Technological Advances in the Construction Sector
IN THE EUROPE OF THE MIDDLE AGES, craftsmen with varying levels of skill manufactured carts one at a time. Even the best of these carts provided little more than basic transportation. Yet in the same cities of Europe, at the same time, master masons and builders created incredible stone cathedrals, using principles of design and construction that were breathtaking for the time.
Today the technologies of both manufacturing and construction have changed, but not nearly to the same degree. Part of the reason for the different degrees of change can be found in the basic differences between manufacturing and construction. Construction is essentially the process of moving and assembling materials and equipment into a completed, operational facility. Although many construction operations are repetitive, they are performed neither in a fixed sequence nor at a fixed location. Also, since construction, unlike manufacturing, rarely involves production of a standardized product, the demands on the material supply functions of buying, expediting, receiving, warehousing, and delivery are much more complex. For many of these reasons, the basic construction process of building stick by stick, piece by piece, has remained unchanged since the Middle Ages.
But that basic process is critical to the world’s economy. Construction is larger than any single manufacturing segment of the U.S. economy. It contributed $174 billion, or 4.7 percent of the gross national product (GNP), in 1986, whereas all manufacturing contributed 22 percent of the GNP. Residential work was 47 percent of the total contract awards. Commercial work awards were 19 percent. Heavy construction—which includes utilities, pipelines, and other energy work—was 17 percent. The picture is equally impressive beyond our borders. For example, in 1984, the value of new
construction put in place, defined as new residential and nonresidential construction but generally excluding maintenance and repair construction, was $317.2 billion for the Soviet Union, $200.1 billion for Japan, $71.3 billion for the Federal Republic of Germany, and $43 billion for the United Kingdom.
The Great Wall of China, the space shuttle launch facility, a petrochemical plant, a neighborhood shopping center, the Erie Canal, a nuclear power plant, a single-family home—all are construction projects, yet each requires different skills and technologies. Collectively, they represent the many sectors of the construction industry.
The residential and commercial construction sectors involve the creation of facilities that are essentially structural in function. These facilities include the service utility systems necessary to support the people who use them, including power distribution, heating, ventilation, and lighting. By contrast, the industrial sector creates facilities incorporating industrial process systems and equipment designed to produce an end product, such as automobiles, textiles, chemicals, refined metals, or electric power. The heavy civil sector encompasses major public works, including dams, highways, airports, and water distribution and sewage facilities—in short, most of what we now call infrastructure.
Over the past 10 years the impacts of technology on the construction sector have varied by the type of construction being performed, but in general, the changes have been largely evolutionary. Today’s constructors have not come as far from the cathedral builders of the Middle Ages as today’s automakers have from the cartwrights. In the future, however, there is a high potential for significant developments that will change the basic nature of construction. These developments will capitalize on advances already apparent in other sectors. They will be global in origin and in scope, with applications driven by both continued technological innovation and competitive pressures. They will include direct technological impacts on the performance of specific construction activities and major changes in the manner of managing a construction business.
This paper addresses the most significant changes in construction by examining technological trends and how they affect the entire construction sector. These trends fall into four major areas: construction-related design; construction equipment and methods; automation and expert systems; and construction management.
Computer-aided design, or CAD, is now a fact of life in the design-construction process. The benefits to the construction industry already have been significant in several respects. These include reduced interferences, which are instances where the design of separate systems, such as electrical
conduit and high-voltage alternating current ducting, compete for the same physical space; better feedback to the design cycle on the impact of constructability enhancements, which are design factors intended to simplify construction and reduce job hours; and improved communication between the designer and supplier to ensure that the right component is available at the construction site when it is needed.
CAD also has been a positive adjunct to the process of “fast-track” construction, an approach in which engineering and construction proceed concurrently. In this approach, construction might begin when 40 percent of the project’s design is completed, rather than waiting for the design to be 100 percent finished. CAD systems, which are used extensively in commercial and heavy industrial construction but have yet to prove cost-effective in residential work, are able to generate design information faster and more accurately and can implement midstream changes with more ease than conventional drafting can. Construction work is able to begin earlier because the design is more rapidly developed. The savings in time-related design costs can be significant; in the time it takes an engineer at a drafting table to produce one drawing, an experienced CAD technician can produce four.
