Rafael Sacks

Interaction of lean and building information modeling in construction

Lean construction and Building Information Modeling are quite different initiatives, but both are having profound impacts on the construction industry. A rigorous analysis of the myriad specific interactions between them indicates that a synergy exists which, if properly understood in theoretical terms, can be exploited to improve construction processes beyond the degree to which it might be improved by application of either of these paradigms independently. Using a matrix that juxtaposes BIM functionalities with prescriptive lean construction principles, fifty-six interactions have been identified, all but four of which represent constructive interaction. Although evidence for the majority of these has been found, the matrix is not considered complete, but rather a framework for research to explore the degree of validity of the interactions. Construction executives, managers, designers and developers of IT systems for construction can also benefit from the framework as an aid to recognizing the potential synergies when planning their lean and BIM adoption strategies.

Parametric 3D modeling in building construction with examples from precast concrete

Buildings are complex products containing relatively large numbers of distinct parts that are collected in multiple assemblies for different design, analysis and production purposes. Modeling buildings in fully parametric 3D computer-aided design (CAD) systems offers numerous benefits in terms of productivity, the ability to rapidly generate design alternatives at different levels and elimination of errors that result from the disparity between different drawings in current practice. However, full realization of these benefits requires specialized functionality, including top-down modeling, objects with functional behavior, the ability to embed contextual design intent, automation of layout and detailing and appropriate management of similar objects. An effective system must provide such functionality while maintaining adequate response times. The requirements, features and performance have been examined as part of specification of a new 3D parametric CAD platform for the North American Precast Concrete Software Consortium (PCSC). They are described and discussed after a review of solid and parametric modeling, with examples from the domain of precast concrete construction.

Semantics of model views for information exchanges using the industry foundation class schema

The industry foundation classes (IFC) data schema is generic, designed to support the full range of model exchanges needed in the construction industry. For any particular working exchange for some sub-domain of building construction, a set of model view definitions (MVD) is required to specify exactly what information should be exchanged, and in what form and structure the IFC entities are to be used. Defining model view definitions requires principle decisions and workarounds because the IFC itself does not address a number of semantic issues comprehensively. Some of the issues identified and discussed include the typing of objects, instances, geometry, relationships, and rules, which are supported in the IFC schema, and the complexities of exchanging such information accurately between applications. This paper advances the idea of MVD Concepts as an object-oriented and modular mechanism for embedding semantic meaning in model views. We conclude that although the IFC product model schema is richly expressive, it lacks formal definition of its entities, attributes, and relationships. To achieve standardized and re-usable model views, further research towards a modular and logical framework based on formal specification of IFC concepts is recommended. This research is expected to impact the overall interoperability of applications in the building information modeling realm.

Toward automated generation of parametric BIMs based on hybrid video and laser scanning data

Only very few constructed facilities today have a complete record of as-built information. Despite the growing use of Building Information Modelling and the improvement in as-built records, several more years will be required before guidelines that require as-built data modelling will be implemented for the majority of constructed facilities, and this will still not address the stock of existing buildings. A technical solution for scanning buildings and compiling Building Information Models is needed. However, this is a multidisciplinary problem, requiring expertise in scanning, computer vision and videogrammetry, machine learning, and parametric object modelling. This paper outlines the technical approach proposed by a consortium of researchers that has gathered to tackle the ambitious goal of automating as-built modelling as far as possible. The top level framework of the proposed solution is presented, and each process, input and output is explained, along with the steps needed to validate them. Preliminary experiments on the earlier stages (i.e. processes) of the framework proposed are conducted and results are shown; the work toward implementation of the remainder is ongoing.

Life-cycle data management of engineered-to-order components using radio frequency identification

Management of engineered-to-order (ETO) components and their related information is a challenging task due to the complexity of information and its flow. Different information items are generated, accessed and exchanged between different organizations and they must continually flow through design, production, construction, and operations and maintenance. Current manual and labor-intensive methods are inefficient; as a result, information is frequently incomplete, inaccurate or unavailable during the life-cycle of a facility. This paper provides a vision of intelligent components, which know their identities, locations and history, and communicate this information to their environments. It proposes streamlining information flow through supply chains by utilizing radio frequency identification (RFID) technology. To explore the technical feasibility of intelligent components, component-related information flow patterns in ETO supply chains were identified and analyzed. Requirements analysis and corresponding technology deployment and testing were performed for three types of ETO components through different life-cycle phases. These experiments demonstrated that it is technically feasible to have intelligent components in construction supply chains by using RFID technology; that status information can be collected automatically; and that maintenance information can be stored and retrieved during the service life of a facility.

