Kildashti, K, Samali, B, Mortazavi, M, Ronagh, H & Sharafi, P 2019, 'Seismic collapse assessment of a hybrid cold-formed hot-rolled steel building', JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH, vol. 155, pp. 504-516.View/Download from: Publisher's site
Mortazavi, M, Sharafi, P, Ronagh, H, Samali, B & Kildashti, K 2018, 'Lateral behaviour of hybrid cold-formed and hot-rolled steel wall systems: Experimental investigation', Journal of Constructional Steel Research, vol. 147, pp. 422-432.View/Download from: Publisher's site
© 2017 Elsevier Ltd The seismic design of light steel frames (LSF) can not only rely on the application of cold-formed steel (CFS). Some mixed systems and integrated solutions such as hybrid systems can offer new possibilities, in particular with regard to applications in mid-rise construction. A hybrid solution is to replace some CFS chord studs with hot-rolled square hollow section SHS, in order to achieve higher capacity. This paper provides the results of experimental studies on the lateral behaviour of a hybrid light-weight steel panel and investigates the implication of any further system improvements for mid-rise construction. Each hybrid wall panel (HWP) consists of a hot-rolled SHS frame, laterally incorporated in a cold-formed panel. The study includes investigating the lateral performance of HWP, while a CFS top chord acting as a load collector, and a hot-rolled steel frame acting as a lateral load resisting system. The behaviour of specimens is investigated under monotonic and cyclic loads, and the step-by-step enhancement is implemented according to the results. The outcomes revealed that although the hysteretic behaviour of the HWP represents pinching effect, mainly due to poor performance of the cold-formed steel collector, by strengthening the top chord design the behaviour is improved. Relying on the cold-formed part to resist the major portion of gravity loads, while the hot-rolled collector transfers the entire lateral load to the hot-rolled frame, results in significantly improved hysteretic behaviour.
Sharafi, P, Rashidi, M, Samali, B, Ronagh, H & Mortazavi, M 2018, 'Identification of Factors and Decision Analysis of the Level of Modularization in Building Construction', Journal of Architectural Engineering, vol. 24, no. 2.View/Download from: Publisher's site
© 2018 American Society of Civil Engineers. In the majority of ordinary housing development projects, instead of using complex multicriteria decision-making systems, companies still rely on expert knowledge, checklists, or similar tools to decide on an appropriate level of modularization. Generally, in these types of projects the level of modularization is mainly driven by site constraints, such as accessibility and harsh weather conditions. Because of the lack of appropriate decision support tools, it is very hard for decision makers to include factors, such as lifecycle costs, quality, productivity, efficiency, and design complexity, into their decision, even if they are willing to do so. Simple decision support tools are required to provide practical assistance to the decision makers to adopt an appropriate level of modularization for such projects. This study, as a part of a broad ongoing research project on the optimum level of modularization in building construction, has compiled the expert knowledge for decision support that enables the decision makers to perform an easy initial feasibility study on the use of an appropriate level of modularization in their construction projects. First, a list of critical decision-making criteria is created. These criteria are obtained from an extensive literature review, qualitative survey questionnaires, and semistructured interviews with researchers and professionals in the construction industry as well as modular manufacturers. Then, using the results, a simple multicriteria decision analysis (MCDA) approach is developed as a practical decision support system to facilitate the decision-making process for selecting appropriate construction systems as well as determining the proper level of modularization for building construction projects. The validation of the study is demonstrated through a local actual case study.
Sharafi, P, Mortazavi, M, Samali, B & Ronagh, H 2018, 'Interlocking system for enhancing the integrity of multi-storey modular buildings', Automation in Construction, vol. 85, pp. 263-272.View/Download from: Publisher's site
© 2017 Maintaining the structural integrity against severe loading conditions and accidental loads is one of the primary concerns when designing multi-storey modular buildings. Connections between the modular units play a central role in providing integrity in modular buildings. This paper describes the development of an innovative interlocking system for improving the integrity of multi-storey modular buildings. The concept of Modular Integrating System (MIS) and the procedure used to develop an efficient interlocking system, which can be widely used in the construction of modular buildings, is investigated. MIS is a patented joining system including a set of interlocking connections and the method of assembly of modular units that provides a high level of integrity that prevents accidental disassembly and stress concentrations at the points of attachments in case of extreme loading occurrence. The creative easy to install, self-fit and self-locking mechanism of this system can also considerably facilitate the automated assembly of modular buildings and provide an effective solution for controlling construction tolerance. The robustness provided by the proposed system is demonstrated through numerical and experimental analysis.
A new lateral force-resisting wall panel is presented for applications in mid-rise prefabricated lightweight steel construction in seismic prone regions. This panelised system is composed of a hot-rolled frame and cold-formed studs and tracks, which works as a lateral force resisting system in lightweight steel framing. The proposed hybrid panel system exhibits proper ductility and energy dissipation behaviour. The hysteretic responses of full-scale panel experiments demonstrate that the system can safely resist high cyclic loads. The hot-rolled steel part, on the other hand, can significantly improve the initial lateral stiffness of the total system that will control the maximum allowable drift of multi-story buildings. Finally, in a case study, by applying the proposed system to the design of a mid-rise building in a high seismic area, the performance of the hybrid panels, are compared with those of fully hot-rolled systems (moment resisting frames) and fully cold formed systems. The findings indicate that applying hybrid panels will result in lower weights and better performance in seismic prone regions.