El comportamiento climático

Fast-track is a technique that sets its basis in concurrency principles to achieve the simultaneous performance of product design and construction. It recurs to the overlapping of project design and construction, thus, early phases of the project are correspondingly under construction while later stages are still under design. This procedure of overlapping the design and construction can substantially reduce the total time required to reach project completion (Clough et al. 2000).

b. Implementation

Much of the information on this schedule acceleration technique is merely anecdotal because there is no formal process to fast-track a project. However, there is a series of general actions that can be taken to improve its implementation.

Fast-tracking is generally defined as the compression of the design and construction schedule through overlapping activities or reduction in activities duration (Bogus et al. 2002). The typical fast-track process is to divide design activities into work packages. As design progresses and different phases are finalized, the work is released in packages for construction; hence construction is started before the entire design is complete. This process is also defined as “phased construction”. In some cases, fast-tracking involves starting construction on a work package before its design is completed.

Fast-track implementation can begin by creating a viable phasing plan. This can be done with close input and coordination from members representing the design and construction phases, in addition to owner representatives and the construction manager. Input from design and

construction members helps in identifying how the work should be divided into feasible

packages for work. Once the design of each package is completed, it is immediately released for construction. Detailed construction schedules are developed as design packages are received. Nonetheless, an overall plan for construction can be developed following the phasing plan. Thus, dates and milestones determined in the phasing plan for design information release are used to develop construction planning in general terms.

The process of fast-tracking, in addition, generates important flows of information that need to be effectively managed to allow design and construction progress satisfactorily. In order to speed project delivery time, design information needs to be released as quickly as possible for construction to proceed. This process involves increased flows of information, not only from upstream design to downstream construction, but design also requires feedback from

construction outputs in order to improve the generated upstream information. Hence,

construction performance with uncompleted design information generates outputs that have an important impact on design. It is crucial then to create an effective system for delivering

output’s feedback from construction to design in a promptly and accurate manner (Elvin 2003).

c.

Advantages

Fast-tracking and phased construction can offer attractive advantages to the owner in terms of project time. Beginning project construction when design is still under execution can

Additionally, overlapping project design and construction involves the need of integration and constant interaction between the design and construction teams. Thus, the input arriving from construction production through constant interaction allows engineers and designers to come up with innovative methods for speeding the design-construction process both related to the design itself and in the interdisciplinary relationship between project team members. The involvement of engineers and designers in the actual construction offers as well significant input in

construction performance and design advance.

Lastly, integration between the design and construction phases gives the opportunity for team collocation. Intellectual capital at the beginning stages of the project can derive into superior quality, improved constructability, and better means for construction, eventually leading to cost reduction, particularly project life-cycle costs.

d. Key elements to ensure a high degree of success

The following are key factors that enable the implementation of fast-track production to successfully reduce project delivery time:

™ Communication

The increased integration of different participants and schedules between design and

construction generates higher levels of information. Effective communication is indispensable to effectively manage the increased information flows in the best interest of the project. When information is amplified and the means of communicating and transmitting information are not efficient, this can be translated into noise generation impossible to be understood and properly used by the end-users. Lack of effective and rapid means of communication between the different disciplines involved hinders fast-track’s intention of speeding up project completion. Moreover, incorrect, overloaded or delayed information increase the schedule because extra time is spent in revisions, and improperly sacrificing revision time can have negative impacts in quality and increase the risks of rework. Strategies for overcoming these obstacles in an integrated project environment include developing a shared project language, enhancing

iteration and feedback, and ensuring early input of downstream information-users, strategies that are discussed more in detail below (Elvin 2003).

Building a shared language improves communication among the different parties. Face-to-face meetings allow developing a common language, but information technologies are also good tools to link all participants, and to allow faster and efficient information flow. Technology allows the capturing, storage, and retrieval of project knowledge and information, resulting into a valuable means of integration. Extranet is one such technology that supports an environment of constant communication and shared information. It allows the exchange of design information and documentation among team members at any time disregarding of their location. Extranets can also enable project members to optimize schedules by diminishing the time required for information exchange between the activities that add value to design and construction, reducing thus waste and elapsed time that add no value to the project.

™ Iteration and feedback

Iteration and feedback are very important aspects in fast-tracking projects. The overlapping of design and construction results in an iterative process in which not only the design process generates information input to construction, but construction also creates information that affects

design. Therefore, the project team has to develop a communication system with the capability of capturing feedback between activities as construction output becomes an important input that has to be properly delivered to improve design.

