ffi: }*'''. C,.t. F t r! Fn f' z a z z - v) X A = > (t o 7- ffi *. = \ J F, ^ J F. rr,. 1 r, 4. a . 1O o it) a z. A C r=1 \J F i E t. I'l - X F 4 ^ |!,! fn '?&. 2 2A a l F a t: \ E F. IRC Guidline for the Design of Plain Jointed Rigid Pavements Design for Highways. IRC_ - Guidelines for the Design of Flexible Pavements (Third Revision) Irc 37 Design Flexible Pavements. Irc 37 raudone.info Free Download Here Microsoft PowerPoint - IRC http:// raudone.info IRC GUIDELINES.
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The guidelines were revised again in when pavements were required to be . The cracking and rutting models in IRC: were based on the findings. The Pavement designs given in the previous edition IRC were applicable to design traffic upto only 30 million standard axles (msa). The earlier code is. civil engineering code book,is code, Indian standard code books, anna university code books, IRC37 ,IRC 37 ,IRC
You can change your ad preferences anytime. Irc 37 revised Upcoming SlideShare. Like this document? Why not share! Embed Size px. Start on. Show related SlideShares at end. WordPress Shortcode. Published in: Full Name Comment goes here. Are you sure you want to Yes No. Show More. No Downloads. Views Total views. Actions Shares. Embeds 0 No embeds. No notes for slide. Irc 37 revised 1. Puram, New Delhi July Price: September, Reprinted: December, First Revision: December, Reprinted: October, Incorporates Amendment No.
April, Second Revision: July, Reprinted: March, Reprinted: April, Reprinted: June, Reprinted: October, Reprinted: July, Third Revision: July, All Rights Reserved. No part of this publication shall be reproduced, translated or transmitted in any form or by any means without the permission of the Indian Roads Congress Printed at: Personnel of Highways Specifications and Standards Committee i 1.
Introduction 2. Scope of Guidelines 3. General 4. Traffic 4. Sub-grade 5.
Principles of Pavement Design 6. Pavement Composition 7. Perpetual Pavement 5. Pavement Design Procedure 9. Pavement Design Catalogues Internal Drainage in Pavement Design in Frost Affected Areas Equivalence of thickness of bituminous mixes of different moduli Annex-IV: Drainage layer Annex-VI: Roads Constructed in India with Alternate Materials 6.
Kandasamy, C. Basu, S. Chief Engineer Retd. Bongirwar, P. Bordoloi, A.
Chandrasekhar, Dr. Director Tech. Datta, P. Executive Director, Consulting Engg.
Services I Pvt. Gangopadhyay, Dr. Gupta, D. Gupta, K. Jain, R. Haryana PWD, Sonepat Jain, Dr. Jain, N. Kadiyali, Dr. Chief Executive, L. Katare, P. Krishna, Prabhat Chief Engineer Retd. Kumar, Ashok Chief Engineer Retd. Momin, S. Nashkar, S. Patankar, V. Member Tech.
Pradhan, B. Prasad, D. Raju, Dr. Rathore, S. Principal Secretary to the Govt. Gandhinagar Reddy, Dr. Reddy, K. Sharma, Dr. Sharma, S. Shukla, R. Sinha, A. Singh, B. Sinha, S. Yadav, Dr. Chief Engineer Plg. Justo, Dr. Emeritus Fellow, Bangalore University, Bangalore 2.
Khattar, M. Consultant, Runwal Centre, Mumbai 3. Agarwal, M. Engineer-in-Chief Retd. Borge, V. Secretary Roads Retd. These guidelines were revised in in which design traffic was considered in terms of cumulative number of equivalent standard axle load of 80 kN in millions of standard axles msa and design charts were provided for traffic up to 30 msa using an empirical approach.
Multilayer elastic theory was adopted for stress analysis of the layered elastic system. A large number of data collected from different parts of India under various research schemes of MORTH were used for the development of fatigue and rutting criteria from field performance data.
