Modular Building Research Articles

Mechanical performance study of a novel modular gymnasium inner sleeve all-bolt cross connection joint – part Ⅰ: Experiments and finite element modeling

The authors propose a novel movable modular gymnasium based on modular building technology to meet people's sports needs. However, the huge roof load puts higher requirements on the performance of modular units and their connecting joints. In light of this, the authors propose a novel connection joint using the inner sleeve and bolted connections, which connect the upper and lower columns of the modular unit to give it higher performance. In addition, it connects the upper and lower beams of the modular unit by bolts to improve its overall performance. The authors evaluated the mechanical properties of the connecting joints through experiments and simulations. The results indicate that the welding quality determines the beam-oriented bearing capacity of the connections while having little impact on the column-oriented bearing capacity. It is difficult for the inner sleeve to enhance the initial stiffness and beam-oriented bearing capacity of the joints due to the initial gap between the inner sleeve and the modular column. The restraint effect of the stiffening ribs induces the deformation of the inner sleeve, and its bearing capacity increases up to 91%. The inner sleeve improves the column-ward bearing capacity and deformation capacity of the joints, and its bearing capacity rises to 135%.

Seismic performance of self-centring connections with two energy dissipation stages for reusable modular steel buildings

This paper presented a feasibility study on a self-centring connection with two energy dissipation stages for use as a combined inter-module and intra-module connection in reusable modular steel buildings. The proposed connection was equipped with shape memory alloy (SMA) disc washers and friction dampers, the former for self-centring and the latter for energy-dissipation functions. The design concept of two energy dissipation stages was to achieve structural longevity and member reuse by 1) enabling rapid recovery after small and medium earthquakes, and 2) facilitating prompt repair if at all needed after large earthquakes. A spring analytical model was proposed, wherein each connection component was symbolised as a rotational spring. Based on the model, a design methodology to meet the two-stage performance goals was derived, where the critical story drift ratio between the two stages was expressed as a function of the properties of friction dampers and SMA disc washers. Detailed finite element simulations were used to validate the proposed design concept and the spring model and to assess the influence of the friction dampers and SMA disc washers on the hysteresis behaviour of the connection. The results demonstrated that the proposed connection would facilitate the design objectives when designed based on the proposed spring model to ensure structural longevity, member reuse, and efficient recovery and repair after seismic events.

Development of a build volume reduction kit for studying epitaxial re-solidification in laser powder bed fusion

Laser powder bed fusion (PBF-LB/M) is a promising additive manufacturing process that enables the production of complex and high-performance parts. However, the high cost of materials and the need for large quantities of powder in conventional industrial-grade systems pose challenges for experimental materials development and testing activities. This study focuses on the development of a modular build volume reduction kit for an existing EOS EOSINT M-series PBF-LB/M machine. The proposed build volume reduction kit can be customized and adapted for specific research needs, expanding the capabilities of existing infrastructure without significant capital investment. This study describes the design and characterization of the build volume reduction kit and a detachable Pt-heater module, which allows for preheating of the substrate material above 500 °C. The kit’s operation was validated by manufacturing simple cuboid samples using EOS 316L stainless steel powder on a 316L stainless steel substrate. The results demonstrate the feasibility of using the reduction kit for cost-effective experimental investigations, as well as highlighting its potential for studying the epitaxial solidification of PBF-LB/M-built functional materials.

Experimental and numerical simulation study of mechanical properties of inner sleeve T-joint in modular gymnasia

In response to the contradiction between the insufficient number and unreasonable distribution of stadiums in cities and the increasing demand of people for fitness, the authors propose movable modular gymnasiums. This gymnasium takes advantage of the modular building, which can be quickly built, dismantled, and reassembled to fully utilize the temporary empty land in the city to meet the fitness demand of the people. However, the box modules bear a huge roof load, which puts higher demands on the performance of the modular units and their connecting joints. This study proposes a novel joint using an inner sleeve and bolted connections. The proposed connection uses an inner sleeve and bolts to connect the upper and lower columns of the modular unit to give it a higher bearing capacity. Bolts connect the lower unit's ceiling beam and the upper unit's floor beam to provide a better overall performance of the modular unit. The authors conducted experimental studies of 2 full-scale models and 24 finite-element parametric analyses. The results show that the welding quality determines the beam-ward bearing capacity of the joints, while it has little effect on the column-ward bearing capacity. In practical engineering, the authors suggest that the initial stiffness of the joints does not consider the contribution of the inner sleeve. The setting of stiffening ribs forces the inner sleeve to deform and force, improving the joints' mechanical properties, with the initial stiffness in the column direction increase of 25 %, the initial stiffness in the beam direction increase of 31 %, and a bearing capacity in the beam direction increase of 38 %. The design thickness of the inner sleeve and stiffening ribs should be close to the wall thickness of the modular beam and column. The results of this paper contribute to the development of fitness for the whole population and the expansion of the application of modular buildings.

