Parallel construction method
The parallel method involves the simultaneous performance of a number of works on a separate building or the construction of several buildings of the same type. An independent team will work at each of the sites under consideration. Ideally, all teams will begin work at the same time and complete the construction of buildings at the same time. With the parallel method, the total duration of construction of a separate building is equal to the time required to complete all work, but at the same time the need for workers for simultaneous work will increase several times.
The parallel method ensures a minimum duration, since the construction period is equal to the construction period of one house. However, here, just as with the sequential method, the type and quantity of resources consumed constantly changes depending on the construction period.
But the modern level of construction production and construction organization, when construction and installation work is mainly carried out by powerful contracting general construction organizations, excludes the use of sequential and parallel construction methods in their pure form. This is primarily due to the need for uniform use of resources (machines, work teams, etc.), as well as the limitations of these resources.
For example, during the construction of any facility, as work is completed in a certain technological sequence, mechanisms and crews that have completed work at a certain stage are released. So, first, earth-moving equipment is freed up, then installation teams, installation cranes, etc. In order for these capacities not to be idle, they must be switched to the construction of another facility. Thus, certain work begins at the second object, and at the same time ends at the first, etc.
When performing work on many objects simultaneously during certain periods, the need for homogeneous resources may significantly exceed their actual availability. Therefore, as work on one site is completed, these resources will be sequentially transferred to another, etc.
The flow method, while maintaining the corresponding advantages of sequential and parallel methods, avoids their disadvantages. With the flow method, work on the construction of each house is divided into several processes, the completion of which is allotted the same amount of time. On a complex of N houses, homogeneous processes are performed sequentially one after another, and heterogeneous processes are performed in parallel. The duration of construction of N buildings divided into several processes will be longer than with the parallel method, but less than with the sequential method. The intensity of resource consumption here will also be greater than with the sequential method, but less than with the parallel method.
SEQUENCE OF WORK AND CONSTRUCTION OF BUILDINGS
The sequence of work is determined by the following main factors, the phased development of which ultimately leads to the implementation of the construction process:
development area;
site preparation (work of the preparatory period);
construction of the underground part;
construction of the above-ground part;
construction of enclosing structures;
installation of engineering equipment;
interior finishing works;
installation of technological equipment;
external finishing works;
landscaping.
Selecting a development area is the very first stage of construction implementation. At this stage, based on the assigned tasks, the most optimally located land plot is determined, meeting both the requirements for a rational supply of building materials, structures and resources for the construction period, and meeting the necessary operational requirements, and geotechnical surveys are carried out. They carry out state registration (examination of buildings and structures planned for the development of a given land plot), allocation of a land plot for construction and preparation of architectural and planning assignments.
Site preparation is a mandatory stage, approximately similar in scope of work for industrial and civil construction. Basically, site preparation means carrying out engineering surveys, tying the building being constructed to the ground, demolishing old buildings, relaying networks, erecting temporary buildings and structures.
The accepted sequence of work during the construction of a separate building or a complex consisting of adjacent buildings of the same type can significantly influence the overall construction period.
Let's consider one of the methods for constructing buildings or performing interrelated work - sequential.
The sequential method provides that when constructing a separate building, a team of workers completes each subsequent work only after completing the previous one. Consequently, the total duration of construction of a building is equal to the sum of the durations of individual types of work, i.e. in this case, a small number of personnel working at one facility will be required. In the case when a number of buildings of the same type will be built one after another, each subsequent building only after the completion of the previous one, then a single team of workers will erect these buildings sequentially, moving from one completed object to the next. With this method, the total duration of construction of a complex of buildings is equal to the product of the duration of construction of one house by their number, but in the same way as in the construction of an individual building, a relatively small number of workers are required, working for a long time in one place.
Sequential methods are characterized, on the one hand, by the sequence of execution of the work of the complex, and on the other, by the absence of simultaneity in their implementation.
The need for their use is determined:
specifics of production;
design features of structures;
technology of work;
safety precautions.
Advantages of the method:
simplicity of its organization;
low sensitivity to changes and even abandonment of the rhythm of work;
a high degree of alternativeness of the chain (sequence of work), since its nature can be quite freely changed at any time (Fig. 3.).
Disadvantages of the method:
The long duration of a set of works is maximum compared to other methods with equal intensity of work;
The great need for resources is maximum compared to other methods with the same deadline for completing a set of works.
As a result of these shortcomings, sequential methods of organizing work as independent ones are used very rarely, except in cases where these methods are the only ones possible (pipes, masts, towers, cooling towers, etc.).
Work production schedule
With the sequential method, all technological cycles are carried out first on the first gripper, then on the second, etc.
The transition to the next occupation is carried out after completion of work on the previous one.
T = t × m
T is the total duration of work, t is the duration of work on one grip; m – number of grips
A team of workers will move sequentially from job to job, requiring a small number of personnel working at one site.
Q = T × n, (person days)
Q is the total labor intensity, T is the total duration, n is the number of people.
Diagram of labor movement
After constructing a calendar schedule and determining the construction period, they begin to construct a diagram of the movement of labor, which serves to determine the need for human resources and the need to provide them with the appropriate volume of household services, temporary buildings and structures, required equipment, personal protective equipment, and so on.
The diagram displays the number of workers on the construction site (vertical scale) at any point in time (horizontal scale) throughout the entire construction period.
