No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
A novel framework for set-based steel connection design automation
Abstract
Existing computational design tools for steel connection design predominantly employ a point-based design (PBD) approach, which requires iterative re-evaluation whenever there are changes in design specifications. This paper introduces a new framework that adopts a set-based design (SBD) approach, aiming to substantially reduce the iteration and time cost associated with steel connection design and rework. The framework integrates a component-set connection design model with a database storage and query-based data retrieval method. The first method enables the flexible and efficient generation of a large connection design space from all possible component combinations, and automated identification of valid connection configurations within it. The latter method allows for automated design space refinement from preference-based evaluation of connection design efficiency and high-speed comparison and selection of optimal connection designs. To evaluate the relative performance of SBD and PBD approaches, the framework is applied to a steel floor system design case study with 62 connections. Results showed that the SBD approach achieved near-instantaneous connection design automation, with a total execution time of fewer than 55 milliseconds, making it over 10 times faster than the corresponding PBD approach.
ResearchGate has not been able to resolve any citations for this publication.
The demand for more sustainable structures has been shown as a growing tendency, and engineers can use optimization techniques to aid in the design and sizing stage, achieving solutions that minimize its cost and environmental and social impacts. In pedestrian bridges, which are subjected to human-induced vibrations, it is also important to ensure the users' comfort, besides the security verifications. In this context, the objective of this paper is to perform a multi-objective optimization of a steel-concrete composite pedestrian bridge, minimizing cost, carbon dioxide emissions , and vertical acceleration caused by human walking. For this, the Multi-Objective Harmony Search (MOHS) was applied to obtain non-dominated solutions and compose a Pareto Front. Two scenarios were considered with different unit emissions obtained from a life cycle assessment in the literature. Results show that by increasing 15% the structure cost, the vertical acceleration is reduced from 2.5 to 1.0 m/s 2. For both scenarios, the optimal ratio for the web height and total span (L e) lies between L e /20 and L e /16. The web height, the concrete strength, and the slab thickness were the design variables with more influence on the value of the vertical acceleration. The Pareto-optimal solutions were considerably sensitive to the parameters varied in each scenario, changing concrete consumption and dimensions of the welded steel I-beam, evidencing the importance of carrying out a sensitivity analysis in optimization problems.
With decades of research, semi-rigid beam-to-column connections have been widely accepted. However, most studies have been restricted to the local connection level, leaving system-oriented analysis and design methods with a meager investigation, which leads to the fact that the active use of semi-rigid connections in practice is rare. This study aims to provide a system-level design method to bridge the gap between element and connection design, and the two main contributions are to propose a method for designing semi-rigid steel frames by pre-establishing a performance-based connection database and to formulate refined classification criteria for connection performance levels. In this method, the frame design is transformed into finding an appropriate matching of performance requirements between elements and connections. The classification criteria for connection performance levels are based on the assumption that the structural responses (stability, resistance, and deformation) are only slightly affected by the properties of connections within the same level. The emphasis is on the rotational stiffness and moment resistance of the connection. Finally, the results of examples indicate that the connection database is portable and can be applied to various frames, avoiding the repetitive design for connections in different projects. In addition, tuning the performance requirements of the connection can greatly reduce the number of design variables compared to tuning its geometry, and more importantly, it provides designers with a clearer update path, which can significantly shorten the process of trial-and-error and quickly arrive at the final design.
The Parametric FEM Toolbox is a plug‐in for the visual programming environment Grasshopper which implements the RF‐COM API of the Dlubal RFEM finite element software to establish a connection between these two platforms. Both the transfer of data from Grasshopper into RFEM and back from RFEM into Grasshopper are supported. Thus, new possibilities are enabled beyond the options of the conventional graphical user interface (GUI) of RFEM: the use of the Rhino 3D modelling tools to create NURBS curves and surfaces; the possibility of the parametric modification of an existing FE model or part of it; the export and processing of FE model data, which sometimes is not even available through the program GUI, e.g. 3D shapes of beam elements; etc. With these functionalities, the object‐oriented structure and compact GUI, this tool can easily be adapted to numerous workflows and optimization processes. This paper explores which possibilities exist for implementing a commercial FEM software in a parametric design platform. Existing approaches are reviewed, the development of the Parametric FEM Toolbox is described and some of the possible workflows with this new tool are explored through a collection of real‐world case studies.