Comparative Analysis of the Acoustic Performances of Modular and Ordinary Classrooms

Since 2016, modular construction system was introduced to Korean school buildings as it gave both of benefits in time and economical gain. Though the modular school buildings are temporarily employed during the period while students were rapidly increasing due to the regional developments, government has a responsibility to maintain the building performance for the education purposes. The purpose of this study is to investigate the classroom acoustic performance of modular school buildings. To this end, room acoustic parameters were measured in classrooms in four modular school buildings. In addition, acoustic parameters including standardized sound insulation levels were measured to analyze the sound insulation performance of walls and floor impact noise performance. At the same time, equivalent acoustic parameters were measured in normal school classrooms for comparative analysis. As a result, it was found that background noise levels of each classroom are satisfactory with the standard of 35 dB(A). Concerning room acoustic performance, modular classrooms were found to have better values than ordinary classrooms. Als, as for the sound insulation of walls and floor, it was found that modular classrooms have better sound insulation performance than the ordinary classrooms beyond the general expectations.

Evaluating the Circular Economy Potential of Modular Construction in Developing Economies—A Life Cycle Assessment

Circular economy (CE) is an emergent concept that promotes resource circularity in multiple product systems. Modular construction (MC), an evolving construction technique, which includes an off-site manufacturing environment, increasingly supports CE strategies such as reuse due to the elevated potential for design for disassembly (DfD). Design-stage environmental assessments are paramount in aiding the early decision making of modular construction projects to successfully plan and implement DfD strategies. Research on synergising modular construction, circular economy and environmental sustainability is rare in developing economies. Thus, the current study aims to conduct a design-stage life cycle assessment of a DfD and linear versions of a modular building unit in Sri Lanka to evaluate the potential environmental benefits. The life cycle assessment results highlight that the DfD strategy has the lowest environmental impacts in all categories, with a 63% reduction in global warming potential and an approximately 90% reduction in terms of human toxicity compared to the linear version. Further, it showed the elevated potential of reuse compared to recycling practices in improving the environmental performance. Sensitivity assessment revealed that steel was the most sensitive to the change in reuse percentage among main building materials. The analysis outcomes highlight the importance of long-term thinking, architectural design creativity and industrial and technology development to uptake the CE-driven MC in the Sri Lankan context. Finally, strategies are proposed to support the CE approach in MC in developing regions. Both quantitative and qualitative outcomes provide a basis for construction industry stakeholders, academia, and policy makers to explore further and promote modular construction practices to enhance the circularity of building materials and components in developing regions.

Effects of module-to-module connection rotational stiffness on the structural performance of high-rise steel modular buildings

With advantages including high productivity and sustainability, modular construction has attracted increasing interest in building project developments. As modular buildings are stepping higher, the modular systems should be better designed to ensure structural safety. In such systems, different types of connections, such as module-to-module (M2M) connections, play an important role in the loading transfer. However, the investigation into the rotational stiffness of the M2M connection was still insufficient in the literature. This paper aims to examine the effects of M2M connection rotational stiffness on the structural performance of high-rise steel modular buildings. A theoretical analysis was conducted on a hypothetic three-storey three-span steel frame to simplistically demonstrate the significant effect of connection rotational stiffness on the internal force distribution of modular buildings. To assess the applicability of preliminary findings in real-life high-rise steel modular buildings, validated numerical models were employed to determine the rotational stiffness of a newly proposed innovative and practical M2M connection. Subsequently, structural models of a 40-storey steel modular building with different M2M connection rotational stiffness values were established to conduct comprehensive investigations. The analysis results indicated that the rotational stiffness of M2M connections plays a critical role in determining the behaviours of critical structural members. The findings provide important references for the design of M2M connection stiffness and structural performance analysis of high-rise steel modular buildings.