As a rule, the resulting diagram of the movement of workers does not look entirely successful: there are peaks and valleys - sharp (by more than 30%) short-term (several days) changes in values. To ensure a more uniform workload of work crews, the diagram is optimized based on the following requirements:
1. As the scope of work unfolds, the total number of workers on the construction site should increase, then gradually decrease.
2. The value of the coefficient of uneven movement of workers (the maximum number of workers on the site, determined by the diagram, divided by the average number of workers, determined by dividing the area of the diagram by the length of its base) should tend to 1.5.
Methods of organizing construction production. The essence and basic principles of the continuous organization of construction production.
The organization of construction production can be carried out by three methods - sequential, parallel and in-line.
With the sequential method, there are a number of disadvantages - the level of resource consumption is minimal, and the duration of consumption is maximum; each type of resource will be involved for a short time, since the process of building a house periodically requires workers of different specialties, various machines, mechanisms and materials. Machine downtime and losses due to their relocation are also inevitable. Frequent changes in types of materials, products and structures introduce great difficulties into the work of manufacturing enterprises, transport and supply chains.
The parallel method ensures a minimum duration of construction, but the consumption of resources increases many times, the number of workers and mechanisms also increases greatly, which is not always economically feasible.
The flow method, while maintaining the corresponding advantages of sequential and parallel methods, allows one to avoid their disadvantages. With the flow method, the work of constructing each house is divided into n processes. On a complex of N houses, homogeneous processes are carried out sequentially one after another, and heterogeneous ones in parallel (Fig. 5.3). The duration of construction of N buildings divided into n processes will be longer than with the parallel method, but less than with the sequential method. The intensity of resource consumption here will also be greater than with the sequential method, but less than with the parallel method.
The flow method is characterized by the following features:
1. Division of work into component processes in accordance with the specialty and qualifications of the performers.
2. Dividing the scope of work into separate sections to create the most favorable working conditions for individual performers.
3. Maximum combination of processes over time.
The flow method ensures the uniformity of resource consumption and the rhythm of production of finished products (in this example, houses). The flow organization creates, in turn, favorable conditions for the work of related organizations: contracting organizations, supplier factories, transport, supply operations.
The task of flow design is to determine such parameters that, taking into account rational technology and organization of work, ensure the total duration of construction of the complex within the normative limits and continuous loading of resources (brides, machines, mechanisms).
The organization of production flow in construction provides for:
1. Identification of objects that are similar to each other in terms of volumetric planning and design solutions, and the technology of their construction.
2. Dividing the process of constructing objects into separate works, preferably equal or multiple in labor intensity.
3. Establishing an appropriate sequence of work, connecting interrelated works into a common integrated process and synchronizing them, thereby achieving continuity of construction production.
4. Assigning certain types of work to certain brigades of workers, establishing the sequence of inclusion of individual objects in the flow and the movement of brigades in the process of performing work at individual objects.
5. Calculation of the main flow parameters, taking into account the simultaneous combination of the majority of work and the coordination between the duration of certain types of work and the number of driving machines and work teams.
6. Calculation of the sequence of transition of leading construction teams of workers and machines from site to site, taking into account compliance with the planned rhythm of construction.
For each group of buildings of the same type, a technological sequence of work is established and the rational sizes of areas (areas) and their number are determined. The dimensions of the grips depend on
-mainly on the space-planning structure of the facility, the composition of the equipment, as well as on the nature of the development of specialized flows, the composition of the work they perform and their power (productivity).
An occupation is a part of a building, the scope of work for which is carried out by a team (unit) of a permanent composition with a certain rhythm, ensuring the flow organization of the construction of the facility as a whole.
The flow method is a method of organizing construction that ensures the systematic, rhythmic production of finished construction products (completed buildings, structures, types of work, etc.) based on the continuous and uniform work of labor collectives (teams, streams) of a constant composition, supplied with timely and complete supply of all necessary material and technical resources.
The use of in-line methods is a natural organizational form for performing construction and installation work using permanent construction teams that are stable in composition and number of workers.
The use of flow methods is determined by the tasks that are set and solved by construction organizations of various levels (briad, site, SU, trust, plant, etc.) in the process of constructing objects for various purposes. All resources in such an organization must be used constantly and continuously. This condition must be ensured for each individual labor resource of the brigade (link) and all the means interconnected with it in the process of work (mechanisms, equipment, etc.).
The composition and number of brigades should remain constant on average for a sufficiently long period of time, even during the construction of heterogeneous objects. This condition ensures both a sustainable increase in labor productivity and the creation of a favorable socio-psychological climate in the team.
Possible periodic partial changes in the set of jobs are compensated by the combination of professions by workers of complex brigades.
28 Classification of flows by structure and type of product, rhythm and duration. Flow parameters: spatial, technological and temporal.
Classification of flow by structure and type of product, rhythm and duration. Flow parameters – spatial, technological and temporal.
Classification of flows is carried out depending on the structure and type of final product.
Private stream- this is an elementary construction flow, which is one or more processes performed by one team (team, unit). The products of a private flow can be excavation work, laying foundations, laying walls, installing a house, plastering work, etc. A private flow is organized mainly where it is possible to perform work on different sections in a flow-dissected manner.
