Kingdom of Cambodia. Ministry of Public Works and Transport. Ministry of Rural Development WORKSHOP ON

Transcription

1 Kingdom of Cambodia Ministry of Public Works and Transport Ministry of Rural Development WORKSHOP ON PLANNING, PAVEMENT DESIGN AND OVERLOADING PREVENTION

2 The Damaging Effects Of Overloaded Heavy Vehicles On Roads Presented by H.E LIM Sidenine Under-Secretary of State, MPWT

3 Acknowledgements Intech Associates TRL ILO NRDP IRAP Component ADB DFID Participants

4 Table of Contents 1. Introduction 2. The Road Network 3. Road Deterioration Factors 4. Maximum Load Limitations 5. The effects of axle loads on roads 6. The effects of tyre pressure on roads 7. Heavy Vehicle Overloading Statistics 8. The need to inform heavy vehicle operators

5 Introduction Road networks are the most important transport communication in the country and are used by almost everyone on a daily basis. Roads are provided for the benefit of the road users, promoting economic growth and living standards of the population. By means of roads, people have access to markets, places of work, clinics and hospitals, educational institutions, places for sport and leisure activities and vacations.

6 Inadequate law enforcement on vehicle overloading allows some transport operators to deliberately grossly overload their heavy vehicles, which not only benefits them in terms of substantially higher profits but also exposes the lawabiding operators to unfair competition. Research has shown that damage to the road by axle loads exceeding the legal limit, increases out of all proportion to the loads: for example, an axle carrying double the legal load may cause from 4 to 60 times as much damage as one legal axle load, depending on the condition of structure and type of road.

7 Since the greater percentage of goods transported by road is increasing, it is expected that heavy vehicles will remain a common sight on our roads in the foreseeable future. Because of the limited funds available for the reconstruction, rehabilitation of existing roads and also for road maintenance, it is essential that effective enforcement of the axle load regulations be carried out throughout Cambodia in order to protect the country s most value asset

8 The Road Network Road Length by Type No. Road Type Length, Km * 1 Primary National Roads, 1 st digit 1,988 2, Secondary National Roads, 2 nd digit 2,165 2, Provincial Roads 3,555 Region I 3, II 2, , III 2, Tertiary Roads - 28,000 Total length - 40, Road Density - 223Km/1000Km 2 Source: *Road Infrastructure Department, 2003 The total road network in Cambodia represents a huge investment. This asset is currently facing a crisis in terms of funding for road maintenance and also in terms of the growing vehicle population.

9 Overall Investment ADB WB KOICA Grant(Japan) RGC Private Grand Total: MUSD 54.0 MUSD MUSD MUSD MUSD 11.5 MUSD MUSD

10 Road Network Condition Length (Km) National 4,000 (4,805) Provincial 3,500 (7,559) Tertiary 28,000 Good and Fair (Km) Poor (Km) Bad (Km) Total 35,500 (40,364) 9,800 12,250 12,250 Source: info shop, the world bank, Report No.AB25 Road Condition Survey, 2002 Bad 29% Under construction 6% Good&Fair 29% Poor 36%

11 Primary National Road Network Phnom Penh City

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13 Road Deterioration Factors Roads carry bulk of road traffic, deteriorate for a number of reasons. It is the vehicular traffic on the road which is the major cause of road deterioration, especially on heavily trafficked roads.

14 Road Deterioration Factors

15 Axle Load Limitations Heavy vehicles traveling from origin to destination use the public road network, which includes roads as well as bridges structures. If the size and mass of a vehicle are not controlled, heavy loads may cause excessive damage to the road infrastructure.

16 6. The Effects of Axle Loads Equivalency Factor F = [Actual Axle Load P(t)/Standard Axle Load (10t)] n This formula compares the damaging effect on the road structure of any axle load, P with that of a standard single axle load of 10 ton. An average of n=4 Example: An axle carrying twice the legal load (20t) has 16 times the damaging effect of legal axle load

17 LOAD.W NOT DRAWN TO SCALE w PAVEMENT STRUCTURE P0 P1 LOAD.W P1 SUBGRADE ( a ) ( b ) LOAD.W NOT DRAWN TO SCALE PAVEMENT STRUCTURE NOT DRAWN TO SCALE PAVEMENT STRUCTURE P0 SUBGRADE COMPRESSION TENSION P1 P1 epþkg;lan dit Cab;t Yfñl ; P SUBGRADE ( a ) ( b ) X D

18 LOAD.W NOT DRAWN TO SCALE LOAD.W PAVEMENT STRUCTURE P0 P1 P1 SUBGRADE ( a ) ( b ) NOT DRAWN TO SCALE LOAD.W NOT DRAWN TO SCALE PAVEMENT STRUCTURE PAVEMENT STRUCTURE SUBGRADE COMPRESSION TENSION SUBGRADE epþkg;lan dit Cab;t Yfñl ; P X COMPRESSION D TENSION

