Edition 2. Aerodrome Design Manual. Follow Book. Buy access. Links To. Links From. In Catalogs. The space below is provided to keep a record of such amendments.
Date Entered by No. In such cases, a correction is applied to the load-deflexion curve so that the DSM is obtained from the linear portion of the curve see Figure Correction factors to account for these conditions have not been developed. Therefore, the evaluation should be based on the normal temperature range, and, if a frost evaluation is desired, the DSM should be determined during the frost melting period. Although a section of pavement may supposedly be of the same type and construction, it should be treated as more than one pavement group when the DSM values measured in one section of the pavement are greatly different from those in another section.
The DSM value to be assigned to a pavement group for evaluation purposes will be determined by subtracting one standard deviation from the statistical mean. After determination and correction of the measurement of the DSM, the evaluation procedure depends upon the type of pavement, rigid or flexible. The corrected DSM is used to enter Figure and determine the allowable single-wheel load. Step 2 The radius of relative stiffness R is computed as.
Step - 3 Using R , determine the load factor FL from Figure , , or , depending upon the gear configuration of the aircraft for which the evaluation is being made. Multiply the allowable single-wheel load from Step 1 by the FL value determined from Step 3 to obtain the gross aircraft loading.
Multiply the gross aircraft loading from Step 4 by the appropriate traffic factor from Table to obtain the allowable aircraft gross loading for critical areas for the pavement being evaluated. For the case of high-speed exit taxiways, the computed allowable gross load should be increased by multiplying by a factor of 1. Step 6 The allowable loading obtained from Step 5 assumes that the rigid pavement being evaluated is structurally sound and functionally safe.
The computed allowable loading should be reduced if one or more of the following conditions exist at the time of the evaluation: 1.
If more than 50 per cent of the slabs show load-induced cracking, the pavement should be considered failed;. Using the DSM corrected for non-linear effects and adjusted to the standard temperature, determine the pavement system strength index S from Figure Using the total thickness t of flexible pavement above the subgrade, compute for critical pavements as.
Using Ft determined in Step 2, enter Figure and determine the ratio of the subgrade strength factor SSF to the pavement system strength index Pp. Step 4. The evaluation procedure presented herein is what must be referred to as a first generation procedure.
That is, further work is under way to extend the applicability of this procedure, and it will be updated as appropriate. In addition, research is under way which will establish the NDT evaluation procedure on a more theoretical basis and thus further enhance its applicability. The allowable loadings determined using the procedure presented herein are within acceptable limits of accuracy as compared with those determined using other recognized evaluation procedures.
This procedure has the added advantages of being less costly, presenting less interference to normal airport operations, and providing the evaluating engineer with much more data on which to base his decisions. Also, in addition to their utility for arriving at allowable aircraft loading, the DSM values are useful for qualitative comparisons between one pavement area and another DSM values on flexible pavements should not be compared with those on rigid pavements and for locating areas which may show early distress and which may warrant further investigation.
As more experience is gained with the NDT techniques and interpretation of data, it is envisioned that many other uses of the concept will emerge.
Aircraft tire contact areas and total number of main gear wheels Tire Contact Area cm2 in2. Yore: 1 compaction of subgrade surface i s specified 1 5 m m deep In cohesive soii and 3 0 m m deep In non-cohesive soil. Surface condition evaluation 4. Shonsr wsvelength roughness only reflected lo msaruremantr; separate Profile anslynlr iaqutred. Pavement l i f e. The "normal l i f e " of. Wheel assembly mounted o n o n e l e g.
Static distribution. F o r example: a. Materials treated with hydraulic binders coarse aggregate concrete, s l a g , f ly-ash g r a v e l , sand-based concrete. Materials treated with cold h y d r o c a r b o n bi-nders e n u l s i o n gravel. Except w i t h s p e c i a l dispensation following c o n s u l t a t i o n of Administration. F o r example:. Rigid Pavement - typical undercarriage leg - dual tandem Loads ranging from 15 to 30 tonnes.
Deterinining t h e PCN i s a l o n g and complex operation. Solution S t e p 1. Flexible reinforcement. Rigid reinforcement. The 4. Although m e t r i c equivaZents are provided, i n accordance with standard I C A O practice, they cannot be taken a s being as precise as the figures quoted i n inches. Sllta, rsnciy a i l t r. See above "A". Pavement foundati.
