Carl T. Haas

Accurate and frequent construction progress tracking provides critical input data for project systems such as cost, schedule control, and billing. Unfortunately, conventional progress tracking is labor intensive, sometimes subject to negotiation, and often driven by arcane rules. Attempts to improve progress tracking have recently focused on automation, using technologies such as three-dimensional imaging, global positioning systems, ultra wide band (UWB) indoor locating, handheld computers, voice recognition, wireless networks, and other technologies in various combinations. However, one limit of these approaches is their focus on counting objects or milestones rather than value. In this paper, a four-dimensional model recognition-driven automated progress tracking system that transforms objects to their earned values is examined via the analysis of data from the construction of a steel reinforced concrete structure and a steel structure. It is concluded that automated, object oriented recognitio...

To improve the efficiency and effectiveness of the geometric data collection and processing for automated construction operations, a light-weight hybrid light amplification for detection and ranging (LADAR) system was developed to enable semi-automatic targeted data collection, such that an operator can quickly obtain high-quality data for parts of the workspace critical for an on-going operation. To further improve the precision of separating needed data from background and irrelevant data, using this custom-designed system, the relationships were investigated among the amplitude of data points, the scanning distance, time-of-flight, and the grayscales of objects. Thus, positive control of scanning position, orientation, field of view and amplitude is enabled. For construction robotics applications in confined spaces such as power plants, such positive control is a critical capability. The evaluation results indicate the efficiency and effectiveness of the semi-automatic targeted scanning approach on reducing the scanning time and data size, and the effectiveness of the proposed target-focused data collection approach.

Automated earned-value tracking

Current applications of BIM in the architecture, engineering and construction (AEC) industry are primarily limited to presentational purposes for clients, design clash detection, walk-through simulations, 4D animations, and on-site construction coordination. This paper examines the use of BIM as a platform to perform labor productivity studies considering alternative construction methods. This research exploits the CIS/2-standarded steel structural information within existing steel BIM and integrates the model with a unit rate labor productivity and material attributes database to perform an evaluation of the productivity impact of using quick connection steel systems on a typical industrial project. The results of analyses show that the proposed steel connection system used 38% fewer work hours than conventional steel connection (bolt and weld) systems did on the model project. The impact of the proposed construction method on the model project's schedule performance and work packages both before and after adopting the innovation were presented.

Concrete activities are typically critical to a project's schedule, therefore examining how to improve their labor productivity can have a direct impact on a project's overall performance. As part of a research program to improve construction productivity sponsored by the Construction Industry Institute (CII), the authors investigated innovations in the concrete trades and their impact on labor productivity. The innovations studied were 100ksi steel reinforcement, self-consolidating concrete (SCC), and modular formwork. The 100ksi reinforcing steel study analyzed a typical beam cross-section and compared its total weight to that of a typical 60ksi reinforcing design. Often, high strength reinforcing steel is a lower cost alternative to a standard design due to lower amounts of steel. The SCC study collected quantities and unit rates of SCC and a comparable conventional mix at several projects. The projects using SCC had faster placement unit rates compared to conventional concrete mixes. Modular formwork was found to have significant advantages in productivity over stick-built formwork systems. From the analysis of a sample project, modular formwork gains a cost advantage at varying floors based on local labor rates. The findings should help management understand performance of these concrete innovations when considering their use.

Materials tracking and locating, which can be accomplished through various technologies and data sources, are key elements affecting construction productivity. The need for developing fundamental methods to take advantage of the relative strengths of each technology and data source while dealing with their limitations motivates the development in this paper of data fusion methods for improving materials location estimation. Particular attention is paid to situations in a construction environment in which radio-frequency identification (RFID) tags are attached to each piece of material, and the materials may be repeatedly moved around the site. The construction dynamics, the high noise ratio, and the limitations of the utilized sensing systems result in imperfect data that is imprecise and uncertain. A key challenge is using this imperfect data to improve accuracy and precision while maintaining cost-effectiveness and scalability. To address this issue, a hybrid data-fusion method was developed to increase...

Data fusion can be defined as the process of combining data or information for estimating the state of an entity. Data fusion is a multidisciplinary field that has several benefits, such as enhancing the confidence, improving reliability, and reducing ambiguity of measurements for estimating the state of entities in engineering systems. It can also enhance completeness of fused data that may be required for estimating the state of engineering systems. Data fusion has been applied to different fields, such as robotics, automation, and intelligent systems. This paper reviews some examples of recent applications of data fusion in civil engineering and presents some of the potential benefits of using data fusion in civil engineering.

Successful, large scale field trials were conducted on two sites in Texas and Toronto using an integrated system of RFID tags, GPS technology, map software, and hand held computing to automatically track materials in the projects' respective lay down yards. This paper addressed the unresolved research question, that how will this technology impact projects if it is implemented upstream in the supply chain in an integrated and automated materials management system? This question is addressed by modeling the impact of automated materials tracking technology on increasing visibility within the construction supply chain. It is concluded that automated materials tracking has the potential to improve construction productivity, cost, and schedule performance.

This paper presents a new approach that allows automated recognition of three-dimensional (3D) computer-aided design (CAD) objects from 3D site laser scans. This approach provides a robust and efficient means to recognize objects in a scene by integrating planning technologies, such as multidimensional CAD modeling, and field technologies, such as 3D laser scanning. Using such an approach, it would be possible to visualize the 3D status of a project and automate some tasks related to project control. These tasks include 3D progress tracking, productivity tracking, and construction dimensional quality assessment and quality control. This paper provides an overview of the developed approach and demonstrates its performance in object recognition and project 3D status visualization, with data collected from a construction job site.

The highly influential Brundtland report released in 1987 was the first document to define the three pillars of modern sustainable development as environmental, social, and economic. The Rio Summit in 1992, the Kyoto Protocol in 1997, and the Johannesburg Meeting in 2002 followed up with primary focus on the needs of society and the environment. Economic issues were secondary at these meetings. This movement was the beginning of what has been passed down to the construction industry as sustainable construction. Within the industry, however, confusion reigns, and attitudes toward sustainable construction vary wildly. Understanding perceptions of sustainability in the industry would help to navigate a path towards a common understanding of the issues, to reach a point from which a reasoned dialogue could ensue concerning the relative merits of different approaches to sustainability and to sustainable construction itself. To understand perceptions of sustainability in the construction industry, a survey of c...