Automation and Robotics in Construction XVI © 1999 by UC3M

ROBOTS AND CONSTRUCTION AUTOMATIONBy

Guillermo Morales , Master of Engineering, billmorales uhotnrail.comDr. Zohar Herbzman , Associate Professor, zherb(ace.ufl.eduDr. Fazil T. Najafi, Associate Professor, fnaja@ce.ufl.edu

UNIVERSITY OF FLORIDACivil Engineering Department345 Weil Hall, PO BOX 116580Gainesville, FL 32611-2450

ABSTRACT

The United Slates lacks in the research anddevelopment of robots and constructionautomation. In comparison, constructioncompanies in Japan take more aggressive stand inthe research and development of this technology.This paper studies both Japan and US basicconstruction activities, research and development,social implications , automation technology, andconstruction robots economic feasibility.Construction robot productivity is always higherwhen materials are standardized, and repetitionactivities are involved. Improving productivity,reducing manpower, shortening construction time,reduction of costs, improving quality, improvingwork conditions, safety, and benefits to theenvironment are presented in this paper.

1. INTRODUCTION

Application of robots in the construction industryfor performing various tasks is growing. Basicactivities in building construction, and civilengineering projects developed by robots are:positioning, connecting, attaching, finishing,coating, concreting, building, inlaying, covering,jointing, scaffolding, demolishing, tunneling,inspecting, and repairing elements [1]. Japaneseconstruction companies are research leaders in thedevelopment and application of robots in theirconstruction projects.In the United States, there is a growing interest inthe academic circles, research institutions, andconstruction companies for the development ofconstruction robots. In the future, the constructionindustry in the United States will face shortages of

skilled laborer [2]. According to the U.S.Department of Commerce, the volume of newconstruction in the United States has increasedapproximately from US$388.82 billion in 1987 toUS$644 billion in 1998, employing approximately5,881 million workers [3].This paper is the state of art informationcomparing Japanese and U.S. construction robots.

2. RESEARCH AND DEVELOPMENT

The large Japanese contractors , such as Shimizu,Takenaka , Obayashi, Taisei, and Maeda Co., havebeen involved in research and development (R&D)since 1940 . Since 1980, Japan ' s constructionindustry began to experience shortages of skilledlaborers and decrease of productivity [4].Through research prototype development andrepeated field testing , the large Japanesecontractors are gaining understanding of thestrengths and limitations of applied roboticsystems. Each of the large contractors spendsapproximately 1% of its gross revenues on R&Dactivities . This amounts to about $ 150 millioneach, on average per year. There is visibleevidence that application of robotic systems, suchas construction automation , is gaining momentum[4].Despite that the construction industry in the UnitedStates, which account for 6% to 10% of grossnational product , the investment in R&D in thisgigantic industry is relatively very small. Forexample, the National Science Foundationinvested $ 30 million a year (3% of its R&D total)in 1982 in civil engineering R&D, but more than$15 million of this small budget is devoted toearthquake engineering and design alone [5].Likewise, it has never calculated how much of this

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budget has specifically been allocated on the R&Dof robotic technology for construction.In Japan, government "develops" rather thansimply "regulates"; in the United States,government "regulates", and like the constructionindustry itself, it makes few R&D initiatives[6].

2.1 Advantages ofRobots in the ConstructionIndustry

Robots and construction-automated systems arecomplex, not only in design but also in operation.However, they present the following advantages[5]: a) improvement in work quality, b) reductionof labor costs, c) savings accrued on safety andhealth improvements , d) time savings, and e)improvement in productivity.

2.2 Disadvantages of Robots in the ConstructionIndustry

Robots and construction automation were bomfrom robots of the manufacturing industry.Therefore, many problems faced by industrialrobots are similar to robots in the constructionindustry. Problems valid include among others[5]: a) robot mobility, b) weight and seize ofrobots, c) robot accuracy, d) robot operation, ande) external factors such as dispersion of projects,lack of repetition, dependability among workers,negative attitudes to change, fragmentation of theconstruction industry, and instability of the market.

3. SOCIAL IMPLICATIONS

The objective need for any technological change,which may contribute toward and advancement ofthe building sector in terms of work productivityand quality, seems to be more compelling inconstruction than in almost any other industrialsector. This trend of the productivity decline inbuilding is attributed by various sources to theaging of construction workers, decline intraditional working skills, and a tendency of youthto move to more challenging and more convenienttasks.The U.S. Labor department estimates that the laborforce age 45-64 will grow faster; the labor force 25to 34 years of age is projected to decline by almost3 million, reflecting the decrease in births in thelate 1960's and early 1970's[7]. As a result, theaverage craft worker's age is 47, and continues torise as fewer young men and women choosecareers in construction [2].

