Use of GIS and Topology in the Identification and Resolution of Space Conflicts

Construction activities need space on the jobsite for their execution. Workers, equipment, materials, temporary facilities, and the developing structure share the limited jobsite space during the construction period. Multiple types of spaces for different purposes on various locations are required to execute various activities at different times. Hence, space planning helps provide a safe and productive environment. Planners mentally link two-dimensional (2D) drawings and execution schedules to generate dynamic multiple types of space requirements, which is a complex task. Therefore, researchers suggest the use of four-dimensional (4D) modeling and building information modeling (BIM) for space planning. Both simulate the construction process by linking the execution schedule with a three-dimensional (3D) model to visualize the construction sequence in space planning. However, both still lack features such as topography modeling and geospatial analysis, which affect space planning. In this work, 4D geographic information systems (GIS) were used for space planning that facilitates topographic modeling, different types of geospatial analyses, and database management. GIS was also used to generate multiple types of spaces corresponding to various activities. A feature attribute table (FAT) associated with each space describes when, where, and how long that space will be required on the jobsite. GIS-based area topology was implemented through a set of validation rules that define how working areas have to share the jobsite. A GIS-based methodology that enables space planning, time-space conflict identification, and conflict resolution prior to the construction was developed and implemented.     

Feasibility Study of 4D CAD in Commercial Construction

This paper concludes that 4D models are a useful alternative to project scheduling tools like CPM networks and bar charts. They enable more people to understand a schedule quickly and identify potential problems. By developing a 4D model for a commercial construction project, we were able to detect the incompleteness of the original schedule, find inconsistencies in the level of detail among the schedule activities, and discover an impossible schedule sequence. We were also able to anticipate potential time-space conflicts and accessibility problems. The results of the case study show that 4D models are effective in evaluating the executability of a construction schedule. The case study also highlighted the need for improvements to 4D tools. 4D tools should include bar charts, component lists, and annotation tools in their graphical user interface. Automating schedule data preparation and 4D model generation in the design stages of a project can expedite 4D model development and use. Users need to be able to generate 4D models at multiple levels of detail and generate and evaluate alternative scenarios rapidly.     

Four-Dimensional Visualization of Construction Scheduling and Site Utilization

Four-dimensional (4D) models link three-dimensional geometrical models with construction schedule data. The visual link between the schedule and construction site conditions is capable of facilitating decision making during both the planning and construction stages. The emphases of these 4D developments have often been placed at the level of construction components. Practical features assisting site management are at times lacking in the following areas: (1) generation of site usage layouts; (2) estimation of quantities of construction materials; and (3) cost evaluation. In order to pinpoint these deficiencies, the objective of this work is to enable visual study of the effects of job progress on the logistics and resource schedules. This paper presents a 4D visualization model that is intended both to help construction managers plan day-to-day activities more efficiently in a broader and more practical site management context and to thereby add to our knowledge and understanding of the relevance of modern computer graphics to the responsibilities of the construction site manager. A brief site trial of the software is described at the conclusion of the paper.     

Construction Scheduling and Progress Control Using Geographical Information Systems

Traditional scheduling and progress control techniques such as bar charts and the critical path method (CPM) fail to provide information pertaining to the spatial aspects of a construction project. A system called PMS-GIS (Progress Monitoring System with Geographical Information Systems) was developed to represent construction progress not only in terms of a CPM schedule but also in terms of a graphical representation of the construction that is synchronized with the work schedule. In PMS-GIS, the architectural design is executed using a computer-aided drafting (CAD) program (AutoCAD), the work schedule is generated using a project management software (P3), the design and schedule information (including percent complete information) are plugged into a GIS package (ArcViewGIS), and for every update, the system produces a CPM-generated bar chart alongside a 3D rendering of the project marked for progress. The GIS-based system developed in this study helps to effectively communicate the schedule∕progress information to the parties involved in the project, because they will be able to see in detail the spatial aspects of the project alongside the schedule.     

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.     