The data-oriented paradigm has proven to be fundamental for the technological transformation process that characterizes Industry 4.0 (I4.0) so that big data and analytics is considered a technological pillar of this process. The goal of I4.0 is the implementation of the so-called Smart Factory, characterized by Intelligent Manufacturing Systems (IMS) that overcome traditional manufacturing systems in terms of efficiency, flexibility, level of integration, digitalization, and intelligence. The literature reports a series of system architecture proposals for IMS, which are primarily data driven. Many of these proposals treat data storage solutions as mere entities that support the architecture’s functionalities. However, choosing which logical data model to use can significantly affect the performance of the IMS. This work identifies the advantages and disadvantages of relational (SQL) and non-relational (NoSQL) data models for I4.0, considering the nature of the data in this process. The characterization of data in the context of I4.0 is based on the five dimensions of big data and a standardized format for representing information of assets in the virtual world, the Asset Administration Shell. This work allows identifying appropriate transactional properties and logical data models according to the volume, variety, velocity, veracity, and value of the data. In this way, it is possible to describe the suitability of relational and NoSQL databases for different scenarios within I4.0.
In the current context of Big Data, a multitude of new NoSQL solutions for storing, managing, and extracting information and patterns from semi-structured data have been proposed and implemented. These solutions were developed to relieve the issue of rigid data structures present in relational databases, by introducing semi-structured and flexible schema design. As current data generated by different sources and devices, especially from IoT sensors and actuators, use either XML or JSON format, depending on the application, database technologies that store and query semi-structured data in XML format are needed. Thus, Native XML Databases, which were initially designed to manipulate XML data using standardized querying languages, i.e., XQuery and XPath, were rebranded as NoSQL Document-Oriented Databases Systems. Currently, the majority of these solutions have been replaced with the more modern JSON based Database Management Systems. However, we believe that XML-based solutions can still deliver performance in executing complex queries on heterogeneous collections. Unfortunately nowadays, research lacks a clear comparison of the scalability and performance for database technologies that store and query documents in XML versus the more modern JSON format. Moreover, to the best of our knowledge, there are no Big Data-compliant benchmarks for such database technologies. In this paper, we present a comparison for selected Document-Oriented Database Systems that either use the XML format to encode documents, i.e., BaseX, eXist-db, and Sedna, or the JSON format, i.e., MongoDB, CouchDB, and Couchbase. To underline the performance differences we also propose a benchmark that uses a heterogeneous complex schema on a large DBLP corpus.
The planning and design of buildings and civil engineering concrete structures constitutes a complex problem subject to constraints, for instance, limit state constraints from design codes, evaluated by expensive computations such as finite element (FE) simulations. Traditionally, the focus has been on minimizing costs exclusively, while the current trend calls for good trade-offs of multiple criteria such as sustainability, buildability, and performance, which can typically be computed cheaply from the design parameters. Multi-objective methods can provide more relevant design strategies to find such trade-offs. However, the potential of multi-objective optimization methods remains unexploited in structural concrete design practice, as the expensiveness of structural design problems severely limits the scope of applicable algorithms. Bayesian optimization has emerged as an efficient approach to optimizing expensive functions, but it has not been, to the best of our knowledge, applied to constrained multi-objective optimization of structural concrete design problems. In this work, we develop a Bayesian optimization framework explicitly exploiting the features inherent to structural design problems, that is, expensive constraints and cheap objectives. The framework is evaluated on a generic case of structural design of a reinforced concrete (RC) beam, taking into account sustainability, buildability, and performance objectives, and is benchmarked against the well-known Non-dominated Sorting Genetic Algorithm II (NSGA-II) and a random search procedure. The results show that the Bayesian algorithm performs considerably better in terms of rate-of-improvement, final solution quality, and variance across repeated runs, which suggests it is well-suited for multi-objective constrained optimization problems in structural design.
Set-based design (SBD), sometimes referred to as set-based concurrent engineering (SBCE), has emerged as an important component of lean product development (LPD) with all researchers describing it as a core enabler of LPD. Research has explored the principles underlying LPD and SBCE, but methodologies for the practical implementation need to be better understood. A review of SBD is performed in this article in order to discover and analyse the key aspects to consider when developing a model and methodology to transition to SBCE. The publications are classified according to a new framework, which allows us to map the topology of the relevant SBD literature from two perspectives: the research paradigms and the coverage of the generic creative design process (Formulation–Synthesis–Analysis–Evaluation–Documentation–Reformulation). It is found that SBD has a relatively low theoretical development, but there is a steady increase in the diversity of contributions. The literature abounds with methods, guidelines and tools to implement SBCE, but they rarely rely on a model that is in the continuum of a design process model, product model or knowledge-based model with the aim of federating the three Ps (People–Product–Process) towards SBCE and LPD in traditional industrial contexts.
Increasing system complexity has provided the impetus to develop new and novel systems engineering methodologies. One of these methodologies is set-based design (SBD), a concurrent design methodology well suited for complex systems subject to significant uncertainty. Since the 1990s, numerous private, public, and defense sector design programs have successfully implemented SBD. However, concerns regarding SBD's complexity, tendency towards qualitative methods, and lack of quantitative tools have limited its use. To address these issues, our research surveys 122 refereed journal articles and conference papers to assess SBD's state-of-practice and identify relevant research opportunities. To accomplish these tasks, we perform a structured literature review to identify and assess relevant and influential research. We found that SBD's state-of-practice relies heavily upon decision and tradespace analysis with increasing emphasis on uncertainty modeling and MBSE. We found that the majority of SBD research consists of quantitative methodologies focusing on component and small system applications. We also found that complex system applications used mostly qualitative methodologies. We identify SBD research opportunities for requirements development, MBSE, uncertainty modeling, multiresolution modeling, adversarial analysis, and program management. Finally, we recommend the development of a comprehensive SBD methodology and toolkit, suited for complex system design across all stages of the product development life cycle.
