Modular Building Research Articles

Research on seismic behavior of tapered-head bolted inter-module connection of modular steel buildings

Modular steel buildings (MSBs), which comprise prefabricated modular units, are a new type of assembled buildings. The inter-module connection of MSBs plays an important role in the connection between modular units and structural safety. At present, several types of inter-module connections are in use, such as welded, bolted, prestressed, or self-locking. However, they present problems such as poor welding quality, low construction efficiency and no operation space for the internal connection. To solve these problems, this study proposes an innovative tapered-head bolted inter-module connection. Cyclic tests were conducted considering three different parameters: the modular beam section form, axial compression ratio, and thickness of the modular floor beam. Seismic behavior indicators such as stiffness degradation and energy dissipation of the specimens were investigated. Subsequently, a refined finite element model (FEM) was established to verify the corresponding test results. Finally, based on test fitting and nonlinear regression analysis, a restoring force model of the tapered-head bolted connection was established. The results indicated that the calculated ratios of the restoring force model to test results were within 0.07 on the yield, maximum, and failure points and the coefficient of variation (COV) was 0.03, with high accuracy and application. This research provides a reference to some extent for designing MSBs.

Multi-objective Optimization Design of Low-carbon Modular Building

In recently architectural research, there is a well-documented emphasis on energy-saving design optimization. However, there is a conspicuous deficiency in studies that address multi-objective optimization related to the long-term carbon emissions associated with building lifecycles. In this study, modular buildings in construction sites are taken as the research object, and box-type rooms are taken as the prototypical model. A set of multi-objective optimization methods for architectural design is established by series modeling tools, building performance simulation tools and NSGA-II non-dominated sorting genetic algorithm tools, combined with Python programming tools. This method is to optimize the reduction of carbon emissions, energy consumption and costs throughout the life cycle. The purpose of this investigation is to establish a methodology for assessing and optimizing architectural designs with a primary focus on carbon emissions during the design phase. The goal is to provide architects with practical insights to enhance their designs while simultaneously achieving intelligent, eco-friendly buildings.

CROSS Safety Report: MMC and robustness

This month we present a report relating to the design of a low-rise modular building and the requirement, or otherwise, for positive fixings between the superstructure and the substructure.

Pull-out performance of grouting sleeve connection with short studs shear keys in modular steel building

In this paper, a new type of grouting sleeve connection joint with short studs shear key is proposed for the connection of high-rise modular steel structures. To study the tensile properties of the grouting connection in the modular structure, seven groups of 21 specimens were tested by push-out test. The results show that: (1) The axial bearing capacity of the specimen with a diameter of 16 mm studs is between 3549.2 kN and 3922.4 kN, and the anchorage strength is between 15.07 MPa and 16.66 MPa; (2) The bearing capacity of the connection consists of four parts, including the shear capacity of the studs, the shear capacity of the studs weld collar, the friction and bonding force of the interface. The shear capacity of the stud provides about 65 % of the bearing capacity; (3) The ultimate displacement ranges from 4.69 mm to 6.93 mm, and the ductility coefficient is 2.42–3.05. Then, combined with the test and simulation, the force mechanism of the connection is analyzed, and the design suggestion and the calculation method of the bearing capacity of the connections are put forward. Compared with the existing grouting connection joints, the bond strength of the connection proposed in this paper is 26.7 % higher, showing stronger pull-out resistance.

Evaluation of human-induced vibration in floors of modular hospitals

Construction of modular hospitals has gained significant attention since the global pandemic. One important design requirement for hospitals that is critical for their safe operation is to control floor vibration. Floors in modular buildings are often more prone to vibration because they are lightweight and less restrained. This study first presents a standardized design layout for modular hospitals developed based on Canadian code requirements. Then, the human-induced vibration of various floor systems designed for this sample modular hospital is investigated using different analysis methods including a new method developed by the authors. It is found that conventional floor designs may not be suitable for modular hospitals considering the strict vibration limits for hospitals and the need for lightweight construction. Using detailed finite element analysis, it is shown that the proposed method can accurately predict the vibration response of various floors including those that have frequencies well beyond the application range of existing design methods.

