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Construction: The five-dimensional world

Bryn Fosburgh
Senior President – Engineering & Construction, Emerging Markets
Trimble

New tools to capture and visualise geospatial data are spawning high-efficiency methods for construction and operations. As GIS technology moves indoors, it is creating a wave of new applications for contractors, facilities operators and emergency managers
 

The basics haven't changed: construction projects operate in five dimensions – schedule, cost and threedimensional positions. Scheduling and (increasing) costs have remained constant dimensions; however, in the coming years, the positioning components – geographic information systems (GIS) and geospatial technology – will expand from simple positioning to take a wider and deeper role in the construction and operation of buildings and facilities.

Accurate positioning and measurement have always been primary concerns in building and construction. Preconstruction surveys for engineering and environmental studies are common tasks; improvements must be accurately placed on the land and post-construction records are acquired and maintained for a variety of purposes. Over the past decade, conventional surveying technologies such as optical total stations and global positioning system or global navigation satellite system (GPS/GNSS) have done the bulk of the work for geospatial measurement. In addition to these primary sensors, handheld devices for measurement and data collection have played a steadily increasing role.

While many people perceive geospatial technology as georeferenced, high-density data (often gathered using remote sensing, imagery or scanning techniques) combined with analytical software, a broader definition works well for most purposes. For this article, we will discuss geospatial technology as the variety of ways used to collect, manage and utilise geographic information. This includes legacy technologies for positioning as well as new systems that are only now arriving in the market.

BUILDING AND CONSTRUCTION ARENA
There are several distinct segments in the construction industry. Heavy construction includes highways and transportation systems, waterworks, utilities and other infrastructure projects. Building construction ranges from large industrial, commercial and residential buildings down to individual homes and small business structures; these segments include both exterior layout and interior finishing. Regardless of size, most projects require some grading and site preparation. And while new construction plays a dominant role, redevelopment, renovation and restoration occupy a significant part of the construction industry.

Different types of projects require different contractors and skills. Large construction companies often deal with long-term projects covering large geographic areas and multiple layers of regulatory requirements. Smaller companies focus more on local projects with shorter time frames and simpler project plans.

Systems for measurement, management and analysis of geospatial information will be at the core of the work. But in many cases, the location of a given object is just one, sometimes minor, component of the body of knowledge about that object. Parallel to geospatial positioning technologies, new systems have emerged that offer new applications for building and construction. These "adjacent technologies" often do not provide traditional positioning data. Instead, they add value by providing additional information and efficiency to the work of collecting and using geospatial data.

As a result of these changes, many building and construction firms have changed the ways in which they utilise positioning; they no longer operate with just positions and measurements. Instead, they have become multilayered enterprises involved across multiple aspects of a project.

GEOSPATIAL TECHNOLOGY IN CONSTRUCTION
Advances in site positioning and data management have transformed construction sites. Aerial maps and pre-construction surveys are delivered directly to designers in digital format. Building plans and CAD files are loaded into field computers for layout on site, where professional surveyors conduct fieldwork using state-of-the-art instruments. One of the largest changes is in earthwork and grading, where 2D and 3D machine control is providing significant gains in productivity. A 2006 study in Germany by Caterpillar, our partner in construction automation, demonstrated that automated construction systems provide time savings of more than 50 percent and a 43 percent reduction in fuel consumption. A separate study on machine automation for excavation of a pipeline trench was conducted in 2008 by the School of Science and Engineering at Reykjavík University. The test showed that automated systems produced savings of more than 20 percent in machine time and fuel consumption and virtually eliminated costly overexcavation. In spite of the benefits, many construction companies have not adopted the new approaches.
 

Today, the economic climate is driving the change towards new technology. Construction is a very competitive business and productivity has become a fact of life to maintaining margins. Less productive firms may fall victim to companies that have invested in new technologies and processes. Larger companies have led the way and off-board automation (such as site surveys and layout) is the norm on large sites. Small to mid-size firms are now engaging new technologies as well.
 

The trend of increased automation of construction machines is closely tied to electronic design. Conventional, paper-based site plans or plan/profile diagrams must be converted to 3D design models of the site.

The models are then loaded into a machine's onboard computer, which compares the actual position of the machine against the design data and provides guidance to the machine or its operator. As automated processes take hold, hard copies of a site design may become redundant. However, this trend is tempered by the conservative nature of the construction business; paper plans remain at the core of many projects.

Geospatial systems also play an important role in construction project planning. As an example, consider a renovation and upgrade of a commercial building. Using a mobile mapping system, project owners can create detailed 3D models of the building and surrounding areas. Visualisation and simulation software uses the models to create realistic images of the project and its effects on nearby structures. Contractors can use the images to verify that there is adequate clearance for trucks, cranes and other large equipment to travel to the site and operate safely and efficiently. For retrofit or renovation work, 3D scanners create precise models of existing, often complex, structures. By using visualisation tools with the highly-detailed 3D models, architects and engineers can test designs in the virtual world before any construction takes place. This approach reduces the risk of costly rework when something doesn't fit correctly.

Interior commercial construction is making rapid inroads into automated processes using geospatial technologies. For example, interior tradesmen can use instruments and techniques similar to site surveyors. A worker canlay out and install hangers or floor penetrations for mechanical, electrical and plumbing (MEP) before the concrete floors are poured. This eliminates the need for drilling into the freshly poured floors.

Because the locations are stored in the project database, installers can verify that all of the fixtures have been marked and installed before concrete is poured. There may be hundreds of hangers and penetrations in a single floor, so the time savings from the automated layout are enormous.

