FACTA UNIVERSITATIS Series: Architecture and Civil Engineering Vol. 17, No 1, 2019, pp. 1-17 https://doi.org/10.2298/FUACE180318028M AVAILABILITY CLASSIFICATION FOR APPLICATIONS IN CONSTRUCTION PRODUCTION SYSTEMS: A REVIEW UDC 624:658.562.5 Milan Mirkovic Consulting Experts System, Zrenjanin, Serbia Abstract. The aim of the paper is to improve availability classifications of components for application in construction systems. Construction production systems belong to projectbased systems with serial-parallel structures with or without redundant components, and the availability function has a significant impact on the performance indicators of components and systems. The main indicators of function of the components are the availability, capacity, costs, and project time. A new approach to classification makes it possible to choose the most appropriate methodology for assessing component availability in the bidding phase, and managing company's machine park. The new classification approach was tested on a practical example. The results obtained confirmed the justification for extending the classical approach to the classification of the availability of components. Key words: availability, construction component, component indicators, production system 1. INTRODUCTION Availability is key when designing industrial systems. The capacity of the (system) components and the system as a whole can be changed from a state of full operability to failure and reduced operability. The status of the components may affect the capacity, unit costs, and total costs, and project time. Estimating the availability of components in such situations is of great importance in the bidding phase [1], [2]. According to Eq.1, the general measure of availability is a ratio of usable/operational time to a total given period or cycle time [1], [2]. Availability = Operational Time/Time Period (1) Production systems exploit sets of elements and the interrelationships between them and their characteristics, in order to perform a function. This means that the connections between the components and subsystems are in accordance with the specificity of the production system, i.e. technological process. Received March 18, 2018 / Accepted April 15, 2019 Corresponding author: Milan Mirkovic Consulting Experts System, Takovska 69A, 23000 Zrenjanin, Serbia E-mail: milan.mirkovic@highways.rs 2 M. MIRKOVIC Construction production systems are a specific type of industrial system where temporality and uniqueness are key. This means that there are no two or more identical construction projects. Each construction project has a clearly defined start and, end of work in the goals set. Furthermore, there is no system for completing construction projects with an identical organizational structure [2]. Construction systems in the field of civil engineering, where highly mechanized work is involved are highly complex in terms of the production system's availability. This complexity is reflected in the specifics of the environment in which the building is performed, frequently with unknown total costs, functioning in open spaces, with production lines that are significantly distant from each other, variable durations in the construction time (from several months to several years), and fairly specific contractual relations between the investor and the contractor. [2]. The availability of system components, subsystems, and systems as a whole affects the probability of whether the system will operate successfully and the range of permitted deviations of the set criteria function in the given time and given environmental conditions. Their availability is predicted, estimated, and evaluated in direct relation to the bid level of the system (general, conceptual, and detailed bids) [2]. The significance of the availability function is gaining in importance in designing and analyzing production systems, and this is reflected in the simultaneous analysis of the reliability, availability, and maintainability. Availability is a fundamental aspect in the performance of the maintained (repaired) systems. Also, availability is an indicator of the probability that the system/component will function satisfactorily, at any time when used under the specified conditions, where the time considered refers to the time of operation and the downtime[2]. The first classification of availability resulted in a division into two groups in terms of application to military components and systems [3]-[5]. The next extensions of the definition and classification were made with regard to application to military systems, also [6], [7]. In the 1980s, availability was applied to production systems, but without any improvement in definitions, nor in any additional knowledge about their classifications. The first works in the area of reliability, availability, and maintainability with new classifications of availability from the aspect of construction systems emerged in 1990s [8], [9]. Expanding the definition of production availability from application to construction components and systems created the conditions for additional research in this field [10]-[12]. The research of a large number of published works, professional literature, new standards, guidelines, and practical experience, influenced the selection of the subject research, i.e. modern approach for defining availability of construction components. 