Specialized thread consists of a number of private flows, united by a single system of parameters and flow diagram. Specialized threads are the basic building blocks of a thread. Their products are completed types of work, structural elements and parts of buildings (underground part of the building, roof, finishing work). Depending on the nature of the object, the type and degree of combination of work on the same grip(s), when performing work manually, various specialized flows can work simultaneously, for example, teams of electricians and plumbers during the construction of a residential building. Private and specialized flows can have different directions of division, which depend on the space-planning solution of the building, the types of work performed
and their stages, used construction machines and mechanisms. They can be horizontal, vertical, inclined and mixed (Fig. 5.4).
The horizontal direction of flow is carried out when constructing foundations, installing structures of one floor, roofing work, etc. The vertical direction of flow can be vertically upward, vertically downward, or a combination of these two directions. The vertical scheme is used when installing multi-storey industrial buildings, when installation is carried out using the “crane” method in separate sections for the entire height of the building, when laying pipes in brick, etc.
Using an inclined pattern, one-story brickwork is carried out, structures are installed at different elevations, etc. The combination of different directions gives combined flow patterns. The predominant pattern of flow development in multi-story construction is horizontal-vertical, and in single-story construction it is horizontal.
Object stream- a set of specialized flows, the composition of which ensures the implementation of the entire complex of works on the construction of the corresponding construction project. The products of these flows are completely finished buildings (structures) or a group of buildings (structures). 
Complex flow- consists of object flows simultaneously engaged in the construction of individual buildings and structures that are part of an industrial enterprise, residential area, etc. The products of the complex flow are commissioned industrial facilities, completed residential areas, etc.
The general diagram of the technological structure and flow levels by type of work is shown in Table. 5.1,
The nature temporarilyro development, the following types of flows are distinguished:
1. equal-rhythmic, in which all component flows have the same rhythm, i.e., the same duration of work on all tasks;
2. multiple rhythmic, in which all component flows have unequal but multiple rhythms;
3. heterorhythmic, in which the component flows do not have a constant rhythm due to the heterogeneity of buildings and structures and the inequality of the rates of the component flows.
Flow parameters express temporal, organizational and spatial characteristics and make it possible to determine the dependencies between them.
TO temporary flow parameters include:
T 0- the total duration of work on the flow as a whole;
T l- the total duration of the work flow for the teams to complete all the work in one area;
T br- the total duration of work of each individual brigade on all grips;
t,br- the rhythm of the team’s work, the duration of the team’s work on the capture;
t org- organizational breaks between the work of adjacent teams on the same area;
Parallel-flow methods of organizing work (parallel flows) are a more general case of the formation and calculation of flows. They are usually used when individual flow methods do not give the required results (even when using the reviewed methods for optimizing them). Therefore, the formation and calculation of parallel-flow methods are carried out after the formation and calculation of individual-flow methods. This raises questions: what types of work or work should additional teams be assigned to and how to distribute work between teams of the same type?
A.V. Afanasyev proposed assigning additional teams of the same type to the longest types of work in a quantity that ensures a reduction in their duration to the required value, distributing work between teams of the same type during the flow calculation with critical work identified taking into account resource and frontal connections, distributing work in in accordance with the initial priority with priority loading (with equal opportunities) of the most powerful brigades, and with equal power of brigades - those of them that have the lowest serial number. If there are teams of the same type of different capacities, he recommends placing them on a matrix (in the ODF system) in descending order of capacity.
A number of researchers have proposed modifications of this algorithm, namely, loading brigades not in accordance with the initial order, but selectively, as fronts are released, loading brigades not in accordance with their capacity, but in accordance with the queue awaiting loading or in accordance with the possibility of an earlier completion of work. These modifications in certain cases give better results, but not always. All possibilities for the formation of parallel-flow methods, taking into account the specified modifications, as well as according to a fundamentally different (also proposed by A.V. Afanasyev) method of oriented assignment of additional teams to work that restrains the compaction of flows, are considered in a special course, and in this main course - only first method.
Let us illustrate this method of forming and calculating the parallel-flow organization of work using an example.
Let the same conditions as above be given, and a flow with critical jobs identified taking into account resource and frontal connections be formed and calculated. The resulting flow duration is 40 units. time, does not satisfy. It is necessary to reduce it to 35 units. time due to the introduction of additional teams of the same type.
Consideration of the parameters of an individual flow (initial data) shows that types of work have different durations and in order to reduce the duration of types of work “A”, “B” and “D” to the minimum corresponding to type “B”, that is, to reduce the irregular flow To achieve a harmonious look, it is necessary to introduce additional teams, one for types of work “A” and “D”, and two teams for types of work “B”. The involvement of such additional brigades turned out to be possible, but additional A 2, B 2, B 3 had less power than A 1 and B 1, and brigade G 2 had equal power with G 1 (A 2 = 0.5 A 1; B 2 = 0.5 V 1; V 3 = 0.3 V 1; G 2 = G 1).
