3D/4D CAD Applicability for Life-Cycle Facility Management

A range of studies have shown that three-dimensional (3D)/four-dimensional (4D) computer-aided design (CAD) has positively impacted the productivity and safety of construction processes. However, its potential impact on the entire life cycle of construction projects has not yet been fully investigated. The opinions of construction professionals have generally been reported on the basis of one-time interviews during several case studies. No statistical approach has yet been adopted to examine the whole spectrum of views about 3D/4D CAD use in construction projects. This study presents a comprehensive statistical analysis about how construction engineers perceive the effectiveness of 3D/4D CAD during various tasks of the construction project life cycle. A focus group interview and a review of the literature produced a total of 35?application areas in which 3D/4D CAD can possibly improve existing construction processes. We identified the areas in which 3D/4D CAD has a high potential to significantly enhance project results by using an importance-performance analysis (IPA) and a questionnaire-based survey involving 165?respondents. These study results are expected to provide new business strategies for 3D/4D CAD by broadening its traditional application realm.     

Areas of Application for 3D and 4D Models on Construction Projects

In recent years more and more construction projects used three-dimensional/four-dimensional (3D/4D) models to support management tasks. However, project managers still struggle with evaluating how the 3D/4D model technology can be most efficiently applied on their specific project. One main reason for this struggle is that an account about how 3D/4D models have been used in the past is missing. This paper offers practitioners and researchers such an account of the application areas of 3D/4D model technologies including the purposes for which these technologies have been applied. The paper qualitatively aggregates the results of 26 case studies of 3D/4D model applications on construction projects to show researchers and practitioners how 3D/4D models have been applied to address project challenges. Using a “project challenge—3D/4D model application” matrix the paper explains each application area and describes why the application has been beneficial to the case study projects. The paper then analyzes the challenges that practitioners have faced with 3D/4D models on the test case projects. The main findings of this analysis are that practitioners on most of the test case projects have used the models for only one application area. The paper suggests that further research on the integration of 3D/4D model technologies into work and business processes of project teams is needed to address this opportunity for a more widespread use of 3D/4D models throughout the lifecycle of a project.     

Linear Scheduling and 4D Visualization

Described in this paper is a novel approach to four-dimensional (4D) computer-aided design (CAD). It involves a two-way symbiotic relationship between three-dimensional (3D) CAD software and a software implementation of linear planning that includes the ability to define a project product model and associate it with the process model. Strengths of the approach include the ability to readily modify construction sequences and examine their consequences using 4D CAD, and the ability to treat very large scale projects marked by significant repetition of their components. By building on a shared image of the project product model from both a design and construction perspective, the CAD model can be structured in a way that facilitates communication with the scheduling software and vice versa. Various challenges involved in making the 2-way process work are described, including consistency of product representation in the CAD and scheduling models, and the need to group CAD components at different levels of detail and locations to reflect the kinds of aggregation found in schedule representations of a project. The benefits of the approach include the ease with which different scheduling strategies can be explored and visualized, the links between 3D objects and activities can be maintained, and the completeness of the product model representations can be validated. A case study is used to illustrate the approach adopted and the challenges involved.     

Interactive 3D CAD for Effective Derrick Crane Operation in a Cable-Stayed Bridge Construction

The high expectation of esthetic and functional quality in modern civil infrastructure has resulted in the increased demand for long span bridges. In advanced or developing countries, long span bridges such as cable-stayed and suspension bridges are considered even as landmarks that symbolize the prosperity or culture of the region. These long span bridges require higher level of design and construction technologies than other types of bridges. In particular, the construction of cable-stayed bridges involves precise and sophisticated operation of construction equipment such as derrick cranes. However, it is not easy to plan the operations of a derrick crane before the actual construction process takes place. Unexpected spatial constraints in the construction site may hinder the smooth operation of a derrick crane, which leads to lower than expected productivity and safety. This study applies interactive three-dimensional (3D) computer aided design (CAD) to the derrick crane operation for the purpose of identifying potential problems. Construction managers can have the two way process with the 3D CAD system to interactively test their construction plans and scenarios. The case study shows that the interactive 3D CAD system significantly improves the constructability of the cable-stayed bridge construction.     