MATERIALS IN MOTION: THE FIVE DIMENSIONS OF CONSTRUCTION
Asset and material management provide an important opportunity for efficiency on construction projects. Consider a vehicle dispatch system that uses GPS to track the location of a dump truck and plan efficient routes for the truck's tasks. This is typically a 2-D approach – a simple spot on a map. Much more can be done in such a situation. By using a mobile asset management system, it is possible to augment the truck's location and speed with information about its condition. Sensors on the truck can report temperatures, fluid levels, hours of operation and other parameters. This information can be cross-referenced against the truck's maintenance record. Any problems can be caught early and unneeded or duplicative maintenance avoided.

For materials management, a contractor's objective is to have the necessary materials in the right place at the right time. The geospatial approach to tracking building materials combines positioning with inventory management. To gather this data, we can combine RFID tagging with simple, compact GPS devices. For volumes of excavations and stockpiles, scanners and imaging systems can produce accurate measurements in a fraction of the time required for aerial photos or ground surveys.

A GEOSPATIAL EXAMPLE: CONSTRUCTION FOR ENERGY DEVELOPMENT
The capability of geospatial technologies is evident in the development of energy resources such as oil and natural gas. An energy project can cover thousands of square kilometers and requires accurate information both at large-scale and detailed levels. Developing the resources calls for a variety of construction and development disciplines.
 

Resource exploration and location is often done using mapping-grade GPS systems. Aerial imagery, including satellite images, provides base maps for planning access roads and pipelines. As well sites and pipeline routes are selected, technicians use mapping- grade GPS to locate areas affected by environmental or cultural regulations. Survey-grade measurements are needed to determine cadastral information for leasing and rights-of-way and to create engineering maps for road crossings and other complex areas.

The information gathered by the various sensors becomes part of a GIS that lies at the core of the project. Data from different locations can be compared and cross-referenced to ensure accuracy and consistency across the development. The GIS files can be shared among permitting and regulatory agencies as well as the various construction and production companies on a project. As construction progresses, GIS operators collect position and attribute information for the new installations. The detail is staggering: every pump, valve, pipeline joint and feature is located, often to survey accuracy. Many objects are tagged with RFID, bar codes or simple nameplates. The tags contain serial numbers and other non-positional information that becomes part of the object's operations and maintenance record.

BUILDING INFORMATION MODELS: GIS MOVES INDOORS
The technology is emerging to bring indoor information systems to the same level as conventional GIS. From the geospatial point of view, buildings – planned or existing – are very dense datasets. Even for a small building, the structure, furnishings and equipment represent a large number of objects.

Building information models (BIM) contain three- and four-dimensional information about all aspects of a building. This includes the physical structure (i.e., the building's construction plans) and the various mechanical and utility systems that enable the building to operate. By using BIM and visualisation tools, operators can develop 3D views of any location in a building. BIM information is useful for more than asset management. In an emergency, BIM can give first responders information about a structure's layout, emergency equipment and shutoff points as well as routes for ingress and egress. If a loop in a water line has been shut down for maintenance, fire fighters will know about it and won't waste time trying to connect to nonfunctional hydrants.
 

Specialised geospatial technologies have emerged to gather the data that feed BIM. 3D scanning is becoming common and technicians can use the resultant models to identify specific objects in a building and convert them to CAD entities. Temporal information is vital to any construction and management operation. Instead of a one-time measurement to install or locate an object, stakeholders have the ability to conduct ongoing maintenance of a project's database. A building manager could use BIM to create a time-based view of a building's fire control systems; the view highlights any fire extinguishers that have not been inspected in the past year.

In traditional construction, building plans can go dormant when construction is completed. By contrast, BIM remains active as part of the building management toolbox. The building operates in the same way as a city or region that has a wellmaintained GIS: the BIM keeps track of records, operations, maintenance and renovations. Any changes or additions to the building take place first in the 3D model, where designers can walk through the virtual building and look for problems before spending money on construction. Building construction is a highly collaborative environment and BIM can serve as a hub for the collaboration. Because stakeholders look at data in so many different ways, we must be able to bring information together to give visibility throughout the construction enterprise.

THE FOUNDATION: CONNECTIVITY
Throughout the various stages of a project, managers make decisions that affect the productivity and profitability of the project. The key to making good decisions is to supply stakeholders with accurate enterprise and situational awareness.

As we look at the variety of applications for geospatial technology in construction, the common thread is the need for communications at multiple levels. Field data communications systems carry raw measurements to the office workstations. Office networks move information to technicians and stakeholders in local and remote locations. Results, reports and recommendations are required in specialised formats and multiple languages. The flow of information must be consistent, reliable and omnidirectional. Decisions made in distant offices affect the daily activities of workers on the construction site; any errors or ambiguity in communication can result in expensive delays or rework.

As wireless communications become more pervasive, it is possible to provide real-time visibility into the decision process to more stakeholders. Many geospatial systems include capabilities for direct communications, including cellular modems, wireless networks or hardwire Internet access. In developing nations, the rapid emergence of wireless networks is an important factor. These countries have skipped the so-called "copper generation" of hardwire communications and gone directly to the mature technology of wireless communications. As a result, communications systems can grow faster and at lower cost. The once-remote construction sites can be easily reached via wireless communications. Similarly, BIM technology has been through several cycles of refinement. As measurement systems continue to combine with data management and integration, opportunities will expand for geospatial technology in the building and construction arenas. The future belongs to a virtual world in which our customers can visit any point on their construction sites, buildings or facilities. It will be possible to "see" – without the need to physically travel to the site – the condition and status of the structures, materials, tools and personnel.