News / Press

SEAONC Post Newsletter - California Office of Emergency Services

Published on 7/1/2022

SFSU’s VR Engine: Introducing Virtual Reality to SEAONC’s SAP Evaluator Training

Jenna Wong (PhD, PE), Shahrukh Humayoun (Phd), Khanh Nguyen, Yongjian Pan, Steffi Wu, and Thomas Yu

In 2021, Dr. Jenna Wong (Assistant Professor in Civil Engineering at SFSU, SEAONC member) and Dr. Shahrukh Humayoun (Assistant Professor in Computer Science at SFSU), in collaboration with Structural Engineering Association of Northern California (SEAONC) and San Francisco State University (SFSU) initiated a grant research program to implement virtual reality (VR) into structural engineering. The program received its grant funding from SEAONC in 2022, who contributed a $10,000 Special Projects Initiative grant towards the program's initiative. Upon funding, Dr. Wong and Dr. Humayoun formed the VR Engine (Virtual Reality Engineering) team - comprised of structural engineering and computer science graduate students from SFSU (Khanh Nguyen, Yongjian Pan, Steffi Wu, and Thomas Yu). The team has since been developing a VR training tool for use in SEAONC's Safety Assessment Program (SAP) Training for California Office of Emergency Services (CalOES).

The SAP is managed by CalOES to provide local governments access to certified evaluators holding a CalOES approved professional license - such as civil or structural engineers, for post-disaster building evaluations. Applicable events cover a wide range of disasters including - but not limited to earthquakes, fires, and floods. Although efforts are concentrated in California, SAP evaluators can be deployed to other locations where the state has pledged mutual aide. Evaluators primarily provide rapid evaluations to discern a building’s state, denoted by a green (safe), yellow (restricted use), or red (unsafe) tag. These rapid evaluations are based on the Applied Technology Council’s (ATC) ATC-20 standard.

As a service to its members, SEAONC’s Disaster Emergency Services (DES) committee has hosted CalOES approved trainings since 1987. These trainings provide an overview of the process, share real-life stories of deployment by the training’s presenters that are certified evaluators and/or instructors, and utilize case studies to challenge trainees to apply the ATC-20 evaluation criterion in mock scenarios. Trainings are hosted approximately every 18 months at pre-selected locations, in which buildings in the vicinity are marked with drawings or photos of theoretical damage. Trainees then walk the vicinity to perform mock evaluations of the building. More recently due to the COVID-19 pandemic, virtual trainings have used slide decks with photographs showcasing real damage to structures from previous earthquakes as case studies in lieu of the in-person mock experience. After taking a virtual SEAONC SAP training in 2020, Dr. Wong collaborated with SEAONC DES’ Molly Seto and Stefanie Rae Arizabal to envision ways the training could be further augmented using VR.

VR is an emerging and affordable technology that immerses users in an artificial interactive environment that can produce both visual and auditory stimulation using a headset and hand-held controllers. Various applications of entertainment - such as video games and movies, as well as sectors of the A/E/C industry- such as the use of virtual walkthroughs for architectural programs, have seen increased popularity over the years. Likewise, the ability to simulate a variety of environmental and physical conditions (e.g., lighting, sound, structure), gives the potential to transform SEAONC’s mock scenario approach into an even more life-like experience.

In 2021, VR Engine started work alongside Seto and Arizabal to develop an initial prototype structure (IPS), soliciting additional input from Kelly Cobeen and David Ojala, two of SEAONC’s SAP training presenters and technical experts in the field of post-disaster evaluation. VR Engine is currently hard at work producing an initial virtual environment system, which will allow trainees to explore a post-earthquake scenario with a 360-degree viewpoint of a damaged structure and the capacity to do a full walk-around of the building exterior on a desktop computer. This is the first step to producing a full VR training platform.

The structure being developed is a representative three-story, timber framed apartment building with a masonry parking garage that has experienced a seismic event (see Figure 1). The lobby features a multi-story glass atrium with exterior emergency stairwells located on the far ends of the building. This structure is comparable to many apartment buildings found throughout California, especially the San Francisco Bay Area. In this initial phase, emphasis is being placed on exterior access only.

Figure 1: Representative Undamaged Model Developed in Autodesk Revit

The development of the structure will be ongoing over several stages. Outside of the damage plan, there are various elements to consider including incorporation of the various materials or textures (e.g. wood, stucco, brick) and developing the environment surrounding the structure (see Figure 2).

Figure 2: Initial Environment System

In parallel to developing the surrounding environment, development of the damage scheme for the prototype structure is being conducted. Figure 3 presents initial work on the development of diagonal cracking at opening corners, joint separation at timber/concrete interfaces, and cracking of masonry walls. Shattered glass at the atrium lobby is also incorporated. These features were created utilizing assets from the Unity toolkit with added detailing. Further work is being done to develop additional forms of damage such as non-uniform crack propagations, stairwell separation, and out-of-plane movement. All forms of damage being modeled are expected types of damage identified in discussions with Seto, Arizabal, Cobeen, and Ojala. One of the key features of the SEAONC SAP training is challenging the trainees to find evidence of damage while navigating around the structure in its surroundings. Some evidence of damage will be less obvious than others, encouraging trainees to observe the structure carefully. In current approaches, trainees are guided with the presentation of photographs directly displaying damage. As such, the VR approach will further test the trainees’ ability to effectively evaluate a structure’s condition with minimal assistance.

(a)

(b)
Figure 3: Preliminary Damage Scenarios with Crack Propagation, Glass Shatter, and Masonry Damage from the (a) front and (b) back of structure

Figure 4: Low Lit Environment Example (Shadow Effect)

Further developments that are anticipated in the VR training tool include tracking trainee’s identification of damage, providing obstacles to the evaluation process (e.g., low lit environments - see Figure 4), and allowing ease of navigation around the structure and in the garage level. The environment will be navigated in the first-person perspective with current work focusing on defining sensitivity to movement and camera viewpoint control.

Once the full initial prototype is developed, SEAONC DES and SAP training presenters will be solicited to participate in pilot studies to evaluate the usability and effectiveness of the VR platform using a desktop interface. The feedback from the pilot studies will be applied to developing the full VR training tool for use in an upcoming SEAONC SAP Training. The next SEAONC SAP Trainings are anticipated in the Fall of 2023 and Spring of 2025.

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