19 LOAD.W TENSION PAVEMENT STRUCTURE NOT DRAWN TO SCALE P0 epþkg;lan ditcab;tyfñl ; P1 P1 SUBGRADE ( a ) ( b ) P LOAD.W NOT DRAWN TO SCALE PAVEMENT STRUCTURE SUBGRADE X COMPRESSION TENSION epþkg;lan dit Cab;t Yfñl ; P D X D

20 P NOT DRAWN TO SCALE PAVEMENT STRUCTURE SUBGRADE COMPRESSION TENSION

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27 Summary Heavy vehicles play an important role in the economy, and are expected to remain a common sight on our roads in the foreseeable future. The relative damage to the road caused by any heavy vehicle axle load can be related to the damage caused by a standard 80 kn axle load. This relation is exponential, in that an axle carrying double the legal load may cause from four to sixty times as much damage as one legal load. Road pavement structures are designed to carry a given number of standard axle load repetitions. Overloading reduces the design life of these structures. Overloaded vehicles are estimated to be responsible for R400 million of unnecessary roaddamage per annum.

28 Transport operators can play an important role in selecting road structure friendly vehicles. Improved liaison and communication must be developed between road engineers and transport operations managers. The overloaded heavy vehicle is a traffic hazard especially regarding the vehicle s braking system and the additional braking distance involved. This situation is further aggravated by steep downhill slopes and sharp curves in the road. Traffic accidents caused directly or indirectly by overloaded heavy vehicles are normally not included when the total cost to the country, caused by overloading, is calculated. All persons involved in the road transportation of goods, road pavement design and law enforcement should be made aware of the multifaceted impacts of road freight transport and overloading. Operators that continually overload their heavy vehicles affect the ability of operators that do not overload to compete on equal terms in the transport market.

29 Pavement Pavement is a structure, which separates the tires of vehicles from the underlying foundation material. Terms you need to know GVM (Gross Vehicle Mass): is the maximum laden mass of a motor vehicle as specified by its manufacturer. GTM (Gross Trailer Mass): is the maximum laden mass of a trailer as transmitted to the ground by its axle (s). GCM (Gross Combination Mass): is the maximum laden mass of a motor vehicle (its GVM) plus the maximum laden weight of any trailers (s) it can tow. Heavy vehicle: refers to any motor trailer with a GVM exceeding 4.5 tonnes. Heavy trailer: means any trailer with a GTM exceeding 4.5 tonnes. A pavement is a layer or layers of compacted material that is designed to withstand the stresses applied by vehicle or other traffic types.

30 Articulated vehicle: is a motor vehicle/trailer combination in which the hauling unit (a prime mover) is coupled to a semi-trailer such that the forward portion of the trailer is superimposed over the rear portion of the hauling vehicle. Standard axle: An axle carrying a load of 8 t was arbitrarily defined in AASHTO road test as standard axle, with a damaging affect of unity. Equivalent Axle Load Factor (EALF): EALF defines the damage per pass to a pavement by the axle in question to the damage per pass of a standard axle load, usually the 18-kip single axle load (18-kip ESAL) Fourth Power Damage Law: For theoretical analysis of fatigue analysis equivalency factor can be estimated as:

31 Where F j =(L j /L s ) n L j =Load on axle in question L s =Standard load, n= Exponent of the fatigue relationship for asphalt concrete (n varies from 3-5, 4 is the average value; fourth power damage law.

32 Purpose of the Road The purpose of road is to meet the following two criteria Functionality Structural stability For functionality purposes pcu (passenger car unit) is taken as standard i.e 60% of damage to the road network in South Africa is caused by illegal overloaded heavy vehicles.

33 Truck weight data are used for a wide variety of tasks. These tasks include, but are not limited to, the following: Pavement design Pavement maintenance Bridge design Pavement and Bridge loading restrictions Determination of the need for and success of weight law enforcement actions Determination of the need for geometric improvements related to vehicle size, weight and speed Determination of the economic value of freight being moved on roadways Determination of the need for and effect of appropriate safety improvements.

34 Measures There is the need to inform operators of the consequences of overloading, both in terms of road and vehicle damage.

35 Road Infrastructure Regions Region 2 : North Region Region 3 : Clock wise East South Region Region 1: West South Region

36 Overloaded vehicles become a traffic hazard, especially regarding the heavy vehicle s braking system and additional braking distance involved. There were appro.1.4 millions registered commercial vehicles in Since the greater percentage of goods transported by road is increasing, it is expected that heavy vehicles will remain a common sight on our roads in the foreseeable future. It is estimated that between 15-20% of all heavy vehicles traveling on National Roads are overloaded. Because of the limited funds available for the construction, rehabilitation of new roads and also for road maintenance, it is essential that effective enforcement of the axle load regulations be carried out throughout Cambodia in order to protect the country s most value asset.

37 The Objective of the Seminar To assist the government of Cambodia to develop a pragmatic and economic strategy for infrastructure planning and design to overcome the common overloading problem on the Cambodian Road Networks. The issues related to road policy, road management, transport infrastructure planning and prioritization, and Technical issues related to pavement design process and special measures to overcome the overloading problem.

38 THANK YOU FOR YOUR ATTENTION