Empirical Study on the Merit of Web-Based 4D Visualization in Collaborative Construction Planning and Scheduling

This paper reports an empirical study that tested the usefulness of Web-based four-dimensional (4D) construction visualization in collaborative construction planning and scheduling. Several recent construction projects have employed 4D visualization to better understand the construction schedule and make proactive decisions to prevent logical errors in the construction sequence. Other groups have shown that construction information management with asynchronous Web-based communication can improve decision making among dispersed industry practitioners. It seems reasonable to anticipate that combining 4D visualization with Web-based information management would facilitate dispersed industry practitioners to make collaborative decisions for construction planning and scheduling. The empirical study presented here reports how experiment participants at separate locations collaboratively detected logical errors in a construction schedule when the 4D visualization model of the schedule was represented on the Web browser. Our results show that teams using 4D models detected logical errors more frequently, faster, with fewer mistakes, and with less team communication, than teams using 2D drawings and bar charts. These findings show industry practitioners empirical evidence that Web-based 4D construction visualization can improve team collaboration on construction planning and scheduling.     

Automated Generation of Construction Plans from Primitive Geometries

Current construction simulation systems need detailed architectural models and schedules in order to estimate costs and visualize the construction process. However, the process of developing a building model, formulating a schedule, and eventually synchronizing them is a time-consuming and laborious process. When changes occur, the model and schedule must be modified or rebuilt using the same time-consuming and laborious process. Therefore, systems of this kind are used only for some demonstrations. This paper describes a new way to automate construction simulations using simple architectural information and predefined “construction method templates.” A number of construction method templates are computer readable and are stored as a knowledge base. The writer proves the concept by implementing a computer system to process building models and construction methods. The concept allows designers and construction engineers to build a model and simulate construction processes in a short period of time in the early stage of construction projects.     

Prototype Tool for Mechanical, Electrical, and Plumbing Coordination

Effective mechanical, electrical, and plumbing (MEP) coordination requires recalling and integrating knowledge regarding design, construction, and operations and maintenance of each MEP system. Currently, the MEP coordination process involves a series of meetings where representatives from each MEP trade overlay drawings of their respective systems to detect and eliminate numerous types of interferences. Tailored computer tools used to design and fabricate MEP systems almost always generate these drawings, but no knowledge-based computer technology exists to assist in the multidiscipline MEP coordination effort. The purpose of this research was to develop a technology that integrates a number of knowledge bases—design criteria, construction, and operations and maintenance—into a knowledge-based system that is able to provide valuable insight to engineers and construction personnel, to assist them in resolving coordination problems for multiple MEP systems. This research provides a foundation for future researchers to build from and for industry to create a revised work process, using information technology, to assist in multidiscipline coordination efforts.     

Methodology for Integrated Risk Management and Proactive Scheduling of Construction Projects

An integrated methodology is developed for planning construction projects under uncertainty. The methodology relies on a computer supported risk management system that allows for the identification, analysis, and quantification of the major risk factors and the derivation of their probability of occurrence and their impact on the duration of the project activities. Using project management estimates of the marginal cost of activity starting time disruptions, a heuristic procedure is used to develop a stable proactive baseline schedule that is sufficiently protected against the anticipated disruptions that may occur during project execution and that exhibits acceptable makespan performance. We illustrate the application of the methodology on a real life construction project and demonstrate that our proactive scheduler generates baseline schedules that outperform the schedules generated by commercial software packages in terms of robustness and timely project completion probability.     

Automated Generation of Work Spaces Required by Construction Activities

To provide a safe and productive environment, project managers need to plan for the work spaces required by construction activities. Work space planning involves representing various types of spaces required by construction activities in three dimensions and across time. Since a construction schedule consists of hundreds of activities requiring multiple types of spaces, it is practically impossible to expect project managers to specify manually the spatiotemporal data necessary to represent work spaces in four dimensions. This paper presents mechanisms that automatically generate project-specific work spaces from a generic work space ontology and a project-specific IFC (industry foundation class) based 4D production model. The generation of these work spaces leads to a space-loaded production model. Within this model, work spaces are represented as being related to the relevant construction activities and methods and as having attributes that describe when, where, and how long they exist, and how much volume they occupy. These space-loaded production models enable richer 4D CAD simulations, time-space conflict analysis, and proactive work space planning prior to construction.     

