HIGHDEFINITIONSCANNING Uses of Scanning in Construction ... · Construction craft training Clearance evaluations for assem-bly personnel and tooling The notion here is that for “con-struction”

HIGHDEFINITIONSCANNING

Geoff Jacobs

Many professionals areaware of the benefi-cial use of laser scan-ning for creating as-builts for use by engi-

neers or designers. However, scan-ning is used successfully in all stagesof a capital asset’s lifecycle, not justthe “design stage.” These other usesinclude the Proposal Stage, the Con-struction/Fabrication Stage, and theAsset Management (or maintenance& operations) Stage.

This article is the second in a seriesthat looks at the use of scanning invarious stages of an asset’s lifecycle.The January 2006 Professional Survey-or article examined uses in the Pro-posal Stage; this article focuses onbeneficial uses of scanning in the Con-struction & Fabrication Stages andwhat the latest trends are in this area.A future article will cover in-depthlooks at uses in Asset Management.

OverviewThe use of high-definition survey-

ing during the Construction Stage hasbecome virtually commonplace forcertain types of civil, architectural,and plant projects. For many proj-ects, scanning can be more cost-ef-fective than traditional survey meth-ods, while also providing more accu-rate and complete information. Usesof laser scanning in construction &fabrication include:

■ Quality assurance (QA) ■ Designing temporary structures ■ Quantity surveys■ Path planning

■ Final as-built deliverables■ Pile & crane locations■ Construction & demolition sequencing■ Design verification■ Deformation monitoring■ Litigation protection■ Construction craft training■ Clearance evaluations for assem-

bly personnel and tooling

The notion here is that for “con-struction” applications, the specificclient of the as-built survey is a Con-struction Contractor or the Construc-tion Department (as different from aDesign/Engineering Consultant orDept.). For the purposes of this arti-cle, as-built surveys that are conduct-ed for engineering/design clients ordepartments—even if these engineer-ing/design plans will eventually beimplemented via construction—areconsidered as being part of the “Engi-neering or Design Phase” of a project

(not for direct use during the “Con-struction Phase”). This article focuseson direct Construction Phase uses.

Risk Reduction: A Key Benefitfor Contractors

One of the primary drivers for therapid growth of high-definition sur-veys in construction is the fact thatcontractors place a high value onservices that can significantly reducerisk to their construction budgets andschedules. High-definition surveyshave proven over time to sport threeadvantages over traditional methodsthat can provide valuable risk reduc-tion benefits for cost- and schedule-conscious project managers. Theseconstruction risk-reducing advan-tages are:

■ Higher level of completeness■ Better accuracy ■ Quicker availability of as-built data

Construction and FabricationConstruction and Fabrication

Laser scanning is commonly used in construction projects. Image Courtesy:3D Laser Imaging

Uses of Scanning in

DISPLAYED WITH PERMISSION • PROFESSIONAL SURVEYOR MAGAZINE • February 2006 • WWW.PROFSURV.COM • ALL RIGHTS RESERVED

HIGHDEFINITIONSCANNINGReduced Risk of Interferences

For complex structural projects,scanning’s higher level of complete-ness translates into less constructionrisk in the area of “construction inter-ferences.” A construction interfer-ence is a case where a structure, suchas piping or steel framework, is in theprocess of being installed and thecontractor makes an ugly discoverythat the planned layout physicallyclashes with existing structures.When this discovery is made, con-struction halts. Designers and projectmanagers scramble to figure out on-the-spot workarounds. Welders breakout their torches to cut existing struc-tures or modify new piping, etc. Theconstruction budget takes a hit. Theschedule takes a hit. The projectmanager can’t sleep. And the endclient—the owner/operator of the as-set—may become very upset if it af-fects their project cost. They may be-come absolutely irate if it delays theirfacility from becoming available forcommercial use.

Reduced Risk of “Fit-Up”Problems

For many projects, the higher over-all accuracy of a high-definition sur-vey translates into less risk of “fit-up”problems. A fit-up problem is one inwhich during an installation, the con-tractor makes the unpleasant discov-ery that some element does not quitefit-up exactly with another elementfor which it was intended. Some fit-up problems can be easy to fix on-the-spot with minor changes to ei-ther the existing structure or to layoutplans. However, some fit-up prob-lems can be just as disastrous to proj-ect budgets and schedules as con-struction interferences can be. Whathappens if a new 16" pipe doesn’tquite fit up with an existing 16" pipeflange? It’s not nearly as easy to bend16" pipe to tie-in as it is to bend 1/4"tubing for a tie-in. It’s not surprising,therefore, that high-definition as-built surveys are often focused oncapturing large elements, such aslarge piping, structural steel, HVACconduit, large vessels, and concrete

elements, rather than capturing ele-ments such as tubing and woodenstructures that may be easy to modifyin the field.

Construction Project ExamplesSeveral projects/firms that have

successfully taken advantage of high-definition surveys in their Construc-tion & Fabrication Stage are discuss-ed in the following pages. In some

cases, these same projects/firms mayhave also used high-definition sur-veys for the Proposal Stage, DesignStage, and/or Asset ManagementStage. These Construction Stage ex-amples cover civil, architectural, andplant projects.

