Geotechnical Engineering in Contracts for Civil
Projects
Léon TIGGELMAN a , Paul LITJENS b , Jan Jaap HEEREMA b and Annemarij KOOISTRA c
a
Heijmans, Rosmalen, the Netherlands
b
Rijkswaterstaat, Ministry of Infrastructure & Environment, Utrecht, the Netherlands
c
Municipality of Amsterdam, Amsterdam, the Netherlands
Abstract. Geo-Impuls is a Dutch nationwide programme with the aim to reduce geotechnical related failures in projects. During the last 5 years, a large number of teams have been working within three themes (techniques, communications and contracts) on a procedure for coping with the natural uncertainties of the Dutch subsoil.
The large variation in the mainly soft subsoil in the Netherlands involves geotechnical risks. These risks need to be managed and controlled. The main focus of one of the themes of Geo-Impuls – theme ‘Geo-Engineering in Contracts’ – is how to deal with these risks during the different phases of a project and especially during the drawing up of the contract. Which party is able to manage geotechnical risks most effectively in which phase of the project? In addition, which party is responsible for which risks? Moreover, how can this responsibility be reduced, allocated and established?
These questions are of current interest due to a shift in the methods of contracting. Nowadays the traditional form of contracting changes towards a more integrated form. Several parties are responsible for the project design or realization instead of only one party. Furthermore, the way of selecting the contractors is also changing. All this makes it difficult to make clear-cut agreements on how to deal with the geotechnical risks. It is no longer the responsibility of only the geotechnical consultant, but of the whole project team.
Within ‘Geo-Engineering in Contracts’, research has been done on how to determine a method to deal with geotechnical risks in all phases of the project. Eventually, the following topics were identified and researched by different teams. 1. The determination of a risk controlled approach for the executing of soil investigation during all phases of the project. 2. The awareness of geotechnical risks and how to allocate these risks to the parties involved during all phases of the project. 3. The presentation of guidelines on how to successfully integrate geotechnical aspect in different contract forms. The article outlines the activities and results of these three topics of the Contracts-teams.
Keywords. contracting, Geo-Impuls, risk management, risk allocation, geotechnical baseline report
1. Introduction
Geo-Impuls is a Dutch nationwide programme with the aim to reduce geotechnical related failures in projects. During the last 5 years, a large number of teams have been working within three themes (techniques, communications and contracts) on a procedure for coping with the natural uncertainties of the Dutch subsoil.
The large variation in the Dutch subsoil entails geotechnical risks. Risks that need to be controlled. Geo-Impuls is a non-profit organization devoted to reduce underground related risks. For instance by developing a risk-based method, in addition to which it is essential to make clear agreements about the geotechnical risks. That way possible risks (and opportunities) will be identified in an early stage and the
appropriate measures can be taken. This reduces the chance of any problems during the design, construction and maintenance of projects considerably.
Therefore, within Geo-Impuls a number of teams did research on several known problems with geo-engineering in Contracts. One team worked on how to allocate geotechnical risks to the parties involved during all phases of the project. A second team published a guideline for a risk controlled approach for the executing of soil investigation during all phases of the project. The awareness of all kind of geotechnical risks was the work of a third team. In addition, a fourth team tried to determinate guidelines how to successfully integrate geotechnical aspects in different contract forms. In this paper the end results of the teams are presented.
Geotechnical Safety and Risk V T. Schweckendiek et al. (Eds.) © 2015 The authors and IOS Press.
This article is published online with Open Access by IOS Press and distributed under the terms of the Creative Commons Attribution Non-Commercial License.
doi:10.3233/978-1-61499-580-7-129
2. Geo Risks Management & Principles All Geo-Impuls participants embraced Geo Risk Management (GeoRM) as the leading working method to realize projects within budget and planning. GeoRM is an explicit, structured, communicated, and continuous way of dealing with geotechnical risks, in order to achieve project objectives effectively and cost-efficiently. The process of geotechnical risk management is similar to the process of project risk management and involves the same sequence of steps.
Therefore, GeoRM fits well in any sort of project risk management. The difference is that GeoRM is a more detailed and in-depth approach of project risk management, for giving geotechnical risk the attention it requires in all phases of engineering and construction projects. Figure 1 presents the six GeoRM steps.