The volume of tandem, tridem and multi-axle vehicles has increased manifold and heavier axle loads are common. Experience has been gained on the use of new form of construction and materials such as stone matrix asphalt, modified bitumen, foamed bitumen, bitumen emulsion, warm asphalt, cementitious bases and sub-bases, since the publication of the last revision of the guidelines.
Conventional as well as commercially available chemical soil stabilizers are being successfully used in trial sections. Attention is focused on fatigue resistant bituminous mixes with high viscosity binders for heavy traffic with a view to construct high performance long life bituminous pavements. The guidelines contained in this document reflect the current knowledge in the subject.
This has shifted focus from large scale use of conventional aggregates to use of local, recycled and engineered marginal aggregates in construction.
Some trials in India have performed well Annex XI. A designer can use his sound engineering judgment consistent with local environment using a semi-mechanistic approach for design of pavements.
Sunil - Co-Convenor Nirmal, S. Bhanwala, Col. Krishna, Prabhat Bongirwar, P.
Lal, Chaman Das, Dr. Animesh Nigam, Dr. Dushaka, Vanlal Pachauri, D.
Gajria, Maj. Pandey, R. Sarma, Dr. Sivaram B. Jain, Rajesh Kumar Tyagi, B. Wasson, Ashok Kandhal, Prof. Prithvi Singh Yadav, Dr. Dongre, Dr. Raj Sharma, S. There after the draft, after further revision, was presented at the joint meeting of Flexible Pavement Committee and Composite Pavement Committee H-9 under the joint convenorship of Shri A. Sinha and Shri P.
Bongirwar held on The Executive Committee in its meeting held on 7. The document was approved by the IRC Council in its meeting held on 3. The comments have been incorporated and the document has been finalized for printing as one of the revised Publications of IRC. These guidelines do not form a rigid standard and sound engineering judgment considering the local environment and past pavement performance in the respective regions should be given due consideration while selecting a pavement composition.
Towards this end, it is suggested that all the organizations intending to use the guidelines should keep a detailed record of the year of construction, subgrade CBR, soil characteristics including resilient modulus, pavement composition and specifications, traffic, pavement performance, overlay history, climatic conditions etc.
The same approach and the criteria are followed in these revised guidelines as well, except that the cracking and rutting have been restricted to 10 per cent of the area for design traffic exceeding 30 million standard axles. The cracking and rutting models in IRC: In the absence of any further research in the field to modify or refine these models, the same models are considered applicable in these guidelines as well.
These revised guidelines, however, aim at expanding the scope of pavement design by including alternate materials like cementitious and reclaimed asphalt materials, and subjecting them to analysis using the software IITPAVE, a modified version of FPAVE developed under the Research Scheme R for layered system analysis. Conservative values of material properties are suggested in these Guidelines because of variation in test results on materials from different sources and based on National Standards of Australia, South Africa and MEPDG of the USA as well as those adopted in some of the satisfactorily performing pavements constructed in the country using cementitious and RAP bases Ref Annex XI.
The material properties should be tested in laboratory as per test procedures recommended in Annex IX and X. Surface cracking of the bituminous layer i. Published literatures on fatigue and rutting of different types of bituminous mixes have helped in better understanding of these problems 20, 24, 27, 38, 42, 43, 47 and The present guidelines strongly recommend that these problems need serious consideration.
Bituminous mix design needs to be considered an integral part of pavement design exercise with a view to provide i fatigue resistant mixes in the bottom bituminous layer to eliminate bottom-up cracking ii rut resistant bituminous layers of high tensile strength to eliminate rutting and surface cracking. Such bound layers would display shrinkage and traffic induced cracks after the construction and the long term effective moduli would be much lower than those determined in the laboratory by Elastic Moduli of such layers are to be judiciously selected, which can ensure long term performance as a structural layer in the pavement.
Their fatigue fracture behaviour is analyzed on the same principles that are applied to concrete pavements.