Nonreciprocal vibration transmission using dislocated displacement feedback

This paper examines absolute displacement feedback using dislocated sensor-actuator pairs to design and implement an active metamaterial cell for nonreciprocal vibration transmission. Comprehensive stability and performance analyses are carried out, both theoretically and experimentally. The theoretical analysis yields a simple condition on parameters of the example two-degree-of-freedom metamaterial cell to guarantee the stability. If the condition is respected, very large feedback gains can be implemented so that the difference in vibration transmission in the two opposite directions may be substantial. This is confirmed experimentally: the nonreciprocity measured in terms of the amplitudes of two characteristic transfer mobilities of the cell amounts to about 30 dB in the frequency range between 30 and 1000 Hz. As shown in the Appendix to the paper, the cell could be used as a prefabricated and pre-tuned modular building block to form a functional active metamaterial for nonreciprocal vibration transmission.

Intelligent floor plan design of modular high-rise residential building based on graph-constrained generative adversarial networks

In the context of Modular High-Rise Residential Buildings (MHRBs), designing floor plans involves intricate complexities due to the need for adherence to numerous domain-specific design rules. To address this issue, our research introduces a novel framework based on a Graph-Constrained Generative Adversarial Network (GC-GAN) specialized for generating MHRB floor plans. This enhanced GC-GAN incorporates knowledge graphs that encapsulate domain-specific constraints and guidelines, thereby generating floor plans that exhibit realism, diversity, and conformity to established design principles. Additionally, the framework integrates a sophisticated image-to-vector conversion algorithm that enables seamless alignment with a predefined flat-design standardization library. A salient feature of this framework is the automated generation of Building Information Modeling (BIM) models, which rigorously conform to the modularity specifications essential for efficient modular construction. The efficacy and practical applicability of our approach have been validated through an exhaustive analysis covering fifteen cases across five diverse scenarios.

Robustness of Corner-Supported Modular Steel Buildings with Core Walls

This paper studies the dynamic response of corner-supported modular steel buildings with a core wall system, under progressive collapse scenarios, associated with corner module removals. Since using secondary systems such as concrete core in mid- to high-rise buildings is currently unavoidable, understanding their impact on load transfer between modules during collapse scenarios becomes essential. The designated four-, eight-, and twelve-story buildings were modelled using the macro-model-based finite element method in Abaqus. In addition, three different locations are considered for the concrete shear core within the building plan, leading to nine various case scenarios. Each vertical and horizontal inter-module connection was modelled by one axial and two shear springs with predefined nonlinear force-displacement behavior. The local and global buckling, which plays an essential role in the building’s stability, was considered to obtain accurate results. Finally, parametric studies on the building response were carried out, including the intra-module connection rigidity and inter-module connection stiffness. The results demonstrated that the core wall could maintain the robustness of a modular steel building through two mechanisms dependent on its location within the plan. In addition, preventing plastic hinges from forming in beams could be introduced as an anti-collapse mechanism in the corner module removal scenarios.

Integrated Value Model for Sustainable Assessment of Modular Residential Towers: Case Study: Ten Degrees Croydon and Apex House in London

Modular construction can become sustainable by making all aspects of the design and construction process more effective during all phases. This paper aims to develop and use a sustainability assessment model for modular residential buildings in two case studies. This research uses the Integrated Value Model for Sustainable Assessment (MIVES), which is a multi-criteria decision-making model for sustainability assessment. This model considers all aspects of sustainability, environmental, economic and social, and helps stakeholders make decisions. Few previous studies have assessed all these aspects in full and MIVES make this assessment possible. For assessment purposes, two modular buildings have been chosen, namely “Ten Degrees Croydon” as the tallest high-rise modular residential building in the world and “Apex House” as the second tallest modular building in the world, both in London. These residential towers were assessed using MIVES, demonstrating a very satisfactory sustainability index in all the above aspects.