There are several ways to classify major CAD trends, including the trend toward engineering workstations as special-purpose computer terminals dedicated to the automated design process. Such standard design details as typical civil, structural, piping, and electrical schematics are now available on many CAD systems. The trend toward lower-cost, more powerful workstations will continue indefinitely, although the cost per unit will probably stabilize. Further, most design depictions will be achieved by means of three-dimensional computer models with sophisticated, standardized design symbols and aids. There will be a reduced need for today’s orthographic and isometric drawings when three-dimensional models are available.
With the rise in CAD has come the need for common CAD products. Compatibility is still a problem, because vendors continue to emphasize enhanced features on their own systems, as opposed to compatibility with other systems. Some standardization efforts have made considerable progress but require further efforts to be fully effective. For example, in the area of initial graphics exchange specification (IGES), a loosely organized group of CAD vendors, users, and manufacturers has recently undertaken a collaborative effort to develop IGES guidelines for standardized design symbols and common design standards for all CAD machines.
Improvements are continuing in checking the interfaces between standard systems, such as between mechanical and structural systems or between electrical and plumbing systems, including the use of expert systems in limited ways. Closer coordination at these interfaces reduces the risk of overruns in construction cost and increases the reliability of the construction process.
One example of the use of expert systems developed in the Bechtel Group is a three-dimensional coordinate system that allows people to “walk through” a facility before it is built. It significantly benefits construction by reducing interferences because the facility and its systems are displayed in three dimensions, not just the two dimensions of traditional plan and section drawings. The system automatically raises a flag when two components in the drawings occupy the same physical space, and allows corrections to be made before the problem reaches the field. Future improvements in design capabilities will allow closer linkage of design to operations and maintenance, better life-cycle costing linked to design alternatives, and improved methodologies for cost estimating and procurement linked to electronic design program software.
These enhanced design capabilities allow earlier review of all designs from a constructability viewpoint, benefiting all members of the project team. Further, linkage of design documents to computerized simulation of the built facility is gradually becoming common, optimizing design from an operational viewpoint. These trends benefit the owner, who will push hard to include them as a standard part of the design process.
The drive toward CAD has implications beyond the improvement of the design process. For example, electronic communication of data among the owner, designer, material supplier, and builder of a project is a very significant trend, so the industry must prepare for all project team members to have common networked workstations and to meet electronically. Bar-code technology is now playing a role in tracking and locating materials and equipment, with identification codes linked directly to CAD systems.
CONSTRUCTION EQUIPMENT AND METHODS
Construction equipment, in general, assists in moving and assembling materials. Emphasis has been on moving larger pieces or on moving material faster, with greater reliability and accuracy. In the recent past, improvements in such conventional construction practices as slipforming—the use of a moving form for pouring concrete—have continued on an incremental basis. Heavy equipment for use at the job site, such as cranes, conveyors, and earth movers, continues to become more efficient. Dramatic improvements have been made on specific machinery, such as laser-based survey equipment, laser-guided excavation equipment, and new tunneling equipment.
Today’s job site also features the more prominent use of advanced materials: honeycomb structures and foams for greater strength; polyester fiber for improved durability in the refitting of sewage and water pipes; fiberglass fabric for rapid repair work; and specialized materials for arid, arctic, undersea, radioactive, and extraterrestrial environments. However, the basic building blocks of construction—steel and concrete—are expected to remain
relatively unchanged. Specific qualities of these materials will be improved, but no major substitute material is on the horizon. All types of construction are being affected by these trends in construction equipment, methods, and materials, although customer preferences are a significant restraint in some areas. The preference for wood and natural materials over plastics in residential construction is a good example of this restraint.
Off-site fabrication and assembly is a trend that has been clearly established. Equipment modules of 2,500 tons are no longer uncommon, and the trend toward even larger modules will continue. For example, lifts of 10,000 tons have already been made in the construction of North Sea oil platforms. Although certain constraints still exist, such as proximity to water transport and the limits of lifting equipment, the pattern of maximum off-site assembly and close coordination of delivery logistics is expanding.