Only low strength cementitious bases are recommended for use since high strength rigid bases develop wide shrinkage cracks which reflect to the bituminous surface rapidly. Due to lower strength requirement of the cemented sub-bases and bases, the required compressive strength can be easily achieved even by stabilizing local and marginal materials. Each of the items listed above has been discussed in these guidelines at appropriate places.
Axle load spectrum data are required where cementitious bases are used for evaluating the fatigue damage of such bases for heavy traffic. Following information is needed for estimating design traffic: Expressways and Urban Roads may be designed for a longer life of 20 years or higher using innovative design adopting high fatigue bituminous mixes. In the light of experience in India and abroad, very high volume roads with design traffic greater than msa and perpetual pavements can also be designed using the principles stated in the guidelines.
For other categories of roads, a design life of 10 to 15 years may be adopted. In case of cemented bases and sub-bases, stage construction may lead to early failure because of high flexural stresses in the cemented layer and therefore, not recommended. In case of cemented bases, cumulative damage principle is used for determining fatigue life of cementitious bases for heavy traffic and for that spectrum of axle loads is required. It is defined as equivalent number of standard axles per commercial vehicle.
The VDF varies with the vehicle axle configuration and axle loading.
Irc 37 2001 Design Flexible Pavements
Minimum sample size for survey is given in Table 4. Axle load survey should be carried out without any bias for loaded or unloaded vehicles. On some sections, there may be significant difference in axle loading in two directions of traffic. In such situations, the VDF should be evaluated direction wise.
Each direction can have different pavement thickness for divided highways depending upon the loading pattern. Table 4. In the absence of adequate and conclusive data, the following distribution may be assumed until more reliable data on placement of commercial vehicles on the carriageway lanes are available: If vehicle damage factor in one direction is higher, the traffic in the direction of higher VDF is recommended for design.
For dual three-lane carriageway and dual four-lane carriageway, the distribution factor will be 60 per cent and 45 per cent respectively. Where significant difference between the two streams exists, pavement thickness in each direction can be different and designed accordingly.
For two way two lane roads, pavement thickness should be same for both the lanes even if VDF values are different in different directions and designed for higher VDF. For divided carriageways, each direction may have different thickness of pavements if the axle load patterns are significantly different. The traffic in the year of completion is estimated using the following formula: It should be well compacted to limit the scope of rutting in pavement due to additional densification during the service life of pavement.
Subgrade shall be compacted to a minimum of 97 per cent of laboratory dry density achieved with heavy compaction as per IS: The select soil forming the subrade should have a minimum CBR of 8 per cent for roads having traffic of commercial vehicles per day or higher. The guidelines for preparation of samples, testing and acceptance criteria are given in sub-paras given below. Compaction in the field is done at a minimum of 97 per cent of laboratory density at moisture content corresponding to the optimum moisture content.
In actual field condition, the subgrade undergoes moisture variations depending upon local environmental factors, such as, the water table, precipitation, soil permeability, drainage conditions and the extent to which the pavement is waterproof, which affect the strength of the subgrade in terms of CBR. In high rainfall areas, lateral infiltration through unpaved shoulder, through defects in wearing surfaces or through cracks may have significant effect on the subgrade moisture condition.
As a general practice, the worst field moisture is simulated by soaking the specimens in water for four days. The 90th percentile of these values should be adopted as the design CBR such that 90 per cent of the average CBR values are equal or greater than the design value for high volume roads such as Expressways, National Highways and State Highways.
For other categories of roads, design can be based on 80th percentile of laboratory CBR values. Pavement The maximum permissible variation within the CBR values of the three specimens should be as indicated in Table 5. Table 5. The effective CBR of the subgrade can be determined from Fig.
IRC 37 - 2001 Flexible Pavement Design
For other compacted thickness of subgrade, ref 4 may be consulted for guidance. Use of the CBR of the borrow material may be adopted for pavement design with proper safeguards against development of pore water pressure between the foundation and the borrow material.
