 0 - 10 If the two-axle classification differs from the five-axle, use the . 11, nr 1/2010, s.187-202. Equivalent axle load factor: An equivalent axle load factor (EALF) . This procedure is called "Level Rule" Level Rule should only be applied to the axle load at the support. The reference axle load is an 18,000-lb. A "load equivalency factor" represents the equivalent number of ESALs for the given weight-axle combination. 6.Design InputEquivalent Single Axle Loads6.1.6.2.6.3.6.4.IntroductionCalculate the Load Factor for Each Vehicle CategoryCalculate Design ESALsHistorical ESALs6.1.IntroductionThis chapter applies to designing normal pavement structures for highway projects.