intensive system that was integrated with current critical-path-
method (CPM) scheduling software (Kartam, 1997). In this
framework, extensive safety data and knowledge were coded
and stored in a database system which was linked to other
construction management files. However, in these studies, the
H&S data is hardcoded in the system and they do not
dynamically use any geographic information from the site and
represent it visually to the user.
Recently, GIS technology is being effectively used for route
selection, feasibility studies, progress monitoring, asset
management, and operation and maintenance management for
linear projects (Luettinger and Thayne, 2005; Prest, et al. 2007;
Zheng, 2008). Furthermore, hazard map preparation is a very
common use of GIS in risk assessment in natural catastrophes
such as earthquake risk assessment, hurricane impact risk
assessment and environmental risk assessments such as oil
spilling at the sea and fire risk assessment modelling at forestry
(Sala and Vighi, 2008; Zhang et al. 2009). However, a GIS
based system was not developed for use in health and safety risk
assessment as a part of daily working plans in linear
construction projects.
1.3 Problem
Currently, the H&S personnel performs risk assessment for each
construction method and keeps this information attached to the
method of statement that is submitted to the owner at the
beginning of the project. However, usually site workers and
superintendents do not use this risk assessment information at
site since it is recorded on based documents which are kept in
the office. Also this information is only associated with method
of statement, not related with daily individual activities. This
results in low awareness in H&S among workers and engineers
and leads to hazards and fatalities at construction sites.
The primary objective of the paper is to develop a GIS based
system for H&S planning as a part of daily work plans and
effectively integrating various types of document based H&S
data used in the risk assessment in GIS environment.
The following sub objectives were also achieved in developing
this system by means of GIS functionality: (1) Development of
the H&S database in relation with GIS environment, (2)To
replace the manual methods to extract the information from the
available database and (3) Integrate H&S risk assessment data
with spatial data.
2. MATERIAL AND METHODS
2.1 Proposed System Model
In the first step of system design, end users need was assessed
and information products were described. The information a
GIS based DSS generates was described and end users need to
be interviewed in order to determine what their job involve and
what information they need to perform their tasks.
In the second step the scope of the system was defined and
system designed. This phase was performed in three step;
conceptual, logical and physical modelling. After that data
design was created. In this step spatial and H&S database
design were actualized. Following the data design stage system
requirements determining was realized. In this stage examine
the system functions and user interface needed along with the
hardware and software requirements.
Briefly, users need was assessed, system scope was defined,
data design was created, and system requirements were
determined in design phase.
The IDEFO model of the proposed decision support system
(DSS) is given Figure 1. To create a risk map of the area, main
inputs are the topographic map, site layout plan and the major
obstacles identified in the project's construction site such as,
other pipelines, power lines. These maps and obstacle
information will be integrated to determine potential hazards
and health and safety risks according to the H&S regulations
and the project specifications. The final outputs of the system
are the risk map that highlights the risk factors and their ratings
and proposed mitigation measures to be taken at those high-risk
locations (Atay et al. 2010).
Project H&S
Specifications ^ Regulations
Topographic | Ë rF
Map . E
i i Risk Map w/ risk
H&S Decision ratings 2
os Support System | => Proposed
Mitigation
Site Layout Plan Measures
List of Obstacles
Determine hazard
risks
Figurel. IDEFO model of the proposed H&S DSS
Currently most commercial Web-based decision support
systems are designed around a three or higher tiered
architecture. (Yeung and Hall, 2007). Therefore, GIS based
H&S decision support system was developed based on n-tier
web based system architecture that is shown in Figure 2.
Data Tar
(ArcGIS GeoDB) (Sot pa)
Figure2. System Architecture
Three tier models were chosen for the application which has
data tier, business tier and presentation tier (Figure 2). The
processes of information storing and retrieving from a database
or a file system are executed at data tier. Business tier
coordinates the applications, processes commands, implements
reasoning mechanisms, makes logical decisions and evaluations
and perform calculations. Finally, the main function of
presentation tier is to visually present the results to the user.
In the developed system, data tier is composed of H&S
Database and Geo-database. H&S data is stored on a MS SQL
server 2008
file on Arc
using Arc-(
are perfor
geometry a
object API
designed b
developmer
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Tablel.