2. LITERATURE REVIEW The first works on the reliability of components and systems emphasized the need for the maintenance criteria. Research in the field of system's maintenance in terms of the maximizing reliability values resulted in two maintenance approaches: reliability-centred maintenance (RCM) and availability-centred maintenance (ACM). These two approaches positioned availability as a measure of the reliability of the maintained systems. Maintenance criteria, with all the necessary logistical and administrative activities, opened a new chapter in an integral approach to reliability and availability analysis; Availability Classification for Applications in Construction Production Systems: a Review 3 maintainability (M). The first works (1960s) in the field of integral access (RAMDependability) emphasized the importance of the availability function. In the first availability classifications availability was simply classified into [3], [4]:  A (t)  instantaneous or point availability  A (T)  average up time or mean availability  A (∞)  steady state availability Further research in the field of repairable systems emphasized the need to divide the availability into two groups [5] in relation to:  the time interval  the downtime type 2.1. Availability as a function of the time interval 2.1.1. Instantaneous or point availability – A (t) Instantaneous or Point Availability represents the probability that the system will be in operational condition at random time "t", that is, in the specified time interval [0, T]. Unlike reliability, current availability includes information regarding maintainability. In this case, the system will be operational at a time if the following conditions are met:  The component functioned correctly from "0" to "t" with the probability R (t)  The component has functioned correctly since the last repair in the "u" time, where:  0 <u <t, with probability:   t duumutR 0 )()( (2) Where: function of system recovery density According to Eq. 3, the instantaneous availability is the sum of the two previous probabilities [5]: 0 ( ) ( ) ( ) ( ) t A t = R t + R t u m u du (3) 2.1.2 Average up time or mean availability – A (T) Average up time availability or mean availability is the proportion of time in system operation or the expected probability of system availability at time [0, T] [5]:  T dtTA T TA 0 )( 1 )( (4) 2.1.3 Steady State Availability – A (∞) Steady state availability is the limit value of the instantaneous availability of the function during the "t" time which tends to infinity: 4 M. MIRKOVIC ( ) ( ) t A A tlim   (5) In industrial systems, as well as in construction machine systems and plants for the creation of project positions, steady state availability is most often used due to the sufficiently high total time (t) of the functioning of the system. In such situations, the time tends to infinity, thus it follows that the failure rate (λ) and the repair rate (μ), are the constant value, i.e.:  )(t (6) And:  )(t (7) In this case, it follows that: e t tA )( )(           (8) Where:    )(A (9) Due to the status of the component, it follows: MTTRMTTF MTTF A  )( (10) Where: MTTF mean time to failure MTTR mean time to repair The mean time to repair has been redefined in recent papers in this field as the mean time to restore (MTTRS) due to the additional time (ALDT) after the active component has been repaired and put back it into operation. It means that: MTTRS = MTTR + ALDT. According to Eq. 10: MTTRSMTTF MTTF A  )( (11) 2.2. Availability as a function of downtime type Availability as a function of downtime type, as well as availability as a function of time interval has its own classification [5]:  A (i) inherent availability  A (a) achieved availability  A (o) operational availability Availability Classification for Applications in Construction Production Systems: a Review 5 2.2.1. Inherent availability – A (i) Inherent availability is defined as the probability that the system in use under the given conditions will function satisfactorily at a given moment of time, without taking into account any planned or preventive repairs. The inherent availability relates only to the time of corrective repair of the system, assuming 100% availability of the personnel and repair equipment. This type of availability represents the fulfilment of the requirement for achieving the expected performance of the planned downtime in operation. The availability of the system component is[5] : MTTRMTTF MTTF iA  )( (12) 2.2.2. Achieved availability – A (a) Achieved availability