A change to a new technology requires planning,education, participation, communication, andfeedback. Displaced workers are generally givenpreferential treatment in this type of work, andretraining can also give workers new opportunitiesin their careers.For all those reasons, it seems that the prospect ofautomation, at least of some parts of theconstruction process, is not only highly desirablefrom a general socioeconomic point of view butalso perceived as such by the public and its variouspolicymaking institutions. The automation ofconstruction works will require some changes inthe composition of the labor force involved inthem. Workers in charge of robotized constructiontasks must be able to teach the robots, start them,monitor their work, and cope with variousmalfunctions of the robot and its material systems.The robotization process in construction willcertainly be slow, gradual, and confined, at leastinitially, to large and well adaptable project [1].

4. TOTAL AUTOMATED BUILDINGCONSTRUCTION SYSTEM (ABC)

The construction industry in Japan began tounderstand in the late 1980 's that experimentingwith single-task robots the economic results werelimited unless more of the process could beautomated . In the context of overall buildingconstruction work, construction automationdeveloped by the utmost construction firms inJapan has signified a valuable effort in theautomated integration among resources andprocesses [9]. However, the effort of coordinatingand integrating construction automation processhas resulted in problems that inhibit overallproductivity improvement [4].To solve these problems industry researcherscreated the Automated Building ConstructionSystems, called ABC, That are based on many ofthe concepts of industrialization found in themanufacturing industry [8]. An example of theABC system is the BIG CANOPY system byObayashi Co., where the truss is build first andlifted up and the remaining internal structure canbe built (figure 1,2). Figure 3 presents the internalcomponents of Shimizu's SMART system.The system has three different areas of work.First, a computerized office, where designersworking with CAD systems lay out a set ofpredefined structural elements. Second, a factory

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Figure 1- BIG CANOPY System by Obayaslu Co. - A Crane Luting a Pre-cast CotumnSource : Reference 10

Figure 2 - BiG CANOPY System by Obayashi Co. -- Installation ProgressSource : Reference 10

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Figure 3 - SMART System by Shimizu Co. - Crane Attached to Canopy Lifts Floor PanelsSource: Reference 11

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production, where designers at the office transmitinformation required for material and manufactureof elements. This factory has a full computerintegrated manufacturing and transporting process.And third, the construction site transformed into aplace of automated assembly, where a centralconstruction management center is in charge ofcoordinate design information, materials deliveryby the factory and constructive methods (Figure4).

5. ECONOMIC FEASIBILTY

The feasibility is examined using the ValueEstimation method. It compares the purchaseprice of the robot with the value of the robot to theuser. The value of the robot to the user isdetermined by calculating the present worth of thenet annual benefits derived by use of the robotover its economic life. These net benefits are thedifference between the benefits of usage (savingsin labor costs, higher productivity, better quality,and reduced hazards) and the cost of usage(operation, maintenance, and other expenses).This analysis method calculates the maximumprice the owner/ user should be willing to pay forthe robot. The value V of the robot to the usermay therefore be calculated from the followingequation as the discounted net worth of service Vover its entire economic life [1]:

V=( kL-M-O-T+&P) [(1 +I)n- I } /1(1+I)n

Where P= initial investment in the robotL= saved labor cost per year per one

replaced workerK= number of replaced workersM= cost of robot's maintenance per year0= costs of robot's operation per yearT= costs of robot's transfers per year&= Tax reduction rate (%)I= interest rate (%)N= economic life cycle of a robot

5.1- Example

Making an analysis for the "Kote-King", the thirdgeneration of concrete finishing floor robotsdesigned by Kajima, and which is sold byTokirnec from Japan in US$ 50,000 [4], it ispossible to determine the feasibility of the robotemployment. Comparing the value calculated withthe formula, which is the present worth of the netbenefits accrued from its operations, against the

robot cost. The following assumptions were made,according with Warzwaski [1]:

P=$50,000 &=10%L=$20/hour I =10%K= 1 to 3 workers N= 3 yearsM=$5,000/year T=$5,000/year0=$1,500/year

The values of robot for the user calculated underthese assumptions are as follow:

Labor saved(workers) Robot value to user(S)1 33,4802 83,0803 132,680

It may be concluded that under assumptions heretaken, this concrete finishing floor robot willjustify itself economically if it will replace 1,5-2,0workers, which seems quite logical in this kind ofactivity, where finishing workers are at least 3 to5, depending of the area . Factors that affect thefeasibility of a robot's employment are extent ofemployment and the wages of replaced workers.If the user cannot assure as adequate employmentfor the robot, or if the wages of skilled labor arelow, the use of the robot will still be profitableunder the following circumstances [1]: a) in taskshazardous to human health or safety, b ) in taskswhere the precision of work is associated witheconomic gains, and c) under circumstances thatadversely affect the productivity of human labor.In summary, it seems that robotization in buildinghas a good chance of economic viability whenapplied to well-adapted construction works, givencareful design , good maintenance procedures, andadequate work volume . In places with low-costskilled labor, the employment of robots will bejustified only when applied under hazardous orstressful conditions that considerably affect humanlabor productivity [1].