Factory assembly of components has several inherent advantages over job site assembly. For example, a heat exchanger once assembled on-site piece by piece is today fabricated in a vendor’s shop on a structural steel skid complete with ladders, railings, wiring, piping, and instruments and is shipped essentially ready to plug into other modules on the site. Assembly performed in the controlled environment of the fabrication shop has distinct advantages: It avoids the climatic extremes of a field site and benefits from better management of material and parts inventories, maximizing productivity and quality. Similar shop fabrication processes also are used for instrument panels, compressors, pump units, and switch gear buildings. Schedule time is saved, because more assembly work can be done in parallel with on-site activity. Trade interferences are tested and resolved earlier. “As-built” drawing documentation is minimized, thus reducing the potential for design errors or omissions. Labor costs are reduced because (1) the controlled shop environment permits increased automation, which enhances quality and productivity; and (2) shop-performed assembly generally has lower wage rates than comparable work done by field construction personnel.
The construction site is characterized by a high level of activity as men and equipment move materials, tools, and design information from one place to another. A certain degree of inefficiency is normal, depending on the size and complexity of the project, the constraints of procedures, and the degree and effectiveness of detail planning and scheduling. As the use of modular and prefabricated construction methods increases, this inefficiency will decrease. This will hasten the use of robots, which will reduce cost and improve safety; increase productivity, which will shorten construction schedules; and allow for automatic on-line inspection, which will yield a higher-quality product.
Modularization applications, to some extent, will follow the path from simple to complex components. Assembly of similar warehouse and low-rise office buildings is now fairly common. Assembly of similar structural
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.
AUTOMATION AND EXPERT SYSTEMS
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
installed in the preceding 7 years. According to Robotic Industries Association estimates, the total number of robots installed in the United States rose to more than 20,000 at the end of 1985, up from 14,500 at the end of 1984. Some experts predict that as many as 100,000 robots may be at work in this country by 1990, with more than 1 million projected worldwide. These are classic robots—programmed, repetitive machines such as those that are used in production line operations. However, the technology is directly transferable to remotely controlled robots more applicable to the construction site, and it is expected that the development and application of such robots will parallel the expansion of production line robots. First-generation construction robots now on job sites are really microprocessor controllers retrofitted to conventional construction equipment. The use of remote technology is accelerating in areas where laborers are performing repetitive tasks or working in a hazardous environment, or where quality can be improved by continuous inspection of the operation or product.
For example, at the Three Mile Island (TMI) nuclear facility in Pennsylvania, certain areas of Unit 2 are too highly contaminated for workers to enter and perform cleanup activities. As a result, robots—or more precisely, remotely controlled vehicles—have been used instead of humans to carry out decontamination assignments such as surveillance, washing of walls, removing radioactive materials from concrete surfaces, and suctioning sediment from the floor. “Rover,” the robot used at TMI, was developed by Bechtel engineers working with GPU Nuclear, Carnegie Mellon University, and the Electric Power Research Institute. It is a six-wheel-drive robot that can negotiate turns and climb over obstacles. It is operated by tether from a control room.
Feedback of as-built conditions is the step that closes the design-construction loop and will enhance robotic applications in construction. In this process, erection data from construction are fed back in real time and compared with the design data. Installations that exceed tolerances can then be corrected. Of critical significance in the field is the accumulation of deviations; although each of these deviations may be individually within construction tolerances, together they may be enough to defeat automated equipment. The feedback of as-built dimensions can eliminate this problem, as it is usually not necessary to construct to exacting tolerances, but only to know exactly where the construction is located. With feedback, succeeding elements can be adjusted to fit.
The use of robotics for construction, operations, and maintenance or design engineering activities has applications worldwide. For example, a Japanese company has used an articulated robot to weld small-diameter pipe. As a result of the high quality of the weld, the finishing process became unnecessary, and plans are being made to automate all processes by combining the robotized system with computer-aided design and computer-aided man-
ufacturing (CAD/CAM). A Finnish firm is developing a gantry-type welding robot capable of automatically joining ship sections up to 15 meters long. The robot is able to learn from its mistakes and make the needed adjustments. Other firms have developed an approach to the robotization of painting and blasting and the development of wall-walking robots that use vacuum pads or magnets.