identifies the timing of preventive and corrective maintenance. It is determined by a detailed design closely defines the type, quantity, and timetable of equipment for timely repairs i.e. maintenance. The achieved availability can also be considered as a steady state availability which only considers the time of active preventive and active corrective repairs. Achieved availability can be expressed as the following equation[5]: MMTBM MTBM aA  )( (13) Where: MTBM mean time between maintenance  mean time of maintenance This definition meets the requirements for reaching availability when downtimes are planned. The goal of availability of the repaired (maintained) system is to find extreme values of the function, in order for the system to be at the required level of operation. The resulting availability depends on the production system design that determines all possible scenarios during its operation and maintenance strategy. 2.2.3. Operational availability A (o) basic definition Operational availability is a measure of the average availability over a period of time and includes all experienced sources and causes of delays as well as downtimes (administrative, logistic, organizational, etc.). Operational availability is the availability through which the system has passed, and is based on current events that are taking place in the system. Preliminary availabilities are based on estimates, as well as the models of the system that is in the function of statistical distribution of time. Operational availability can be expressed as the relationship between the time in operation and the total time of the system. Mathematically, operational availability is determined by Eq. 14[1] - [6]: 6 M. MIRKOVIC MDTReadyTimeMTBM Ready TimeMTBM oA    )( )( (14) Where: MDT mean down time Ready Time component is available and ready to operate Operational availability is the lowest limit of performance that is experientially determined (by observing the system in operation) for the given projected capacity and other pre-specified criteria. When there is a high probability of the availability of a system with which the system will achieve the set goal, then the construction technology developer expresses the desired availability, i.e. project availability. 2.2.4. Operational availability new approach Additional divisions have been made with the new approach for defining operational availability within MTBM and MDT times. Namely, MTBM has been divided into the time when the component is available and in operation. MDT has also been divided into TCM, TPM and ALDT, i.e. according to Eq. 15 [6], [7]: ALDTTPMTCMSTOT STOT oA   )( (15) Where: Comparing expressions 14 and 15 reveals the following: STOTReadyTimeMTBM  (16) While, ALDTTPMTCMMDT  (17) This approach for defining operational availability provides a more detailed insight into the availability of the component in terms of the causes that led to the state of hibernation of that component. Also, different costs and capacities are associated with each given time [2]. 2.3. Production availability Due to its specific definition and similarity with operational availability, i.e. the availability of the system through which it passed, production availability (PA) deserves a special analysis approach. MDT  mean down time OT  operational time ST  standby time TCM  total corrective maintenance time TPM  total preventive maintenance time ALDT  total administrative and logistic time Availability Classification for Applications in Construction Production Systems: a Review 7 Defining production availability differs from the previous definition of availability in terms of the time intervals and the type of delays. The production availability of the technological process is analyzed through efficiency, utilization, and basic availability of the following capacities and the states in which the component can be found [7]:  maximum capacity  nominal capacity  reduced capacity  stand-by state  state of failure Production (equivalent) availability (PA) can be defined as "the ratio of the equipment's equivalent operational time to a total given period, during which a system achieves a process output that is equivalent to its maximum dependable capacity" [7], [12]. Thus:     )( MDCT MDCnTo PA (18) Where: To  time of component function at maximum capacity MDC  maximum dependable capacity n  ratio of process output T  total time period Equation 19 can be adopted as the basis for a proposal of the production availability model for construction components:       n n A o o i i i ii h nh 1 1 (19) Where: hi  time intervals for the available component with maximum, reduced and zero capacity ni  ratio between the actual (qact) and maximum construction capacity (qmax) of the component 2.4. Availability standards Because of the importance of the reliability, availability, and maintainability, as well as the related attributes, there are hundreds of associated standards. Some are general but more are specific