We will carry out the formation and calculation of a parallel-flow method of organizing work.
| OFR | Types of jobs | Types of work and team indices | |||||||||||
| A | B | IN | G | A 1 | A 2 | B | IN 1 | AT 2 | AT 3 | G 1 | G 2 | ||
| Work fronts | 0 4 | 4 6 | 6 13 | 13 18 | 0 4 | 4 6 | 6 13 | 13 18 | |||||
| I | |||||||||||||
| 4 9 | 9 12 | 13 22 | 22 28 | 0 10 | 10 13 | 13 22 | 22 28 | ||||||
| II | |||||||||||||
| 9 12 | 12 14 | 22 30 | 30 33 | 4 7 | 13 15 | 15 31 | 31 34 | ||||||
| III | |||||||||||||
| 12 16 | 16 19 | 30 36 | 36 40 | 7 11 | 15 18 | 18 36 | 36 40 | ||||||
| IV | |||||||||||||
| Σt j | |||||||||||||
| n additional brig. | - | Power A 2 =0.5 A 1, V 2 =0.5 V 1, V 3 =0.3 V 1, G 1 =G 2 |
Rice. 34. Matrix with the results of the formation and calculation of a parallel flow with the CR at early deadlines for completing work.
Consideration of the calculation results shows that the inclusion of three additional teams in the flow (no work was found for team G 2) did not produce any positive effect. This happened because brigades A 2, B 2 and B 3 had little power.
Indeed, if, instead of these brigades, brigade B 2 with the capacity of brigade B 1 is included in the flow, then the required reduction in duration will be achieved.
| OFR | Types of work and team indices | Ordinal numbers | ||||||||||||
| A | B | IN 1 | AT 2 | G | 5 10 15 20 25 30 35 | T i | ||||||||
| Work fronts | 0 4 | 4 6 | 6 13 | 13 18 | ||||||||||
| I | ||||||||||||||
| 4 9 | 9 12 | 12 21 | 21 27 | |||||||||||
| II | ||||||||||||||
| 9 12 | 12 14 | 14 22 | 27 30 | |||||||||||
| III | ||||||||||||||
| 12 16 | 16 19 | 21 27 | 30 34 | |||||||||||
| IV | ||||||||||||||
| T j |
Rice. 35. Parallel flow with the Kyrgyz Republic when work is completed early.
Based on this, formed as a rational structure of a parallel flow with critical works identified taking into account resource and frontal connections, parallel flows with research work and with the NOF can be calculated.
| OFR | Types of work and team indices | T i | Ordinal numbers | |||||||||||
| A | B | IN 1 | AT 2 | G | 5 10 15 20 25 30 35 | |||||||||
| Work fronts | 0 4 | 9 11 | 11 18 | 18 23 | ||||||||||
| I | ||||||||||||||
| 4 9 | 11 14 | 14 23 | 23 29 | |||||||||||
| II | ||||||||||||||
| 9 12 | 19 16 | 18 26 | 29 32 | |||||||||||
| III | ||||||||||||||
| 12 16 | 16 19 | 23 29 | 32 36 | |||||||||||
| IV | ||||||||||||||
| T j | The reader is advised to draw a calendar chart |
Rice. 36. Parallel flow with research
| OFR | Types of work and team indices | T i | Ordinal numbers | |||||||||||
| A | B | IN 1 | AT 2 | G | 5 10 15 20 25 30 35 | |||||||||
| Work fronts | 0 4 | 4 6 | 6 13 | 13 18 | ||||||||||
| I | ||||||||||||||
| 4 9 | 9 12 | 12 21 | 21 27 | |||||||||||
| II | ||||||||||||||
| 14 17 | 17 19 | 19 27 | 27 30 | |||||||||||
| III | ||||||||||||||
| 17 21 | 21 24 | 24 30 | 30 34 | |||||||||||
| IV | ||||||||||||||
| T j | The reader is advised to draw a calendar chart |
Rice. 37. Parallel flow with NOF
It is of undoubted interest to compare the varieties of parallel flow.
Table 2
Parameters of work organization options
| Method index | T | Duration of types of work | Front duration. complexes | ||||||||
| A | B | IN 1 | AT 2 | G | I | II | III | IV | G | ||
| PP with KR | |||||||||||
| PP with research | |||||||||||
| PP with NOF |
A formal summation of the parameters for each method shows that the most preferable is a parallel flow with critical work identified taking into account resource and frontal connections (with early deadlines for completing work).
However, this approach does not take into account the economic side of the matter, that is, the costs of increasing the duration of each type of work and each frontal set of works and the entire parallel flow as a whole are not taken into account. All this must be taken into account in real conditions.
In conclusion, considering the issue of forming and calculating parallel flows, it should be noted that their duration depends on the sequence of development of work fronts. Therefore, a search must be made for optimal queues that provide the minimum duration. Corresponding directed search algorithms have been developed and are discussed in a special course.
LECTURE No. 8
COMPARISON OF WORK ORGANIZATION OPTIONS.
A modern approach to organizing work requires the development of all competitive options.
Complex flows can be formed:
In the form of combined streams with full preservation of the structure of previously developed object streams;
In the form of aggregated flows, which ensure the immediate start of work by teams in the subsequent object flow after completion of work in the previous one, but at the same time the structure of the object flows changes;
In the form of compacted ones, which ensure the minimum duration of the entire complex stream, but at the same time the structure of the original object streams changes.
The initial data when forming complex flows are presented in the form of parameters of independently generated object flows, presented on matrices in the ODF system. Complex combined flows (CFC) are formed by identifying possible periods of displacement of the subsequent object flow relative to the previous one, based on the interests of the continuous work of each team. In this case, the maximum is taken as the calculated one, eliminating the need for additional teams of the same type. The total duration of the PDA is defined as the sum of all calculated offsets between adjacent object streams and the duration of the last object stream.
