## 2 Literature Review
### Development of Movable Scaffolding System with an Organic Prestressing System
Numerical analysis was used to assist the design of the physical experiment and to set up a comparison, where the results show that the mid-span deflection was reduced about 90% [15]. This research identified future areas for enhancing the MSS with an OPS, focusing on kinematic challenges like actuator placement, monitoring multi-span behaviour and thermal stability, and designing deviation saddles to minimise cable friction and wear [9]. The outcomes of this experiment encourage the application of the OPS in real engineering practices. Thus, to accommodate the massive demands for constructing high-speed rail (HSR) bridges and considering economic factors, they also explored using the OPS to reinforce existing traditional MSSs [16]. This approach was aimed at adapting them for longer spans and heavier bridge construction, rather than spending more of the budget on new construction equipment. Subsequently, in 2007, the first full-scale MSS with an OPSwas demonstrated, achieving over 90% reduction in mid-span deflection, 30% less steel usage, increased load capacity, and safety through sensor monitoring, while also enhancing scaffold versatility, adaptability, transportability, and storage efficiency [17]. Initially focused on the underslung MSS type, [PERSON] et al. [18] shifted to the \"bow-string\" OMSS prototype to increase span and kinematic capabilities, featuring an arched upper chord and an OPS-controlled lower chord that limits mid-span deflection to less than L/2000 during concrete casting. This advanced system reduces equipment weight by 25-30%, acquisition costs by 15%, and operational costs by 10-20%, making it suitable for constructing heavier HSR bridge decks. In applying the OPS in the MSS, there can be a significant reduction (about 6%) in steel and the energy consumption contributing to the carbon footprint control and satisfying the general sustainability goals [19]. The successful application of this equipment in constructing bridge decks with spans of 70 to 90 m led to analysis and design recommendations for both bridges and large MSSs (LMSSs) [20]. The arched upper chord in the temporary modular bridge (LMB120) design reduced structural weight by 18%, increased stiffness by 26%, and maintained lower stress levels compared to traditional truss bridges [21]. To ensure the robustness of the proposed MSS model, [PERSON] et al. [22] developed a methodology that includes experimental tests, checklists, and software integration for validating the operational effectiveness and structural integrity of systems, which could be enhanced with a self-diagnosis function. [PERSON] et al. [23] specifically emphasised that the OPS can significantly boost productivity in bridge projects, as the system could allow lighter construction designs and ensure continuous monitoring, leading to faster construction cycles and improved safety so that the construction delays caused by accidents could be minimised. The development of an overhead MSS with the OPS underscores the importance of addressing fatigue through damage-tolerant methods, stringent material selection, quality control, and robust maintenance plans to enhance durability and safety over extended service periods [2]. MSS M1-90-S was developed based on the sufficient previous research mentioned above, and this model will be the benchmark of this project [4]. With this model, the maximum construction span was extended to 90 m and the corresponding construction cycle was also generated to ensure the largest building efficiency [24]. This construction equipment was further discussed in terms of its efficiency to satisfy the time, economic, and sustainability requirements through its application in the Ankara-Sivas high-speed railway construction in Turkey and was analysed based on its construction processes for continuous concrete bridges [25]. In the implementation of the OPS, its adaptive load control feature was guaranteed through the sensitivity of the integrated sensor systems.