To date, the use of information technology has become part of the human lifestyle. The existence of the demands of fast, precise and accurate design is a common standard that must be met which has significant advantage to compete with practitioners who are working with conventional method. In civil engineering, the use of information technology cannot be avoided, whether you like or not engineers must be able to adapt. This is a logical consequence because the analysis involves considerable calculations, iterative, or trial and error. The solution is to create a program application using Fortran, Pascal, or C ++ which sometimes frustrates engineers who are accustomed to manual methods. This paper presents one solution that bridges the existence of a 'gap' to information technology in the form of short programs as a mediator between conventional and automatic calculations. Eurocode standard was used for design steel connection because this code already established and using metric units that commonly used in Indonesia. The parametric analysis was conducted by means of Excel combine with Visual Basic Application (VBA), the calculation performed iteratively for different dimensions and summarized in the form of a table.
Modern structural design faces new challenges, such as addressing the needs of several stakeholders and satisfying the criteria for achieving sustainability. The traditional design process does not allow resolution of these challenges. The purpose of this project was to investigate the applicability of a Set-Based Parametric Design method to the structural design process of bridges. The focus was on the early design stage, in which the design team evaluates design alternatives against a chosen set of criteria. The main challenge in this stage of design is that the process should be cost-and time-effective while allowing comparison of the different alternatives and their evaluation in terms of the different design criteria. Certainly, structural design is often performed by a discussion between the different stakeholders involved in this process, i.e. the client, contractor, and engineering team. An evaluation of alternatives against criteria requires a more detailed design, which is contradictory to the early design stage when information is scarce. The selected approach was to develop a script that can generate information for decision-making, automate the structural design process, perform common routine design tasks, and control the numerical analysis. The method combined Set-Based Design, Parametric Design, Finite Element Analysis and Multi-Criteria Decision Analysis. Three existing bridges were selected to demonstrate the applicability of the developed method. The method was successfully applied and it was observed that it resulted in bridges that were more efficient in terms of material costs and carbon dioxide equivalent emissions compared with existing bridges. By delaying the decisions and developing the sets of alternatives, various alternatives can be assessed and evaluated, in the design stage, against different sustainability criteria.
Traditional data warehouses are unable to meet the growing needs of the modern enterprise to integrate and analyze a wide variety of data generated by social, mobile and sensor sources. What is remarkable is that many companies have changed their data storage in NoSQL databases. Given the important role played by this type of databases, it is necessary to study NoSQL databases as a data source for the modeling and the implementation of data warehouses. This paper proposes a method to design the data warehouse schema from schema free databases known as NoSQL databases. Our proposal starts with the extraction of schemes from document-oriented databases as an example of NoSQL database. This extraction is performed based on the MapReduce paradigm. Then, it defines the structure identification graph from the extracted schemes. This graph will help the designer to identify the multidimensional concepts for each schema extracted in order to design the global data warehouse schema.
During the early stages of any system design, a thorough exploration of the design space can prove to be challenging and computationally expensive. The challenges are further exacerbated when dealing with complex systems, such as an aircraft, due to the high dimensionality of their design space. Arising from the Toyota Product Development System, set-based design allows parallel evaluation of multiple alternative configurations in the early design stages. At the same time, optimisation methods can be employed at later stages to fine-tune the engineering characteristics of design variants. Presented in this paper, is the Augmented set-based Design and OPTimisation (ADOPT) Framework that introduces a novel methodology for integrating the two areas. This allows for a thorough design-space exploration while ensuring the optimality of the selected designs. The framework has been developed using a process-independent and tool-agnostic approach so that it can be applied to the design process of varying kinds of systems. To demonstrate the implementation and potential benefits, the framework has been applied to the design of a generic aircraft fuel system. The results from the case study and the framework itself are discussed, with a number of areas for further development and future work being identified and presented.
Most part of their time, engineers around the globe are asked to design over and over again the same or very similar structures, without just taking what has already been done or learning from the past. Arguably the same structural elements with given acting forces and constraints have been designed thousands of times and the same can be said for architectural finishing, MEP, and in principle to entire buildings which could be informed from previous similar ones. Also, traditional methods for optimizing structures require a large amount of resources and time, whereas an AI-based approach can draw from previous knowledge [7, 8]. The more such an approach were used, the more the data points collected and therefore the more efficient it would become. This paper tries to take a step further in the realm of structural optimization by having a fresh look at machine learning strategies to address one of the above-mentioned challenges: the automatic design of steel end-plates.