A complex aggregated flow (CAF) is formed by identifying the estimated periods for the deployment of types of work, taking into account the parameters of all object flows. In this case, the structure of object streams is destroyed. The total duration of the CPA is determined as the sum of the deployment periods of types of work and the duration of all works of the last type as part of a complex flow.
A complex compacted flow (CPF) is formed by preserving the structure of the first object flow in the queue and ensuring the continuous execution of all work of the first type as part of the complex flow. The timing of other types of work of object flows as part of a complex flow is determined by the availability of resources and work areas. They can be early or late. In this case, if the early and late deadlines coincide, the corresponding type of work of the object flow is critical. The sum of critical jobs that make up one chain (single-critical path) determines the duration of the CPU.
Let us illustrate the application of this method for calculating complex flows with an example.
Initial data in the form of timing of work types of object flows, duration of work types (t ij) and possible combination of adjacent types (tc) are presented on the M-1 matrix (in the ODF system). Strictly speaking, this information is redundant, since the object flow unambiguously determines either the timing of types of work, or their duration and combination, but when calculating complex flows without a computer, it is convenient to use one in one case, and another in another case.
M-1Rice. 38. Matrix of initial data (characteristics of object flows).
The calculation of the CPC consists of determining the possible displacement value of each subsequent object flow in relation to the previous one, based on the interests of each team (type of work), that is, based on their provision of zero stretching of the inter-object resource connection (t mrsv) and the choice of the maximum displacement between adjacent object flows, that is, calculated (t cm), eliminating the need to attract additional teams of the same type.
After determining the value of the calculated offset, it is added to the terms of the subsequent type of work and the calculation cycle is repeated. By establishing all the deadlines and duration of the complex flow, the stretching of interobject resource connections (t mrsv) and the duration of the types of work as part of the complex flow are established. The durations of object streams in the PDA are preserved.
| M-2 | A | B | IN | G | Ti | M-3 | A | B | IN | G | Ti | |
| I | 0-16 | 9-19 | 11-41 | 27-45 | I | 0-16 | 9-19 | 11-41 | 27-45 | |||
| t cmj | max 16 | t mcrv | ||||||||||
| II | 0-30 | 15-40 | 25-50 | 35-60 | II | 16-46 | 31-56 | 41-66 | 51-76 | |||
| t cmj | max 30 | t mcrv | ||||||||||
| III | 0-20 | 18-30 | 25-45 | 30-50 | III | 46-66 | 64-76 | 71-91 | 76-96 | |||
| t cmj | -5 | max 20 | t mcrv | |||||||||
| IV | 0-30 | 20-45 | 40-65 | 55-70 | IV | 66-96 | 86-111 | 106-131 | 121-136 | |||
| Σt сij | T j |
Rice. 39. Matrices of displacements (M-2) and results of calculation of the CPC (M-3)
The calculation of the CPA consists of determining the possible value of the deployment period for each subsequent type of work in relation to the beginning of the previous one in relation to each front (T p ij) and choosing the maximum (calculated) one, which excludes the premature start of the subsequent type of work on any front.
Various methods have been proposed for determining the estimated value of the deployment period, including those by Aguilar and Mena. In this case, the sum of the durations of the 1, ..., i-th works of the type preceding the j-th under consideration is determined, minus the calculated value of the combination on the i-th front (j-1) and the j-th types of work and the sum of 1, ..., (i -1)-th works of the type under consideration on previous fronts.
After determining the estimated periods for the deployment of the second and subsequent types of work, the timing of the implementation of object types of work as part of a complex flow and its duration, as well as the extension of frontal connections (t fsv), are determined as the difference between the start of work ij and the end of work i(j-1) in minus the calculated combination of adjacent types of work of the object flow (t c).
| M-4 | A | t frsv | B | t frsv | IN | t frsv | G | Ti |
| t s | t s | t s | ||||||
| 0 16 | 39 49 | 41 71 | 68 86 | |||||
| I | ||||||||
| t mrsv | ||||||||
| 16 46 | 49 74 | 71 96 | 86 111 | |||||
| II | ||||||||
| t mrsv | ||||||||
| 46 66 | 74 86 | 96 116 | 111 131 | |||||
| III | ||||||||
| t mrsv | ||||||||
| 66 96 | 86 111 | 116 141 | 131 146 | |||||
| IV | ||||||||
| T p j | ||||||||
| T j |
Rice. 40. Matrix with the results of calculating the KPA.
T r B1 = 16 – 7 – 0 = 9; T r B1I = (16 + 30) – 15 – 10 = 21;
T r B1II = (16+30+20) – 2 – (25 + 10) = 29; T r B1V = (16+30+20+30)–10–(12+25+10)=39.
calc. T r B = 39
T r B1 = 10 – 8 – 0 = 2; T r B1I = (10 + 25) – 15 – 30 = -10;
T r B1II = (10+25+12) – 5 – (25 + 30) = -13; T r B1V = (10+25+12+25)–5–(20+25+30)= -8.
calc. T r B = 2
T r G1 = 30 – 14 – 0 = 16; T r G1I = (30+ 25) – 14 – 18 = 23;
T r G1II = (30+25+20) – 15 – (25 + 18) = 17; T r G1V =(30+25-20-25) –10–(20+25+18)=27.
