# A Web-Based BIM-AR Quality Management System for Structural Elements
## 1 Introduction  
Presently, due to customer demand and high competition in the market, there is pressure on construction enterprises to improve quality in their projects. The main way to achieve this goal and achieve a competitive edge in the market is by adopting a sound quality management (QM) system [1]. Although QM must be applied to all phases of the building process, from conceptual design to demolition, the main challenge of projects and construction managers is controlling the quality during the execution phase, which calls for more resources and time. Based on surveys conducted by [PERSON] et al. [2] and [PERSON] [3], it has been found that failures ascribed to the execution phase are more prevalent than errors in the design process, and the construction phase appears particularly prone to errors. On the other hand, structural elements are considered to be the most fundamental components of a building to be controlled for their quality, since they are directly responsible for structural integrity, strength, and safety, and any defects in them will cause fatal accidents, severe additional costs, or delay [4, 5]. In many projects, structural elements have also proved to have defects after execution but directly related to the execution phase, such as incorrect positioning of the frame in relation to the foundation, or insufficient length of the reinforcement bars [6]. Since there may be differences in the perception of the quality of an object, quality must be defined in a clear way. The ISO standard [7] defines quality as \"degree to which a set of inherent characteristicsof an object fulfils requirements\". Quality in construction projects refers not only to the quality of products and equipment used in the construction of a building or facility, but also to the adopted management approach. As [PERSON] states [8], both the construction cost and time of delivery are also important quality characteristics. Construction project quality is managed through quality assurance (QA) and quality control (QC). [PERSON] interprets QA as \"preventive medicine\" [9], which consists of steps taken to increase the likelihood of obtaining a good-quality product and management processes. The aim of QA is to ensure that the project scope, cost, and time functions are fully integrated. QC as part of QA is \"curative medicine\", which recognizes human fallibility and takes steps to ensure that any (hopefully small) variations from standards that do occur are eliminated. As such, QC is the specific implementation of the QA program and related activities. Effective QC reduces the possibility of changes, mistakes, and omissions, which in turn result in fewer conflicts and disputes, and reduced waste of project resources. Although the procedure of quality check during the execution phase is consolidated and seems to be well organized, it does not work out properly in practice, for instance, due to intensive manual data collection entailing frequent transcription or data entry errors. Supporting this statement, examples can be found in reports and surveys presented by [PERSON] et al. [10] and Meijer & Visscher [11]. However, the complexity of properly controlling the quality of execution of structural elements can be easily recognized by having in mind, e.g., the number of processes and stakeholders involved in the execution of the concrete structure. Recently, information technology (IT) has gained much attention as a key driver of change in the architecture, engineering and construction (AEC) industry. Developments in IT have provided numerous opportunities for the AEC industry, one of which is building information modeling (BIM) [12]. BIM serves as a central data repository that can store information about a facility and is currently regarded as an essential tool in managing the lifecycle of a construction project from the initial design to its maintenance. BIM is not just a technology change, but also a process change.