to domains such as automotive, aviation, electric power distribution, nuclear energy, rail transportation, and software. Standards are produced by both governmental agencies and professional associations, and international standards bodies such as:  The International Electro technical Commission (IEC), Geneva, Switzerland and the closely associated International Standards Organization (ISO) IEC 60050-191:2015  International Standards Organization (ISO), Earth-Moving Machinery Machine Availability Vocabulary ISO 8927 191  The European Committee for Standardization (CEN) EN 61703:2016  The Association Française de Normalization (AFNOR) X60-500  The British Standards Institute (BSI) BS 4778 8 M. MIRKOVIC  The American National Standards Institute (ANSI) ASTM F 2446 04 (2018)  Deutsches Institute F r Normung (DIN) DIN EN 61703:2017-8  The Japanese Industrial Standards Committee (JISC)  The Russian National Standards (ГОСТ) P 27000 2009  The Serbian Institute for Standardization of Serbia (ISS) SRPS EN 61703:2018  Governmental Agencies – primarily in military and space systems (MIL STD721B, MIL HDBK781, MIL STD-781C, DoD 32351H, DoD Guide for Achieving Reliability, Availability, and Maintainability 2005  Other national institutes for standardization By analyzing all the definitions of availability, it can be observed that there are small differences that depend on the type of literature (military, industrial). For a comprehensive definition of availability for components and systems that are expected to be operational over a period of time (minutes, days, years), the following may be adopted: Availability is the probability that a component/system, when used under stated conditions (operating mode and environment) will operate satisfactorily at a given point in time. The basic mathematical definition of availability (A) is [7]- [12]:  TotalTime UpTime A DownTimeUpTime UpTime  (20) 2.5. Availability guidelines Unlike standards, guidelines contain examples from practice with additional explanations. The most cited from the researched field are:  The Institute of Electrical and Electronic Engineers (IEEE), New York, NY, USA, Standard Definitions for Use in Reporting Electric Generating Unit Reliability, Availability and Productivity IEEE 762 2006  The Society of Automotive Engineers (SAE), Warrendale, PA, USA SAE J 199  Verner Deutscher Ingenieure Rihtlinen VDI 3423  AMT The Association for Manufacturing Technology, Production Equipment Availability A, Measurement Guideline, USA IEEE definitions and classifications do not differ substantially from the above standards. VDI 3423 and AMT guidelines refer to production components and systems, and represent an important guidance from the point of view of the application to projectorganized systems. They therefore merit a special approach in presenting definitions and expressions for the availability of components and systems. 2.5.1. VDI 3423 Technical Availability of Machines (VT) and Production Lines According to Eq. 20, the technical availability, the percentage of operational time during which a component/machine is available for production without any technical shortcomings is [13]: 100% 100% 1 100%T T T B B T T V T T                     (21) Where: TT  technical downtime TB  occupied time Availability Classification for Applications in Construction Production Systems: a Review 9 The technical downtime TT is the sum total of all downtimes resulting from shortcomings in the design and construction. Examples of such shortcomings are [13]:  inadequate quantity and quality of material  poor design or construction  poor documentation  need for corrective maintenance  waiting for spare parts  waiting for service personnel  test runs serving for fault location  test runs after fault rectification The occupied time TB is that time within the period under consideration for which any utilization of the machine or plant is planned. According to Eq. 21, [13]: TTTTT WTONB  (22) Where: TN  utilisation time TO  organisational downtime TW  maintenance time The utilisation time TN is the time in which the machine operates in full capacity. The organisational downtime TO is the sum total of all downtimes caused by organisational shortcomings:  energy shortfall  lack of work pieces  lack of tools  insufficient training This also includes downtimes which are caused by shortcomings in plant operation, or ensuring the process. The preventive maintenance time TW includes any work to be done according to the maintenance schedule:  scheduled servicing  routine maintenance  test runs following preventive maintenance This guideline also contains a form for recording downtimes. 