procurement methods and specifications€¦ · bitumen specification frameworks penetration grading...
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Procurement methods and specifications - influence on pavement design and project management
1
Robert Lundström
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Topics
1. Introduction
2. Procurement methods
3. Requirements and specifications
4. Arguments regarding procurement methods
5. Procurement methods and implications: technical design and
project/knowledge management
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Introduction
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Obtaining bread…….
Reciepe:
600 ml milk
100 g butter
50 g yeast
2 tsk. sugar
1 tsk. salt
1 tsk. cinemon
1 kg mjöl
Methodology:
Varm the milk together with the butter until it has melted. Disolve the yeast in water and add the remaining ingrediences. Put it into the oven at 175 degrees for 30 minutes.
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Make or buy decisions… - depends on type of business??
• Nuclear powerplant
• Road
• House
• Car
• Meat
• Bread
1. Cost
2. Frequency
3. Complexity
4. Uniqueness
5. Degree of
transaction
specific investment
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Theory on M&B decisions Transaction cost economics (Williamson, 1985)
15 aug 2012 NCC Roads 6
Uncertainty: 3 aspects:
Transaction frequency
Transaction-specific
investments
Opportunism
Fre
qu
en
cy
Investment characteristics
Re
curr
ent O
cca
tion
al
Non-specific Mixed Idiosyncratic
Ma
rke
t g
ove
rna
nce
(cla
ssic
al co
ntr
actin
g)
Unified
governance
Trilateral governance
Bilateral
governance
(relational contracting)
(neoclassical contracting)
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Another source of uncertainty - projects
Connection Connection
Contractor Client Consultant
Project 1 Project 2 Project 3
..the construction industry typically engage in organizational systems lying somewhere between traditional market and hierarchy models, normally procured based on a market model, while subsequently managed within a hierarchical but temporary project context, which depends on buying procedure and contract type used…
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Procurement methods
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Procurement methods - a definition
i.e.…the way a client invites contractors to tendering, including the type of contract, requirements and payment mechanism used.
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Design-Bid-Build (D-B-B)
Design-Build (D-B)
Design-Build-Maintain (D-B-M)
B W
B W D
B M D
Procurement methods - Contract length and scope of activities contracted
W
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Historical reflection on road procurement - Most contracts has historically been the traditional Design-bid-build (DBB) - The number of D-B (-M) projects is increasing
80s 1992-1993 2002 2005 Efter Jacobsson, L
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Procurement methods - Effect on project organization
D-B-B
Client
Contractor
Consultant Client
Contractor Consultant
D-B(-M)
Supplier Supplier
Consultant
≠
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Procurement methods - effect on specifications
•The D-B approach can be characterized by that the
product is specified by performance requirements, and
consequently, not as in the case of the D-B-B approach
by procedural specifications.
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Requirements and specifications
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”sharp in by clear agreement,
General: - Contractual aspects on specifications
1. All measurement/testing should be based on a METHOD, i.e. clearly
refer to which standard (e.g. SS-EN) that is applicable.
2. REQUIREMENT LEVEL should be clearly adressed.
3. CONSEQUENCE that a given defect results in.
2013-02-06 Technology & Market Days 2013 15
sharp out by clear performance”
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26-May-14 NCC Roads 16
1. User demands
2. Surface
3. Construction
4. Composite mtrl/layer
5. Material
accessibility, safety, comfort, travel time, sustainability
evenness, friction, noise reduction
bearing capacity, strength, durability
resistance to fatigue and permanent deformation, stiffness, durability, thickness
material spec's, aggregate quality, grading, binder content, void content, binder characteristics etc.