™ Early downstream information user input

As just mentioned, in projects undertaking fast-track approaches construction activities generate information that must be used by the designer, however, because of the traditional design process, designers do not always have the knowledge on how to extract and organize

information that arrives from construction. In consequence, designers need to know how to play their new role of users of construction outputs information in order to pull out the proper

information that allows improving design. Conversely, constructors need to be aware and inform designers of their own information needs so that proper design information is released to

construction and within construction time requirements (Elvin 2003).

Communication between designers and constructors enhances designer’s knowledge regarding the construction process, which can lead into increased innovation. Thus, communication is very important to improve and speed up design, but also to create a design that improves and speeds up construction as well.

The release of smaller packages of design information reduces the risk of rework and cost overruns, and they also allow a process where mutual feedback becomes less complex as the information to be exchanged is reduced. Small batches of information also allow a more flexible and rapid process, as a result, faster and better integration between design and construction can be achieved. Nonetheless, extremely small design batches can interfere with workflow and negatively affect productivity.

™ Team Building

Team building is indispensable in the adoption of fast-tracking. Engineers and contractors have to learn to work out their differences in a team approach, and create an environment in which objectives are team and project oriented. Direct experience supports the development of a shared understanding of the project’s goals. Again, communication, common goal definition, effective rewards and shared responsibility can lead to effective teamwork. In addition to these, goal consensus, team autonomy, team-based rewards, and building trust among members multiply the potentials for fast-track success (Elvin 2003).

™ Flexible project organization

Flexibility is crucial to achieve integration. Individuals need to be flexible and open-minded to interact with the team and work in ways different from what they are habituated. Flexibility is also important to integrate design and construction activities. It should be provided not only in an individual level, but also in the project organization level. A fully integrated project

environment supports collaboration among engineers, construction managers, and contractors. Flexibility also allows reducing overhead, smooth workflow and easing scheduling.

™ Team collocation

Team collocation is the share of intellectual capital at the beginning stages of the project to derive innovative and improved methods of construction and use of new materials.

Collocation can improve fast-track performance in different aspects. In a fast-track production, designers produce a series of information that are then passed to the constructors and

transformed into work. If constructors are linked to designers through collocation before the information is produced, the data created in the information flow can be structured taking into consideration downstream needs. Additionally, collocation supports the creation of feedback loops between the design and construction phases. Collocation is also a great enabler of constructability.

™ Planning

Under traditional systems, construction is planned based on completed design specifications and documents. Fast-tracking forces overlap between the construction and design phases, where construction begins before design is complete; therefore not all the required information is available for construction planning. Thus, accurate and efficient planning becomes even more important as it has to consider concurrency in design and construction activities and still enable workflow during the construction phase. In fast-tracking projects, team work between designers and constructors is very important to generate the grounds for efficient and integrated planning.

™ Flexible project definition

Because fast-tracking increases the level of uncertainty in a project since construction is performed with uncompleted design information, it is important that the planning becomes project oriented and product oriented rather than detailed oriented, defining quality in terms of the finished product and the outcome and not based on the details of its configuration. This implies that specifications should give the construction team an agreed-to-measure for evaluating project performance, without committing to intricate design details too early in an environment of constant design changes (Elvin 2003).

™ Synchronized workflow planning

Under traditional project delivery approaches, the different phases of a project are fragmented leading to an outcome that is product of separate processes only linked together at one point. Under this perspective, workflow is mainly considered only during the construction phase. Fast- tracking however requires the consideration of workflow throughout the integration of design and construction. Design and construction activities are reciprocally interdependent because information from one is an input in the other and the result of that input becomes an important input in the first. Therefore, planning has to consider workflow along the whole integrated process instead of pulling design and construction workflow apart. Efficient workflow planning between design and construction is better achieved through work packages. However, effective teamwork is also required to allow smooth integration and workflow between packages to maintain overall process workflow.

e.

Disadvantages

As fast-tracking can offer significant opportunities for shortening project schedule, it can also be the source of coordination problems. Fast-tracking projects can be very sensitive to poor

coordination and planning, which can consequently result into poor construction performance and increased rework, ultimately translating into project delays and increased overall costs.

Implementing fast-track to reduce project delivery time has the risk of affecting the quality of the final product. First, engineers are forced to release design information faster than

traditionally, therefore they have to take less time in developing drawings and specifications which pushes designers to decrease revision time. Design deficiencies are more likely to pass overseeing when revisions are wrongly expedited. So, in addition to having to perform

construction under the uncertainties involved with having incomplete information, deficiencies in design revision also increase the risk of construction rework and overall delays.

Fast-tracking, by nature, forces designers to give less consideration to details, and because construction is performed based on information not complete, the lack of it is frequently

replaced by assumptions. Lack of detail and erroneous assumptions can also compromise project quality, and introduce risks related to the safety functionality of the facility.

