VARGAS, Carlos Luciano S.1, KRUGER, Jose A.2, MENDES JR., Ricardo3, HEINECK, Luiz Fernando M.4
1, 2 Av. Carlos Cavalcanti, 4748, CEP 84030-00, Ponta Grossa,Parana, Brazil + State University of Ponta Grossa, lucianovargas@convoy.com.br, www.uepg.br
3 Federal University of Parana, mendesjr@cesec.ufpr.br
4 Federal University of Santa Catarina, lheineck@geog.uu.nl
Abstract: The development of exercises, games and simulations, which have as their purpose to bring to classroom some real situations, as found in the daily professional practice, has been object of studies of several research institutions.The authors have been developing programming games using reduced physical models. The game consists of the simulation of programming and execution of all the foreseen activities of the model precedences net, the way they appear in a real building site.The objectives of the game are to use the Line of Balance Technique, to simulate the evaluation of productivity and material wastes, as well as to apply the modern concepts of production engineering to civil construction.
Keywords: construction, management, productivity, simulations, wastes
This article describes an application of games for simulation of building construction steps and its application with undergraduate students of Civil Engineering at the State University of Ponta Grossa (south of Brazil). This game uses a simulation of all the necessary activities to build a group of social bathrooms in a building (10 floors) using physical reduced models. The simulation's purpose is to apply job productivity evaluation and waste measurement techniques and to show the validity of modern management techniques, as well as the gains that will come with the use of technological innovations on building sites. The focused point is the importance of bringing to undergraduate courses classes, to masters degree classes and to professionals training some real practical situations, such as: unproductive labor and equipment, materials waste, lack of production sequence, inadequate stocks and the faced difficulties on work planning and controlling.
The exercise intends to use a productivity rising technique called Activities Sampling Technique, largely used in another productive systems (manufacturing industry). The materials waste evaluation is accomplished in agreement with usual materials consumption measurement techniques which were proposed by researchers' of NORIE (Guided Nucleus for the Innovation of Construction) of UFRGS - Federal University of Rio Grande do Sul (SANTOS et al., 1996 and SCARDOELLI et al., 1994). The programming and the control of the activities execution is accomplished through the Line of Balance Technique.
The adopted reduced model tries to simulate all the necessary steps to the execution of a principal bathroom, distributed in 4 charts. These charts represent two of the walls (external and internal) of the bathroom and they happen again along the floors (in this simulation, the number of floors was limited to ten), as shown in Figure 1.
Fig. 1 - Schematic view of the building and detail of the bathroom
The work is done by cutting out and gluing colored cards over the four charts. The colored cards simulate the construction materials and they are supplied to the students. The use of four charts, one for each construction stage allows the verification of the quality of the executed services and the materials wastes. Figure 2 shows some of the four used charts.
Fig. 2 - Charts used in the simulation
The operations are scheduled to be executed according to the most linear possible sequence, based on the net of usual operations sequence applied in the South Region of Brazil. The way it happens on a real site, some activities may be done at the same time as anothers. However, in the accomplished simulation the net elapsed in a linear way due to the little work space, because the bathroom measures around seven square meters (7 m2), and this fact does not permit the permanence of more than a team working at that space.
In this simulation, on a common classroom, 10 small tables were used. A book containing the four charts was fastened on the table. The charts were fixed in order to simulate an important characteristic of Civil Construction: the fixed lay out - the building stands, while workers, materials and equipment walk around. Figure 3 shows the adopted lay out. To simulate the natural difficulty of materials and people vertical circulation on building sites, the tables were disposed in a spiral arrangement, forcing the participants to use always the same pathway, representing what happens on building sites, where the materials and workers circulation happens by stairs or by elevators, passing through all floors to get to the last one above.
Fig. 3 - Adopted lay out in the simulation
Coordination crew: they were identified by orange colored helmets, were responsible for the preparation and conduction of the game. One of the coordinators was responsible for the fortuitous events. Another coordinator was responsible for the liberation of the teams for the execution or preparation of the activities, following the programming of the Line of Balance. The last coordinator was responsible for the management of the activities, the accompaniment of the execution of the Line of Balance and for proposing decisions to the other coordinators, in order to modify the distribution of the teams. The coordinators were also responsible for the verification of the quality of the services.
Inspectors crew: the rising of the productive, auxiliary and unproductive times was accomplished by inspectors, which were identified by red colored helmets. They were responsible for the registration of those times in proper tables. Besides the inspectors, two VHS movie cameras were used. One of them had the resource of time-lapse recording, and it was used to register the times of work of the teams. This way, it was possible to compare the results obtained by the inspectors and by filming.
Site crew: The teams were constituted by one skilled laborer and one helper (unskilled assistant):
Skilled laborers: they were identified by green colored helmets. They were responsible for the work rhythm, for the obedience to the tasks sequence and for the quality of the job. It was recommended that the most sophisticated tasks (to cut out and to glue) were executed by the skilled laborer, to simulate the reality of the sites where he is responsible for this kind of work fronts.
Helpers: they were identified by yellow colored helmets. They were informed to execute the superior determinations or to act productively in less responsibility tasks and in the materials transport.
Surveyor or timekeeper: they were identified by blue colored helmets. In the accomplished simulation there were two (2) surveyors, which were responsible to register the duration of the services in proper sheets and to transfer them to the Production Control Table of the Line of Balance.
Storekeeper: they were identified by blue colored helmets. One of the participants was responsible for the materials supply to the helpers. The materials were liberated in small amounts, in order to force the helpers to do several journeys to maintain the provision of materials in the work fronts.