The construction management process—the system of controls that optimize the design, procurement, and construction process—is key to the ability of the construction industry to capitalize on technological innovations. The process of planning, scheduling, and cost control must address the interfaces between all disciplines and provide the framework that allows new technological developments to be assimilated efficiently into a construction project.
From the management perspective, such technological trends as the increased use of job site robots, with their high capital costs and 24-hour availability, demand improved just-in-time delivery systems for precise material scheduling. This, in turn, requires sophisticated computer data bases linked to design, purchasing, and warehousing systems to ensure effective management. In this sense, most large-scale construction work is becoming essentially fast tracked. In the fast-track approach, design and construction proceed simultaneously rather than waiting for engineering to be completed in advance of construction. This technique is intended to require less time for engineering and construction than is required in a conventional one-step-at-a-time approach. Fast-track construction can be used on any size project and refers to speed of completion rather than size. In addition to these general trends, specific evidence of the impact of technology on the construction management process can be cited, particularly in the areas of bulk staging activities, inventory, construction start-up, training, quality control, and information handling.
Earlier identification of bulk component requirements, allowing earlier bulk staging of commodities at predescribed locations, is a consequence of rapid design capability. We are essentially moving toward an assembly-line process for even the most complex construction sequences.
The application of a modified just-in-time method of supply to construction sites can be used as a method to guide job site activity. In this concept, minimum warehouse and lay-down areas are used, and only small items are inventoried. However, since the contract risks due to faulty delivery systems at the construction site are at least as onerous as those at the factory, we need to adapt factory-based just-in-time delivery schemes to the construction environment.
In job sites of the past, the first tools unpacked were the shovels. Today,
the first things out of the box are often computers. Terminals and graphic workstations give access to the released design documentation. Paper plotting, to the degree required, will be done at the job site. These computers provide communications links with the engineering office, the client, and relevant vendors or fabricators. Over time, the establishment of computer information networks will become a key start-up activity at construction sites, since it will be a crucial part of the construction management process.
The size of the skilled labor force required at the job site will continue to shrink as machines are used for more complicated tasks and to help manage site logistics. However, the people still needed will have to have higher skill levels to operate more complex devices. The required training process will place significant demands on the construction management staff.
The impacts of continued technological change on quality control practices in the construction sector must also be considered. For example, with more accurate robotic machines, we may see dramatic changes in two areas: reduced need to check certain construction devices that already have imbedded high reliability, and the availability of machines that improve the quality-checking process itself. All of these developments reinforce the emphasis the constructor must place on the reliability of the completed construction project. As capital costs rise along with such production costs as labor, raw materials, and energy, increased emphasis is placed on plant availability, a measure of the project’s reliability.
From an administrative standpoint, the proper management of change orders for a job already under way has always been a difficult task for the contractor, with often frustrating results for the entire project team. Improvements in information handling will include the gradual automation of much of the change order process, resulting in smoother activity on the project, savings in time and money, and added flexibility for the owner of the facility.
All of these developments point to the need for construction management personnel—especially site managers—who are able to marshal new technology and apply it effectively in an environment that historically has been less than progressive. Complex issues such as trade union practices and the inertia of field engineers and superintendents must be addressed. Restrictive craft union work rules and jurisdictional disputes have contributed to the steady advancement of the nonunion movement. The application of robots, advanced modularization, and other new construction techniques and methods will be successful only if craft labor and its leadership make a quantum jump in acceptance of new technology. Similarly, site management must plan the transition carefully to ensure that a positive “make-it-happen” attitude exists among both craft and supervisory staffs.
If these new techniques are to be effective, they will require a level of organization and discipline seldom seen on a construction site. Thus, management must be skilled both in the assimilation of new technology and in
the handling of the human factors issues arising from this technology. The challenge is significant and will require training in disparate fields including production control and human relations. The task is manageable, but past problems with the adaptation of limited technological advancements in the construction sector suggest that this issue may be the most difficult of all.