The paper summarizes the main new design provisions included in the recently revised Australian standard for steel storage racks. The standard features multitiered analysis provisions ranging from basic linear-elastic analysis-based provisions to highly advanced integrated design-analysis [geometric and material nonlinear analysis with imperfections (GMNIA)] provisions that allow the analysis and design to be completed in one step. The GMNIA provisions distinguish between beam element-based and shell element-based analysis according to cross section slenderness and provide rules for the imperfections to use for the two types of analysis, including imperfections in the local and distortional buckling modes for the shell element-based analysis. The selection of the system-based reliability (resistance) factor (phi(s)) is discussed. The standard is seen as the most advanced design code of its type currently available for frame-type steel structures. The paper also provides an in-depth discussion about the use of linear and nonlinear elastic analysis methods for the design of steel storage racks and how torsion may be considered in determining design capacities while not in the structural analysis. DOI: 10.1061/(ASCE)ST.1943-541X.0000665. (C) 2013 American Society of Civil Engineers.
In this paper a new hybrid glowworm swarm algorithm (SAGSO) for solving structural optimization problems is presented. The structure proposed to be optimized here is a simply-supported concrete Ibeam defined by 20 variables. Eight different concrete mixtures are studied, varying the compressive strength grade and compacting system. The solutions are evaluated following the Spanish Code for structural concrete. The algorithm is applied to two objective functions, namely the embedded CO2 emissions and the economic cost of the structure. The ability of glowworm swarm optimization (GSO) to search in the entire solution space is combined with the local search by Simulated Annealing (SA) to obtain better results than using the GSO and SA independently. Finally, the hybrid algorithm can solve structural optimization problems applied to discrete variables. The study showed that large sections with a highly exposed surface area and the use of conventional vibrated concrete (CVC) with the lower strength grade minimize the CO2 emissions.
This review focuses on identifying the impacts and future development trends for current structural design practice in integration of building information modelling (BIM) technologies. BIM technologies, as novel information management schemes they are, are changing the conventional structure design processes. Currently, utilising BIM technologies for reshaping structural design has been widely acknowledged and embraced by both academic and industry circles. In this research, the current status and issues of the structural design processes (including modelling, analysis, and optimisation of structures) are fully investigated with emphases on specific design stages. The research put efforts on surveying the benefits of BIM in facilitating current structural design, such as systematic modelling processes, powerful interactive visualization platform, and standardised exchanging data interfaces. Impacts of personnel involvement in structural design when adopting BIM have also been identified in detail. Finally, a predicted cross-functional flowchart of BIM-enabled structural design for the near future is proposed, which shows future developing trends in improving structural design quality and addressing current issues.
Set-Based Concurrent Engineering is sometimes seen as a means to dramatic improvements in product design processes. In spite of its popularity in literature, the number of reported applications has so far been limited. This paper adds new information by describing implementations of Set-Based Concurrent Engineering in four product developing companies. The research took a case study approach, with the objective to investigate if the principles of Set-Based Concurrent Engineering can improve the efficiency and the effectiveness of the development process. The study shows that set-based projects can be driven within an existing organization, if given proper support. The participants claim that a set-based approach has a positive effects on development performance, especially on the level of innovation, product cost and performance. The improvements were achieved at the expense of slightly higher development costs and longer lead time. However, the positive effects are dominating and the companies involved intend to use Set-Based Concurrent Engineering in future projects when appropriate.
How Toyota's product design and development process helps find the best solutions and develop successful products.
To explore the feasibility of improving the delivery process of reinforced concrete, we focus in this paper on reinforcing bars (rebar) used in cast-in-place (CIP) concrete. Specifically, we describe the methodology for set-based design of rebar that we are pursuing in an ongoing research effort. Set-based design makes it possible to maintain feasible solutions for longer in the design process than is otherwise affordable using point-based design. It thereby allows for input from several project participants at the same time and early on, as well as throughout project delivery. Set-based communication helps participants avoid rework and through teamwork develop a more globally satisfactory design solution than would otherwise be the case. To illustrate the methodology, we examine the canonical example of reinforcement at a beam-column joint and study the relationships between those who design the joint and those who fabricate and install it: mainly the structural engineer, the fabricator, and the rebar placer. The set-based approach for concrete design is promising. It warrants further effort in characterizing sets at different levels of abstraction and in articulating what different participants value, both of which are needed for sets to be narrowed effectively and for the process to lead to a solution.