calc. T r G = 27
Calculation of the CPU consists of determining the deadlines for completing work types of object flows as part of a complex flow, provided that the deadlines for completing work types of the first (in queue) object flow are preserved and the continuous execution of work of the first type (with zero stretching of inter-object resource connections) as part of a complex flow. The timing of the remaining types of work of object flows as part of the complex is determined sequentially as resources and fronts are released, with mandatory consideration of the possible combination of related types of work.
| M-5 | A | t frsv | B | t frsv | IN | t frsv | G | Ti |
| t s | t s | t s | ||||||
| 0 16 | 9 19 | 11 41 | 27 45 | |||||
| I | ||||||||
| t mrsv | ||||||||
| 16 46 | 31 56 | 41 66 | 61 86 | |||||
| II | ||||||||
| t mrsv | ||||||||
| 46 66 | 64 76 | 71 91 | 86 106 | |||||
| III | ||||||||
| t mrsv | ||||||||
| 66 96 | 86 111 | 106 131 | 121 136 | |||||
| IV | ||||||||
| T j |
Rice. 41. Matrix with the results of calculating the efficiency factor.
The calculations of the KPC, KPA and KPU showed that these options for organizing a complex flow are characterized by different parameters.
Table 3
Complex Flow Option Options
A formal summation of the parameters for each method shows that the most preferable is the complex flow combined. However, this approach does not take into account the economic side of the matter, that is, the costs of increasing the duration of each type of work and each object flow and the entire complex flow as a whole are not taken into account, as well as the efficiency of the object flows themselves. All this must be taken into account in real conditions.
In conclusion, considering the issue of formation and calculation of complex flows, it should be noted that their duration depends on the order in which object flows are entered into the complex flow. Therefore, a search must be made for optimal queues that provide the minimum duration. Corresponding directed search algorithms have been developed and are discussed in a special course.
Comparison of work organization options
A modern approach to the organization of work, in particular, the St. Petersburg school of continuous work organization, requires the development of all competitive options for their assessment and selection of the most effective, that is, the most appropriate to the specific production conditions. Options for organizing work can be assessed according to one or another criteria.
A criterion (gr. kriterioh) is a “touchstone”, a distinctive feature, a measure. When assessing options for organizing work, various individual criteria can be used (taking into account their priorities) and differential ones, combined (taking into account their significance) into an integral one. .
Individual criteria are presented, as a rule, in absolute terms (in terms of cost, time, labor costs and other natural indicators). The choice of the best option when using individual criteria is significantly influenced by the order of their application, determined by the significance (priority) of each of them. In this case, different systems for using individual indicators are possible (without limiting the discarded options that are less effective than those selected according to the criterion under consideration or with a restriction that allows the use of all criteria, as well as by distributing the compared options for each criterion (according to their corresponding places), summing up the place numbers and recognition as the best option with the lowest score). If it is necessary to strengthen the significance of certain criteria, their significance coefficients are introduced (the numbers that determine the places occupied by the option according to the relevant criteria are multiplied by the significance coefficients).
Differential criteria are always presented in relative values, limited by a certain limit (from 0 to 1, from 0 to 6, from 0 to 10, etc.). They are combined, taking into account the significance coefficients, into an integral one. In this case, significance coefficients are set (accepted) by developers or a higher level of management, taking into account specific production conditions and a more general one in relation to the problem under consideration. There is no (sufficiently strict) methodology for assigning significance coefficients (for example, it is impossible to strictly determine how much more important it is to build an object in a shorter time or cheaper), but experience allows us to assign coefficients, and if the assignment is unsuccessful, to correct them.
The lecturer proposed the following as differential criteria:
1. Timeliness of work (K 1). The criterion characterizes the deviation of the planned duration of work from the specified one, which in most cases causes a disruption in the organization of a wider range of work.
K 1 = T D / T, if T D< Т
K 1 = T / T D, if T D > T
where T is the planned duration of the work package;
T D – directive (normative) duration of the work package.
2. Correspondence between the need for resources and their availability (K 2). The criterion characterizes and largely predetermines the feasibility of the work organization option.
K 2 i = R Hi / R ni if R Hi< R ni
K 2 i = R ni / R Hi if R Hi > R ni
K 2 = Σ K 2i П i / П
where K 2i is the criterion for compliance of the i-th type of resource;
P i – labor intensity or cost of the i-th type of work, or the cost of the i-th type of resources;
P – total labor intensity or cost of the entire complex of work, or the total cost of all resources;
m – number of types of resources.
3. Efficiency of resource use (K 3). The criterion characterizes the stability of resource use, that is, the degree of duration of certain types of work (t i) in the overall complex (taking into account their labor intensity or cost).
K 3 = Σ (t i / T) (P i / P)
4. Time combination of different types of work (K 4). The criterion characterizes the degree of flow of the work organization option.
K 4 = 1 – T / Σ t i
5. Continuity of resource use (K 5). The criterion characterizes the degree of uninterrupted work (within each individual type of K 5 i and K 5 as a whole).
The presence of downtime of resources is undesirable, since it leads to an increase in the cost of construction of the facility, but it is inherent in some methods of organizing work (with NOF, with KR, with organizing work on tours).
K 5 i = t N i / t i ;
K 5 = Σ K 5i П i / П
where t Hi is the duration of the i-th type of work during its continuous execution;
t i is the planned duration of the i-th type of work.
6. Uniformity of resource use (K 6). The criterion characterizes the stability of the use over time of individual types of resources (types of work) and the entire complex.