Object Recognition in Construction-Site Images Using 3D CAD-Based Filtering

Construction-site images that are now easily obtained from digital cameras have the potential to automatically provide the project status information. For example, once construction objects such as concrete columns are accurately identified and counted, the current level of project progress in the column installation activity can easily be measured. However, in order to identify and count the number of concrete columns installed at a particular point of time, a robust object recognition methodology is required. Without the successful recognition and extraction of the construction object of interest, it is almost impossible to understand the current level of project progress. This paper presents a robust image processing methodology to effectively extract the objects of interest from construction-site digital images. The proposed methodology makes use of advanced imaging algorithms and a three-dimensional computer aided design perspective view to increase the accuracy of the object recognition. Tests show that the methodology is promising and expected to provide a solid base for the successful, automatic acquisition of project information.     

Building Integrated Architecture/Engineering/Construction Systems Using Smart Objects: Methodology and Implementation

Integrated project systems hold the promise for improving the quality while reducing the time and cost of architecture/engineering/construction (AEC) projects. A fundamental requirement of such systems is to support the modeling and management of the design and construction information and to allow the exchange of such information among different project disciplines in an effective and efficient manner. This paper presents a methodology to implement integrated project systems through the use of a model-based approach that involves developing integrated “smart AEC objects.” Smart AEC objects are an evolutionary step that builds upon past research and experience in AEC product modeling, geometric modeling, intelligent CAD systems, and knowledge-based design methods. Smart objects are 3D parametric entities that combine the capability to represent various aspects of project information required to support multidisciplinary views of the objects, and the capability to encapsulate “intelligence” by representing behavioral aspects, design constraints, and life-cycle data management features into the objects. An example implementation of smart objects to support integrated design of falsework systems is presented. The paper also discusses the requirements for extending existing standard data models, specifically the Industry Foundation Classes (IFC), to support the modeling of smart AEC objects.     

Shape-Based Retrieval of Construction Site Photographs

Digital photographs of construction site activities are gradually replacing their traditional paper based counterparts. Existing digital imaging technologies in hardware and software make it easy for site engineers to take numerous photographs of “interesting” processes and activities on a daily basis. The resulting photographic data are evidence of the “as-built” project, and can therefore be used in a number of project life cycle tasks. However, the task of retrieving the relevant photographs needed in these tasks is often burdened by the sheer volume of photographs accumulating in project databases over time and the numerous objects present in each photograph. To solve this problem, the writers have recently developed a number of complementary techniques that can automatically classify and retrieve construction site images according to a variety of criteria (materials, time, date, location, etc.). This paper presents a novel complementary technique that can automatically identify linear (i.e., beam, column) and nonlinear (i.e., wall, slab) construction objects within the image content and use that information to enhance the performance of the writers’ existing construction site image retrieval approach.     

Real-Time Three-Dimensional Occupancy Grid Modeling for the Detection and Tracking of Construction Resources

Awareness of the construction environment can be improved by automatic three-dimensional (3D) sensing and modeling of job sites in real time. Commercially available 3D modeling approaches based on range scanning techniques are capable of modeling static objects only, and thus cannot model dynamic objects in real time in an environment comprised of moving humans, equipment, and materials. Emerging prototype video range cameras offer an alternative by facilitating affordable, wide field of view, dynamic object tracking at frame rates better than 1?Hz (real time). This paper describes a methodology to model, detect, and track the position of static and moving objects in real time, based on data obtained from video range cameras. Experiments with this technology have produced results that indicate that video rate 3D data acquisition and analysis of construction environments can support effective modeling, detection, and tracking of project resources. This approach to job site awareness has inherent value and broad application. In combination with effective management practices and other sensing techniques, this technology has the potential to significantly improve safety on construction job sites.     

Analytical Approach to Augmenting Site Photos with 3D Graphics of Underground Infrastructure in Construction Engineering Applications

This paper proposes an analytical approach to incorporating computer-generated three-dimensional (3D) graphics of invisible underground infrastructure into site photos so as to present a richer and more integral view of the site situation in construction engineering applications. The proposed approach simulates the image-forming process of a camera and produces a virtual photo of the underground scene, whose virtual coordinate axes coincide with the real coordinate axes of the aboveground site scene. As a result, the virtual photo and the site photo can be seamlessly merged in terms of perspective, position, and scale. This research simplifies the calculation of the camera’s spatial orientation by use of only two reference points’ positions, i.e., the camera station position and the object focus position. The whole procedure of the proposed approach is analytical and can be automated into a computer program. In practice, nondestructive subsurface imaging technologies are generally used to obtain the spatial data of the underground infrastructure, which can be readily processed into a 3D as-built model as one component in composing the virtual underground scene. The proposed approach is demonstrated with a case study in which the underground as-built data are superimposed onto the aboveground site photo for the purpose of quality investigation of a bored pile construction.     