The response of a steel structure is closely related to the behavior of its joints. This means that it is necessary to take explicit account of joint properties in order to ensure a consistent approach to design optimization of steel frames. Semi-rigid design has been introduced into steel construction standards such as Eurocode 3 and AISC. However, in the absence of appropriate guidelines, engineers encounter difficulties when bringing in semi-rigid design to everyday engineering practice. Moreover, connection design significantly affects the production cost of steel frame structures. Thus, a realistic optimization of frame design should take into account the effective costs of different stages of production including manufacturing and erection activities. This paper presents a Genetic Algorithm based method for multi-stage cost optimization of steel structures. In the objective function, the total cost of different production stages is minimized. A new cost model is presented that itemizes costs of all stages of production (material supply, manufacturing, erection and foundation). Design examples are used to validate the proposed methodology. Numerical validation shows that the multi-stage design optimization results in substantial cost benefits between 10% and 25% compared to traditional design of steel frames. Furthermore, the developed methodology is shown to be capable of measuring the possible impact of design choices in the early design stage thus assisting designers to make better design decisions.
Concurrent engineering (CE) involves a widely recognized
revolution in the social organization of product development and a
corresponding revolution in the underlying paradigm of design. We
distinguish between two paradigms-point-based design and set-based
design-and argue that effective, truly concurrent design requires
shifting to a paradigm where design team members reason and communicate
about sets of designs which we call “set-based concurrent
engineering”. A survey of 92 Japanese and 119 US automotive parts
suppliers who design their own products sought to quantify the
pervasiveness and correlates of “set-based approaches”. The
survey evidence indicates that set-based design communication is more
prevalent among Japanese than among US parts suppliers, and is
correlated with certain product development characteristics including
years of experience with early involvement of suppliers in design, the
degree of product-process design overlap, the degree to which subsystems
are interdependent, and the use of quality function deployment (QFD)
Steel connections in building projects are traditionally designed in Canada by the fabricator’s engineer using connection design software or spreadsheets, often supplemented by hand calculations. Implicit in these processes is the desire to optimize the net fabrication and erection costs based on several parameters such as material, task and process repetition, machinery availability, fabrication and erection constraints, and available optimization tools. This study aims to explore the realm of structural optimization by employing evolutionary algorithms to automate and optimize the design of steel shear connections. Evolutionary algorithms are search algorithms used within artificial intelligence to determine an optimal solution from a population of possible solutions within user-defined optimization criteria. A design optimization tool built using parametric modelling and connection design software utilizing component-based finite element modelling is applied to a shear end plate connection. The results are tested and compared against an example end plate connection design from the Canadian Handbook of Steel Construction. The optimization results showcase the potential of using evolutionary algorithms for steel connection design, and the practicality of the optimization tool for use in a professional environment is presented.
This paper presents a new methodology for cost- and carbon-optimal generation of multi-storey building designs. The methodology features algorithms for automatic optimised design of concrete, steel, and timber frames; established as well as novel decking technologies; and foundation options. Applying the methodology, we illustrate the potential carbon and cost savings unlocked by well-informed early-stage design decisions by means of two test cases: a simple rectangular building and another with more complex geometry. We show that the impact of early-stage design decisions such as column grid, site, frame material, and decking choice have much larger emission saving potential than the choice between optimisation objectives.
By using parametric modelling tools, designers can simulate a high number of design‐variants with relatively low effort. Visual programming software's like Grasshopper significantly lowers the threshold for beginners to start building parametric models. This paper discusses how using Grasshopper as a parametric design tool can be applied by structural engineers to improve well‐informed decision making, when designing a steel structure. Finally, worth mentioning further possibilities parametric design workflows can bring are discussed such as optimisation strategies, optimising sustainability and including structural connections in the parametric model.
Product development efforts now more than ever are in need of methodologies that can address the challenges of increased system complexities, shortening time to market, increased demands in mass customization, market instabilities, geographical barriers, improved innovation, and adaptability to emerging technologies. To address these challenges most companies will need to make key decisions early in the product development life‐cycle. In this early phase there are high levels of information uncertainty and information ambiguity. Under these circumstances many companies will converge too early to a point design (Point Based Design—PBD) which will lead to increased cost and schedule delays due to reworking the design later in the product development life cycle. To overcome these challenges many researchers have proposed the Set‐Based Design (SBD) methodology. However, there has been limited guidance on how to define, reason, and narrow sets while improving the level of abstraction of the design. To address such concerns, a literature review was conducted. The contributions of this research include: (1) aggregated literature from over 100 sources on quantitative methods (QM) that has not been considered SBD but does support set‐based thinking, (2) consolidated body of knowledge on QM to help industrial practitioners implement SBD, (3) defined gaps and opportunities for future research, and (4) defined strengths and limitations of QM and techniques to define, reason and narrow sets.
This paper describes how the functional behavior and embodiment of design solutions can be modeled using configurable components. The concept of a system structure composed of configurable components is defined and put in context of business requirements as well as in context of design theory and more specifically the chromosome model and function-means-trees. The paper contends that this kind of product description is necessary from a business perspective in order to successfully manage development of derivative products and product variants based on a product platform concept. The concepts presented in this paper is currently being deployed at Saab Automobile as the next logical evolution of product description systems necessary in order to maintain competitiveness in the automotive business.
