کاربرد سیستم های اطلاعات جغرافیایی در برنامه ریزی ایمنی ساخت و ساز

Execution schedule and 2D drawings are generally used for hazards identification in the construction safety planning process. Planner visualises 2D drawings into a 3D model and mentally links its components with the respective activities defined in the schedule to understand the execution sequence in safety planning. Sequence interpretation and accordingly the hazards identification vary with the level of experience, knowledge and individual perspective of the safety planner. Therefore, researchers suggest the use of four dimensional (4D) modelling or building information modelling (BIM) to create the simulation of construction process by linking execution schedule with the 3D model. Both however lack in the features like: generation and updating of schedule, 3D components editing, topography modelling and geospatial analysis within a single platform which is now a major requirement of the construction industry. This work facilitates 4D modelling, geospatial analysis and topography modelling in the development of safe execution sequence by using geographic information systems (GIS), both 3D model along with its surrounding topography and schedule were developed and linked together within the same environment. During safety review process if planned sequence results a hazard situation, it may be corrected within the GIS itself before actual implementation. Paper also discusses the use of GIS in the development of safety database from which safety information are retrieved and linked with the activities of the schedule or components of a building model. 4D modelling along with topographical conditions and safety database in a single environment assist safety planner in examining what safety measures are required when, where and why. Developed methodology was tested on a real life project in India, lessons learned from the implementation have been discussed in the potential benefits and limitations section. At last, paper highlights major research areas for further improvements.

1.1. Current state of safety planning Construction industry is under resourced and under planned in relation to any other industry. In addition to this construction sites are extremely busy places where working environment is ever changing that becomes difficult to predict before or during construction. Poor safety planning and ever-changing environment of construction sites often lead to accidents which affect people, project economics, and social life and bring additional legal liabilities. Poor safety on site keeps workers and their relatives always in physical and psychological troubles which economically affect the project by increasing direct and indirect costs. Workers in the construction industry face a greater risk of fatality or injury than the workers in other industries; therefore, their protection is of great concern than any other sector. Construction site safety is one of the project’s success factors along with time, cost and quality. Effective safety planning contributes in the prevention of accidents and ill health of site personals. Planning well for safety plays an important role in reducing unnecessary cost and delays. Design and construction professionals must be aware of the relevant safety issues which need to be looked at the earliest stages of project planning (Hare et al., 2006). Johnson et al. (1998) found that workers’ risk-taking behaviour is a significant contributor to the accidents. Organisations which manage complex and potentially hazardous technical operations with a surprisingly low rate of serious incidents show that operational safety is more than the management or avoidance of risk or error (Rochlin, 1999). Langford et al. (2000) studied the attitudes of construction workers towards safe behaviour on the construction sites by using a research model that links three themes: safety management implementation strategies, attitudes of workers about safety and behavioural factors displayed by construction workers. Glendon and Litherland (2001) used a behaviour sampling technique to evaluate the safety performance of each construction crew. Lee and Halpin (2003) depicted that supervision and training are also related to the safety performance. Study by Saurin et al. (2005) analysed safety planning and control model from the human error perspective. Dejoy (2005) compared two prominent safety management rubrics: the behaviour change and culture change approaches in terms of their conceptual and theoretical foundations, defining characteristics and apparent strengths and weaknesses. Safety culture is also becoming important to the safety of employees within the construction site environment. Choudhry et al. (2007) reviewed the literature on safety culture focusing on researches undertaken from 1998 onwards. Safety culture was thought to influence workers’ attitude and behaviour in relation to an organisation’s ongoing health and safety performance. Some clarifications in terms of positive safety culture, safety culture models, levels of aggregation and safety performance were provided by presenting appropriate evidences. Although, the concept of safety culture is relatively new within the construction industry; it is gaining popularity due to its ability to embrace all perception, psychological, behavioural and managerial factors according to Choudhry et al. (2007). Suraji et al. (2001) concluded that planning and control are the two major causes of site accidents. Huang and Hinze (2003) identified the pattern of accidents due to falls from heights. Tam et al. (2002) after comparing safety improvement measures in the construction industry devised a method for allocating resources according to the