SOUTH AFRICAN HIGHWAY TECHNOLOGY AND PRACTICE

Transcription

1 Welcome to TRB WORKSHOP 153 SOUTH AFRICAN HIGHWAY TECHNOLOGY AND PRACTICE Marriott Hotel 21 January

2 TRB WORKSHOP 153 SOUTH AFRICAN HIGHWAY TECHNOLOGY AND PRACTICE Moderator Prof. Kim Jenkins SANRAL Chair in Pavement Eng University of Stellenbosch, South Africa 2

3 Big 5 3

4 TRB WORKSHOP 153 SOUTH AFRICAN HIGHWAY TECHNOLOGY AND PRACTICE 1 South African Roads Technology in Context Mr Nazir Alli CEO South African National Roads Agency Ltd (SANRAL) # v3 4

5 EVOLUTION OF ROAD ADMINISTRATIONS NETWORKS, RESEARCH AND DEVELOPMENT Interdependent Political/Economic/Social Systems Various Stages of Research and Development Birth Growth Upgrading Maturity onwards 5

6 Development of Mountain passes Bain s team (Andrew Geddes and son Thomas),1800 s Result: - Engineered drainage - Selected gravel layers - Geometry At the time applied research did not exist 6

7 INSTITUTIONS Academic The South African College, established in 1829 University of Cape Town, first to offer Civil Engineering Courses during the years Others Roads and Bridges Committee established in January Appointed by Minister of Mines and Industries The Cape Society for Civil Engineers established in requested research use of tar in

8 South African Roads Board Appointed in road surfacing specifications evolved The Cement and Concrete Institute was established in 1938 The Council for Scientific and Industrial Research (CSIR) formed in : CSIR requested to research into tar rather than bitumen from imported crude Use of tar products now discontinued Bituminous Binder Research Unit, 1951: CSIR - 1 st road surfacing experiment 8

9 National Institute for Road Research, 1955: CSIR National Institute for Transport and Road Research, 1975: CSIR Committee of State Road Authorities, late 1970 s Southern African Bitumen and Tar Association established in representing industry 9

10 PAVEMENT ENGINEERING Late 60 s and early 70 s subset of geotechnical engineering Chair in Transportation at the University of Pretoria in mid 80 s - Department of Transport Dedicated Chair, University of Stellenbosch, SANRAL, 2001 Research - properties of materials - behaviour under loads - transfer mechanism 10

11 SOUTH AFRICAN MECHANISTIC DESIGN METHOD Origin of Current SAMDM Damage Models Fatigue of asphalt concrete wearing courses - Freeme 1970s Fatigue of asphalt concrete base layers including temperature - Published data 1970s to 1980s Permanent deformation for unbound material - Maree 1970s to 1980s

12 Effective fatigue and crushing failure for cement stabilized layers - de Beer 1980s Vertical strain criteria for subgrade - Dorman and Metcalf 1965 Stress in Motion, measures 3 D contact stresses - de Beer

13 DESIGN OF CONCRETE PAVEMENTS IN SOUTH AFRICA Design approach of the USA was selected as a guide - late 60 s early 70 s Experimental road on S12 Ogies - Mid 1970 s Department of Transport issued standard details for design and construction based on Road Note 29 (UK)

14 Design Manual M10 launched using nomographs based on mechanistic principles Probabilistic computer program cncrisk released Updated programme cncpave launched cncpave updated based on data from HVS testing

15 Ultrathin continuously reinforced concrete pavement (UTCRCP) cncpave being updated to include UTCRCP

16 PUBLICATIONS Technical Recommendations for Highways - established in the early 70 s - contains the compilation of research technology in a specific field - compiled by state authorities - used by all institutions as references and handbooks Technical Methods for Highways - established the late 70 s - mandatory documents 16

17 ACCELERATED PAVEMENT TESTING Heavy Vehicle Simulator Static linear tracking pavement loading device, late 1960 s Various improvements Mobile Load Simulator, 1991 Various improvements 17

18 OBSERVATIONAL TECHNIQUES Microscope - crack movement on concrete Scanning Electron Microscopy - Bitumen on soil particles - different types of sands Atomic Force Microscopy - Binder surface properties 18

19 Computerised Tomography - aggregate packing - void distribution - density gradients Infrared Thermography - construction control 19

20 FUTURE? Integration of two components Information system based on past performance Mechanistic-Empirical analysis and design system Performance based information system Validation data set for reality checks and calibration Starting point for design coupled with MEdesign using default input values for preliminary design and training 20

21 ME-design component Provides opportunity for design refinement Project specific input combined with design expertise Utilisation of available road-building material Pre-processing Post-processing Traffic loading Axle load and contact stress histograms are timedependent Frequency Frequency Extent of fatigue Frequency ME-design core Time Fatigue life Axle load Contact stress Rut Frequency Terminal rut Spatial variation of field variables Layer thickness Temperature Binder content Relative density Saturation Grading etc. Certain field variables are time-dependent in addition to spatial variability Time Rut life T 1 T 2 T 3 T n RD 1, S 1 RD 2, S 2 RD 3, S 3 RD n, S n Riding quality Frequency σ 1 b, ε1 b σ 2 b, ε2 b σ 3 b, ε3 b σ n b, εn b Unacceptable Time Riding quality life 21

22 PROCUREMENT Advances in contractual arrangements comparable Technological advances in other sectors 22

23 OUR AIM WITH TECHNOLOGICAL ADVANCES Vehicle Now User Vehicle Our aim User Common ground created by legal and technology architecture 23

24 RATIONALE FOR NEW STYLE CONTRACT Where fraud is exposed, complex process required to differentiate between causes: - human responsibility - equipment deficiencies Single point of responsibility Incentivise: - risk sharing - quality - delivery/costs 24

25 BENEFITS OF ADVANCES IN CONTRACTUAL ARRANGEMENTS Business practices Business processes Organisation structures Take advantage of opportunities offered and reflect needs of workforce Law must reflect expectations of society Benefits Pro-active Efficient Quality driven 25

26 THANK YOU 26