The work programming was developed with the Line of Balance Technique (VARGAS and HEINECK, 1997; MENDES JR and HEINECK, 1997). This programming technique proposal is the maintenance of the continuity of the tasks which propitiates effective management, learning effect, wastes reduction and increased quality. Each team crew is responsible only for one kind of service, doing that activity repeatedly in all floors. The Line of Balance programming is generally graphically developed, being easily visualized and understood by all involved workers. To reach the established period for the project, the Line of Balance Technique proposes that the activities will be developed in a certain work rhythm. This work rhythm indicates how much time should be used to conclude each repetitive unit (bathroom). For this programming, the project was divided in two phases: the first phase, until the conclusion of the tiles setting, and the second phase until the end. The rhythm of the first phase was determined in 5 minutes for each bathroom, and 1 minute in second phase for bathroom. Thus it can be determined how many teams will be necessary in each activity to maintain the required rhythm. Figure 4 shows the Line of Balance with the programming used in the simulation and the activities that were accomplished (1st phase). The execution control of the activities is accomplished with the Line of Balance Control Table, where there are suitable control points - after 45 minutes periods in the simulation - for verification of the number of concluded units, being compared with the programming, as shown in Figure 5. Eventual deviations in the conclusion times can be corrected by moving more teams towards a certain activity in the available function. This was done several times at the beginning of the project in this simulation.
In this simulation the timekeeper receives the verified times from the officials (registered in each chart), checks them and makes the transcription to the Control Picture. The times that are being placed in the Control Picture offer a view of the course of the work flux. This way, it could be immediately verified if the work is late or not. The Control Picture was adapted of production graphs used in another productive branches (scheduling matrix - BARRIE, 1992). That picture type is indicated to control the production of repetitive activities. For this reason, it is indicated to be used together with the Line of Balance Technique. In this control type, the official makes the registration of the time at the beginning and at the end of the activity in each unit of repetition and he goes reviewing those information for the timekeeper while he is moving from one unit to another. The timekeeper verifies the marked times, calculates and registers how much time the activity took in each unit and the accumulated time of the activity.
Fig. 4 - Programmed line of Balance and accomplished activities
Fig. 5 -Production control and production card tables
To define each participant's functions, it was used a system of cards, similar to service orders, in order to distribute the activities fortuitously to the teams, timekeepers and inspectors, avoiding that some task will have no workers to do it. To attribute to the simulation exercise the characteristics of a game (scheduling games), it was introduced a list of fortuitous events, such as: loss of productivity due to accidents and absenteeism, rain, elaboration of defective products, project flexibility, project mistakes, delay in material delivery and so on. To simulate low productivity on work, for example, some workers were raffled to work using cotton gloves and protection glasses with blurred lenses. The teams that would receive the cards were also chosen through a raffle. A roulette was used to choose the floor that would be punished with fortuitous events. One of the participants played the role of animating all the job, being responsible for the distribution of the cards and for the registration of the fortuitous events. Afterwards, it was made a comparison with the obtained results with the productivity observations in order to verify the effect that the fortuitous events provoked in the work productivity. On Figure 4, the fortuitous events that happened in the accomplished simulation appear highlighted and bounded. The delay provoked by its occurrence can be observed.
Besides the Graph of Work Programming, the precedences net, the Control Picture of the Line of Balance, the project of the bathrooms (a reduced model), control table and sheets, the following materials were used, too: helmets (16 green, 16 yellow, 3 blue, 3 red and 3 oranges), labels for the participants' identification, 1 scissors, 1 roulette in a small plank, 1 small plank with cards with fortuitous events (several of them), cards of tasks distribution (several of them), 3 small planks, 20 rulers (centimeters graded), colored cards (several colors), glue tubes, 20 soda caps (to place glue portions), ice cream toothpicks, ribbon for access delimitation, 2 cotton gloves, 2 protection glasses, 1 wall clock, 2 VHS recorders (one of them with time lapse), photographic camera.
The results of the productivity measurement using the camera show times
that resemble each other with the times that were measured in exercises
accomplished previously with another models (VARGAS et al., 1998). It can
be noticed the learning effect, the waiting times and the effects provoked
by the fortuitous events on production. The report of the simulation
accomplished with undergraduate students on Civil Engineering at the State
University of Ponta Grossa can be seen at GECON home page (Construction
Management Laboratory), of the Postgraduation Program in Production Engineering
of Santa Catarina's Federal University ( BARRIE, D. S.; PAULSON, B. C. Professional construction management:
including C.M. design - construct and general contracting. McGraw-Hill
series in construction engineering and project management, 1992, 577 p.
(in english).
MENDES JR, R.; HEINECK, L. F. M. Roteiro para programacao
da producao com Linha de Balanco em edificios
altos. Encontro Nacional de Engenharia de Producao ENEGEP97,
Gramado, RS, Resume... Porto Alegre: UFRGS, PPGEP, 1997, CD-ROM: il. (in
portuguese).
SANTOS, A....[et al]. Metodo de intervencao
para reducao de perdas na construcao civil:
Manual de utilizacao. Porto Alegre, SEBRAE, 1996. 103p.
(in portuguese).
SCARDOELLI, L. S....[et al]. Melhorias de qualidade e produtividade:
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VARGAS, C. L. S.; HEINECK, L. F. M. Calculo do balanco entre
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Encontro Nacional de Engenharia de Producao ENEGEP97,
Gramado, RS, Resume... Porto Alegre: UFRGS, PPGEP, 1997, CD-ROM: il.
VARGAS, C. L. S....[et al.]. Avaliacao de produtividade
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utilizando modelo reduzido para demonstrar as vantagens do uso da linha
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tecnologicas no canteiro. Encontro Nacional de Tecnologia do
Ambiente Construido (7.:1998: Florianopolis). Anais...Florianopolis,:
NPC/ECV/CTC/UFSC, 1998, 2 v. p. 159-168.
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