Figure 1. The GeoRM process in six steps.
While these six GeoRM steps are quite straightforward, it helps to take them according to so-called GeoRM principles (Van Staveren et al, 2013).
3. Geotechnical Risks and Availability of Information
The allocation of geotechnical risks in contracts depends on the impact of the geotechnical risks and the ability to manage them. Which party should manage the risk depends on who is best able to manage a specific geotechnical risk most effectively in a certain project phase. Solid and sufficient geotechnical information is essential for consideration of this decision. The reliability and accuracy of the retrieved soil data are also important aspects. Unfortunately, common practice is that sufficient geotechnical
information is not always available. This is due to several reasons:
x The need to perform a soil investigation is not clear. Risks are normally transferred to the next party so why put a lot of effort and time in a soil investigation?
x Due to lack of time, the awareness that a soil investigation is needed came late. To perform a solid soil investigation with field and lab tests takes about a minimum of three months.
x The building site is not accessible due to bad conditions or the current owner doesn’t cooperate.
Another problem is that the principal is not always able to hand out all the information due to legal aspects. Factual information as cone penetration tests and results of lab tests are normally given but interpreted data mostly not. The reason is that the contractor is responsible for the design process and therefore the principal is not inclinable to interfere in this process, providing interpretation of factual data. According to some contractors, this is a lost opportunity because interpretation of many data can consume a lot of time. Time sorely needed in the short period of tendering.
Figure 2. The role of geotechnical soil investigation in different project phases.
The need for information depends also on the phase of the project. Figure 2 shows that mainly in the phases from the preliminary design until construction there is a significant need for such information. What kind of information, such as the quantity and amount of detail, varies
from phase to phase. Therefore, it is very important that enough information is collected at a contract moment where the responsibility for the project is transferred. Otherwise, the quality of the risks analyses for the next phase might not be sufficient due to lack of information.
4. Geotechnical Risks in Contracts
The information that is necessary at a certain time in a project depend on the phase of the project but also on the method of contracting. Figure 3 gives an overview of most common methods of contracting in the Netherlands and the amount of soil investigation needed.
Figure 3. Different forms of contracts and the intensity of soil investigation.
The traditional Dutch contract form used to be the standard RAW contract1. In this contract form the principal, mostly with assistance of a consultant, makes a detailed design and a construction method. The principal is responsible for risks that can occur related to the uncertainty of the subsoil. This seems normal since the principal is responsible for the design and other choices. All the geotechnical information that is needed is obtained for the call for tenders. The principal is responsible for the collection of all information in all phases of a project and has the responsibility to collect the information on time.
Nowadays integrated contracts are more common for civil projects. A big difference is that multiple parties are involved in the design before the construction starts. The contractor can
1
RAW is a Dutch specification system for works of civil engineering constructions in which the principal is responsible for the design and construction method.
also use a consultant and both can be involved in the design, as shown in figure 3. The geotechnical information needed for a good risk assessment will be collected by several parties during different phases of the project. The problem at hand is that per phase the needed information is not always available on time. In addition, it is not always possible to gather all information for all possible design solutions. This makes it more difficult to make a responsible design because the right information is not at hand. It is possible that the risks profile will increase considerably.
Different contracts and conditions of contracts as UAV-gc2 don’t provide much guidance in determine the minimum of information needed. The text is mostly written in terms as ‘all the reasonable’, ‘sufficient’ or, ‘adequate’. The exact meaning of these texts are different per phase and per project. It is also not easy to determine what kind of information is needed to make a robust design and to realise it. There are little official guidelines or standards to use. It also depends strongly on the type of project or the location in the Netherlands.
5. Geo-Impuls and Contracting
Within the theme ‘contracts’ research has been done by several teams on how to determine a method to deal with geotechnical risks in all phases of the project. These teams focused on the following subjects:
1. The determination of a risk controlled approach for the executing of soil investigation during all phases of the project.
2. The awareness of all kind of geotechnical risks.
3. How to allocate these risks to the parties involved during all phases of the project. 4. The determination of guidelines how to
successfully integrate geotechnical aspect in different contract forms. A new guideline in how to deal with geotechnical information has to be made.
