BIM-based fall hazard identification and prevention in construction safety planning

Highlights

• A literature review on existing construction safety and BIM solutions is presented.

• A framework for design and planning of fall protection systems in BIM is introduced.

• A prototype BIM-based safety hazard detection and prevention algorithm was created.

• Two case studies tested the feasibility and effectiveness of the developed approach.

• Open issues and BIM-based safety design and planning commercialization are discussed.

Abstract

The applications of Building Information Modeling (BIM) in building design and construction planning are growing rapidly. BIM-based modeling and 4D simulation (3D and schedule) has brought many benefits to safety and logistics applications as well. However, only limited automation in modeling and planning safety processes has been exploited so far. The objective of this study is to investigate how potential fall hazards that are unknowingly built into the construction schedule can be identified and eliminated early in the planning phase of a construction project. A survey of research on construction safety and BIM is presented first. Then, a framework was developed that includes automated safety rule-checking algorithms for BIM. The developed prototype was tested using models including an office and a residential building project in Finland. The first case study highlights the comparison of manual vs. automated safety modeling of fall protective systems. It also describes the details to multiple design and as-built scenarios where protective safety equipment is modeled. The second case study presents results of applying the framework to the project schedule. It specifically simulates fall hazard detection and prevention. The contribution of this work is an automated rule-checking framework that integrates safety into BIM effectively and provides practitioners with a method for detecting and preventing fall-related hazards. Presented are also discussions of open issues regarding commercialization of the developed prototype and considerations which explore what impact it might have on resolving safety issues in the field by extending traditional safety management practices.

Introduction

Workplace injury, illness, and fatality statistics indicate occupational health and safety (OHS) in building construction remains a worldwide problem. More than one third (36%) of all US workplace fatalities occur in the construction industry. Similarly, the Finnish construction industry is responsible for one out of four fatal occupational accidents. Similar to several other industries, safety planning has a key position in the field of production planning. However, in the building construction industry safety, planning is carried out separately from the project design and planning phase. Even though falling from heights remains a major safety risk at construction sites according to the US Bureau of Labor Statistics (2012), the fall protection plan typically is not created until construction starts in most of the existing projects (Sulankivi et al., 2010). Additional problems arise when detecting and resolving safety issues during the construction planning phase. For example, safety communication at the worker level is particularly challenging under the harsh (weather, uniqueness) and dynamic (multiple resources, time constraints) conditions that exist at construction projects. Several previous studies reported similar issues (Goodrum and Gangwar, 2004, Hallowell and Gambatese, 2009, Benjaoran and Bhokha, 2010).

One of the major obstacles to effective safety planning is that traditional safety planning still largely relies on paper-based 2D drawings and schedules to understand the needs for safety equipment on a construction site (Chantawit et al., 2005). In terms of fall protection, Fig. 1 presents an example of a traditional fall protection plan where various fall prevention systems have been marked into a construction plan with different colors (Kiviniemi et al., 2011). Such manual fall hazard identification and planning relate to several inefficiencies. Some of these are:

• It requires professional safety engineers to detect potential safety hazards and determine safety equipment based on their experiences.

• Many of the safety issues are implicit, being the result of partially complete conditions not shown on the building plans.

• The dynamic nature of the construction project results in changes in safety needs. It is difficult to identify the potential fall hazards at different construction stages/schedules based on static drawings.

• Construction schedule is subject to change based on various conditions such as weather, material delivery, which leads to change in the safety plan. It is time-consuming and labor-intensive to update the safety plan every time schedule changes.

• Falls of humans to a lower level at a leading edge are easier to recognize than smaller holes that cause foot injury, for example. These holes are hardly or never drawn in paper-based plans and thus might never be detected, even by experts.

Inefficiencies are witnessed in the current methods which are utilized for processing and reporting safety and health related issues on a construction project (Abraham et al., 2004, Egan, 1998). Technology that assists construction safety experts in the task of easier recognizing and resolving safety hazards while addressing the complexity and dynamism of jobsite conditions (Ku and Mills, 2010) can lead to safer construction with less effort.

Building Information Modeling (BIM) is a digital representation of physical and functional characteristics of a facility. A BIM is a shared knowledge resource for information about a facility forming a reliable basis for decisions during its life-cycle; defined as existing from earliest conception to demolition (National BIM Standard, 2013). The growing implementation of BIM in the Architecture/Engineering/Construction (AEC) and Facilities Management (FM) industry is changing the way safety can be approached (Zhang et al., 2013). The application of BIM is currently increasing rapidly in construction operations planning and management and also in safety management. One starting point is to emphasize safety aspects early on in the building design and engineering phases (Zhou et al., 2012). Zhang et al. (2013) also pointed out that the construction industry is in need of addressing the inefficiencies of existing paper-based and manual safety processes currently in use.

BIM-based methods are being applied in construction design and planning. They are also being implemented more and more in site safety management and supervision (Kiviniemi et al., 2011, Downey, 2012). Manual safety checking generally follows a process like: (1) use the construction schedule to identify the construction actions and sequences or work tasks within the spatial layout of the project; (2) identify temporary conditions that create safety hazards; (3) plan corrective actions to eliminate safety hazards; and (4) integrate these corrections into the schedule. However, the limited human cognitive skill to mentally simulate complex future conditions suggests that a more proactive and simulation based method using predefined pattern checking could greatly strengthen the effectiveness of this sequence of activities. As stated by Kiviniemi et al. (2011), only an integrated approach will succeed in providing the competence of all domains.

Based on previous research efforts (Zhang et al., 2013), this study aims to develop an automatic BIM-based fall hazard identification and planning tool that (1) identifies potential fall hazards dynamically based on the construction schedule, (2) assists labor-intensive modeling and planning tasks of fall prevention system effectively, and (3) improves workers’ safety awareness by visualizing the potential hazards. This case study also aims to evaluate possibilities, benefits and development needs for automated safety code checking and planning. Also, we examine the usability and maturity of the developed BIM-based prototype tool that supports fall prevention planning in building construction projects.

The paper is structured in the following way: Section 2 presents a literature review on traditional hazard mitigation approach and the application of information modeling in construction safety planning. In Section 3, the developed safety rule-checking prototype and its computational algorithms are introduced. Section 4 presents the application of the prototype in two case studies. Manual modeling and automated modeling of fall protective system are discussed in the first case study along with the comparison between the design and as-built scenario. In the second case study, the dynamic characteristics of fall hazard detection and prevention generated by the prototype are shown as it is applied to a construction schedule. Section 5 shows a comparison of several BIM applications for construction safety planning. A summary and discussion of the findings and contributions are in the final section that concludes the paper.