6.0-CONCLUSIONS ANDRECOMMENDATIONS

Through their experiences , the Japaneseconstruction companies have found that roboticstechnology has improved productivity, quality,safety, work conditions , environment , and reducedconstruction time, labor, hard work and costs.Productivity and quality in single -tasks robots hassuccessfully being achieved when a specific workis repetitive . However, due to limitations of robots

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and the complex environment where constructionindustry is developed, additional work force is stillnecessary reducing productivity. In automationconstruction,, productivity promises to increasebecause of better integration among tasks.Reducing the hard work, robots improve in generalsafety in the work place. Because activities areconfined within the building facility in automatedbuilding construction systems, noise and dust arereduced contributing to a healthier workenvironment.Although overall reduction in labor is notapparent, because it is still necessary to completework inaccessible by robots, it is expected areduction of labor using automated constructionsystems. Once the automated buildingconstruction system be refined and used morerepeatedly, it is expected a reduction inconstruction time and costs.In the United States, construction companiescontinue to be reluctant in using constructionrobots. According with Skibniewski andKunigahali, concerns for short-tern profits, fiercecompetition among contractors, and lack of topmanagement commitment to technological changeare often cited as primary obstacles to the rapidintroduction of robots in the construction industryin the United States.Architects and design engineers should addresstheir efforts in designing structures and materialsadaptable to the limited capabilities of robots andautomated construction systems. Simplifying,mechanizing, and automating the constructionprocess is the first step into order to put automatedsystems in the construction industry.It is necessary that the U.S. government providesassistance to the construction companies, robotmanufacturers, research universities, and privateresearchers , in the form of incentives such as taxreductions, loans, and other benefits, to promotethe implementation of robotics and automatedsystems in the construction industry.The United States must learn Japanese ABCsystem application.particularly in downtowndevelopment where the traffic's congestion,storage of materials , and overcrowding presentconstruction problems. In summary, it isnecessary economic efforts from the privateindustry and government to provide funds andresources for research and development of robotstechnology.

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REFERENCES

[1] Warzawaski, Abraham: "Industrialization andRobotics in Building: A Managerial Approach";Harper & Row, Inc.; New York; 1990, pp.369-373, pp. 401-418.[2] Bennet, Daniel J. " The Construction LaborForce in the 21 Th Century"; Paper fromConstruction Congress V: Managing Constructionin Expanding Global Markets; Proceedings of theCongress; ASCE Press; 1997.[3] U.S. Department of Commerce: " ConstructionReview"; http://domino.stat.usa.gov/cen/const.cen; September1998.[4] Cousineau Leslie, Nobayasu Miura;"Construction Robots: The Search for NewBuilding Technology in Japan"; ASCE Press,Reston, Virginia; 1998; pp.l l,pp.l5,pp.49.[5] Skibniewski M.J.; " Robotics in CivilEnginering"; Van Nostrand Reinhold Company;New York; 1988; pp.5, pp.8,pp.10.[6] Webster, Anthony C., Columbia University;"Technological Advance in Japanese BuildingDisegn and Construction"; ASCE Press; NewYork; 1994; pp.90, pp.99.[7] U.S. Department of labor; " Employment byMajor Industry Division"; http://146.142.4.23/pub/news/release/ecopro.txt;September 1998.[8] Skibniewski Miroslaw J. and Stephen C.Wooldridge; " Robotics Materials Handling forAutomated Building Construction Technology";Automation in Construction; Elsevier SciencePublishers; 1992;pp.251.[9] Skibniewski Miroslaw J. and RaghavanKunigahalli; "Automation in ConcreteConstruction"; Concrete Construction EngineeringHandbook"; Chapter 17; CRC Press Boca Raton;New York; 1997; pp.17-18.[10]hM2://www.obayashi.com.siz/constrLict2.lltml.December 1998.[11]htpp://www.iaarc.org/images/smart.flooring. jpg. december 1998.

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