Civil Construction ProjectsA common use of high-definition

surveying in construction projects

High-definition surveys reduce the risk of construction interferences on retrofit projects. Image courtesy: WGI

For quantity surveys, scanning is often more economical. Image Courtesy:G&T Conveyor


that involve moving dirt or rock is aquantity survey. For this application,laser scanning can often be moreeconomical than traditional methodsthanks to its fast, remote data cap-ture. Other benefits include more ac-curate quantities, safer data capture,and faster turnaround of survey re-sults to the contractor client.

The survey department of G&TConveyor (FL) primarily uses high-def-inition surveys in the design stage ofconveyor projects in which conveyorsare to be installed in existing, congest-ed facilities, such as in airport baggagehandling areas. G&T Conveyor’s surveydepartment also provides surveyingservices to the general market. Onesuch recent high-definition survey wasa quantity survey of several large, geo-metrically complex dirt piles for a con-tractor building a new highway clover-leaf interchange. On this project, thecost of deploying high-definition sur-veying was estimated to cost less thanthe cost of conducting the quantitysurveys traditionally. Quantities werealso considered to be more accuratefrom scanning, thanks to the high den-sity data capture of the irregularlyshaped dirt piles.

Another common ConstructionStage application of scanning onroadway projects is pavement sur-veys. BSC/Cullinan has used high-definition surveying extensively on

Point clouds provide more complete data for more accurate quantity surveys.Image courtesy: G&T Conveyor

Laser scanning has proven highly cost-effective for pavement QA surveys.Image courtesy: BSC/Cullinan Associates

HIGHDEFINITIONSCANNINGBoston’s BigDig project for quality as-surance (QA) surveys of newly pavedroadways and tunnels. Several high-accuracy laser scanners have beenused simultaneously on this massiveproject over a period of several years.The use of laser scanning for pave-ment QA surveys has been estimatedto provide cost savings on the orderof 75% or more over traditional meth-ods. In addition, pavement QA sur-veys done with scanning have caughtlocalized low- and high-spots thatwould otherwise be very difficult tocapture traditionally. In addition topavement QA surveys, laser scanninghas also been used extensively on thisproject for “final as-built surveys”that are part of the overall project de-liverables. It has been estimated thatthe use of scanning just for final as-built surveys for the BigDig projectwill save the project more than $2million in survey costs.

Another interesting use of laserscanning in civil construction proj-ects is construction monitoring relat-ed to excavations near existing struc-tures. Dasan Engineering, a Koreancivil/survey firm, has used high-defi-



nition surveying to accurately assessthe movement of road piers and re-taining structures adjacent to an ex-cavation project. In contrast to dis-crete point surveys, scanning offersthe advantage of monitoring entire

surfaces for movement and deforma-tion. A challenge with the use of laserscanning for this application is thatmonitoring must be done in refer-ence to some fixed points or struc-tures that are not affected by the

excavation. Such reference structuresmay be a fair distance (e.g., >300' or100m) from the excavation area,hence it is very important that thescanning system be able to achievehigh accuracy results (e.g. <1/2" or12mm positional accuracy), even atsuch ranges.

Architectural ConstructionProjects

3D Laser Imaging (AZ) is a goodexample of firm that provides high-definition surveying services exten-sively during the construction phaseof projects involving buildings.

The 2005 construction of the newCardinal Stadium involved a heavylift of a roof structure onto a set offour large columns. Each of the fourcolumns features a slot that runs thelength of the column; the slot was de-signed to accept the roof structureonce it had been lifted into place. TheHunt Construction Group retained3D Laser Imaging to provide criticalon-site construction QA measure-ments to help ensure that the heavylift went without incident. The firstQA task was to measure the center-lines of each column to ensure thatthey had been built in the correctgeometry to receive the new roof. Ac-curate measurements were also need-ed from the inside notch of the supercolumns to verify if the steel structure(i.e., the roof ) was going to haveenough spatial clearance as the con-tractor lifted it into its final restingplace. An advantage of high-defini-tion surveying over traditional meth-ods for measuring the notch is theability to pick up localized geometrychanges along the full surface of thenotch. Another advantage of scan-ning was the ability to analyze thenotch surface survey on-site, provid-ing virtually real-time feedback to thecontractor. This avoided any con-struction delays that may have other-wise resulted from a traditional sur-vey and the time needed in the officeto reduce and analyze its data.

3D Laser Imaging has similarlyprovided cost-effective constructionQA services with laser scanning on

High-definition surveys are used for monitoring structures near excavations.Image Courtesy: Dasan Engineering

Scans of excavationarea, monitoredroad piers, and reference buildingstructure. Imagecourtesy: DasanEngineering


the Phoenix Civic Plaza & SymphonyHall Expansion Project. The objectivewas to see how far the project’s com-plex steel structure was deviatingfrom its proposed design. On thisproject, the 3D point cloud allowedthem to easily model and depict or-nate building overhangs, cornices,and facades. After the initial scan wascomplete, 3D Laser Imaging was ableto import the proposed design direct-ly into the laser scan data and give thecontractor a real time, as-built refer-enced to design.