An end-to-end computational platform is presented, which automates seismic design, nonlinear structural model construction, and response simulation (static and dynamic) of steel moment resisting frames. A modular framework is adopted along with the object-oriented programming paradigm to ensure the adaptability of the platform. The seismic design module iteratively generates code-conforming section sizes and detailing for beams, columns, and beam-column connections based on the relevant input design variables including the building configuration (e.g., the number of stories, the number of lateral-force resisting systems, and the building dimensions), loads (e.g., dead and live loads on each floor), and site conditions (mapped spectral acceleration parameters). The nonlinear model construction and analysis module takes the design results as input and produces structural models that capture flexural strength and stiffness deterioration in the frame beam-column elements, and performs pushover and response history analyses. Illustrative examples are presented to demonstrate the reliability, accuracy, and efficiency of the platform, which significantly reduces the time and effort involved in producing iterative structural designs and conducting nonlinear analyses, both of which are necessary for performance-based seismic design. Additionally, the platform can be used to create an extensive database of archetype steel moment frame buildings towards the development of analytics-driven design methods.
This paper presents a new method to quickly and accurately estimate the material, fabrication, and erection cost of steel frames based on early-design information. To use the proposed Integrated Steel Design (ISD) method, engineers first upload a structural model consisting of a frame layout with preliminary member sizes and connection types specified. The frame connections are then automatically detailed to produce a bill of quantities suitable for fabrication. Next, the total installed cost is estimated based on unit rates maintained by suppliers on a secure web portal. Finally, the cost feedback is provided in the context of the 3-D model in near real-time. We apply the proposed analytical method to several moment frames to illustrate its advantages compared to more approximate approaches. These initial results demonstrate the potential of the ISD method to improve early stage design decision-making through better vertical integration of project information in the AEC industry.
In general, for a complex engineering structure with a large number of nodes or members, the inherent symmetry is not easily recognizable. Even though someone succeeds in recognizing certain symmetry properties of the structure, these might be partial ones, and the others will be possibly unnoticed. To overcome this difficulty and enable the integration of computational analysis and symmetry methods, we propose an automated detection method for engineering structures with cyclic symmetries. Only the nodes and the connectivity patterns of the members are needed for implementing this algorithm. Using group theory, we first describe different cyclic groups of symmetries and their symmetry operations. In order to establish a group-theoretic algorithm for automated symmetry detection, several theorems and corollaries are presented. Then, on the basis of matrix representations of symmetry operations, the equivalence of the nodes and members of a structure is evaluated. Hence, the inherent symmetry operations of the structure are identified one by one. Illustrative examples show that the proposed automated symmetry detection method is robust and applicable to both 2D and 3D structures. Highly symmetric structures are recognized accurately and effectively. In addition, asymmetric structures and 2D structures can be recognized in a very small number of iterations.
This chapter is an introduction to the various aspects of structural engineering. It starts with a discussion of structural systems, structural member, and components and highlights the significance of cross-sectional analysis and design. It continues to discuss the basic concepts and procedures for structural analysis and design, including a discussion of the development of structural design philosophy and progression of design approaches, terminating with a discussion of performance-based design. The chapter also discusses the basic concepts of stiffness, nonlinearity of relationships between deformations and corresponding actions, etc. and lays the foundation for the remaining chapters in the book.
In the present paper the development, calibration and experimental validation of two component-based models of dissipative steel links connecting a reinforced concrete wall to a steel gravity frame is presented. The dissipative capacity of such structures is greatly influenced by the effective hysteretic behavior of the wall-to-column coupling system. Within the present work, experimental tests results on two different configurations of wall-to-column coupling system are presented. The development and calibration of two non-linear cyclic component-based models, one for each configuration, are described, allowing a better understanding of the force transmission mechanisms and their influence on the global structural behavior.
Database can accommodate a very large number of users on an on-demand basis. The main limitations with conventional relational database management systems (RDBMS) are that they are hard to scale with Data warehousing, Grid, Web 2.0 and Cloud applications, have non-linear query execution time, have unstable query plans and have static schema. Even though RDBMS's have provided database users with the best mix of simplicity, robustness, flexibility, performance, scalability and compatibility but they are not able to satisfy the present day users and applications for the reasons mentioned above. The next generation NonSQL (NoSQL) databases are mostly non-relational, distributed and horizontally scalable and are able to satisfy most of the needs of the present day applications. The main characteristics of these databases are schema-free, no join, non-relational, easy replication support, simple API and eventually consistent. The aim of this paper is to illustrate how a problem being solved using MySQL will perform when MongoDB is used on a Big data dataset. The results are encouraging and clearly showcase the comparisons made. Queries are executed on a big data airlines database using both MongoDB and MySQL. Select, update, delete and insert queries are executed and performance is evaluated.
