BIM-supported Tunnel Light Environment Evaluation: a Case ...

1 BIM-supported Tunnel Light Environment evaluation : a Case Study on Shanghai Chenxiang road Tunnel Project Jun Wang1, Lei Hou2, and Peng Wu3. 1) Candidate, Australasian Joint Research Centre for Building Information Modelling (BIM), Department of Construction Management, School of Built Environment , Curtin University, Perth, WA, Australia. Email: 2) Lecturer, Griffith School of Engineering, Griffith University, Gold Coast, QLD, Australia. Email: 3) Senior Lecturer, Department of Construction Management, School of Built Environment , Curtin University, Perth, WA, Australia. Email: Abstract: The design of Tunnel Light is of significant importance for road safety and should take into account a number of factors such as the black hole effect at the entrance, the glaring effect at the exit, and sufficient reaction time/stopping distance when a hazard is identified.

2 As project scale increases and many projects can be rendered as fast-track projects, a quality design of Tunnel illumination keeping abreast of the times requires the designer applying more efficient design approaches to handle growing workload and project complexity. The conventional Tunnel illumination design process is recognised as highly reliant on both prescriptive rules of technical standards and two-dimensional (2D) CAD design systems. This approach is becoming limited because it is time-consuming for the designer to query design specifications and make relevant adjustments in case of project change. Meanwhile, a CAD-based design, although being able to yield Light parameters for the different segments of a Tunnel , does not allow Light designers to review the Light conditions throughout the entire Tunnel .

3 To address these challenges, this article proposes an innovative Building Information Modeling (BIM) supported design approach, which incorporates three-level tasks: inputting geographical and meteorological conditions, simulating Tunnel lighting and solar access, and evaluating simulation results. According to Shanghai Chenxiang road Tunnel Project, this paper demonstrates how BIM technology could efficiently and comprehensively be applied in real case Tunnel Light design process, for instance, mitigating the design errors, verifying the alternative design schemes and assisting with the fast-tracking design making process. Keywords: Tunnel Light design, black hole effect, glaring effect, BIM.

4 1. INTRODUCTION AND LITERATURE REVIEW. The design of Tunnel Light is of significant importance for road safety, and a quality design should allow traffic to enter, pass through and exit the enclosed section safely and comfortably (Du et al., 2007). First and foremost, the design of the Tunnel luminance level should mitigate the black hole' effect to motorists travelling from a very bright external Light level (Buraczynski et al., 2010; Yeung and Wong, 2013). Besides, an appropriate luminance level ought to ensure the motorist is able to have sufficient reaction time and stopping distance when a hazard is detected, for instance, a stalled car, a traversing pedestrian, a closed lane, and as such.

5 To understand Tunnel Light design, this paper starts to review a number of global-scale standards and sets out a number of key factors that a Tunnel Light designer needs to take into account for meeting the design purposes. First of all, the Guide for the Light of road Tunnels and Underpasses, denoted as CIE 88 2004, is a standard targeting on the major requirements and technical details of designing day-time and night-time Tunnel Light systems for three major Tunnel forms: geometrically long tunnels, optically long tunnels (short but bent), and short and straight tunnels (Sliney, 2007; Buraczynski et al., 2010). As an advisory guide for designing, installing and maintaining Light systems in the Tunnel , this standard generalises a number of principal factors to be considered in the aspect of road safety, which generally are: objects/hazards visibility, Light contrast, Tunnel design speed, flow volume, length, structure, comfortability, serviceability, wall luminance, orientation, and many others (Mashimo, 2002).

6 Nevertheless, this standard does not take into account the trade-off between the energy consumption issue and the criterion itself, which is very critical in luminary design. The European Committee for Standardization has supplemented in this regard by explicating that a satisfactory solution for the luminous system design in the enclose section is usually achieved by applying a certain level of manual adjusting and closed-form formulae techniques (Pachamanov and Pachamanova, 2008). It is also noted that this could be viewed as a mathematical optimisation problem. As well, most countries have their own standards. For example, the Australian/New Zealand Standard Light for Roads and Public Spaces' specifies performance and design requirements for Light schemes for tunnels and underpasses, and also specifies the luminaire data and other design data that is needed to facilitate the Light design and the assessment of compliance with the requirements of this standard (Boyce et al.)

7 , 2009); The UK issues and updates its own standard named Section 300 Light Design' and the latest one outlines 1023. the engineering standard practice for designing Light systems for accurate and comfortable vision along roadways at night, and through tunnels (Stokes et al., 2004); from the last decade, the Washington State Department of Transportation also started to issue a series of guidelines and handbooks for the Tunnel Light design and defines a series items the design requirements need to meet, , adaptive Light system, average Light level, complex ramp alignment and grade, continuous load, and so on (Committee, 2000; Association, 2010; Colorimetry, 2010).

8 In China, a focus on roadway Tunnel illumination issues emerged since 1980. However, until late 1999, China issued its first national Tunnel illumination design standard (JTJ, 1999). At present, China has issued JTJ. and JT/T 609-2004 (Ministry of Communications, 1999; Ministry of Communications, 2004), while several other design specifications are being edited. Nevertheless, there is still a discerned lack of clarify among these standards and specifications with regard to a standardized design procedure that is irrelevant to Tunnel type, safety, equipment selection, energy, and as such (Xiaotian, 2010; Tu and Chen, 2009). To cope with these challenges, optimisation approaches have been extensively applied.

9 Designing an optimal Tunnel Light system should be based on a synthetic consideration of the road condition, the energy consumption and the effects of adjacent luminaries. Feng et al (2010) applied polynomial cosine functions and feedback functions that involving average luminance ratio, luminance uniformity and adjacent luminary coefficient to approach the optimized illuminance for different types of roads. It is also demonstrated that a method-variable separation mapping method capable of establishing the correspondence between Light source variables and the target illuminated region can eventually overcome the irradiance problems of discontinuous lens surface (Wang et al.)

10 2007;. Pachamanova and Pachamanova, 2008). Qi (2006) presented a microprocessor-embedded system underpinned by a dynamic energy adjustment strategy to overcome the black-hole' and energy-saving challenges. Experiments demonstrate that this system is very effective to dynamically measure, calculate and control the level of Light in the Tunnel as well (Jialin et al., 2006). The Tunnel Light design also arouses safety concerns (Kircher and Ahlstrom, 2012). To reduce the probability of severe accidents that are likely to occur due to a poor Tunnel Light design, Kircher and Ahlstrom (2012) carried out a simulator-based study and identified several Tunnel design principles that can help the driver get rid of attentive and visual troubles.