ROAD PAVEMENT FORUM

RECENT EXPERIENCES ON PPGS PROJECTS

HISTORY

• 1993 RPF (BMLC) PPGS Task Group Formed

• 1994 CAPSA Resolution to promote concept

• 1996 Initial SANRAL Pilot Project

• 1999 CAPSA Papers on PPGS issues and initial projects

RECENT EXPERIENCE WITH PPGS

DISADVANTAGES (CONSTRAINTS) IDENTIFIED

AT CAPSA 1999:

• Acceptance of change in roles of employer and contractor

• Selection of appropriate guarantee sums

• Lack of contractor quality assurance systems

• Lack of contractor design skills

• Shortcomings in establishment of appropriate and attainable performance acceptance criteria

• Shortcomings in methods for specifying and measuring performance

• Selection of realistic performance guarantee periods

RECENT EXPERIENCE WITH PPGS

N3/1 PROJECT

Length: 8,8 km of 3 to 4 lane freeway

Pavement History: 40mm AS (1985)40mm AS120mm BC150mm C3 (1974)150mm C4 G7

Traffic: AADT – 105 000ADTT – 5 000

Accumulative traffic (1974 – 2000): 25 x 106 E80/directionRemaining Structural life: > 15 yearsFunctional distress: - rutting

- surface cracking- riding quality

N3/1 PPGS

DELIVERABLES OF PROJECT

• To minimise noise generated by vehicles

• To limit ingress of surface water into the pavement

• To remove all rutting ≥ 6mm

• To improve and/or strengthen the pavement where visible distress is evident

• To improve riding quality and skid resistance

• To provide a medium to long term maintenance free and serviceable surface

N3/1 PPGS

CONTRACTORS OBLIGATIONS

Contractor to submit the following with his tender:

• Design constraints for PPGS related products

• Quality Assurance Plan

• Use of “professional partner”

• Technical report (Pre-treat/repair method, product selection etc)

N3/1 PPGS

FUNCTIONAL PERFORMANCE PROPERTIES

Visually Assessed Parameters Visually Assessed Parameters (TMH 9)(TMH 9)

Instrumentally Assessed Instrumentally Assessed ParametersParameters

Deformation (shoving)Deformation (shoving) Roughness (Riding quality)Roughness (Riding quality)

Surface failuresSurface failures Surface Friction (skid resistance)Surface Friction (skid resistance)

Surface crackingSurface cracking Rut depthRut depth

Surface ravellingSurface ravelling Surface macro-textureSurface macro-texture

BleedingBleeding

N3/1 PPGS

Acceptance Criteria for roughness

Time (years) after Time (years) after issue of completion issue of completion certificatecertificate

Limit ValueLimit Value

(Ave. 100m IRI)(Ave. 100m IRI)

Max (%) of 1 km Max (%) of 1 km segment with IRI more segment with IRI more than limit valuethan limit value

22 1,61,6 20%20%

1,91,9 5%5%

2,32,3 0%0%

44 1,91,9 20%20%

2,12,1 5%5%

2,62,6 0%0%

66 2,12,1 20%20%

2,42,4 5%5%

3,13,1 0%0%

N3/1 PPGS

Guarantees

PPGS Defects Liability Period : 6 years (after issue of completion certificate

Lane rental (after 4 years) : R 500.00 / hr / lane km

Performance assessment periods : 2, 4 and 6 years

Product performance guarantee: R4 500 000.00

R 1 500 000.00 release of year 2

R 1 500 000.00 release of year 4

R 1 500 000.00 release of year 6

N3/1 PPGSItem Description Unit QTY Rate Amount

  MATTERS CONCERNING WORK RELATED TO THE PRODUCT PERFORMANCE GUARANTEE SYSTEM (PPGS) The provision of a guarantee in terms of the requirements of the Product Performance Guarantee System Additional expenses and supervision costs for undertaking all work related to the Product Performance Guarantee of the surfacing Assessment and remedial work in respect of the Contractors obligation relating to the Product Performance Guarantee of the surfacing over the Guarantee Period Pre-treatment and surfacing in terms of the Product Performance Guarantee System

     L/Sum   L/Sum    L/Sum    m2

     1.0   1.0    1.0    260000.00

   

C10.01

C10.02

C10.03

C10.04

N3/1 PPGS

TENDERS RECEIVED

PPGSPPGS NON PPGS NON PPGS ALTERNATIVEALTERNATIVE

Estimate Estimate R25, 084 mR25, 084 m

Contractor A (Alt)Contractor A (Alt) R24, 374 mR24, 374 m R24, 202 mR24, 202 m

Contractor BContractor B R24, 887 mR24, 887 m

Contractor AContractor A R25, 114 mR25, 114 m

Contractor CContractor C R25, 852 mR25, 852 m R22, 882 mR22, 882 m

Contractor A (Alt) Accepted

IRI ComparisonSlow Lane(13) - km9 - 17

South to Durban

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

9.00 10.00 11.00 12.00 13.00 14.00 15.00 16.00 17.00

km

IRI

2000 2001 2002

IRI ComparisonFast Lane(11) - km9 - 17

South to Durban

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

9.00 10.00 11.00 12.00 13.00 14.00 15.00 16.00 17.00

km

IRI

2000 2001 2002

N3/1 PPGS

COMPARATIVE COSTS

CONSTRUCTION

SUPERVISION

Lowest tender PPGS - R24,374 m

Premium for PPGS - R 1,492 m

Lowest conventional tender - R22,882 m

Savings in supervision costs =± R0,90 m (3-4% of contract value)

Supervision costs on PPGS project = 5%

Supervision costs are recently completed conventional project of similar nature and scale = 8,7%

Overall premium = ± R600 000,00

N3/1 PPGS

CONCLUSION

CAPSA 1994 resolution:

“PPGS is necessary for the development of cost-effective transportation infrastructure in South Africa. PPGS should be developed and implemented incrementally with due recognition of the principles of RDP and the need for education in the concepts of PPGS (paradigm shift). This will be necessary in order to prevent PPGS from developing into a barrier for the entrance of smaller entrepreneurs into the market.”

Are we achieving this?