Strategies for connecting whole-building LCA to the low-carbon design process

Decarbonization is essential to meeting urgent climate goals. With the building sector in the United States accounting for 35% of total U.S. carbon emissions, reducing environmental impacts within the built environment is critical. Whole-building life cycle analysis (WBLCA) quantifies the impacts of a building throughout its life cycle. Despite being a powerful tool, WBLCA is not standard practice in the integrated design process. When WBLCA is used, it is typically either speculative and based on early design information or conducted only after design completion as an accounting measure, with virtually no opportunity to impact the actual design. This work proposes a workflow for fully incorporating WBLCA into the building design process in an iterative, recursive manner, where design decisions impact the WBLCA, which in turn informs future design decisions. We use the example of a negative-operational carbon modular building seeking negative upfront embodied carbon using bio-based materials for carbon sequestration as a case study for demonstrating the utility of the framework. Key contributions of this work include a framework of computational processes for conducting iterative WBLCA, using a combination of an existing building WBLCA tool (Tally) within the building information modeling superstructure (Revit) and a custom script (in R) for materials, life cycle stages, and workflows not available in the WBLCA tool. Additionally, we provide strategies for harmonizing the environmental impacts of novel materials or processes from various life cycle inventory sources with materials or processes in existing building WBLCA tool repositories. These strategies are useful for those involved in building design with an interest in reducing their environmental impact. For example, this framework would be useful for researchers who are conducting WBLCAs on projects that include new or unusual materials and for design teams who want to integrate WBLCA more fully into their design process in order to ensure the building materials are consciously chosen to advance climate goals, while still ensuring best performance by traditional measures.

Seismic behavior of a novel liftable connection for modular steel buildings: Experimental and numerical studies

Modular steel buildings (MSBs) have achieved considerable popularity in multi-to-high rise constructions due to the favorable mechanical characteristic, eco-friendliness, cost-effectiveness, and enhanced construction efficiency. As the critical part of MSBs, the inter-module connection has an important influence on determining the seismic performance of MSBs. This study presented an experimental-numerical investigation on an innovative fully prefabricated liftable connection (FPLC) for MSBs. To study the seismic performance of the FPLC, quasi-static tests were conducted on four full-scale specimens. The seismic behavior of the specimens, including failure mode, hysteretic response, strength and stiffness degradation, deformation characteristic, etc. was evaluated and compared in detail. The effect of the section of the twin-beams, the dog-bone weakening of the beam and the connecting method between the corner fitting and twin-beams on the seismic behavior of the FPLC was revealed. Moreover, the feasibility for seismic application of the FPLC was evaluated according to Chinese code GB 50,011–2010 and Eurocode 3 Part 1–8. The results indicated that the proposed FPLC met the limit of elastic and elastic-plastic inter-story drift ratios required by GB 50,011–2010. According to Eurocode 3 Part 1–8, the FPLC with welded beams should be classified as “semi-rigid” connections, while the FPLC, whose beams were connected to the column walls by the steel angles and bolts, was classified as a “pinned” connection. Then, a refined finite element model (FEM) was developed and verified by the test results. Furthermore, the verified FEM was utilized to analyze the distribution of the equivalent plastic strain, the stress variation path, and the yielding area of the twin-beams to further reveal the energy dissipation and damage mechanism of the FPLC. Finally, a simplified FEM was established and the comparison with the test results proved its reliability and efficiency. The present study will contribute to provide a comprehensive understanding on seismic performance and design of the inter-module connection for MSBs.