Point-Cloud-Based Comparison between Construction Schedule and As-Built Progress: Long-Range Three-Dimensional Laser Scanner’s Approach

This research compares the work process at a construction site with the original construction schedule using point-cloud records that were retrieved using a long-range 3D laser scanner. The comparison was used to quantify the differences as a reference for the verification and modification of the original building design. This study compared 4D computer models with 3D clouds of a campus building. The differences could easily be identified from the perspectives and elevations of different views. To determine the degree of progress more precisely, a slice of clouds was defined to show the differences when compared with a cross section of a computer model. The format of the point cloud provided a new way to inspect construction progress.     

Automating Schedule Review for Expressway Construction

An expressway project is often divided into subprojects with different tendering packages, and carried out by several general contractors that apply different scheduling practices. Each schedule may contain hundreds of activities, each of which is associated with multiple pay items that determine its earned monetary value. With such huge amount of information, the reviewer can only check a sample piece of information, and the quality of review highly depends on the reviewer’s experience and devotion. Automated schedule review provides a solution to reduce such problems encountered in the industry. This paper presents a module-based schedule generation and review model, which includes a predefined set of network modules, network builder assistant computer system that helps schedulers manage and reuse the modules to build a new schedule, and another computer system network review assistant (NRA) that helps reviewers review schedules. The NRA uses generalized rule forms to represent the schedule critique knowledge collected from the industry. When potential errors are found, the NRA adopts case-based reasoning to suggest possible correction based on similar cases. The evaluation conducted by the practitioners using real projects indicates that NRA reduces review time, and provides more accurate review on finding activities and related pay items not conforming to standards, and reminding users of important but often omitted activities.     

Constructing a Complex Precast Tilt-Up-Panel Structure Utilizing an Optimization Model, 3D CAD, and Animation

This paper presents the concept used to construct a complex residential tilt-up-panel structure utilizing three-dimensional (3D) modeling and animations. The residence comprises of 108 precast concrete panels of varying rectangular shapes with “dog legs” and window and door “cutouts” that look like an assembled jigsaw puzzle. The erection and installation procedure called for a maximum panel-to-panel joint tolerance of 1.27?cm (0.5?in.), often in 90° joints between panels. 3D animations were used to experiment with the construction process on the computer screen prior to construction in order to avoid potential costly on-site errors. In addition, the 3D animations were also used as a training tool for the contractors. This paper focuses on describing the methodology used to integrate a crane selection algorithm and optimization model with 3D modeling and animation for the selection, utilization, and location of cranes on construction sites. Analytical optimization processes were used to decrease the traveling time and distance of the selected crane, to improve the crane lifting sequence and to minimize the use of panel casting slabs.     

Efficient Repetitive Scheduling for High-Rise Construction

A new scheduling and cost optimization model for high-rise construction is presented in this paper. The model has been formulated with a unique representation of the activities that form the building’s structural core, which need to be dealt with carefully to avoid scheduling errors. In addition, the model has been formulated incorporating: (1) the logical relationships within each floor and among floors of varying sizes; (2) work continuity and crew synchronization; (3) optional estimates and seasonal productivity factors; (4) prespecified deadline, work interruptions, and resource constraints; and (5) a genetic algorithms-based cost optimization that determines the combination of construction methods, number of crews, and work interruptions that meet schedule constraints. A computer prototype was then developed to demonstrate the model’s usefulness on a case study high-rise project. The model is useful to both researchers and practitioners as it better suits the environment of high-rise construction, avoids scheduling errors, optimizes cost, and provides a legible presentation of resource assignments and progress data.     

Merging Architectural, Engineering, and Construction Ontologies

Ontologies have emerged as a means of facilitating semantic interoperability among computer systems. However, recognizing that no single universally agreed-on ontology can ever be defined for a domain, a tool that allows ontologies to interoperate becomes essential to semantic interoperability. This paper presents an ontology integrator (Onto-Integrator) for facilitating ontology interoperability within the architectural, engineering, and construction (AEC) domain. The Onto-Integrator offers a heuristic for ontology merging, including the merging of concept taxonomies, relations, and axioms. Unlike existing tools, the integrator addresses ontology merging requirements that are specific to the AEC domain. The integrator heuristic was implemented into a prototype Web-based tool and was evaluated through a focus group.     