K 6 i = 1 – f i / F i
K 6 = Σ K 6i П i / П
where f i is the total area protruding above the line of uniform consumption over time of the i-th resource;
F i – total area characterizing the consumption of the i-th resource over time.
7. Criticality of work (K 7). The criterion characterizes the degree of criticality of work within each type (K 7 i) and as a whole (the entire complex).
K 7 i = P k r i / P i
K 7 = Σ K 7i P i / P = Σ P kpi / P i
P kр i – labor intensity or cost of critical work as part of the i-th type;
P – labor intensity or cost of the entire complex of work.
8. Continuity of development of work fronts (K 8). The criterion characterizes the lack of downtime in work within the frontal complexes (K 8 j) and in general (across all frontal complexes). The presence of downtime in work fronts is undesirable, since it leads to freezing of working capital, but it is inherent in some methods of organizing work (with research work, with the Kyrgyz Republic, with the organization of work on tours).
K 8 i = t Hj / t j ;
K 8 = Σ K 8j P j / P
where t Hj is the duration of the j-th frontal set of works during their continuous execution;
t j is the planned duration of the j-th frontal set of works;
P j – labor intensity or cost of the j-th frontal set of works;
n – number of frontal complexes (fronts) of work.
9. Saturation of work fronts with resources (K 9). The criterion characterizes the degree of use of work fronts during production (normal, that is, providing normal working conditions for performers; not completely saturated with performers; oversaturated with performers, worsening the working conditions of everyone, but increasing the total volume of production; extremely saturated, that is, not providing further saturation of the front works performed by performers have no positive effect.
K 9 i = R opt i / R i if R opt i< R i ;
K 9 i = R i / R opt i, if R opt i > R i;
K 9 = Σ K 9i П i / П
where R opt i is the optimal composition of performers of the i type of work;
R i is the planned composition of performers of the i-th type of work.
10. Efficiency of resource use and development of work fronts (K 10). This aggregate criterion proposed by A.V. Afanasyev allows one to simultaneously take into account the influence of two alternative factors. If necessary, significance coefficients can be introduced into the criteria, establishing the relationship between the efficiency of resource use and the development of work fronts:
K 10 = (K 5 + K 8) / 2
With different significance of downtime of resources and work areas:
K 10 = (Z 5 K 5 + Z 8 K 8) (Z 5 + Z 8),
where Z 5 is the significance of resource downtime, Z 8 is the significance of work front downtime.
11. Efficiency of dynamics of capital investments (investments). The criterion was proposed by the lecturer together with V.Z. Velichkin and V.I. Vtyurin and characterizes the degree of rationality of the dynamics of capital investments determined by the planned organization of work.
When forming the criterion, it is accepted that before investing funds (in the form of performing any work, manufacturing any structure, installing any equipment), they are in circulation and provide income (according to the accepted rate of efficiency), and after investment of income do not bring, that is, there is a loss (corresponding to the efficiency norm). The total effect of the i-th capital investment is determined by the difference between income and loss (calculated using the compound interest formula). The overall absolute effect is determined by the sum of the effects of all capital investments, and the relative indicator is defined as the ratio of the sum of the maximum possible loss and the achieved efficiency to the base, that is, the sum of the maximum possible income and the maximum possible loss.
Let the i-th capital investment take place at time t i (K t i). At the same time 0< t i < T, а нормативный коэффициент эффективности Е Н.
Then after 1 year, through capital investment, its value will increase:
K ti+1 = K ti + E H K ti = K ti (1 + E H)
After 2 years, its value (at compound interest) will increase:
K ti+2 = K ti+1 + E H K ti+1 = K ti+1 (1 + E H) = K ti (1 + E H) 2
After 3 years, its value (at compound interest) will increase:
K ti+3 = K ti+2 + E H K ti+2 = K ti+2 (1 + E H) = K ti (1 + E H) 3
After the period T – t i (before the facility is put into operation), its value will increase:
K T- ti = K ti (1 + E H) T-ti
In accordance with this, the amount of loss from the diversion of Kt i from circulation for the period T – t i will be determined equal to
Y Kti = K ti (1 + E H) T-ti – K ti = K ti [(1 + E H) T-ti – 1]
However, before the investment, this amount of funds was in the national economic circulation and brought a certain income. The reduction of capital investment K ti to the start of construction is determined by the value K 0i.
Using the above formula:
K ti = K oi (1 + E H) ti
can be determined (by compound interest) K oi
K oi = K ti
In accordance with this, the amount of income from the presence of K ti in the national economic turnover will be determined equal to:
D k+i = K ti – K oi = K ti – K ti= Kti
(1 + E H) ti (1 + E H) ti
The total value of the effect from the i-th capital investment is determined as the difference between the income and loss values:
E Kti = D Kti –U Kti = K ti – K ti [(1+ E H) T-ti –1] = K ti
(1 + E H) ti (1 + E H) ti
To ensure brevity, you can enter the notation
a = (1 + E H) ti
E Kti = K ti
The total value of the effect from all capital investments during the entire period of construction is determined equal to:
E K = S K ti
where n is the number of capital investments.
In accordance with the accepted system of differential criteria, this criterion must be presented in the form of a relative value. This can be achieved by calculating the total economic effect relative to zero (on the graph), that is, by adding its value to the maximum possible loss (investing all funds on the first day of construction), and by relating this amount to the value of the base, that is, to the sum of the maximum income and the maximum loss.