MULTICELLULAR SPHEROID ENGINEERING USING BIOINSPIRED MATERIALS FOR OSTEOCHONDRAL TISSUE REGENERATION

Recently, technologies to culture one or more cell types in three dimensions have attracted a great deal of attention in tissue engineering. Particularly, the improved viability, self-renewal capacity, and differentiation potential have been reported for stem cell spheroids. However, it is crucial to modulate spheroid functions with instructive signals to use multi-cellular spheroids in tissue engineering. We have been developing ECM-mimicking fibrous materials decorated with cell-instructive cues, which were incorporated within 3D stem cell spheroids to fine-tune their functions as modular building blocks for bottom-up tissue-engineering applications. In particular, we created composite spheroids of human adipose-derived stem cells (hADSCs) incorporating nanofibers coated with instructive signal of either transforming growth factor-β3 or bone morphogenetic growth factor-2 for chondrogenesis or osteogenesis of stem cells, respectively. The bilayer structure of osteochondral tissue was subsequently mimicked by cultivating each type of spheroid inside 3D-printed construct. The in vitro chondrogenic or osteogenic differentiation of hADSCs within the biphasic construct under general media was locally regulated by each inductive component. More importantly, hADSCs from each spheroid proliferated and sprouted to form the integrated tissue with interface of bone and cartilage tissue. This approach may be applied to engineer complex tissue with hierarchically organized structure.

Failure mechanisms of hexagonal-shaped intra-module connections in modular steel building

Modular construction has gained popularity for its cost-effectiveness, time savings, and environmental benefits. This research delves into innovating modular buildings to enhance their aesthetic value in contemporary architectural designs. Traditional rectangular modules have lost architectural significance in the modern era. The study focuses on the failure mechanisms of hexagonal intra-module connections under nonlinear static analysis, aiming for advanced structural design and performance in modular construction. The study tested a control model, a Welded Flange Bolted Web (WFBW) connection, and three variations with different parameters: boundary condition, bolt arrangement, and steel grade. For the boundary condition, the tie constraint between the beam's flanges and the diaphragm was removed. Bolt arrangement was assessed with staggered and non-staggered bolts. Steel grade variations included S275 and S355. Results showed that the WFBW connection outperformed the Bolted Web (BW) connection in load resistance. The most damaged component was the beam, with bearing failure at the upper bolt hole. Non-staggered bolts exhibited larger displacements than staggered bolts. The study emphasized the significance of steel material strength in terms of stress and strain on bolt capacity. It highlights the importance of intra-module connections in modular steel structures and the need to consider design parameters carefully. The findings offer insights into improving modular connections' performance and failure mechanisms, facilitating the creation of aesthetically pleasing and structurally sound modular structures. This nonlinear static analysis aids in developing advanced modular construction designs, enhancing architectural significance in the modern era. By merging structural performance and aesthetics, the study promotes innovative modular construction to meet contemporary architectural demands.

PerQueue: managing complex and dynamic workflows.

Workflow managers play a critical role in the efficient planning and execution of complex workloads. A handful of these already exist within the world of computational materials discovery, but their dynamic capabilities are somewhat lacking. The PerQueue workflow manager is the answer to this need. By utilizing modular and dynamic building blocks to define a workflow explicitly before starting, PerQueue can give a better overview of the workflow while allowing full flexibility and high dynamism. To exemplify its usage, we present four use cases at different scales within computational materials discovery. These encapsulate high-throughput screening with Density Functional Theory, using active learning to train a Machine-Learning Interatomic Potential with Molecular Dynamics and reusing this potential for kinetic Monte Carlo simulations of extended systems. Lastly, it is used for an active-learning-accelerated image segmentation procedure with a human-in-the-loop.

