5.1.2. Challenges faced by technologies
In order to operate with visualized objects for improving construc
tion safety management, it is necessary to create an effiffifficient system for
the user. For achieving such system, the actions as: scaling; navigating
in visualized 3D space; selecting sub-spaces, objects, groups of visual
elements (flflow/path elements) and views; manipulating and placing;
planning routes of view; generating, extracting and collecting data
(based on the reviewed visualized data) should be realized. However,
some signifificant challenges are still existing as the following:
•How to classify the input information (see
Fig. 9) at various levels for di
quirements in construction safety?
•How to enhance the connectivity and interoperability of VR/AR
systems with input information (seeFig.8) which collected by other
information and communication technology(ICT)tools to reduce the
How to select the customized hardware (i.e., user-friendly inter
faces) and software (customized and reusable contents, models and
databases) to achieve multi-level requirements of VR/AR-CS sys
5.2. Classifification of application domains and major challenges
The typical applications of VR/AR-based construction safety man
agement consist of safety planning, safety training and education, and
safety inspection[4]. Safety planning gets high priority for safety
management teams to identify the hazards or risks before actual work
at the site[40]. Safety training and education are aimed to make no
vices understand the safety concerns in terms of work location,type of
work, type of risk, and behavior risk exposure. The safety inspection is
for construction inspector to check unsafe conditions and deliver the
risk information to workers. This study will take the three management
focus as the main application domains to give a systematic analysis.
5.2.1. State-of-the-art studies of VR/AR applications
5.2.1.1. Hazard identifification. Hazard identifification (or risk
recognition) relies on the capability of safety planning team in
sensing, analyzing, and extracting potential dangers during the
construction[41]. Based on the site situation evaluation, they could
make practical plans such as safety facilities selection, education
Fig. 9.A Taxonomy of VR/AR Output Devices.
A taxonomy of VR/AR systems according to the technology characteristics.
Classifification criteria Number of
Least-immersive VR 16 17.80% 18.80%
Semi-immersive VR 22 24.40% 25.90%
Immersive VR 6 6.70% 7.10%
Tangible AR 32 35.60% 37.60%
Collaborative AR 4 4.50% 4.70%
Distributed AR/VR 5 5.50% 5.90%
Automation in Construction 86 (2018) 150–162
155requirement, working sequence adjustment, and safety patrol[4].
Traditional methods of hazard identifification focused on desktop
concepts and conventional sources on the drawings, accident cases,
and heuristic knowledge are being used to prepare prevention measures
against expected safety risks through project meetings[23]. Such
approaches are hard to directly catch the precautions from
construction participants and reflflect the realfifield (i.e., dynamic and
unpredictable) circumstances[42]. To enhance participants' immersive
and interactive experience, modeling and visualization of VR
environments for hazard identifification emerged[36,43].
By far several systems for identifying hazards have been developed,
including Design-for-Safety-Process (DFSP) system[43], System for
Augmented Virtuality Environments (SAVEs)[42], Cave Automatic
Virtual Environments (CAVEs)[36], Visualized Safety Management
System (VSMS)[4]. These systems are designed for designers, site
workers with difffferent trades, students, safety managers respectively.
The comparative studies and experiments have been conducted in these
systems. Results indicated that most users in the virtual environment
assessed higher risk levels and identifified more hazards than the ones
who studied photographs and documents[44]. Meanwhile, these sys
tems also provide immediate feedback to subjects regarding identififi-
5.2.1.2. Safety training and education. Computer-based training and
education are becoming more popular in construction phase as is
recognized to enhance the cognitive learning of the user. Students or
novices are used to learn from an experienced professional through a
series of curricula by using chalkboard, handouts, and computer
presentations that are many words and few visual elements[45].
They have historically lacked a comprehensive knowledge of onsite
construction tasks as well as the dynamics and complexities involved in
a typical construction project[46]. Although on-the-job training can be
more effiffifficient[34]because of the engagement and hands-on
experience, it is time-intensive, expensive, and potentially hazardous
depending on actual site situations (i.e. schedule conflflicts, access
diffiffifficulties, weather situations, overriding need for safety and
liability)[47]. VR/AR technologies afffford new opportunities for
effffectively training and educating novices or students with higher
level of cognition and fewer hazards.
VR/AR related technologies have also evolved from visualization
based training to experience-based training in construction safetyfifield
(SeeFig.10)[15]. They could be applied as a complement to digital
modeling, leading to better communication in vocational construction
safety education to enhance the students' safety awareness. The study
conducted by Lin et al.[48]shown that VR/AR motivate students'
learning interests enhances their safety knowledge and help frost their
optimistic attitudes towards using the game scoring to reflflect their
learning performance. Le et al.[49]proposed an online social VR
system framework, which allows students to perform role-playing,
dialogic learning, and social interaction for construction safety and
health education. In order to achieve more interactions between the
real world and virtual objects, Behzadan and Kamat[50]presented an
innovative pedagogical tool that adopting remote videotaping, AR, and
ultra-wideband (UWB). The developed system brings live videos of re
mote construction job sites to the classroom with an intuitive interface
for students to interact with the objects in the video scenes. It further
visually delivers location-aware instructional materials to students
5.2.1.3. Safety inspection and instruction. Traditional communication
methods make inspectors or workers carry construction drawings to
the site, and require plenty of efffforts to look for the correct drawings to
obtain the information they need[39]. They also need to transfer the
information from a 2D representation to an imaginary 3D
representation, as well as to identify numerous predefifined symbols on
the drawings[37]. In order to enhance the abilities of recognizing
safety risks accurately and promptly, AR has been studied and applied
in the construction process of inspection, supervision, and strategizing
[51]. AR-assisted building assessment is one kind of inspection
application on construction safety. Kamat and El-Tawil[52]discussed
the possibility that previously stored building information can be
superimposed onto a real structure in AR, and that earthquake-related
structural damage can be evaluated by measuring and interpreting
critical difffferences between a baseline image and the actual facility.
Dong et al.[37]proposed an AR post-disaster reconnaissance
framework that enables building inspectors to rapidly evaluate and
quantify structural damage sustained in seismic events such as
earthquakes or blasts. As for infrastructure maintenance, AR visual
excavator-utility collision avoidance system was developed to enables
workers to display buried utilities hidden underground, thus helping
prevent accidental utility strikes[53].
Some researchers focused on improving interfaces to provide well
interpreted information for inspectors. The effffort has been made on
embedding VR or AR for better information representation for safety
instructions. ihelmet, developed by Yeh et al.[39], allows inspectors to
input their current location at the site, and automatically retrieve the
related safety information by AR display. With the applications of AR
confifigured Building Information Modeling (BIM), the exact information
context can be disseminated, and safety information can be visualized
not only through images or 3D models, but also that of the indoor
thermal environment for preventing an uncomfortable working en
vironment[20,54,55]. Workers are able to catch and monitor the dif
ference between unsafe site condition and the standard safety re
quirements. Taking the function of real-time reporting into account,
Bae et al.[35]developed a robust system which adopts a vision-based
marker-less AR approach using point cloud for effiffifficient accident pre
cautions. For the cases of sitefifire or construction disaster, time spent on
evacuation is a signifificant determinant of survival. VR based emergency
evacuation simulation, as well as a wayfifinding method, is also a vali
dated approach for construction safety instructions to shorten evacua
tion performance[56].
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