2.5.2. AMT Production Equipment Availability A Measurement Guideline This guideline defines all the times in which the components of the production systems can be found, according to Figure 1, [14]: 10 M. MIRKOVIC Total Time (A) Component Component Operating Time (C) Shut Down (B) Scheduled Scheduled Operating Time (E) Downtime (D) Delay Time Potential Production Time (G) (F) Repair Time Production Time (I) (H) Fig. 1 Component Availability Parameters Component availability is defined as the percentage of potential production time (G) during which equipment is operable, that is, operations are not prevented by component malfunction (or process difficulties in turnkey systems) [14]: %100 )( )(  GimePotentialT ITimeProduction yvailabilitEquipmentA (23) This guideline also introduces the term "overall availability". According toEq.24: %100 me(E)peratingTiScheduledO Time(I)Production ilabilityOverallAva (24) 3. COMPONENT AVAILABILITY MANAGEMENT IN CONSTRUCTION PROJECTS Managing the availability of components / machines in construction projects involves:  defining and classifying the availability function  establishing a database of the availability of components from previous work (operational availability – Ao)  predicting the project availability (Ap) of components  determining the current availability of components at the end of the project and business year  analysis of current and projected values  updating the database with new values of current (operational) availability Availability Classification for Applications in Construction Production Systems: a Review 11 3.1. Defining and classifying equipment availability The availability of a construction machine or plant is the probability that will perform the function at a random time t, that is, at a given time t of the interval [0 T]. The basic equation of availability according to Eq. 25 is: DownTimemeStandbayTilTimeOperationa meStandbayTilTimeOperationa A    (25) The component may be available, but without a function due to the failure of other parts of the system. Specifically, the component can be found in the following states:  operational time with maximum capacity  operational time with reduced capacity  stand-by time (component is available with zero capacity)  down time (component is in the state of outage or under scheduled or unscheduled maintenance) This means that Eq. 19 needs to be modified to differentiate the time in which the component has the capacity of zero. Namely, the times "hi" belong to the different capacities of the components (zero, reduced and maximum) in the case of an available component. The times "hj" belong to the capacities of the zero value when the component is not available. So, the term for the production availability of a component of construction production systems can be adopted according to the Eq. 26: 1 1 1 i no h ni i i ocurrent n fno n hhi j i j A        (26) Where: no the times in which the component is available with different capacities nf the times in which the component is unavailable This approach to defining availability provides a realistic view of the cost of components for all the states in which the component can be found. Equation 26 is the consequence of the expansion of Eq. 15 for the operational availability of a component from a cost perspective. By observing the time in which the component functioned and ignoring the oscillations in capacities, it follows that: OT ST A OT ST TCM TPM ALDT       = 1 1 1 no h ni i i n fno hhi j i j       (27) 12 M. MIRKOVIC 3.2. Assessment of equipment availability The first estimates of availability in the field of technical systems were based on the determination of statistical distributions for failure time and repair time [3]. Due to the long enough time in which the production systems function, probability distributions reach a statistical equilibrium, which means that production processes are in a steady state [8], [9]. The availability of components in such cases would be estimated on the basis of Equation 10, while the given time in the equation can be determined by the frequency balancing method. Taking into account the life cycle of the components (LC), three characteristic periods are observed in which these components function. In fact, the life cycle of the components consists of early, constant, and late failure rates (λ). Each construction system consists of components with different stages in the life cycle which is non-homogeneous in terms of the age of the components. This feature of the components and systems leads to the modification of the frequency balancing method so as to increase the accuracy of component availability estimates. The results obtained did not differ significantly from the application of the frequency balancing method and the Monte Carlo simulation method [1], [2]. Specifically, when there are data on availability from the previous work (operational availability), then the availability estimates for periods I, II and III can be made on the basis of Eq. 28, 29 and 30 [1], [2]. Equation 27 is used to estimate the project operational availability of components (ApoI) from period I [1], [2]: 2/)max( Ao,A meanco,aritmetiA I po  (28) Equation 28 is used to estimate the project operational availability of components from the middle