Magnetic Levitation Remote Control Laboratory Based on Matlab and Websockets

This work proposes a novel architecture for constructing remote laboratories, employing modular building blocks: Matlab/Simulink software for control system design and simulation, WebSocket communication technology for continuous data exchange, and a front-end application developed using the Angular framework. To facilitate WebSocket communication on the Matlab server side, the MatlabWebSocket library is implemented. Beyond the Angular framework, interactivity within the remote laboratory is further enhanced through 3D visualization of the controlled system using a Three.js based library.These combined technologies are applied in the development of a remote laboratory for a fast, unstable, and nonlinear magnetic levitation system. The laboratory allows users to remotely set desired values and control parameters for experiments, while also providing continuous data visualization in various forms, including numerical readouts, graphs, and 3D animations. This approach demonstrates the effectiveness of the proposed architecture for building remote laboratories for complex systems.

The Obstacles to Promoting the Modular Building Project: A Tentative Assessment of the Literature

The Obstacles to Promoting the Modular Building Project: A Tentative Assessment of the Literature

Resilience and Performance of Prefabricated Modular Buildings Against Natural Disasters

Earliest global movement towards modular construction originated as a solution to the sudden housing demand which occurred during events such as British colonization, the California gold rush, the world wars and post war settlement. Present day, modular construction is explored by researchers aiming to maximize from the benefits of Industry 4.0 technology. Buildings of the 21st century frequently face natural disasters such as earthquakes, pandemics, floods, cyclones, and bushfires. This review is developed around recent episodes such as the Covid-19 pandemic which demands design resilience and the intraplate earthquake of Australia, which stresses on the necessity of improved structural performance of modular buildings. To understand the performance of modular buildings against natural disasters, this paper critically reviews recent developments in modular construction research and applications. Through the extensive analysis of literature, this paper identifies future research domains of modular construction that are required to confront natural disasters. The outcomes of this review facilitate timely and sustainable research directives towards resilient modular buildings.

Bearing capacity of a steel frame of a multi-storey modular building with consideration of the rigidity of quick-assembled connections

The article is devoted to the analysis of calculation and design problems and features that arise when designing multi-storey modular buildings with a steel frame. The article describes the main features of the classification and trends in the construction of volumetric block buildings in Russia and the world.
 The object of the study is quick-assembly connections of compressed-bent load-bearing elements of frame modular systems.
 The main purpose of the study is to obtain reliable analytical and theoretical data to determine the characteristics of the rotational stiffness of module connection nodes and assess its influence on the stress-strain state of the frame and its elements.
 Within the work, the concept of an experimental modular building was developed using I-beam columns as part of the frame, as well as inter-module joints for their connection. Flange connections with high-strength bolts without controlled tightening are considered as the main design solution for the inter-module connections. The designed connections include inspection windows to access the hardware.
 A numerical study was performed to evaluate the bearing capacity and stiffness of the connections. The influence of the stiffness on the behavior of the frame in relation to two groups of limit states was assessed using the finite element method.
 The paper substantiates the relevance of using I-beam profiles as columns of the frame of a modular building, which is not a common solution in modern practice.
 The developed concept of quick-assembly inter-module flange connections makes it possible to ensure the safety of the building while reducing the time and labor costs for its installation.

Investigation of thermal and air efficiency in trombe wall of modular building

Investigation of thermal and air efficiency in trombe wall of modular building

Applying shape grammar and BIM for generating the mass modular housing design in ShanLiChenJia village, ZhaoYuan, China

ABSTRACTThis paper proposes a method for floor plan designs that combines shape grammar with Building Information Modeling (BIM) technology to create plan module libraries by using the mass modular housing project in ShanLiChenJia village as an example. The modular building is composed of several component modules, and shape grammar can manipulate their graphics and functions to enrich the combination relationship between component modules. The rule-making of the combination process can code the size relationship that affects the module form by adding space and size constraints. In the rule system of shape grammar, geometric dimensions, and functional attributes are first embedded in the shape graph. Then, the mapping relationship is established between the shape graph and the attributes of the modules. Finally, the BIM platform can establish the module library using Autodesk Revit. In addition, a spatial relationship in the scheme is selected in Revit software for generative experiments, which confirms the feasibility of shape grammar in generative design and spatial diversity of modular buildings.