TECHNICAL AND ECONOMIC ANALYSIS OF THE SYSTEM LONG-WAVE INFRARED HEATING IN DIFFERENT TYPES OF BUILDINGS

The paper presents the calculation of energy costs for heating buildings with three different heating systems, in order to determine the feasibility of using long-wave radiant heaters. The current rules of energy certification of buildings and related state standards of Ukraine were used as the calculation method. A technical and economic analysis was carried out, thanks to which savings from the transition to a radiant heating system in residential, public and industrial buildings located in the same weather environment were determined. The feasibility of radiant heating systems beyond the usual scope of use, namely in residential buildings, which make up the majority of all heating structures in Ukraine, and small architectural forms, such as, for example, modular buildings of retail establishments, public catering, etc., has been studied and provided. Bilux electric infrared long-wave heaters were chosen as the main research system. Competing systems are a water two-pipe system with free-flowing radiators and electric wall convectors. The key difference between traditional water heating systems, from the point of view of calculating energy consumption, is determined, which is the absence of losses in pipelines. It is justified that radiant heating systems are more appropriate in buildings with a floor height of more than 4 meters. It has been proven that in buildings of smaller volume, the cost reduction is also quite significant.

The Potential Contribution of Modular Volumetric Timber Buildings to Circular Construction: A State-of-the-Art Review Based on Literature and 60 Case Studies

When facing the increasing demands of the housing market and balancing the requirements of sustainable development in the construction sector, building design methods should practise material conservation and adopt carbon reduction measures to alleviate the current environmental burden through the implementation of a circular economy approach. Volumetric modular timber design is recognised as a practical application to test the feasibility of a waste-reduced approach. Driven by the aim of further improving volumetric modular timber construction and increasing its use in a circular economy framework, this paper presents a case study review of 60 modular timber building projects constructed using volumetric modules. The dimensions, the architectural and structural design, and the manufacturing and assembly processes of the three-dimensional modular units were assessed to explore their potential for contributing to a circular built environment. The results show that the similarly sized modular volumetric timber units have the potential to serve different functions, and to be reused in subsequent projects. The stacking design allows modular volumetric units to be reused in a way that supports function conversion and satisfies project coordination criteria. The case studies illustrate that modular timber buildings are increasingly used for flexible design solutions, and to meet carbon emission reduction targets. The analysis results can address prevalent misconceptions regarding modular wood construction, provide interested parties with a better understanding, and promote the use of modular volumetric timber units in general.

Developing a systematic performance measurement framework for benchmarking steel modular building construction

PurposeModular construction is an innovative method that enhances the performance of building construction projects. However, the performance of steel modular construction has not been systematically understood, and the existing measurement methods exhibit limitations in effectively addressing the features of steel modular building construction. Therefore, this study aims to develop a new performance measurement framework for systematically examining the performance of steel modular construction in building projects.Design/methodology/approachThis study was conducted through a mixed-method research design that combines a comprehensive review of the state-of-the-art practices of construction performance measurement and a case study with a 17-story steel modular apartment building project in Hong Kong. The case project was measured with data collected from the project teams and other reliable channels, and the measurement practices and findings were referenced to establish a systematic performance measurement framework for steel modular construction.FindingsConsidering steel modular construction as a complex socio-technical system, a systematic performance measurement framework was developed, which considers the features of steel modular construction, focuses on the construction stage, incorporates the views of various stakeholders, integrates generic and specific key performance indicators and provides a benchmarking process. Multifaceted benefits of adopting steel modular construction were demonstrated with case study, including improved economic efficiency (e.g. nearly 10% cost savings), improved environmental friendliness (e.g. approximately 90% waste reduction) and enhanced social welfare (e.g. over 60% delivery trips reduction).Originality/valueThis paper extends the existing performance measurement methods with a new framework proposed and offers experience for future steel modular construction. The measured performance of the case project also contributes in-depth understanding on steel modular construction with benefits demonstrated. The study is expected to accelerate an effective uptake of steel modular construction in building projects.

Thermal storage characteristics of microencapsulated phase change material coatings in low-energy rural prefabricated building walls

ABSTRACT Prefabricated buildings in rural areas of China waste a large amount of energy due to poor thermal insulation. Phase change materials (PCMs) are able to stabilize room temperature by latent heat absorption and release during the phase change process. This study incorporated PCMs in the form of microcapsules into the interior wall coatings of prefabricated buildings, and by taking advantage of PCMs’ energy storage capacity, the thermal storage characteristics of PCM-coated bricks were investigated. The results show that microencapsulated phase change material(MPCM) coatings for prefabricated walls exhibit excellent thermal stability properties and effectively reduce the heat flux of prefabricated walls, with coatings having a MPCM mass fraction of 15% and a thickness of 5 mm providing the highest overall benefits. By fitting the numerical simulation results with experimental data, a novel multifunctional passive solar phase change heat collection and storage wall system was developed. This study innovatively combines energy storage materials with interior wall coatings in prefabricated walls of modular buildings investigating how it enhances the thermal stability of the external insulation walls and effectively reduces the reliance on heating equipment for auxiliary heating in rural residences. This essay aims to provide feasible recommendations for optimizing the dual-stage energy-saving and carbon reduction goals in both the construction and operation of rural areas.

