components and fixtures for more complex facilities, such as hospitals and high-rise office buildings, is also part of this trend. In addition, individual heavy components, such as large power-generation boilers, are beginning to be manufactured in the factory and then disassembled, shipped separately, and reconnected in the field using advanced manufacturing techniques.
However, not all technological trends point toward fabrication away from the job site. For example, the automation of field welds by means of standardized robotic devices will provide reliability at the job site as high as that in the factory, and may even be more cost-effective for those materials that are best shipped in smaller pieces. We must be careful to balance our assessment, since advances are taking place on both sides of the fabricator-job site equation.
The use of computerized expert systems for construction applications is a growing trend. Current examples include systems to diagnose vibration problems in rotating machinery and systems to verify weld performance qualifications. Extensive research to develop construction-based systems is under way at both the U.S. National Bureau of Standards and the U.S. Army Corps of Engineers in such areas as evaluation of concrete durability and building air infiltration dynamics. The use of expert systems will probably be the most important application of artificial intelligence techniques for construction over the next decade. By the turn of the century, there is good potential for increased use of self-directed robots controlled by expert systems. Such advanced-application robots would finish concrete and spray paint buildings (already being done in Japan), apply sprayed insulation to structural steel members, and even install structural steel. Robots in construction would differ from those in a manufacturing or production line setting, where the robotic units generally are stationary and tasks are performed on products as they move by. In construction, the building is stationary and the robot would have the ability to move about in the performance of its tasks.
Technologies such as laser range-finding and geodetic positioning can be used to pinpoint exact locations, to automate storage areas on the job site, and to set guide tracks for remotely operated vehicles. These technologies will gradually be integrated into a coherent system for the highly automated control of certain job site activities.
Automation in the construction sector is usually seen in terms of robotics, and the development and application of robotic systems in all industry sectors is relatively new. According to the EPRI Journal*, only 6,000 robots were delivered in the United States by the end of 1981, and most of those were