THE IMPACT OF TECHNOLOGY ON CONSTRUCTION MARKETS
Since before the building of the Pyramids, a fundamental business relationship has existed in the construction sector among the owner, the designer, the material supplier, and the builder. Technological change cannot destroy this relationship, but it will continue to cause subtle alterations in the patterns that characterize it. In particular, the increased capability to catalog and manipulate knowledge will enhance the role of those owners who become more involved in the study of options available to them. Further, the global availability of basic design-build capability will permit tighter competition on a technical level for conventional construction projects. The so-called first-of-a-kind projects involving sophisticated custom design and construction will still require specialized capabilities, and firms will meet these requirements using advanced tools and techniques. In the widest sense, construction itself will feel the impact from several continuing global trends: (1) a shift toward more decentralized market activity with more players, both large and small; and (2) increasing access throughout the world to more information about basic human needs such as food storage and sanitation, particularly in developing countries. The point here is that as knowledge is disseminated more broadly and deeply into global society, there will be increasing understanding of both the need for facilities that satisfy basic human needs and the knowledge of how these facilities can be built simply and cheaply.
Technology is changing the nature and shape of the markets served by the construction sector, just as it is changing specific activities in the construction process. One of the most obvious of these changes is the addition of new markets because of technological progress in general. Two examples are the so-called clean rooms required for the assembly of complex electronic components, and the gradual expansion of construction work related to the containment and disposal of toxic wastes. The design and construction of facilities for innovative sources of energy is an ongoing challenge. Extraterrestrial activity—construction in outer space—motivates unusual solutions and creates new possibilities. The more prosaic but no less important requirements of infrastructure replacement, such as underground urban utilities, call for extensive application of new construction capabilities to minimize costs and disruptions. Further, to the extent that technology allows a wider range of
design options to meet market needs, the construction sector will respond with new interactions with clients and diversification into new business lines.
Technology is also continuing to change the way we create and modify building codes. In the era before robotics and automation, code-setting required attention to a considerable number of safety factors based on the uncertainties allowed for in many design calculations. Despite the traditional constraints that retard the changing of codes, it is likely that various automated construction technologies will reduce physical quantity requirements and costs considerably, simply by reducing the overprotective limits in some of today’s codes.
In the next 10 years, the greatest technical impact in the construction sector is expected to come from improved management methods and automation. Advancements in management methods to improve productivity and schedule performance will employ automation and expert systems to a great degree. Construction design will see increased sophistication in the conceptual phase and real-time data base communications networks to support estimating, scheduling, and project management.
Procurement activities will improve by the use of CAD systems to provide a direct interface with major vendors and suppliers. Automated warehouses, staging areas, and related support facilities will also play key roles. In the construction process itself, expanded use of computerized scheduling, tracking, and control using real-time networks and robotics-assisted operations will play increasing roles, where practical, to meet quality, safety, and cost objectives.
Several major companies and government institutions throughout the world have active and comprehensive construction research programs, including companies such as Bechtel and countries such as the Federal Republic of Germany, Sweden, and the United Kingdom. These programs are executed sometimes in company laboratories. The companies are competing in all overseas markets. In Japan, for example, more than 50 construction companies have their own research facilities. Such laboratories are part of parent company activity to expand vertical market positions. Significant efforts are expended worldwide on applied research to develop new construction technologies. Although some firms liberally promote the more glamorous aspects of construction research and development as a marketing tool, many have planned seriously for improvements to their knowledge base. The knowledge gained by this research will undoubtedly improve their competitive edge for major construction jobs. All firms in the construction sector must reexamine the cost-effectiveness of their research and development commitments in relation to the competitive advantage they expect to derive.
In the future, design and construction, in general, will become ever more closely integrated. More effective design optimization studies and constructability decisions will be made during the engineering phase. We will, in effect, maximize the use of automated job site machinery by designing with it in mind. Procurement, as a generic process, will also be more closely tied to design decisions. Trade-offs among procurement, scheduling, and constructability will be more easily understood through improved, computerized analysis of procurement options.
Construction itself will undergo significant changes in methods of management and work performance. Technology is having major impacts on methods and systems for constructing all types of projects. The most significant challenge will be that of management coordination. Historically, the management of construction activity has been too reactive—dominated by archaic methods, restrictive trade union practices, and ineffective planning. In some ways, we are still building the cathedrals of the Middle Ages when we need to build space stations and advanced factories on earth.
The technological capability exists for vast improvement in our methods, and it will be our management effectiveness that determines our success in the long run. With the vision of what can be done and the commitment to make full use of available technology, the future for construction should hold many extraordinary developments.