part of the life cycle (period II) [1], [2]: A yearlastoA meanaritmeticomaxA poII   ,,, (29) Equation 29 is used to estimate the project operational availability of components from the last part of the life cycle (period III) [1], [2]: A yearlastoA III po  , (30) 3.3. Algorithm / procedure for equipment availability management The management of the availability of components / machines (Cij) of construction production systems is shown in Fig. 2. For "i" and "j" the following applies: ni ,...,2,1 (31) IIIIIIj ,, (32) Where: n  number of system components I, II, III  life cycle periods of components Aoij  operational availabilities from data base according to Eq. 26 Apoj  estimated component operational availability according to Eq. 28, 29, 30 Aocurrent  current component operational availability (availability after project completion) according to Eq. 26: Availability Classification for Applications in Construction Production Systems: a Review 13 START Cij – Aoij Apoi LCi Machine's Park LCI LCII LCIII Eq. 28 Eq. 29 Eq. 30 PROJECT CONSTRUCTION Analysis Aocurrent (Eq.26) / Apoj i = n END No Yes Fig. 2 Algorithm / procedure for equipment availability management 14 M. MIRKOVIC 4. ILLUSTRATIVE EXAMPLE In this section, the component production availability discussed above is illustrated with an example from the data base of an asphalt plant from a road construction company (Vojvodinaput-Zrenjanin). The asphalt plant has a maximum capacity of 100 tons per hour (t/h) and has produced 92,780.00 tons of bitumen bounded materials for a period of 1077 hours. The planned hours of work with the nominal capacity were 92,780.00 / 90 = 1031 hours. In the period of question, according to Eq. 26, the plant was under the following conditions:  maximum capacity Qmax = 100 t/h, h1 = 180  nominal capacity Qnom = 90 t/h, h2 = 370  reduced capacity Qred = 85 t/h, h3 = 488  stand by Qstb = 0 t/h, h4 = 22  state of outage Qout = 0 t/h, h5 = 17 Capacity as a function of time for component availability is illustrated in Fig. 3. Fig. 3 Ratio between capacity and time as a function of plant availability Figure 4 shows the planned amount of work (Q) and events (E) related to oscillations in capacities during the project. Fig. 4 Planned quantity of work as a function of capacity variation 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Qi 13050 20050 20050 27020 33770 33770 37510 43410 45840 50140 60340 60340 61140 69960 69960 72210 81815 81815 92780 E 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 0.00 10,000.00 20,000.00 30,000.00 40,000.00 50,000.00 60,000.00 70,000.00 80,000.00 90,000.00 100,000.00 Q (t / h) h 90 100 0 0 0 0 0 100 100 100 90 90 90 90 85 85 85 85 85 145 215 224 306 381 385 429 488 515 5580 678 687 695 793 801 826 939 948 1077 Availability Classification for Applications in Construction Production Systems: a Review 15 According to equation 26, the production availability of the component is: Aocurrent = 1031/1077 = 0.9573 According to equation 29, the estimated production availability of the component is (see appendix): Apoj(II) = 0.9555 The difference between the current and estimated availability is: Aocurrent / Apoj(II) = 0.9583/0.9555=1.0029, i.e., 0.29 % 5. DISCUSSION AND CONCLUSION The choice of the appropriate equation for the production availability of construction system components is influenced by oscillations in the capacities that are constantly presented in practice. Also, the separation of the time when the component is in a standby and a failure, i.e. at times when it is available and does not perform the function (ST) and the time when it is in failure (MDT). This approach is justified by the different costs that belong to the specified times and obtaining real data on the operational availability of the components / machines. Operational availabilities are the part of a database on the behaviour of components from the previous work. Using the classic approach to defining the availability according to Eq.20 and not respecting the oscillations in capacities and availabilities when the component does not perform its function, the availability value is: A = (1077-22-17)/1077= 0.9638 This approach creates a misconception about the behaviour of the component and increases the risks in the cost estimation in the bidding phase. Also, by applying Eq.15, which recognizes the availability when the component does not perform the function (ST), but does not respect time with different capacities, it may consequently have the above mentioned omissions. Namely: Ao = (1077-22)/1077=0.9796 We believe that the equation proposed in this work for determining the operational availability of production components in project-organized (construction) systems (Eq. 26) is both appropriate and effective In fact, the test result obtained, which varies by 0.29% in relation to the estimated value, i.e. 2.9 ‰, confirms the feasibility of using an equation and assessment methodology based on the non-homogeneity of construction systems in terms of the different life cycles of the components. Acknowledgements. The author would like to express special gratitude to colleagues from the Department of Project Management at the Faculty of Civil Engineering, University of Belgrade, for their support. The author would like to express his gratitude to colleagues from the management sector of the Vojvodinaput's machinery park and the bidding department. 