It i s problem. R i g i d pavements. DC, t h e geometry 3 above. Owing gear geometries, t h e wide b o d y. The 0. Riturninous base course Cold l a i d bituminous base c o u r s e Mixed i n - p l a c e base course. The equivalency f a c t o r r a n g e s are presented in Table below. Figure 4 - 6 4 is a graph enabling the designer to select the appropriate F value to yield a final condition close to that shown in Figure 4 - 6 3 b. The condition factor Cg applies to the existing rigid pavement.
The Cb factor is an assessment of the structural integrity of the existing pavement. The determination of the proper Cg value is a judgement decision for which only general guidelines can be provided. A Cb value of 1.
The designer is cautioned that the range of Cq values used in bituminous overlay designs is different from the Cr values used in rigid overlay pavement design. The minimum Cb value is 0. A single Cb should be established for an entire area. The Cb value should not be varied along a pavement feature. After the F factor, condition factor Cb, and single thickness of rigid pavement have been established, the thickness of the bituminous overlay is computed from the following formula:.
Use the exact value of h: do not round off. Evaluation report. D i r e c t sampling procedures. Deficiency i n base course thickness. Thi i? T h i s pre:;sllrc? In wet conditions p decreases gradually with increase in V.
HARSH micro-textured surfaces permit substantial penetration of thin fluid films; general level of friction is high. In wet conditions p decreases rapidly with increase in V. Tread grooves are most effective on this type of surface. The chippings may b e from o n e o f ehe f o f lowing groups : Basalt, Gabbro, Granite, Gritstone, H o r n f e l s , Porphyry o r w a r t z i t e. When weather conditions d i c t a t e , s u i t a b l e protectton mst be afforded to t h e chippings during d e l i v e r y.
When masking o f the- aerodrome markings is nor indtcated, they may be o b l i t e r a t e d. Immediately before spraying the binder, the existing surfaces m s t b e t h o r o u g h l y c l e a n e d by mechanical broms , s u p p l e mented by hand brooming if necessary. A l l vegetation, loose marerials, dust and debris, etc.
Then the entire surface mst again be thoroughly r o l l e d at l e a s t three more times. A l l chippings must adhere f i r m l y t o the finished surface which should be of uniform texture and colour. The surface nust be e n t i r e l y free of irregularities due to scabbing, scraping, dragging, droppings, excessive overlapping, f a u l t y lane or transverse junctions, or other d e f e c t s , and it nus t be left clean and t2dym Under no circumstances should swept up chippings be re-used.
There are no operational objections ta rhe grooving of existing surfaces. Experience of operating a l l t y p e s of aircraft from grooved surfaces over a nunber of years indicates that t h e r e is no limit w i t h i n the foreseeable future t o t h e a i r c r f t size, l o a d i n g o r type for w h f ch such surfaces w i l l be satisfactory.
Based on current techniques, saged grooves p r o v i d e a more uniform w f d t h , depth, and alignment. However, p l a s t i c grooving and w i r e combing are also e f f e c t i v e in improving drainage and friction characteristics o f pavement surfaces.
They are cheaper t o construct than t h e sawed grooves, particularly where very hard aggregates are u s e d in pavements. Theref o r e t h e cost-benef i t relationship should be considered in deciding which g r o o v i n g technfque should be used f o r a particular runway.
Pfgure Extreme c a r e must be e x e r c i s e d when g r o o v i n g n e a r inlongitudinal construction joints. Table The purpose of this chapter is to detail the procedures to be used by those associated with such overlaying, viz. A unique feature of such off-peak construction is that a temporary ramp a transition surface between the overlay and the existing pavement must be constructed at the end of each work session so that the runway can be used for aircraft operations once the work force clears the area.
USD Language Choose an Option Format Choose an Option Add to Cart. El Ateneo, Pedro Garcia S. Compras - Irnportacibn, Egypt. Box , Bangkok. United Kingdom. The ICAO Bulletin contains a concise account of the activities of the Organization as well as articles of interest to the aeronautical world.
The Bulletin will also keep you up to date on the latest ICAO publica- tions, their contents, amendments, supplements, corrigenda, and prices. These amendments are available free upon request. This revised and updated vers ion of t h e Aerodrome Design ManuaZ, Par t 3, includes guidance on t he des ign of pavements inc luding the i r charac te r i s t ics and on evalua t ion and repor t ing of t he i r bea r ing s t r eng th.
The material inc luded here in i s c lose ly a s soc ia t ed w i th t he spec i f i ca t ions con ta ined in Annex 14 - Aerodromes.
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