Sensing and Field Data Capture for Construction and Facility Operations

Collection of accurate, complete, and reliable field data is not only essential for active management of construction projects involving various tasks, such as material tracking, progress monitoring, and quality assurance, but also for facility and infrastructure management during the service lives of facilities and infrastructure systems. Limitations of current manual data collection approaches in terms of speed, completeness, and accuracy render these approaches ineffective for decision support in highly dynamic environments, such as construction and facility operations. Hence, a need exists to leverage the advancements in automated field data capture technologies to support decisions during construction and facility operations. These technologies can be used not only for acquiring data about the various operations being carried out at construction and facility sites but also for gathering information about the context surrounding these operations and monitoring the workflow of activities during these operations. With this, it is possible for project and facility managers to better understand the effect of environmental conditions on construction and facility operations and also to identify inefficient processes in these operations. This paper presents an overview of the various applications of automated field data capture technologies in construction and facility fieldwork. These technologies include image capture technologies, such as laser scanners and video cameras; automated identification technologies, such as barcodes and Radio Frequency Identification (RFID) tags; tracking technologies, such as Global Positioning System (GPS) and wireless local area network (LAN); and process monitoring technologies, such as on-board instruments (OBI). The authors observe that although applications exist for capturing construction and facility fieldwork data, these technologies have been underutilized for capturing the context at the fieldwork sites as well as for monitoring the workflow of construction and facility operations.     

Automation and Robotics for Construction

The potential for automated real‐time data acquisition, process control and robotics for remote, large‐scale field operations, such as those on construction engineering projects, is addressed. Classifications of technologies for automation and robotics in such operations include hard‐wired instrumentation, remote sensing, analog and digital telecommunications, optical (laser, infrared and fiber‐optic) data transmission, monitoring via microcomputer‐based instrument control and data recording, on‐site process control for fixed plants, partial or fully automatic control of mobile equipment, fixed‐based manipulators, mobile robots, communications between on‐site computers and automated machinery, electronic ranging and detection, and video‐image pattern recognition. Combining selected technologies with microcomputer‐based software could facilitate analysis, design and control decision‐making, and could provide a means of coordinating various discrete automated components or machines that must work together to perform field tasks. This paper also mentions categories of needs for such technologies on field operations, and potential barriers to implementation. Progress will depend on the interest and support of researchers qualified to advance this field.     

Benefits and Barriers of Construction Project Monitoring Using High-Resolution Automated Cameras

A more rapid and widespread use and implementation of technology in construction often fails since its benefits and limitations remain somewhat unclear. Project control is one of the most variable and time consuming task of construction project managers and superintendents and yet continues to be mostly a manual task. Controlling tasks such as tracking and updating project schedules can be assisted through remotely operating technology such as high-resolution cameras that can provide construction management and other users with imaging feeds of job site activities. Although construction cameras have been around for many years, the costs, benefits, and barriers of their use have not been investigated nor quantified in detail. Subsequently, definitions and understanding vary widely, making it difficult for decision makers at the organizational level to decide on the investment in camera technology. This paper reviews the status of high-resolution cameras and their present use in construction. Results of a multiphased survey to industry professionals were collected in order to identify benefits and barriers and develop a cost-benefit model that can be used for implementation technology in construction.     

Distributed Augmented Reality for Visualizing Collaborative Construction Tasks

Augmented reality is a visualization method in which virtual objects are aligned with the real world and the viewer can interact with the virtual objects in real time. In this paper, a new methodology called distributed augmented reality for visualizing collaborative construction tasks (DARCC) is proposed. Using this methodology, virtual models of construction equipment can be operated and viewed by several operators to interactively simulate construction activities on the construction site in augmented reality mode. The paper investigates the design issues of DARCC including tracking and registration, object modeling, engineering constraints, and interaction and communication methods. The DARCC methodology is implemented in a prototype system and tested in a case study about a bridge deck rehabilitation project.     

三维软件MDT在工业炉设计中的应用

MDT是三维机械设计软件.三维设计是通过建模的方式,将所用的每一个零件、部件真实地创建出来,并把它们按设计思路、要求进行模型间的焊接、拼装,直至完工的设计过程.在建模过程中,设计者既设计又施工,倍感真实,使CAD设计提高了一个台阶.     