DoF
# of demands
General: - requirements and specifications used
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Procedural specifications - mix design objectives
To adress:
Deformation resistance (stability)
Fatigue resistance
Low temperature cracking resistance
Durability
Moisture damage resistance
Skid resistance/friction
Workability
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Main mixture types
Dense graded asphalt
Stone mastic asphalt
Open-graded asphalt
Mastic asphalt (gussasphalt)
Differ in particle size distribution and binder content
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Parameters distinguishing different mixtures
Binder content
Binder type
Void content
Stone aggregate quality
Gradation
Additives
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Mixture requirements - binder content
[%-by weight]
Dense graded 6.0-7.0
Stone mastic 5.5-7.5
Open-graded 5.5 -7.0
Mastic 7.0-9.0
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Bitumen specification frameworks
Penetration grading
Viscosity grading
Superpave performance grading
and more...combinations etc.
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…and test methods used, e.g:
Sweden (Europe)
Penetration@25 °C
Softening point
Resistance to hardening
(RTFOT): retained
penetration, DSoftening
point, change of mass
Flash point
Solubility
Viscosity@60 and 135 °C
Fraass breaking point
USA (pg)
• Viscosity
• Complex shear modulus
• Low temp. stiffness
• RTFO Aging
• PAV Aging
• Flash Point
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Example: Penetration grade
40/60
50/70
70/100
100/150
160/220
330/430
Temperature, traffic
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Comparison regarding particle size distribution
0
10
20
30
40
50
60
70
80
90
100
-1.25 -0.75 -0.25 0.25 0.75 1.25
Sieve size [mm]
Pa
ssin
g [%
-by w
eig
ht]
Dense 16 mm
SMA 16 mm
Open 16 mm
Mastic 16
0.063 0.25 1.0 420.5 5.60.125 8 11.2 16 22.4
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Performance specifications - basic idea
Measurement of actual field behavior
Preferably, relates to driver comfort, security, speed etc.
Mainly based on surface characteristics:
ruts
IRI
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Performance requirements at Level 4: - road surface characteristics
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Longitudinal and transversal evenness
NCC Roads
AB 2011-
01-12
27
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Characterizing different parameters
NCC Roads
AB 2011-
01-12
28
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Characterization of longitudinal evenness - IRI
Simulation of a quarter car running at 80 km/h
Accumulated movement between body and wheel
divided by distance (observational distance)
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IRI-measurement - example of results
0
1
2
3
4
5
6
4900 5400 5900 6400 6900 7400
Sektion [m]
IRI [m
m/m
]
Höger spår
Vänster spår
RosenkällaMossen
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Measurement & evaluation - results from different projects
0,0
0,5
1,0
1,5
2,0
2,5
Norrortsleden 34 Målilla Tvärleden Osby E4 Enånger E6 Solhem
IRI 2
0m
Project 1 Project 2 Project 3 Project 4 Project 5
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Transversal evenness - ruts
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33
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
4,5
5,0
Norrortsleden 34 Målilla Tvärleden Osby E4 Enånger E6 Solhem
Rut depth
2,6
m2
0m
Measurement & evaluation - initial transversal evenness (P95)
Project 1 Project 2 Project 3 Project 4 Project 5
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34
0
2
4
6
8
10
12
14
16
18
20
2007 2008 2009 2010 2011 2012 2013 2014
P9
5[m
m]
År
Linjär regression
Undre gräns prediktion 95 %
Measurement, prediction & evaluation - estimating performance and risk
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Arguments regarding procurement methods
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Procurement methods - 5 basic arguments where main contractors often are pro D-B(-M) contracts (and other actors emphasize cons)
•The single-point responsibility
•Project delivery time
•Quality
•Cost
•Price certainty (limited cost overruns)
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Single-point responsibility
+ High degree of integration of design and build activities.
+ Less risks for client since contractor assumes higher responsibility.
+ Simpler, one counterpart (bilateral governance).
+ Contractor better suited to assess certain uncertainties (e.g.
climatic and site- specific circumstances).
+ Less conflicts due to contractor´s design responsibility.
- Down-played role of consultants.
- Difficult to monitor/safeguard the construction works.
- Difficult for clients to articulate technical solutions.
- Compromised design.
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Delivery time
+ Parallel design and construction.
+ Active design during construction.
+ Extended contractor responsibility: less re-design.
+ Empirical support.
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Quality
+ Experiences of previous projects becomes more important.
+ Increased commitment from contractors.
+ Promotes technical development.