Resilient modulus is the measure of its elastic behaviour determined from recoverable deformation in the laboratory tests. The modulus is an important parameter for design and the performance of a pavement. Since the repetitive triaxial testing facility is not widely available and is expensive, the default resilient modulus can be estimated from generally acceptable correlations which are as follows: The relation between resilient modulus and the effective CBR is given as: The test must always be performed on remoulded samples of soils in the laboratory.
The pavement thickness should be based on 4-day soaked CBR value of the soil, remoulded at placement density and moisture content ascertained from the compaction curve. In areas with rainfall less than mm, four day soaking is too severe a condition for well protected subgrade with thick bituminous layer and the strength of the subgrade soil may be underestimated. If data is available for moisture variation in the existing in-service pavements of a region in different seasons, moulding moisture content for the CBR test can be based on field data.
Wherever possible the test specimens should be prepared by static compaction. Alternatively dynamic compaction may also be used. Both procedures are described in brief in Annex-IV. A flexible pavement is modeled as an elastic multilayer structure.
Stresses and strains at critical locations Fig. The computation also indicates that tensile strain near the surface close to the edge of a wheel can be sufficiently large to initiate longitudinal surface cracking followed by transverse cracking much before the flexural cracking of the bottom layer if the mix tensile strength is not adequate at higher temperatures.
Different Layers of a Flexible Pavement 6. The phenomenon is called fatigue or fracture of the bituminous layer and the number of load repetitions in terms of standard axles that cause fatigue denotes the fatigue life of the pavement.
In these guidelines, cracking in 20 per cent area has been considered for traffic up to 30 msa and 10 per cent for traffic beyond that. Two fatigue equations were fitted, one in which the computed strains in 80 per cent of the actual data in the scatter plot were higher than the limiting strains predicted by the model and termed as 80 per cent reliability level in these guidelines and the other corresponding to 90 per cent reliability level.
The two equations for the conventional bituminous mixes designed by Marshall method are given below: In case of new roads, traffic estimates can be made on the basis of potential land use and traffic on existing routes in the area. Traffic growth rate Traffic growth rates can be estimated i by studying the past trends of traffic growth, and ii by establishing econometric models. If adequate data is not available, it is recommended that an average annual growth rate of 7.
Design life For the purpose of the pavement design, the design life is defined in terms of the cumulative number of standard axles that can be carried before strengthening of the pavement is necessary. It is recommended that pavements for arterial roads like NH, SH should be designed for a life of 15 years, EH and urban roads for 20 years and other categories of roads for 10 to 15 years. Vehicle Damage Factor The vehicle damage factor VDF is a multiplier for converting the number of commercial vehicles of different axle loads and axle configurations to the number of standard axle-load repetitions.
It is defined as equivalent number of standard axles per commercial vehicle. The VDF varies with the axle configuration, axle loading, terrain, type of road, and from region to region.
The axle load equivalency factors are used to convert different axle load repetitions into equivalent standard axle load repetitions. For these equivalency factors refer IRC The exact VDF values are arrived after extensive field surveys.
Vehicle distribution A realistic assessment of distribution of commercial traffic by direction and by lane is necessary as it directly affects the total equivalent standard axle load application used in the design.
Until reliable data is available, the following distribution may be assumed. Pavement thickness design charts For the design of pavements to carry traffic in the range of 1 to 10 msa, use chart 1 and for traffic in the range 10 to msa, use chart 2 of IRC The design charts will give the total thickness of the pavement for the above inputs.
The total thickness consists of granular sub-base, granular base and bituminous surfacing.Numerical example Design the pavement for construction of a new bypass with the following data: Maximum value of the strain is adopted for design. To propose a resistance, favorable light reflecting characteristics, suitable or best methods to a given condition or and low noise pollution. The relation between the fatigue life of the pavement and the tensile strain in the bottom of the bituminous layer was obtained as 1.
The sub-grade deformation is same as the slab deflection. This requires the following information: Initial traffic in terms of CVPD Traffic growth rate during the design life Design life in number of years Vehicle damage factor VDF Distribution of commercial traffic over the carriage way.