2
UAV-gc is a Dutch uniform standard conditions for integrated contracts.
In the following paragraphs the end results of the teams are presented.
5.1. Guideline Soil Investigation
The heterogeneity of the subsoil and the properties of the different soil layers has to be clarified by soil investigation. Which type, the amount and specifications of soil investigation are essential aspects. A good insight in all geotechnical risks is not possible without a proper soil investigation.
A new guideline has been made on how to plan a risk approached soil investigation. This guideline distinguishes between the type of construction, the different phases of a project. Through a risk approached soil investigation it is possible to determine what kind of information is needed in the different phases of a project. In each phase the six GeoRM steps are done to automatically identify new geotechnical risks. During this process six questions, presented in table 1, are important.
Table 1. Research questions
No. Question Action Example
1 Which type of construction?
Determine the soil related constructions
New railtrack next to existing rail 2 Which fail
mechanism?
Determine the relevant geotechnical mechanism
Horizontal deformations of existing rail 3 Which risks? Determine the geotechnical risks
(change x action)
High risk of damaging existing rail 4 Which method? Determine the geotechnical
design method of construction
EEM deformation 5 Which soil
parameters?
Determine the critical parameters for occurrence of risk
Stiffness parameter 6 Which soil
investigation?
Determine the type, amount and specification of soil investigation
CPTU, undisturbed samplind and 20 CRS tests
In separate chapters of the guideline an overview is given of the recommended soil investigation. Besides specifications of soil investigation per design and construction phase, also recommendations are given on how geotechnical information should be transferred between phases. This is always important but especially when a new party takes over. For several types of projects examples are elaborated. These project types are: building site preparation, infrastructure, bridges, viaducts and other engineering structures, spillways and locks, tunnels and aqueducts, retained cuts, dredging, jetty’s, quay walls, pipes (Brassinga et al, 2013).
5.2. Geotechnical Risk Awareness
The awareness of the natural uncertainty of working with, on, or in subsoil conditions is essential for a geotechnical risk management process to be successful. Not only a geotechnical engineer should be aware of the consequences of this uncertainty, also decision makers, such as governors, project managers, should be aware of these consequences. However detailed our surveys and investigations, we cannot map out every cubic centimetre below a construction site. Subsurface risks will therefore always remain, often related to geo-engineering (which can be roughly summed up as ‘subsurface technologies’), such as the construction of foundations, site preparation works, or digging a construction pit.
Within the Geo-Impuls program the following products are developed to enhance the this awareness:
x Standard Risk Matrices/Lists that can be used as a start of the stocktaking. Using this matrices/lists will help to focus on project specific risks more easily. No time will be is lost in identifying standard risks.
x A publication listing project factors that may affect subsurface risks. By focusing on subsurface risks in good time and continuously, it will be possible to manage subsurface risks better. The publication provides information that will help you take the right decisions about your project. The publication therefore helps projects to keep subsurface risks well under control.
Primarily targeting on principals of construction projects, project developers, contractors and architects, the publication also helps geotechnical engineering to talk about their specific field of expertise using the language of these groups (Kooistra et al, 2014).
5.3. Geotechnical Risk Allocation
Only collecting information at proper times will not be sufficient for proper risk management. Reaching agreement on the contents of an underground data report can also help to compare different bids in a tendering process. Better agreements on process and product
specifications could be the result of awareness of what information should be known in each phase of a project.
Naturally, chances are that collected information is not sufficient. For example due to soil heterogeneity in relation to suggested construction methods. In contracts, in general, it is important to agree on how to cope with these deviations in soil composition. Uncertainty in soil composition, and therefore uncertainty in constructing, especially in the Netherlands, remains consistent, no matter how much information was collected. Until now, no clear agreements were made on how to deal with deviations (risks), when more than one party are involved in a single project phase. And it was not clear how to allocate these risks properly in contracting processes (allocation to the party that is able to manage the risk at best).