This paper aims to find sustainable designs of post-tensioned concrete box-girder pedestrian bridges. A hybrid harmony search algorithm combining threshold optimization is used to find the geometry and the materials for which the sum of the costs or the emissions are the lowest, yet satisfying the requirements for structural safety and durability. An experimental design method was used to adjust the algorithm parameters. The parametric study was applied to three-span deck bridges ranging from 90 m to 130 m. The findings indicated that both objectives lead to similar cost results. However, the variables presented some differences. Such deviations suggested greater depths, more strands and a lower concrete strength for CO2 target functions. Carbonation captured less than 1% of the deck emissions over 100 years. This methodology leads to a precise analysis of the practical rules to achieve an environmental design approach.
This paper represents a new algorithm for structural optimization with frequency constraints. The new algorithm is termed Democratic Particle Swarm Optimization. The emphasis is placed upon alleviating the premature convergence phenomenon which is believed to be one of flaws of the original PSO. When considering frequency constraints in a structural optimization problem, the search spaces happen to be highly non-linear and non-convex hyper-surfaces with numerous local optima and naturally the problem of premature convergence is amplified. The proposed algorithm is capable of coping with this problem. Four numerical examples are presented to demonstrate the viability of the algorithm.
As building systems have become more complex, selecting an efficient system for finding the optimal solution in the construction of high-rise building structures has become crucial. To obtain more optimized design solutions and reduce the waste caused by the rework that frequently occurs in Point-based Design (PBD) procedure, Set-based Design (SBD) procedure was recently proposed, and its application to design practice has been extensively studied. However, more research on the design procedure application details is necessary. This research focuses on improving the SBD procedure by the efficient selection of alternatives. The proposed design procedure uses Structural Building Information Modeling (S-BIM) to increase the efficiency of this selection and obtain more optimal solutions to eventually improve the constructability, structural safety, and economic feasibility of the building. The case study in the last section shows that the proposed design procedure achieves higher efficiency than SBD based on existing 2D method in selecting alternatives.
Group theory provides a formal means for exploiting symmetry in the analysis of physical systems. In current group-theoretic formulations, it is assumed that the symmetry properties of the system are self-evident, and the symmetry group of the problem is deduced by the analyst and assigned as an input parameter. However, for complex systems with a large number of nodes or elements, the symmetry properties may not be obvious. The present paper proposes a procedure for the systematic search and identification of the symmetries of 2D and 3D structural configurations, and hence for the automatic recognition of the symmetry group to be used in a group-theoretic analysis of the system.
This paper is concerned with the development of a knowledge-based system for the economical design of tubular trusses using a fabrication-led approach. For this purpose the system employs a cost model for estimating the likely cost of fabrication for these trusses. The cost model, which was developed using the object-oriented methodology, is used for estimating the cost of fabrication of one or a number of trusses, joint detailing, members and individual fabrication operations. Therefore, the relative cost of one design option compared with its alternatives can be obtained. Using the model, the consequences of design decisions on the cost of fabrication can be appraised. This will assist in obtaining economical designs that take into account not only the cost of material but also that of fabrication.
A microcomputer-aided design (MICROCAD) system is presented for interactive design of connections in steel buildings made of standard rolled I-sections. Design of different connections is based on the American Institute of Steel Construction specification. Connecting elements may be plates, angles, or T-sections. Connectors may be bolts or welds. The MICROCAD system can display/plot any isometric view of the connection plus the orthographic views, i.e. front, side, and top views. Program structure and graphic algorithms for the MICROCAD system are presented in an accompanying paper. In this paper applications of the MICROCAD system for design of bolted and welded connections are presented. Different menus available to the user are discussed. Microcomputer graphics for displaying the orthographic views with dimensions and designations, and isometric views are presented. This MICROCAD system can be used effectively for practical design of connections in steel buildings
This paper expands the existing database of semi-rigid steel connections at Purdue University by including additional test data on header-plate and seat-angle, and double-web and seat-angle connections. The experimental moment rotation curves are also compared with several analytical models describing these curves.
A generalised component-based model for semi-rigid beam-to-column connections including axial force versus bending moment interaction is presented. The detailed formulation of the proposed analytical model is fully described in this paper, as well as all the analytical expressions used to evaluate the model properties. Detailed examples demonstrate how to use this model to predict moment–rotation curves for any axial force level. Numerical results, validated against experimental data, form the basis of a tri-linear approach to characterise the force–displacement relationship of the joint components. The relationship of the present development to key prior studies of this topic is also explained.
