Keywords: construction management, activity planning, space scheduling, design constructability, CAD, site layout.

The iterative and information-intensive nature of the design process makes it hard to plan and schedule work using tools for conventional project management. The success of design projects depends on the quality of the available information. Presently the process of data transfer from design to construction is undertaken manually and is repeated for most construction functions. That repetition comes from the fact that the various construction functions require different types of data at different level of detail. In fact, the process of data preparation is one of the most important tasks of the entire process and one of the most time-consuming and difficult. This process has many shortcomings [1] and is a potential source of numerous errors that are often discovered only after an element has been erected, causing additional costs and possible losses due to rework and schedule overruns.

Currently research efforts focus on automating the data transfer from design to construction while automating the construction functions. Reference [2] surveyed CII members to determine trends and status of computer automation in design and construction. The report identified the following areas for improving design and construction operations: integration of multidiscipline design and drafting, integration of materials management, and integration between numerical analysis systems and CAD. The work presented here contributes to the literature in the latter area by presenting a system that ties design data in the form of CAD drawings to an analytical tool for space management on construction sites to achieve improved constructability. Visualization of design and construction plans encourages planners to be more creative in providing and testing solutions by means of viewing the simulated time-lapse representation of corresponding construction sequences. In 4D models the temporal and spatial aspects of the project are linked, as they are during the actual construction process [3]. Such models allow planners of the construction process to visualize the construction process as it would be actually built and to evaluate and review the construction schedule they propose. However, existing 4D models do not include features to support analysis of the construction process. For example, they may show workers and equipment workspaces and materials laydown areas on the construction site but are typically not augmented with analytical tools to evaluate the quality of the schedule and propose solutions to time-space conflicts or space scheduling problems, and other constructability problems.

This paper presents the conceptual design and implementation of a collective information and analysis system where product design, activity planning, resource scheduling and site layout are integrated with some automation. The system, unlike existing 4D models, allows the definition of different types of space requirements associated with performing activities and provides an analytical framework for assessing and solving time-space conflicts by adjusting the schedule.

The system is built by loosely integrating two standalone applications and a library containing knowledge of construction methods used to tie the product model to the construction schedule and the site layout. The first application, Integrated Product and Schedule Planner (IPSP), reads a set of CAD drawings for a facility to be built and transforms them into a structured list of components and subcomponents or product model for the facility where each component is characterized by different properties depending on its nature and location in the facility. The product model is tied to the construction activity schedule via the library of methods. The library of methods is a database of construction methods and associated resources. The activity schedule is built by linking components to main production activities, predefined in the scheduling system of IPSP, and linked together in a structure that suggests the logical order in which they should be carried out. The second application, Integrated Schedule and Space Planner (ISSP) [4], is a space scheduling model that ties the site layout to the activity schedule and manages the impact of schedule changes on the site layout and vice-versa. ISSP and IPSP are loosely linked by the schedule to plan the usage of construction space over time so that time-space conflicts can be identified and resolved at the planning and design stage of the project. The proposed loosely integrated system allows for what-if analysis of possible scenarios to minimize problems arising during construction due to site space limitations and other resource and technological constraints arising during construction, and should provide schedule updating and adjustments based on unforeseen conditions occurring during project execution.

1

P. Teicholz, M. Fischer, "Strategy for Computer Integrated Construction Technology", J. of Const. Engrg. & Managt., ASCE, 120(1), 117-131, 1994. doi:10.1061/(ASCE)0733-9364(1994)120:1(117)

2

K.C. Choi, C.W. Ibbs, "CAD/CAE in Construction:Trends, Problems, and Needs", J. of Managt. in Engrg., ASCE, 8(4), 401-419, 1990. doi:10.1061/(ASCE)9742-597X(1990)6:4(394)

3

M. Fischer, J. Kunz, "The circle: architecture for integrating software", J. Computing in Civil Engineering, ASCE, 9(2), 122-133, 1995. doi:10.1061/(ASCE)0887-3801(1995)9:2(122)

4

P. Zouein, D. Shedid, "ISSP: Integrated Schedule and Space Planner", Proc. CIB W78 Conf. on Distributing Knowledge in Building, 1, 75-83, 2002.

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