Until recently, geotechnical consultants tried to contribute to proper risk allocation by working out a risk allocation method in CUR/CROW 105 ‘Risico Verdeling Geotechniek (RV-G)’3, a method derived from the Geotechnical Baseline Report (GBR) most people will be familiar with. Although promising, application of RV-G in practice seems to be scarce. In their search for possible causes of hesitation in using RV-G, a committee consisting of representatives from contractors, advising agencies and client organisations, carried out an evaluation for a number of recent projects in which the method was used, and a few in which it wasn’t used. In brief the results were that in general both clients as well as contractors were primarily positive about using RV-G. Furthermore their opinions showed that RV-G is a good tool to be used before starting a project to allocate underground-related risks. Besides that, RV-G was found to help facilitate the comparison of bids in a call for tenders.
Despite the fortifying results from the practical evaluation, the committee also made a study to find out whether juridical reasons could be found for the method to be less attractive. RV-G turned out to fit well into the standing contracting formats and their legal basis. But it turned out that in general European tendering laws could complicate the procedure to come to a
3
RV-G is a Dutch guideline for geotechnical risk allocation when integrated contracts are used.
contracting document in which clients and contractors interact to come to a proper risk allocation: merely subjected to very large and very risky infrastructural works. Besides, it must be remarked that during the study period all representatives were found to have slightly different opinions on how specific and precise a RV-G document should be on soil parameters, and risk allocation limits.
In that respect, most important conclusion is that to come to a proper risk allocation, it is of the upmost importance that all parties involved are willing to reduce risks and are enabled to share as much information as possible, especially in early project stages.
5.4. Geotechnical Quality and Process Codes for Contracts
For the management of geotechnical risks two aspects are crucial: information and expertise. If these two aspects are available only the willingness of actual doing risk management is necessary.
Besides the quality of the information, as is discussed earlier, a template has been made for uniform exchange of geotechnical information during the different phases of projects. The relevant geotechnical information consists of all preface soil investigation and geotechnical advice reports. In the ideal world all information is collected and transferred from phase tot phase. Three different type of records are collected: soil report consisting of data and interpretations, calculation reports of all phases and a complete risk report of all phases. This approach is according the 'Euro code 7'.
During a project in which another party is gaining control of the project, certain tasks and responsibilities are being transferred. For a proper transaction both parties need to have the right expertise and must have carried out certain tasks in a proper manner. These minimal tasks are the following.
Principal:
x to collect enough information of high quality for a good risk assessment enabling contractors to make a risk assessment suitable for tendering their L. Tiggelman et al. / Geotechnical Engineering in Contracts for Civil Projects 133
specific engineering- and construction solutions ;
x if necessary the execution of extra risk driven soil investigation to fill in the blanks;
x the expertise to perform a good risks assessment and to evaluate the several design bids and risk reports.
The contractor:
x the expertise to perform a good risk assessment and make a proper bid; x choose construction methods tuned to
the soil characteristics on site;
x enough capacity of qualified consultants to perform a risk assessment in short time;
x if necessary the execution of extra risk driven soil investigation to check on the calculated risks taken in the bid.
The quality of the performance has to be measured. Not only the quality of the information has to be checked but also the amount of expertise within both parties. The expertise can be measured for example by a system of charted engineers, which is momentarily not available in the Netherlands. Another possibility of controlling are documents in which the risk approach method (GeoRM) is presented or other form of risk control document.
Last but not least both parties need to be willing to control the risks in the most effective way. This can be done with the following solutions (incomplete):
x Can a certain risk be part of a contract? Sometimes the principal is better capable in controlling the risk.
x Maintenance as part of the contract. If construction and maintenance are combined the most cost effective designs are made.
x Reward a good risk management plan. This will reduce the possibilities of surprises later in the project.
x Start a dialog about geotechnical risks in all during the contract negotiation. Not only in large, complex projects but also in complex geotechnical projects.
6. Conclusion
At the end of the Geo-Impuls program we can conclude that much is achieved. In the beginning of the program consultation has taken place with other stakeholders in civil engineering especially contract administrators and legal advisors. The response helped to focus on the main goals and legal advisors participated further in the program.
Civil projects with little amount of soil investigation in the first phases of projects are nowadays scarce. Risk registers and methods of risk approaches are more and more asked during tendering and risk management in general is more used. A lot of new tools and ideas are introduced. That does not mean that geotechnical failure has stopped but in general geotechnical risks will be earlier identified so that proper measure and action can be taken when it occurs.
References
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