Georeferenced Registration of Construction Graphics in Mobile Outdoor Augmented Reality

This paper describes research that investigated the application of the global positioning system and 3 degree-of-freedom (3-DOF) angular tracking to address the registration problem during interactive visualization of construction graphics in outdoor augmented reality (AR) environments. The global position and the three-dimensional (3D) orientation of a user’s viewpoint are tracked, and this information is reconciled with the known global position and orientation of superimposed computer-aided design (CAD) objects. Based on this computation, the relative translation and axial rotations between the user’s viewpoint and the CAD objects are continually calculated. The relative geometric transformations are then applied to the CAD objects inside a virtual viewing frustum that is coincided with the real world space that is in the user’s view. The result is an augmented outdoor environment where superimposed graphical objects stay fixed to their real world locations as the user navigates. The algorithms are implemented in a software tool called UM-AR-GPS-ROVER that is capable of interactively placing static and dynamic 3D models at any location in outdoor augmented space. The concept and prototype are demonstrated with an example in which scheduled construction activities for the erection of a structural steel frame are graphically simulated in outdoor AR.     

Dynamic 3D Visualization of Articulated Construction Equipment

Dynamic three-dimensional (3D) animation can be of significant value in improving the verification validation, and communication of discrete-event simulation (DES) models of construction operations, which in turn can make the models more credible and thus useful in operations planning and decision making. This paper presents research that led to the design and implementation of practical 3D animation methods to visualize multiply-articulated construction equipment in 3D animations of simulated construction operations. Using principles of forward and inverse kinematics, the writers designed and implemented generic virtual pieces of articulated construction equipment that accept task-level instructions from external software processes. DES models can configure and instantiate specific pieces of such equipment and instruct them to perform construction tasks using simple parametric text statements that embody a construction work-like terminology. Once instructed to perform specific tasks (e.g., load soil), these “smart” pieces of equipment (e.g., backhoes) automatically decipher the sequence and amplitudes of the elemental motions their components (e.g., boom, stick) must undergo to accomplish those tasks. The animation methods are implemented in a software tool called KineMach that integrates as an add-on with the VITASCOPE visualization system.     

Applicability of 4D CAD in Civil Engineering Construction: Case Study of a Cable-Stayed Bridge Project

Four-dimensional (4D) computer-aided design (CAD) has been credited with improving construction planning procedures. The integration of three-dimensional CAD with schedule information has enabled the effective detection of design and planning flaws in many construction projects. However, the benefit of 4D CAD has been centered on architectural constructions, as other areas such as civil infrastructure have seldom been the target of 4D CAD application. This paper presents a case study in which a cable-stayed bridge construction was analyzed and modeled using the 4D graphic simulation approach. The cable-stayed bridge was chosen for the case study because it suitably represents the complex nature of modern civil infrastructure. 4D CAD models were developed at three different levels of detail: activity, discrete operation, and continuous operation. The clear definitions of the three levels of detail of 4D CAD and their application results for the cable-stayed bridge are presented herein.     

Human-Assisted Obstacle Avoidance System Using 3D Workspace Modeling for Construction Equipment Operation

Equipment operation on construction sites is a major source of construction accidents and injuries related to crushing, electrocution, and falls. Primarily, this is because the operator’s field of view, reaction speed, attention, and depth perception are limited, and also because the construction site is a dynamic environment. Accelerating advances in sensing and equipment control sophistication present new opportunities to address these safety problems. The research described here provides the basis for the development of obstacle-avoidance systems that use models of objects generated by rapid three-dimensional (3D) workspace modeling methods and by sophisticated equipment control capabilities. An explanation of the proposed obstacle avoidance system, together with preliminary results, is presented. Implementation of this system in practice is feasible in the near term for critical and particularly hazardous operations.     

Visualizing Simulated Construction Operations in 3D

Simulation modeling and visualization can substantially help in designing complex construction operations and in making optimal decisions where traditional methods prove ineffective or are unfeasible. However, there has been limited use of simulation in planning construction operations due to the unavailability of appropriate support tools that can provide users with a more realistic and comprehensible feedback from simulation analyses. Visualizing simulated construction operations in 3D can significantly help in establishing the credibility of simulation models. 3D visualization can also provide valuable insight into the subtleties of construction operations that are otherwise nonquantifiable and presentable. This paper describes the methodology and a first version of a general-purpose 3D visualization system that is simulation and CAD software independent. This system, the Dynamic Construction Visualizer, enables spatially and chronologically accurate 3D visualization of modeled construction operations and the resulting products.