16 M. MIRKOVIC APPENDIX Table A.1 shows the operational availabilities with elementary statistics of the tested component/asphalt plant from the data base of the company for road constructionVojvodinaput -Zrenjanin. Table A.1 Operational availabilities of the asphalt plant during the research period Component Asphalt Plant W 100 Year / Parameter MTBF MTTR λ μ Ao 2005 92.80 4.00 0.0108 0.2500 0.9587 2006 102.77 4.46 0.0097 0.2241 0.9584 2007 96.56 4.78 0.0103 0.2093 0.9531 2008 118.67 5.33 0.0084 0.1875 0.9570 2009 126.50 6.33 0.0079 0.1579 0.9523 2010 138.80 6.40 0.0076 0.1563 0.9534 Minimum 92.80 4.00 0.0076 0.1563 0.9523 Maximum 138.80 6.40 0.0108 0.2500 0.9587 Variation interval 46.00 2.40 0.0032 0.0937 0.0064 Arithmetic mean 112.68 5.22 0.0091 0.1975 0.9555 Mid interval 115.80 5.20 0.0092 0.2032 0.9555 Deviation from the right 135.68 6.42 0.0107 0.2444 0.9587 Deviation from the left 89.68 4.02 0.0075 0.1507 0.9523 REFERENCES 1. M. Mirkovic, "The Impact of Failure Times in Construction Production Systems on Economic Risk Assessments in the Bidding Phase", Complexity, Vol. 2018, pp. 1-13, 2018, https://doi.org/ 10.1155/2018/5041803. 2. M. Mirković, "Optimizacija Raspoloživosti Sistema za Proizvodnju i Ugradjivanje Bitumenom Vezanih Materijala", Doctoral Dissertation, Facilty of Civil Engineering, University in Belgrade, 2016, https://uvidok.rcub.bg.ac.rs/handle/123456789/1014. 3. S. Chatterjee, "Availability models of Maintained Systems" MSc Thesis, Kansas State University, Kansas, USA, 1971. 4. F. A. Tillman and S. Chatterjee, "Availability Models of Maintained System", IEEE Transactions on Reliability, Vol. R-24, Issue 1, pp. 69-72, 1975. 5. A. A. El Shanawary, "Availability of Maintained Systems ", MSc Thesis, Faculty of the School of Engineering of the Air Force Institute of the Technology, Air University, Ohio, USA, 1983. 6. J. C. Conlon, W. A. Lilius and F. H. Tubbesing, Test and Evaluation of System Reliability, Availability and Maintainability, Handbook, 3th ed., Office of Director Defense, Test and Evaluation under Secretary of Defense for Research and Engineering, Department of Defence, Washington, D.C., USA, 1982. 7. R. F. Stapelberg, Handbook of Availability, Maintainability, and Safety in Engineering Design, 1st ed., Springer, London, UK, 2009. 8. Ž. Prašćević and B. Ivković, "Teorija pouzdanosti i analiza proizvodnih sistema u gradjevinarstvu", 2nd Jugoslavenski simpozij-organizacija gradjenja, zbornik radova, Opatija, pp. 259-272, 1986. 9. B. Trbojević and Ž. Prašćević, Gradjevinske mašine, 1st ed., Gradjevinska knjiga, Beograd, SFR Jugoslavija, 1991. 10. M. Mirković, "Određivanje modela operativne raspoloživosti sa realnim podacima iz rada građevinskog proizvodnog sistema", Izgradnja, 69, (2015), 3-4, pp.95-105, Beograd, 2015. 11. Ž. Prašćević and N. Prašćević, "Reliability, Availability, and Working Effects of System Construction Machines with Fuzzy Input Parameters" XL Naučno stručni skup održavanja mašina i opreme 2015, Beograd-Budva, pp. 487-494, 2015 12. M. Mirković, "Analysis of production availability impact in construction systems", Izgradnja 71, (2017), 5-6, pp.179-182, Belgrade, 2017. Availability Classification for Applications in Construction Production Systems: a Review 17 13. VDI 3423: 2011, Technical availability of machines and production lines terms, definitions, determination of time periods and calculation, Verlag des Vereins Deutscher Ingenieure, Germany, 2011. 14. Production Equipment Availability-A Measurement Guideline, 4th ed., AMT The Association For Manufacturing Technology, USA, 2011. KLASIFIKACIJA RASPOLOŽIVOSTI SA ASPEKTA PRIMENE NA GRAĐEVINSKE PROIZVODNE SISTEME: PREGLED Cilj rada je unapređenje postojećih klasifikacija raspoloživosti komponenata sa aspekta primene na građevinske sisteme. Građevinski proizvodni sistemi pripadaju projektno organizovanim sistemima sa serijsko paralelnom strukturom, sa ili bez redundantnih komponenata i funkcija raspoloživosti ima značajan uticaj na pokazatelje performansi komponenata i sistema. Glavni pokazatelji funkcionisanja komponenata su raspoloživost, kapacitet, troškovi i projektno vreme. Novi pristup klasifikaciji omogućuje izbor odgovarajućeg pristupa proceni projektne raspoloživosti i upravljanju mašinskim parkom kompanija. Novi pristup je testiran na primeru iz prakse. Dobijeni rezultati potvrdili su opravdanost za proširenje klasičnog pristupa klasifikaciji proizvodne raspoloživosti komponenata. Ključne reči: raspoloživost, građevinska komponenta, indikatori komponenata, proizvodni system