+ Logical connection between performance specification and
user demands.
+ Extended contractor responsibility: less re-design.
- Quality may be compromised due to cost concerns.
- Weak empirical support.
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Increased commitment
Use of specialized equipment and methods
Innovativematerials
Normal
life-length
S10-15% Increased
life-length
Increased life-length of 10-15%
Motives to utilize D-B(-M)
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Costs
+ Life-cycle costs rather than investment costs.
+ Active design reduces costs.
+ Earlier completion provides access to the facility.
+ Competition based on technical solutions reduces risks of
illegal cooperation.
+ Price dumping becomes difficult.
- In D-B-B it is easier to calculate bids and to evaluate them.
- Number of competitors due to design capacity/capability?
- Inconclusive empirical support.
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Price certainty
+ D-B projects implies responsibility for contractor regarding
design and construction and, hence, less additions and
change orders.
- D-B is based on incomplete drawings and descriptions.
Consequently, renegotiations may occur.
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Procurement methods and basic logics
Design-bid-build
o Classic economics; focus on:
- Price
- Many bidders
- Full information (detailed spec´s)
- Homogenous products (same offer)
Design-Build(-Maintain)
o Evolutionary economics :
- Dynamic (Schumpeterian competition)
- Learning- and knowledge perspective
- Innovation
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Procurement methods: - implications for pavement design and
project/knowledge management
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Layer thickness
Material properties
Loading
Response calcul.
Strain
Transfer function
N
D = S n / N n
D > 1 D << 1 Design thickness
Traditional ME-design in D-B-B projects
Flexible pavement design in D-B-B projects - reflections Mainly based on nominal material properties (not real).
Supports existing technical standards and descriptions (procedural specifications).
Weak empirical correlation (difficult to predict performance of individual projects).
Difficult to utilize new materials.
Conclusion: Mainly institutional tool providing clear responsibilities among actors rather than technical tool able to predict performance of a given road project. Limited need of new knowledge for any actor besides the client.
Flexible pavement design in D-B(-M) projects - reflections
Existing design tools lack ability to predict performance (=technical uncertainty)
A fundamental aim of D-B(-M) projects: introduce new materials and production methods and requirements are associated to real performance of the project.
How..?
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Measurement, prediction & evaluation - estimating performance and risk by performance specifications
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
0 500 1000 1500 2000
Ru
ttin
g [
mm
/år]
Traffic volume [AADT,heavy]
Example: rate of rutting for 6 highways
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Procurement methods and contract types - Risk, uncertainty, profit for contractors
Risk, uncertainty
Profit
D-B(-M)
+ Low risks/uncertainties (routines/standardization)
- Low development incentives
+ Competition based on product performance
- Contractor assumes design risks/uncertainties
D-B-B
Risk management
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D-B-B
• Analytical evaluation
• Nominal material properties
D-B(-M)
• Performance measurement
•Empirical evaluation of performance
Type of requirements
Design space(s)
New models
Procurement methods and pavement design
Procurement method
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Project management - design needs continous knowledge transfer
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Time
Focal projects
1990
D-B-B
D-B(-M)
12
3
5
1
2 8
9
10
11
4
6
13
16
14
7
2000 2010
15
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Knowledge management
Variation Selection
Replication Retention
Generate alternatives
•Materials
•Production methods
Select alternative based on:
•Predicted performance
•Costs
Performance evaluation
•Problem solving
•Knowledge sharing
Project management
•Establish project data base
•Establish work routines
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Conclusions:
Different procurement methods exist.
Each is associated with both pros and cons.
D-B(-M) projects provide possibilities to product/process differentiation but also
higher risk/uncertainty.
Choice of technical solution in D-B(-M) requires risk and cost assessment by
empirical inquiry rather than predetermined solutions based on proc. specs.
Performance requirements of a given road project is comparable with other
projects.
Knowledge management is necessary to determine whether and to what extent a
given product portfolio is competitive.
Explorative learning is in general more likely to occur/necessary if a mix of
different procurement methods is practiced – different procurement methods
support each other.