# A Web-Based BIM-AR Quality Management System for Structural Elements
## 1 Introduction
In fact, unlike the traditional approach, the BIM approach allows the project team and the stakeholders to share information and to be constantly aware about the project. BIM is considered to be a multi-dimensional digital representation of the physical and functional characteristics of a project. Every time a specific type of information is added to the model, a different dimension is set, and, for this reason, various dimensions have been defined. Three dimensions are generally sufficient for geometric purposes, but new descriptive modalities and quantities, such as time or costs, introduce a different type of information. According to BIM fundamentals there are seven recognized \"dimensions\". 3D (three-dimensional rendering of the artefact), 4D (time and duration analysis), 5D (cost), 6D (sustainability assessment), and 7D (management phase). Taking advantage of its potential, the BIM methodology can be exploited to manage all the QC data and the complex relationships between them, establishing an effective approach to realize improvements in construction quality management. Various researchers have already proposed to implement BIM concepts into a quality management [13]. As an example, the QC framework by [PERSON] [14] consisted of a 4D model combined with a specific company's process, organization and product (POP) model. According to [PERSON] [15]: \"BIM refers to a combination or a set of technologies and organizational solutions that are expected to increase inter-organizational and disciplinary collaboration in the construction industry and to improve the productivity and quality of the design, construction, and maintenance of buildings\". In this sense, several authors proposed the combination of BIM with other technologies aiming at exploiting their potential in the framework of quality management. There are many examples, involving different techniques and technologies, such as personal digital assistants [16], mobile devices to access design information and to capture work progress [17], radio frequency identification [18; 19; 20], laser-scan point clouds [21; 22; 23; 24; 25], and indoor positioning through magnetic fields and wi-fi signals [26]. In the last decade, augmented reality (AR) has received a considerable amount of attention from researchers in the AEC community [27]. According to [PERSON] et al. [28] AR and BIM are complementary technologies. AR could represent the site extension of the BIM concept and approach, and maximize the potentials of BIM in the construction site. AR allows the overlaying of a virtual object into the real world and can present information on site where it is needed. [PERSON] and [PERSON] [29] classified AR application areas in the AEC industry as follows: (1) visualization or simulation; (2) communication or collaboration; (3) information modeling; (4) information access or evaluation; (5) progress monitoring; (6) education or training; and (7) safety or inspection. Therefore, the benefits of bringing AR to the job site could be truly remarkable. In the framework of quality management, remarkable works can be found in the literature. [PERSON] et al. [30] implemented the D4 AR system for visualizing the deviation from the construction schedule by registering new daily site images and using a traffic light metaphor as feedback to represent discrepancies between the as-planned and the as-built. [PERSON] et al. [28; 31; 32] developed a conceptual framework to investigate how BIM can be extended to the site via AR and investigated the use of BIM and AR for project control, procurement monitoring, visualization of design during construction, and linking virtual to physical objects. [PERSON] et al. [33] presented a conceptual system framework for construction defect management using AR and BIM technologies to enable the storage and retrieval of defect data visually. Following that study, [PERSON] et al. [34] proposed a defect management system for reinforced concrete work by integrating BIM, image-matching, and AR.