order of priority. Hare et al. (2006) integrated health and safety with pre-construction planning. All these studies were set out to identify the risk of accidents and plan measures to reduce them. Analysis and causation of accidents provide basic information for safety planning but these are not sufficient to predict when and where accidents occur. Such predictions need coordination with the schedule that provides necessary information about the identification of time of high risk ( Yi and Langford, 2006). Lots of efforts, for example, association of safety with design, schedule and cost have been made to improve safety management strategies. Cagno et al. (2001) developed an algorithm for scheduling of safety measures within the safety improvement programme. Hadikusumo and Rowlinson (2002) developed a tool for the visualisation of construction process that identifies the safety hazards. Saurin et al. (2004) developed Safety Planning and Control model that integrates safety management with production planning and control process. Kartam (1997) developed Integrated Knowledge Intensive System (IKIS-safety system) for construction safety and health performance control by integrating safety and health requirements with the critical path method (CPM) schedule. This integration provides a way to manage safety and health performance proactively rather than reactively. IKIS-safety system helps user to know when and what safety measure is needed. However, it does not provide adequate information for analysis like where and why a safety measure is important. Safety planning in the construction industry is generally done separately from the project execution planning; however, there must be a link between them (Chantawit et al., 2005). There are two reasons behind the importance of this link. First, because safety engineers need to identify when and where safety measures are required. Secondly, because design drawings/procedures have the information related to why and what safety measures are needed ( Chantawit et al., 2005). Therefore, safety planner needs to be involved in analyzing construction drawings/procedures for developing a safety plan during the project planning stage. Safety planning involves the identification of all potential hazards and accordingly deciding the safety measures. Identification of safety hazards is the most important part in the safety planning process because failure in the hazards identification indicates that construction sequence is not adequately investigated. Project execution planning and safety planning together convey what is to be built, what safety measures are necessary when, where and why. To carry out project execution and safety planning prior to actual construction, planners use 2D drawings and mentally associate their components with corresponding activities defined in the execution schedule to visualise the construction sequence and accordingly decide the safety measures. There is no dynamic linkage between the schedule and drawings that results variations in construction sequence interpretation which affect safety planning. The sequence interpretation depends upon the level of experience, knowledge and individual perspective of safety planners. The use of such approach in project execution and safety planning results dissimilarities in construction sequence interpretation that lead to the poor safety planning. Chantawit et al. (2005) and Hadikusumo and Rowlinson, 2002 and Hadikusumo and Rowlinson, 2003 removed the variations in sequence interpretation in safety planning by using 4D CAD and virtual reality for hazards identifications. 4D CAD facilitates 3D visualisation of construction processes on a computer screen; users need not to interpret sequence in their minds. In these studies construction process visualisation was found useful in the identification of potential hazardous situations prior to the construction. Despite of much research in 4D CAD technologies their use is not very common in the construction industry. These technologies are somewhat difficult to use and the visualisation provided by them is not easily customisable (Issa et al., 2003). Existing 4D CAD systems are unable to aggregate and distribute the information between spatial and non-spatial databases. These tools are based upon the object-oriented concepts and are used primarily for planning, design phase and appraisal types of analysis. Furthermore, 4D CAD models have a single level of detail which hinders the collaboration among general contractors and sub-contractors (Poku and Arditi, 2006). Koo and Fischer (2000) suggested that the construction industry requires a tool that can generate, manipulate and link the execution schedule and 3D components in a single environment. Therefore, after 4D CAD there is a major revolution of BIM that provides strong premises to overcome the fragmented nature of the construction industry. The main idea behind BIM is a single repository where every item is described only once (Aouald et al., 2007). The invention of BIM facilitates 3D modelling, scheduling and linking them together to visualise the execution sequence in generating the safe construction alternatives. 