Visualization of Work Flow to Support Lean Construction

Implementation of advanced production management techniques, such as lean construction concepts like filtering of work packages to stabilize work flows, pull flow of teams and materials, and in-process quality control, demands effective and timely flows of information both to and from the workface. The key requirement—making the process state transparent to all participants—is more difficult to achieve in construction than in manufacturing, because work crews move continuously within a physical environment that is itself changing. Novel computer-aided visualization tools can fulfill the needs that simpler tools, such as Kanban cards, fulfill in manufacturing. Two prototypes with user interfaces designed to facilitate process flow have been devised and implemented within the context of building information modeling (BIM) software systems. They demonstrate aspects of the synergy between BIM and lean construction. Given the dynamic and dispersed physical environments and the fractured contracting arrangements typical of construction, BIM-based visualization interfaces are important tools for providing process transparency.

Building Information Modeling Education for Construction Engineering and Management. I: Industry Requirements, State of the Art, and Gap Analysis

AbstractAs building information modeling (BIM) becomes increasingly standard practice in the construction industry, universities providing construction engineering and management education seek to incorporate BIM concepts and skills in their degree programs. The goal of this research was to compile a framework for BIM education that lays out the necessary topics and the levels of achievement required at each stage of degree programs. Industry’s requirements for graduate engineers were elicited through surveys, workshops, analyses of job advertisements, and in-depth interviews. An outline of 39 topics in three broad classifications was established. Targets for competency in each topic were developed using the cognitive domain of Bloom’s taxonomy, which expresses the learning objectives on six levels (from understand to evaluate). Gap analysis, which compared the state of the art in leading universities to industry requirements, led to the compilation of a framework for the development of BIM content for un...

Construction safety training using immersive virtual reality

Construction workers’ ability to identify and assess risks is acquired through training and experience and is among the key factors that determine their behaviour and thus their safety. Yet researchers have questioned the effectiveness of conventional safety training. This research tested the hypotheses that safety training in a virtual reality (VR) construction site would be feasible and more effective, in terms of workers’ learning and recall in identifying and assessing construction safety risks, than would equivalent training using conventional methods. Sixty-six subjects were provided training in construction safety and their safety knowledge was tested prior to the training, immediately afterward, and one month later. Half of the subjects received traditional classroom training with visual aids; the other half were trained using a 3D immersive VR power-wall. Significant advantage was found for VR training for stone cladding work and for cast-in-situ concrete work, but not for general site safety. VR training was more effective in terms of maintaining trainees’ attention and concentration. Training with VR was more effective over time, especially in the context of cast-in-situ concrete works. Given the need for improved training and the advantages of training using VR, incorporation of VR in construction safety training is strongly recommended.

A project model for an automated building system: design and planning phases

Abstract The purpose of an automated building system (ABS) is to automatically generate maximum information and the related documents for the preliminary design, detailed design and construction planning of a building project. The ABS under development, described in this paper, includes features such as: representation of project information by a tri-hierarchical project model, step-by-step progress through predefined design and construction planning stages, use of knowledge-based modules, linkage to various data bases, and implementation of intelligent parametric ‘templates’ of building layouts and work assemblies. The main benefits of the system are the high quality of generated information, and the considerable saving of human input needed for this purpose. The project model for the system is described in the paper and various knowledge modules are defined with respect to their input and output. Interface screens and drawings from a prototypical testing of the system are also presented.

Eliciting information for product modeling using process modeling

A product model is a formal and structured definition of product information. The most common procedure for defining a product data model is to first describe the business and/or engineering process in a formal process model, then to create a product data model based on the process model. However, there is a logical gap between process modeling and product modeling methods in the current ISO 10303 standard product modeling process. We propose a new formal approach, called Process to Product Modeling (PPM) in which process and product modeling can be logically linked. This paper focuses on the semantics and syntax for the Requirements Collection and Modeling (RCM) of PPM. The new RCM method aims to model heterogeneous business processes and their information flows. The major difference between the proposed method and traditional requirements collection methods is that it provides a theoretical linkage to integrate process models and a set of specific information items used in them. This theoretical linkage enables modelers to capture the contents, scope, granularity, and semantics of information used in activities, which are depicted in process models. A PPM method, called Georgia Tech Process to Product Modeling (GTPPM), has been developed and was deployed for the North American Precast Concrete Software Consortium; examples from this effort are presented. Experience to date indicates that the new RCM method and the GTPPM tool hold the potential to improve and expedite elicitation of information for product model development.