Another potential disadvantage from fast-track projects is that compressed schedules do not always allow engineers to optimize every design. Because decisions are made under time pressures, there is not much time to consider and analyze different alternatives to find the most appropriate. Decisions have to be made with the information available at the time. Moreover, to speed up design delivery, facility performance is built to only meet a specific criterion, which hinders opportunities for optimization. This can equally create a negative impact on quality (Elvin 2003).

The feedback processes that are caused by uncertainty make the construction process more dynamic and unstable, which can create a negative effect on project performance. When a project under fast-track is not properly planned, those feedback processes can cause disruptions affecting workflow which eventually will cause an adverse impact in productivity.

Overhead expenses are increased under fast-track adoption too. The increased need for coordination and integration requires more people to be involved in the management and coordination of the project team. Additionally, site office facilities which are added to bring designers and constructors together successfully execute the fast-track project are typically associated to increased overhead expenses.

f.

Applicability and use

Much of the applications of fast-track design and construction have been conducted within the design-build domain. Because under the design-build project delivery method both design and construction activities are included under a single contract, where design and construction are performed by the same organization, or a joint venture is agreed between a design and

construction firms, the work can easily be divided into work packages and overlapped to reduce project duration (Barrie and Paulson 1992, Bogus et al. 2002). In addition, because the

responsibility of both design and construction phases of the project fall under one party, there is more opportunity for design and construction integration.

g. Other special characteristics

One strategy for reducing project delivery time within fast-tracking is the overlap of design and construction activities. Bogus et al. (2002) have developed a methodology to reconfigure the design-construction interface for fast-track projects. The methodology aims at creating a process for overlapping design and construction activities with the objective of integrating design- construction activities to reduce overall project delivery time.

The extent to which sequential activities can be overlapped is defined by the nature of the information exchange between those activities. This information exchange between activities can be described in terms of the natural rate of information development in the upstream task and the sensitivity of the downstream activity to changes in upstream information. The natural rate of information development in upstream activities is known as its evolution (Bogus et al. 2002).

Within a project and generally speaking, upstream activities include project conception, specifications and design, while construction, operation, maintenance and decommissioning compose the downstream activities (de la Garza et al. 1994, Bogus et al. 2002). Only activities included on the critical path and activities with a high duration variance should be overlapped to achieve overall project schedule reduction.

The degree to which two activities can be effectively overlapped depends on the relationship between them. Four types of relationships are possible between activities: 1) dependent activities, 2) semi-independent activities, 3) independent activities, and 4) interdependent

activities. When two activities are dependent, the downstream activity requires information from the upstream activity before it can be started. Semi-independent activities are characterized by one activity requiring only partial information from the other activity to proceed. Independent activities require no information from other activities before they can be completed.

Interdependent activities require a two-way information exchange between them before each can start (Bogus et al. 2002).

Only independent activities can be overlapped with no risk of delay or rework. The other three types of relationships present a risk when overlapped. Overlapping semi-independent activities present the least risk, because the downstream activity requires only partial information from upstream tasks. Therefore, the downstream activity can start as soon as the required upstream information is released with little o no risk of delay or rework. In contrast, overlapping

interdependent activities will always involve risk of delay or rework regardless of the degree of overlap, as both activities need a two-way information exchange. Dependent activities involve the highest risk of delay. When two activities are dependent, the downstream activity relies on information from the upstream activity to be completed. However, when two dependent activities are overlapped, the downstream activity has to start with uncompleted upstream information. Consequently, the potential risk of delay and rework is increased (Bogus et al. 2002). The present method for overlapping design and construction activities only considers independent and dependent activities.

Methodology for overlapping design and construction activities

Figure 4 presents an overview of the methodology.

Project decomposition Project database Activity characterization DSM algorithms Activity relationships Network scheduling Presumptive schedule program Enhanced DSM Shared databases Overlapping opportunities Network scheduling Ideal overlapped schedule program

Figure 4. Proposed methodology (taken from Bogus et al. 2002, pp. 263)

™ Project decomposition

The first step is to decompose the project into design and construction activities or tasks. The purpose of dividing the project into activities is to form smaller packages of work that can be characterized and potentially overlapped. This decomposition can be quite general. The project is decomposed in design and construction activities. An alternative to decompose the work in smaller units is to identify similar work that can be done by one person or group. For example, a design activity can consist of the structural design of a certain component, and a construction activity can be the work on one element such as a wall, floor, foundation, etc. Design and construction activities can be divided into more detailed activities if desired.

™ Activity characterization

The objective of this step is to identify the information generated by each design and construction task and the information required to begin subsequent design and construction tasks. In addition to identifying information requirements by the activities and the information produced, it is also important to identify when the information is produced and when it is

required by each activity. This information is then used to characterize activities in terms of their