Other service providersequipped with suitable high-ac-curacy scanners have also usedthem extensively in the Con-struction Stage of projects thatinvolve building claddings. Inthis application, scanning isused to accurately extract the lo-cation of tie-point clips thathave been installed on new steel.The clip locations are then usedto accurately fabricate frame-work for the external cladding to en-sure smooth installation.

Plant Construction ProjectsHigh-definition surveys are used

extensively worldwide in the Con-struction & Fabrication Stages ofplant projects. Plants were one of thevery first application success areasfor laser scanning, in general, back in1990s when the technology was firstcommercially introduced. Thus, it’snot surprising that its use has spreadextensively from its initial use in theDesign Stage into the Constructionand Fabrication Stages.

A good example of an organizationthat uses high-definition surveyingextensively for plant Construction &Fabrication is the Metrology ServicesDepartment of Framatome ANP (VA),an AREVA (France) and Siemens(Germany) company. Framatomespecializes in providing services tothe nuclear power plant industry.

These services include project de-sign, specialty construction, and fab-rication. For a recent reactor head re-placement project, Framatome usedhigh-definition surveying for threedifferent applications to support theconstruction phase of the project:■ Interference Detection■ Simulate component load-path

movement sequences■ Identify interferences■ Mock-up Training■ Create welding & machining mock-

ups to train craft on actual geometry■ Tool Clearance evaluation■ Ensure sufficient clearance for safe

operation of automated weldingand machining tooling


Scan of super column notch at Cardinal Stadium construction. Image courtesy:3D Laser Imaging

Steel structure scan for construction QA at Phoenix Civic Plaza project.Image courtesy: 3D Laser Imaging


High-definition surveying is used heavily in the power plant industry.Image courtesy: Framatome ANP

In addition to these applications,Framatome has also used high-defi-nition surveys for the design of tem-porary structures needed during con-struction. These temporary struc-tures have included scaffolding andtemporary radiation shielding. Whenspeaking with users worldwide whoprovide services with their scanners, Ioften hear of its use for accurately lo-cating and designing scaffolding thatis used during construction. A similar-ly popular application is its use for thedesign of specialty derricks and the lo-cation of cranes for construction.

Fabrication QAJust as scanning is widely used in

the Construction Stage of plant proj-ects, it is also widely used in the Fab-rication Stage. Here, the most com-mon application is to check the fabri-cated geometry of complex struc-tures, such as piping “spools” or largevessels with multiple nozzles. The QAcheck is intended to make sure thatsuch structures have been accurately

fabricated according to plans andthat they will fit-up properly on sitewhen they are installed.

Many users will scan both thesite/structure where the installationwill take place and the fabricatedstructure in the fab shop. The twoscans are then merged together on acomputer and an “electronic fit-up”check is performed before the actualstructures are physically brought together. The benefit to the contrac-tor is that if there are potential prob-lems, it’s a lot less expensive to fixthem while the structure is still in thefab shop than it is to fix it on-site inthe field. If these problems are notcaught until the fabricated structureis being installed in the field, thencostly construction crews and equip-ment are often standing idly by whilethe fixes are being implemented.

Marketing the Benefits ofScanning to Contractors

One of the keys to the successfuluse of high-definition surveying in

construction is making contractors,especially project managers, aware ofthe benefits of the technology.

Although the technology deliversConstruction Stage benefits everydayworldwide, many project managersare still unaware of the technologyand these benefits. My observation isthat when service providers take thetime to explain these benefits to proj-ect managers, these professionals arequick to recognize the significant val-ue of the project benefits in contrastto the relatively low cost of deployingthe service. To be sure, project man-agers will likely want to use the tech-nology primarily on critical-path as-pects of the project and not on everydetailed task. Nevertheless, it hasbeen my observation that such ef-forts to educate project managershave met with a good pay-off for boththe service provider and the client.Firms that have successfully providedlaser scanning services to construc-tion project managers report thatthese clients return for repeat busi-ness and repeat benefits.

SummaryHigh-definition surveys are regu-

larly used during the Constructionand Fabrication Stages of capital con-struction projects. They have provento save money on as-built and quan-tity survey costs. In addition, scan-ning has also proven to reduce con-struction budget- and schedule-risk—a major benefit to contractors.Over time, it is expected that this ap-plication of the technology will con-tinue to grow rapidly as more andmore project managers becomeaware of these benefits.

GE O F F JAC O B S hasbeen employed by Le-ica Geosystems, HDS,Inc. since 1998. Hecurrently acts as Sen-ior Vice President,Strategic Marketing.He is also a contri-buting writer for the magazine.


Laser scanning is commonly used forequipment removal path planning.Image courtesy:Framatome ANP

3D models created from scans can be used for construction animations.Image courtesy:Framtome ANP


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HIGHDEFINITIONSCANNING Uses of Scanning in Construction ... · Construction craft training Clearance evaluations for assem-bly personnel and tooling The notion here is that for “con-struction”