Struct-MRT: Immersive learning and teaching of design and verification in structural civil engineering using mixed reality

Structural engineering lectures are core parts in undergraduate civil engineering curricula and the content demands advanced analytical thinking and abstract perception from real-world structures to computational surrogate models and applicable design schemes. On the other hand, Extended Reality (XR) technologies such as Augmented, Virtual and Mixed Reality (AR, VR, MR) currently influence developments in many industries, including the AEC sector. Especially MR enables immersive experiences of blending interactive digital contents with the real. Our goal is to transform traditional paper-based instruction into an immersive lesson. To that end, this paper presents the conception, workflow and deployment of two MR applications for verification of typical yet geometrically complex structural members: a reinforced concrete corbel and a steel frame. The aim of this research is threefold: (i) to develop and implement the technological feasibility of such applications, (ii) to demonstrate possible use cases in the context of structural engineering lectures and (iii) to evaluate the presented MR examples and the future potential of such MR applications in structural engineering lectures through a survey. The workflow and especially the two MR teaching applications presented in this paper were developed based on Apple's Preprint. Under review ARKit and are thus natively deployable on iPhones and iPads. The verification process was reproduced in the MR applications based on conventional exercises that were taught on paper. Users can navigate independently through the applications and review every single step, including a true-to-scale, spatial representation of the specific component (concrete corbel or steel frame) as well as associated verification formulas in the respective step. Likewise, these applications were used to assess the demand and expectations for such immersive teaching techniques among students through a survey of 89 civil engineering students and instructors. The participants were asked to test the MR applications on their devices or watch pre-recorded video demonstrations, afterwards perception was elicited through a questionnaire. The results of a subsequent data analysis show a generally positive judgement of the MR application over the six questioned categories (style, usefulness, ease of use, enjoyment , attitude as well as intention towards using). The statistical analysis revealed some (positivity) biases for users with prior XR experience w.r.t. to usage and navigation, while inexperienced/novice users underlined increased enjoyment or excitement with this learning format. The outlook covers identified shortcomings and future developments in this field.