Particle Swarm Optimization for Preemptive Scheduling under Break and Resource-Constraints

This paper introduces a particle swarm optimization (PSO)-based methodology to implement preemptive scheduling under break and resource-constraints (PSBRC) for construction projects. The PSBRC under study allows the preemptive activities to be interrupted in off-working time and not to resume immediately in the next working period because all the limited resources are to be reallocated during a break. The potential solution to the PSBRC, i.e., a set of priorities deciding the order to start the activities or restart the interrupted activities, is represented by the multidimensional particle position. Hence PSO is applied to search for the optimal schedule for the PSBRC, in which a parallel scheme is adopted to transform the particle-represented priorities to a schedule. Computational analyses are presented to verify the effectiveness of the proposed methodology. This paper provides an attempt to make use of preemption and break for the resource-constrained construction project with the objective of minimizing project duration.     

Research in Modeling and Simulation for Improving Construction Engineering Operations

Construction simulation, a fast-growing field, is the science of developing and experimenting with computer-based representations of construction systems to understand their underlying behavior. This paper provides a history of construction simulation theory, explores the CYCLONE modeling methodology and its major subsequent developments, examines the development of the Simphony.NET and COSYE modeling environments and their functionality as more generic simulation platforms, and reviews effective strategies for applying simulation in construction. A construction simulation case study is presented that illustrates one successful approach for adopting simulation technology in the industry and outlines the benefits to industry of integrating these technologies. The paper provides an overview of long-term simulation initiatives leading to the next generation of computer modeling systems for construction, where simulation plays an integral role in a futuristic vision of automated project planning and control.     

VDC and the Engineering Continuum

In this paper, we provide a brief overview of the historical underpinnings of the design-construction industry and the development of design engineering and construction engineering as independent but related subdisciplines of civil engineering. The effects of the first and second generation of computer tools on design engineering are identified. The complementary and evolving definitions of construction engineering and design engineering are examined, specifically in the context of structural design engineering activities and deliverables and the corresponding construction engineering activities and deliverables. The concept of an “engineering continuum” is introduced, and the process is recast in light of that concept. Several case studies are used to examine the promise of third generation design-construction computing technologies such as virtual design and construction and their potential beneficial impact on the cost and schedule of the typical design-construction project. Refinements to the definitions of construction and design engineering that have the potential to maximize the benefits of third generation technology are proposed with an eye toward the form of fourth generation computing technologies that are on the horizon.     

Development of a Web-GIS Based Geotechnical Information System

The construction industry benefits greatly if all the existing three-dimensional (3D) geotechnical subsurface information of a city/country can be accessed at any time using the Internet. The geographic information system (GIS) is well suited for such problems; however, GIS was originally developed for two-dimensional planes. Recently, some 3D capabilities for GIS have been developed, but these capabilities in their present form alone are not suitable for storing and presenting three-dimensional geotechnical data. One way to overcome the limitation of data storage is integration of GIS with a relational database management system (RDBMS). A Web-based geotechnical information system that can perform online spatial queries, generation of professional borelogs, and various geotechnical analyses was developed. The system has been developed as a national geotechnical information system (GeoInfoSys) for Singapore. The system provides easy-to-use functions to: (1) locate and purchase boreholes of interest; (2) view borelogs and cross sections that are generated online; (3) provide downloadable data in a standard format for downstream analysis; and (4) perform geotechnical queries using a geotechnical search engine (GSE). The geotechnical information was stored in a digital format rather than as static images; this provides many opportunities to explore the data, and these opportunities are discussed herein.     

Role of Simulation in Construction Engineering and Management

Construction simulation is the science of developing and experimenting with computer-based representations of construction systems to understand their underlying behavior. This branch of operations research applications in construction management has experienced significant academic growth over the past two decades. In this paper, the author summarizes his views on this topic as per his Peurifoy address, given in October 2008. The paper provides an overview of advancements in construction simulation theory as reported in literature. It then summarizes the key factors that contribute to successful deployment of simulation in the construction industry, and the key attributes of problems that make them more amenable for simulation modeling as opposed to other tools. The paper then provides an overview of long-term simulation initiatives leading to the next generation of computer modeling systems for construction, where simulation plays an integral role in a futuristic vision of automated project planning and control.