1.2. Why GIS in construction safety planning Safety planning is not solitary related to construction sequence visualisation developed in BIM or 4D models. For example, safety planning of gravity dam construction where topography plays a major role could not be simulated without the geospatial capabilities which are missing in BIM and 4D CAD (Isikdag et al., 2008). There are other factors like environmental conditions, site topography, thermal comforts, access route planning, etc., which influence workers safety but cannot be modelled with BIM. Both, BIM and 4D CAD lack in geospatial analysis like: evaluation of new job site with respect to flooding (because during flood entire safety measure planned earlier need to be modified), site drainage planning in the event of flood, thermal comfort at work places, route planning of vehicle carrying consignment from different access routes to job site, etc. All these factors need to be considered in safety planning because of their important role during the construction stage. Keeping the importance of geospatial capabilities in view contractors and organisations create, store and share information about 3D modelling up to floor level detail along with surrounding topography. Therefore, 3D model along with surrounding, 4D scheduling and geospatial analysis capabilities together on a single platform may help in effective safety planning process. This work brings 4D sequence visualisation along with its surrounding topography, database management and geospatial analysis capabilities on a common platform for construction safety planning by using GIS. It improves execution planning and safety planning by integrating geospatial-editing with spatial and non-spatial information in a single environment. Study makes use of 4D GIS tool developed earlier by Bansal and Pal (2008). They generated and linked construction schedule with corresponding spatial details to make the construction sequence easier to understand in GIS. Several other studies have also suggested the usefulness of GIS to handle various construction projects’ requirements such as data management, integrating information, complex visualisation, cost estimation, site layout, construction planning (Bansal, 2007). Hadikusumo and Rowlinson, 2002 and Hadikusumo and Rowlinson, 2003 developed safety database in MS Access while this work discusses the development of the safety database in GIS itself from which safety measures can be retrieved and linked with the schedule/components. Hadikusumo and Rowlinson, 2002 and Hadikusumo and Rowlinson, 2003 used virtual reality in safety management without giving much importance to geospatial factors on other hand this work gives significance to geospatial capabilities which is the main reason to use GIS in safety planning. Chantawit et al. (2005) used early start and finish time for construction simulation in safety planning and recommended future research to incorporate late start and finish time. In this work, construction sequence may be developed either by early start and finish time or by late start and finish time. Chantawit et al. (2005) stored schedule in MS Access after importing it from MS Project, therefore, their system do not support real time schedule update because it cannot be corrected/updated in 4D CAD/MS Access. In this work, during safety review process or during construction if planned construction sequence results a hazardous situation it may be corrected/updated within GIS itself. This paper discusses how safety planning approach was designed and tested in GIS environment. 4D modelling along with project site conditions and safety database in a single environment assist safety planner in examining what safety measures are required when, where and why. The proposed approach may also be used in integration with earlier studies made by the authors on 4D GIS ( Bansal and Pal, 2008 and Bansal and Pal, 2009a), cost estimates ( Bansal and Pal, 2007) and direct sunlight visualisation ( Bansal and Pal, 2009b).

This study uses GIS based navigable 3D animation in safety planning process that facilitates easier understanding of construction sequence and predicts places and activities which have higher potential for accidents. Editing 3D components, generation and update of CPM schedule, geospatial analysis capabilities and visualisation of surrounding topography in a single environment improves the effectiveness of safety planning. The developed GIS based approach allows project planner and safety planner to manipulate the schedule, components and sequence on a single platform, which in turn facilitates the rapid generation of safe construction sequence and promotes the interaction and collaboration between the members from various fields. This approach integrates safety code provisions and expert’s recommendations with components or activities which makes safety planning more realistic. The rapid retrievals of information from the safety database were found useful for professionals responsible in planning construction activities and developing worksite safety programmes. GIS together with the safety database helps in identifying the safety hazards and picking up the relevant information. The developed approach was found useful in analyzing what safety measures are needed when, where and why. Study proves that decisions of designer and project planner have direct impact on workers safety. Designer and project planner must consider workers safety as a part of design and planning processes, therefore, their interaction with safety professionals need to be encouraged to make them more responsible for workers safety. They must be made aware of various means by which their design and decisions improve the site safety conditions. Both must know the fact that construction safety is not solitary the responsibility of contractor or employer. Therefore, safety planning process was designed in such a way that safety could be addressed right from the design stage. At last, GIS based safety planning along with geospatial analysis capabilities has its own strength where construction may be perceived together with its surroundings. GIS not only provides a tool for construction safety planning but it may also be utilised to fulfil different project requirement in various stages (Bansal, 2007).