Data-driven integration framework for four-dimensional building information modeling simulation in modular construction: a case study approach

Abstract Modular construction is becoming more popular because of its efficiency, cost-saving, and environmental benefits, but its successful implementation necessitates detailed planning, scheduling, and coordination. Building information modeling (BIM) and four-dimensional (4D) simulation techniques have emerged as invaluable tools for visualizing and analyzing the construction process in order to meet these requirements. However, integrating distinctive data sources and developing comprehensive 4D BIM simulations tailored to modular construction projects present significant challenges. Case studies are used in this paper to define precise data needs and to design a robust data integration framework for improving 4D BIM simulations in modular construction. The validation of the framework in a real-world project demonstrates its efficacy in integrating data, promoting cooperation, detecting risks, and supporting informed decision-making, ultimately enhancing modular building results through more realistic simulations. By solving data integration difficulties, this research provides useful insights for industry practitioners and researchers, enabling informed decision-making and optimization of modular building projects.

Heat Transfer Analysis of Full-Scale Safe Rooms Exposed to Bushfire Conditions

Sheltering in place is identified as an accepted behaviour during disasters while safe rooms are purpose-built buildings used for sheltering or storage of valuables under these circumstances. However, ensuring the integrity of safe rooms in bushfires is complex and challenging due to many factors. This study aims to advance the understanding of the bushfire fire heat transfer in steel framed bushfire safe rooms using a numerical modelling approach. Both small-scale models of individual external walls and full-scale models of safe rooms were developed and validated using the results of an experimental study of a full-scale safe room. Then the study was extended to address the identified challenges in the design of safe rooms influenced by the factors such as, the fire exposed area, internal compartment arrangement, location of the safe room in the bushfire-prone areas, and the external environmental temperatures during summer on the tenability requirements. The results of this study provide considerable details of the performance of above-ground bushfire safe rooms detached from the associated dwelling under realistic fire conditions. They showed that the integrity of the doors is very important and that having multiple internal compartments is favourable for the bushfire performance of safe rooms. This study shows that safe rooms can be constructed using available building materials to satisfy the bushfire heat transfer requirements and provides conditions for their usage. Furthermore, the modelling methods emphasise their applicability to evaluate safe rooms and modular buildings in bushfire and building fire related scenarios.

FaÇade system design process on the basis of energy simulation tools

The façade is not only the outer layer of a building that brings aesthetic beauty to the structure but also serves the function of regulating temperature, natural lighting, and ventilation for the building. Belonging to the group of passive design solutions aimed at achieving energy efficiency for the building, optimizing façade design has increasingly garnered attention and investment of time and resources from investors and architects alike. With the aid of building energy simulation tools based on heat exchange calculations and Computational Fluid Dynamics (CFD) modeling, the authors have developed a process to optimize façade systems based on parameters such as position, orientation, ventilation area, and materials. This calculation process will serve as a valuable tool for architects in implementing their design ideas, helping achieve optimal results in terms of aesthetics and energy savings for the building. The paper presents the calculation process and its application to a two-story wooden modular building at the Institute of Building Science and Technology.

The role of LCA in the renovation’s early decision-making for the design of a multifunctional, modular building envelope system

The renovation of buildings has a high capacity to influence the environmental impacts and global objectives of climate change mitigation. In the context of designing low-energy buildings with minimized environmental impacts, the life cycle assessment (LCA) has been proven a straightforward method, to evaluate the direct and indirect environmental impacts of a building concept. Even though it is the most energy-intensive element, the use phase is not only a source of environmental concern but also the whole life cycle of the building and its components. However, energy-efficient renovation decisions tend to be financially motivated events, subject to exogenous constraints or barriers, that do not integrate whole life cycle thinking. This study aims to identify how the LCA information can be considered in comparing renovation options. compare renovation options, taking into account the modular envelope system developed as part of the European research project ENSNARE (ENvelope meSh aNd digitAl framework for building Renovation) case study. The study analysed different renovation scenarios, generated according to combinations of renewable energy sources and compare them to the base case and typical renovation scenario. Such information can support the design team in making decisions that consider the whole building and its components’ life cycles.