A substantial effort has been made in recent years to characterise the behaviour of semi-rigid connections. Recent studies and modern codes, in particular EC3 and EC4, not only include methods and formulas to define both their resistance and stiffness, but also emphasise the importance of a correct modelling of the panel zone under shear and compressive forces. The traditional approach of modelling the connection by means of springs attached to the end of the beams at both sides of the joint implies the use of an interaction parameter, called the β factor in EC3 and EC4, that depends on the moments and shear forces acting on the panel zone. Both the stiffness and strength of the springs depend on this parameter. However, the definition of the β factor implies an approximation of the internal forces at the joint, and therefore its use requires an iterative process at the time of performing the global analysis of the structure.This paper deals with a new component-based approach to model internal and external semi-rigid connections for the global analysis of steel and composite frames. The method is based on a finite dimensioned elastic–plastic four-node joint element that takes into consideration, in a congruent and complete way, its deformation characteristics (components in Eurocode), including those of the panel zone, and all the internal forces that concur at the joint. As a consequence, this new element avoids the use of the β factor and the inherent iterative process that it requires. In addition, the eccentricities of the internal forces coming from the beams and columns that meet at the joint are also considered. Examples are solved that validate the new approach and demonstrate its efficiency. In addition, it is shown that when using the β factor the iterative process may not converge for elastic–plastic analysis. Moreover, the limitations imposed on β by EC3 and EC4 may lead to substantial errors in the internal forces and moments.
Modern standards for the design of steel structures give new and advanced options for the design of efficient and economic steel structures. As far as the design of joints is concerned, the exploitation of the advanced possibilities is rather time consuming for the designer if no appropriate tools for a quick and easy design are available. Different design tools now have been established: design sheets providing simple sets of formulae, design tables and software. The paper presents a complete set of such design tools. Aspects of economic design, optimisation of connection detailing as well as possibilities for learning and education on connection behaviour using these tools are discussed.
This work is motivated from set-based concurrent engineering (SBCE) paradigm. In contrast to the traditional design practice,
SBCE considers a broader range of design possibilities (i.e., design space) from the outset, explicitly communicates and reasons
about sets of design alternatives, and gradually narrows the sets to eliminate inferior alternatives until a final solution
remains. Thus, the key to success of SBCE is the proper implementation of the space representation method to define the possible design region, the space mapping method to obtain the performance space achievable by the initial design space, and the space narrowing method to eliminate infeasible subspaces from the initial design space. This paper proposes a novel space-based design methodology
for preliminary engineering design. The main characteristic features of our approach are to incorporate the designer’s preference
structure with degrees of desirability in specifying both design space and performance space, and to find a ranged set of
design solutions that satisfy changing sets of performance requirements through set-to-set space mapping from design space
to performance space and space narrowing to eliminate infeasible design subspaces. Central to the proposed design methodology
is the integration of meta-modeling techniques, modified fuzzy arithmetic, design of experiment (DoE), robust design techniques, and uncertainty analysis. A preliminary parametric design example of a vehicle side impact beam
is demonstrated to show the effectiveness of the proposed methodology and its availability in the large-scale multi-objective
design synthesis problem.
A Structal Design Language (SDL) has been developed in INTERLISP environment for building coupled knowledge-based expert systems for integrated design of a class of structures. The integrated design includes the preliminary design, structural analysis, design of members, design of connections, and computer-aided drafting of the final design. The complex body of knowledge needed for detailed design of a structure is fractionated into smaller and more manageable knowledge sources which are organized into a hierarchy of cooperating conceptual specialists. SDL provides a multiwindow graphics interface capable of displaying both the orthographic and isometric views of the frame structure and beam-column connections. A three-dimensional face frame representation sentation is used for the graphic display of the beam-column connections. SDL has been used to develop a prototype knowledge-based system for integrated design of steel building structures consisting of moment-resisting frames.
During conceptual design, engineers deal with incomplete product descriptions called design concepts. Engineers must compare these concepts in order to move towards the more desirable designs. However, comparisons are difficult because a single concept associates with numerous possible final design specifications, and any meaningful comparison of concepts must consider this range of possibilities. Consequently, the performance of a concept can only be characterized imprecisely. While standard multi- attribute utility theory is an accepted framework for making preference-based decisions between precisely characterized alternatives, it does not directly accommodate the analysis of imprecisely characterized alternatives. By extending uncertainty representations to model imprecision explicitly, it is possible to apply the principles of utility theory to such problems. However, this can lead to situations of indeterminacy, meaning that the decision maker is unable to identify a single concept as the most preferred. Under a set-based perspective and approach to design, a designer can work towards a single solution systematically despite indecision arising from imprecise characterizations of design concepts. Existing work in set-based design primarily focuses on feasibility conditions and single-attribute objectives, which are insufficient for most design problems. In this article, we combine the framework of multi-attribute utility theory, the perspective of set-based design, and the explicit mathematical representation of imprecision into a single approach to conceptual design. Each of the component theories are discussed, and their combined application developed. The approach is illustrated using the conceptual design of a fixed-ratio power transmission as an example. Additionally, important directions for future research are identified, with a particular focus on the process of modeling abstract design concepts.