Department of Civil Engineering,
National Institute of Technology
Kurukshetra, Haryana, INDIA
[email protected]
Mahesh Pal
Department of Civil Engineering,
National Institute of Technology
Kurukshetra, Haryana, INDIA
[email protected]
Aconstruction project contains information in several spatial (drawings, layouts and blueprints) and non-spatial (schedule, cost estimate, specifications, etc.) forms that are maintained separately by various project members using different commercially available tools.
The overlaps and lack of consistency among such information may often lead to the construction errors, which results in miscommunications those are expensive and time-consuming in nature. The software from various disciplines (architecture, construction, structural and civil engineering) are being used to maintain and analyse such information throughout the lifecycle of a construction project. Drafting groups generally use CAD tools; planners use Primavera and Microsoft Project whereas construction and operations group use blueprints or printedpaper, etc. Information flow between various groups working in a project is not through well-defined standards and procedures, which results in an inefficient process characterised by data redundancy, redundant processes and poor information quality. If both, spatial and non-spatial information are maintained in a single environment and changes are made to these documents at one place only, drawings, schedule, cost estimate and specifications of a construction project will be consistent to each other.
Figure 1. Linking the construction schedule with spatial aspects of the project activities.
CURRENT STATE OF GIS APPLICATIONS IN CONSTRUCTION INDUSTRY
The information required for planning and design in construction industry are stored in the form of drawing, specifications and bar charts. During the planning process, planner has to repetitively reorganise and interpret the information collected from various resources. GIS improves construction planning and design efficiency by integrating locational and thematic information in a single environment. Its capability to store large database may be utilised to maintain construction data in digital form that provide a wide range of information to construction industry with a mechanism for rapid retrieval and manipulation capabilities. Bansal and Pal (2006) suggested the use of GIS to develop the database for rate analysis in construction project. Bansal and Pal (2007) suggested a GIS based approach for construction quantity takeoffs and cost estimation. For quantity takeoffs architectural drawing is divided into different layers those were classified according to basic design components in an architectural design. Area and perimeter are used as the basic parameters in GIS based quantity takeoffs.
Cheng and Yang (2001) integrated GIS based cost estimates with material layout planning. It integrates cost estimates with construction schedule to generate dynamic materials requirements. The system is designed to pass on information dynamically to construction site for material planning. Based on information regarding quantities and locations of materials required in a project, proposed methodology identifies suitable site to store construction materials.
GIS environment improves the real time schedule monitoring system as well as improves construction efficiency. Cheng and Chen (2002) developed an automated schedule monitoring system by using GIS. It assists construction managers to control erection process for precast building construction. Structural elements were prefabricated in manufacturing plant and transported to job site for installation. Erection of prefabricated structural components was considered a critical activity. The schedules for prefabrication and transport of structural elements to job site are developed based on installation schedule. GPS and GIS technologies were also integrated so that managers from the headquarters and construction sites get real time information to control cargoes/vehicle coming through road to sites, so as to reduce the waste generation on sites.
Construction material trading involves: buyers, suppliers and agents, links among them may be organised in three ways: (1) buyers and suppliers form direct connections, (2) buyers and suppliers form connections through agents, and (3) buyers and suppliers form connections through electronic markets. Li et al. (2003) presented an internet-based GIS model for e-commerce business based on the type (3) trading situation. Buyers may easily search and compare products of different suppliers through online system and contact the suppliers directly. If required, buyers can also invite agents to undertake certain tasks required in order to complete a transaction. In all kind of construction business activities transportation cost is involved, thus, internet-based GIS provide an ideal solution to manage costs of transportation and market analysis in all e-commercial activities.
In urban areas, obstacles such as existing public utility lines, railways, canals and roads influence routes significantly. There may be a limited number of feasible crossing points; selection of a suitable route to avoid existing obstacles in a path reduces the risk of damaging the existing utilities. It also minimises the cost required during construction. Cheng and Chang (2001) developed a GIS based system to automate the process of routing and design of an underground power supply system. The conventional approach of laying out Temporary Facility (TFs) at construction sites involves designing site layout using sketches and templates. The resulting layout through this process is based on the incomplete information stored in different form. Such visual representations of TFs do not yield adequate and descriptive results. As TFs should be located close to their supporting activities in order to reduce the time for travel. Cheng and O'Connor (1996) explored the use of GIS and developed an automated site layout system using GIS.
The construction process simulation is proved to be an effective tool for planning and improving the performance of a construction process in many of successful case studies. However, simulation tools lack the capabilities to represent explicit geographic information in the simulated construction process. Zhong et al. (2004) suggested that GIS could be utilised to overcome this limitation.
Traditional scheduling techniques such as bar charts and critical path method fail to provide information pertaining to spatial aspects of a construction project. The methodology presented by Bansal and Pal (accepted in ASCE) integrates construction schedule with corresponding spatial details so as to make understanding of the project sequence easier (Fig. 1). This link allows easier understanding of the project sequence as well as helps to detect the possible problems in construction schedule. Non-spatial schedules only convey 'what' is built 'when', whereas schedule in GIS conveys 'what' is being built 'when' and 'where'.
CONCLUSION
As GIS is one of the fast emerging fields being utilised in various engineering projects, its complete potential to the construction industry has not been realised yet. GIS is generally not being associated with construction industry, therefore, professionals need education and training on the use of GIS technologies in construction.