An edge-weighted graph triumvirate to represent modular building layouts

Representing building layouts as graphs can extract critical design patterns that would facilitate space syntax analyses as well as design mining and automation but traditional approaches (e.g., non-weighted adjacent graphs) encountered problems in modular buildings, as they are largely shaped under the principle of ‘modularity’ rather than freeform cast in-situ elements. This paper attempts to develop a novel analytical tool called ModularGraph to represent modular building layouts (MBLs) as graphs considering their unique adjacency, connectivity, and conjoint relationships in a triumvirate. It does so by developing a prototype then applying it to 36 modular buildings for iteration, finetuning, and finalizing. It is found that ModularGraph can effectively translate heterogeneous forms of MBLs into unified graph-based representations with rich graphic and semantic information. This study not only contributes an innovative graph analytic tool for design pattern mining, but also lays a stepping stone towards generative AI for modular building design.

Research on steel structure system of assembled building and its mechanical performance analysis

Abstract In this paper, the steel structure system of the assembled building is studied, the box modular building stiffness matrix reduction is proposed, and the calculation method of nodal stiffness matrix reduction is proposed based on the concept of nodal degrees of freedom coalescence and substructure to make full use of the repeatability of the box unit to reduce the order of the matrix equilibrium equation. Then, an engineering profile and a comparison of the calculation results of reaction spectrum analysis are carried out for the assembled steel structure system, and studies on the distribution of overturning moments between the frame and core and the distribution of shear forces between the core and the frame are carried out. Lastly, the assembled steel structure system is examined for damage analysis. The results show that the total overturning moment between the box-type modular structure and the conventional structure differs by 5979.6 kN·m and 2.67% in the X-direction and by 4694 kN·m and 2.18% in the Y-direction. The quality and safety of construction projects can be guaranteed more reliably with the help of this study.

Client-engaged collaborative pre-design framework for modular housing

Although modular construction benefits from standardized and repeatable modules, clients for housing projects seek tailor-made designs, making mass customization necessary. However, challenges persist in promptly identifying and satisfying these unique client needs during the early design phase, despite previous research efforts to address this limitation. This paper introduces the Client-engaged Modular Housing Platform (CEMHP), a collaborative design framework for the early phase of modular housing projects that supports the capture of client requirements, their analysis, the creation of visual content, and the reception of feedback from clients in an integrated manner. The results indicate that CEMHP enhances client decision-making, improves collaboration, and reduces unnecessary repetition. However, further data collection from clients and the enhancement of an algorithm for recommending suitable design samples based on this data remain necessary.

Suitability of Modular Technology for House Construction in Sri Lanka: A Survey and a Case Study

Prefabricated volumetric modular building construction is an emerging technology in many countries used to develop the construction industry through its value-added benefits. The adoption of these novel technologies in the Sri Lankan construction industry has been relatively slow compared with other developing countries, delaying the development of the construction industry and the attainment of the added benefits of these technologies. Therefore, this study aims to identify the suitability of modular construction for the Sri Lankan construction industry via a survey and case study. A questionnaire survey was developed and distributed to assess and identify the benefits of implementing the concepts and constraints in Sri Lanka. Then, the construction cost of a proposed single-story house delivered through conventional and modular practices was compared. The survey results showed that introducing a modular concept to the industry is suitable and would benefit the Sri Lankan construction industry. Further, survey participants believed that the economic benefits brought in by modular construction are significantly more important than environmental and social benefits when selecting modular construction. The case study on a single-story affordable modular house showed a 32% reduction in total construction costs and a 36% reduction in labour costs compared to conventional house construction. Further, costs for total modular construction and labour were 32% and 36% less than those of conventional construction costs and labour costs. Moreover, a 16% reduction in embodied energy was observed when compared with conventional construction. Therefore, the modular concept could be used to construct affordable houses and will be cost-effective with the correct choice of material.

Experimental study on effect of assembly process on seismic performance of modular precast composite shear wall structures

Modular buildings utilize prefabricated volumetric modules to resist gravity and lateral loads and can achieve a high prefabrication level. Different from cast-on-site reinforced concrete structures, the seismic performance of precast structures is affected by the construction process. This study investigated the effect of assembly process on the seismic performance of an innovative modular precast composite shear wall structure. Contrastive shaking table tests were carried out on two 1/4-scaled modular models, one by the fully modular precast method and the other by the modular cast-on-site method. Test results showed that the bottom vertical joints were the most critical components and dominated the failure patterns for both modular models. The weakening of screw threads induced by the small model size and assembly process decreased the ultimate capacity of the modular precast model. The modular precast model showed up to a 6.7 % lower initial frequency and 17.6 % lower initial damping ratio than the modular cast-on-site model. The assembly process had no essential influence on the displacement and acceleration responses before vertical joint failure but significantly increased the displacements as the joints approached failure in the limit state. The test work highlights the importance of ensuring bolt strength and protecting bolt threads in practical engineering applications.