Maximum income from the entire amount of investment (D K)
max D K = K (1 - b T)
Maximum loss from the entire investment amount (U K)
max U K = K (a T - 1)
Base size:
B = max D K + max U K = K (1 - b T) + K (a T - 1) = K (a T - b T)
K 11 = max U K + E K = K (a T - 1) + S K ti (2 - b ti - a T-ti)
B K (a T - b T)
It is easy to verify that when all investments are made at the start of construction (t 1 = 0), the numerator is equal to zero, and, accordingly, K 11 = 0.
When making all investments at the time of completion of construction, that is, when purchasing an object built without intermediate payment of costs (t i = T), the numerator is equal to the base and, accordingly, K 11 = 1.
12. Efficiency of duration (term) of work (K 12). The criterion characterizes the positive effect of reducing the duration of work.
K 12 = 1 / (1 – E N) T
The considered differential criteria for the quality of work organization are reduced to an integral one:
where Z i is the significance coefficient of the i-th criterion (specified)
n – number of differential criteria defined and taken into account.
It was noted above that the significance coefficients are set taking into account the specific conditions of work and the solution of a more general (in relation to the problem under consideration) problem. It should be added to this that at least one significance coefficient (from the entire set) must be equal to one (the rest may have a larger value), and the coefficients for alternative and, above all, criteria opposite in the direction of influence must be different, that is take into account the real requirements for the organization of construction and the conditions of work (for example, K 1 and K 12, K 2 and K 3, K 4 and K 6).
In conclusion, considering the methodology for comparing options, it should be noted that any integral criterion for assessing quality, including coefficients of significance of individual or differential criteria, is a measure of quality only in relation to the considered options for organizing work, which are in the same conditions. When conditions and, accordingly, significance coefficients change, the same options for organizing work will have different indicators of integral criteria.
In construction practice, there are three methods of performing work: sequential, parallel and continuous.
With the sequential method (see diagram below, pos. a), work on each subsequent section (building, facility) begins only after completion on the previous one. This method, characterized by a reduced time for completing work on one site (building, facility), causes irrational use of personnel and a longer duration of construction as a whole. The duration of construction T with the number of occupations (objects) m and the duration of the production cycle Tc will be T = m Tc. The intensity of consumption is characterized by a graph with ordinate q.
With the parallel method (see diagram below, pos. b), work is performed on all objects (grips) simultaneously. In this case, the duration of construction is reduced and becomes equal to Tc, but this method requires the simultaneous involvement of a large amount of labor and material resources. They increase m times and amount to mq.
The most progressive is the flow method, which achieves rhythmic production and high labor productivity. It allows you to reduce construction time (compared to sequential ones), increase labor productivity through the rational use of workers, machines and mechanisms, and significantly reduce the cost of construction. The essence of the flow method is to divide the construction process into parts, for example, digging pits, constructing foundations, walls, ceilings, coverings, etc. - there are only n parts that are rhythmically performed by the corresponding teams. In this case, work on the subsequent object (grip) begins after the end of the first process on the previous object (grip). In this way, homogeneous processes are executed sequentially without interruption. Crews move from one object (capture) to another after a set period of time, ensuring a certain rhythm of flow.
A - graph of the sequential production method; b - the same, parallel; c - the same, in-line; d - cyclogram; d - schedule of stages of development of the construction flow; e - diagram of the types of construction flow.
In the flow method of construction, heterogeneous processes are carried out in parallel. In this case, the duration of construction T and the intensity of resource consumption nq are reduced. This method effectively combines the advantages of sequential and parallel methods.
The construction flow consists of a number of private flows, which are simple construction processes distributed among performers. It is characterized by technological, spatial and time parameters. Technological parameters of a construction flow are its structure, determined by the number of private flows, volumes of work, labor intensity, machine intensity and flow intensity. The spatial parameters of the flow are the sections, sections, plots and tiers into which the construction project is divided. The time parameters are the flow step and the modulus of its cyclicity. The cyclicity module determines the rhythm of the flow and is characterized by the duration of the partial flow in the area.
In construction practice, for planning and managing construction processes, they are modeled using graphical images: line graphs, strip charts, cyclograms and network graphs. Construction flow graphs that display its development in time and space are convenient for practice. The ordinate axis represents captures, areas or objects, and the abscissa axis represents time. Partial flows that make up processes are depicted as slanted lines. The bases of the inclined lines correspond to the beginning of work, and their tops correspond to the end. In this case, the cyclicity modules of all flows are the same; such a construction flow is called rhythmic and is depicted as a system of parallel lines.
On a linear graph, partial flows (see diagram below) are indicated by horizontal lines on a time scale in compliance with the technological sequence:
A - linear; b-network
The network diagram is a model of the construction process. The solid arrow on this graph shows the work, the circle shows the result of the work. The name of the work is indicated above the arrow, and its duration is indicated below the arrow. Arrows are not to scale, circles are numbered. For the correct relationship of work, when constructing a network diagram, dependencies are introduced, which are represented by a dotted arrow. In the graph, the longest continuous sequence of activities and dependencies from the initial event to the final event forms the critical path. The length of this path determines the duration of the entire construction process. The critical path is depicted with a thick line.
The peculiarity of the network schedule is that it does not indicate deadlines, but only the calendar duration of individual work. When construction conditions change and work deadlines are missed, the network schedule, unlike other modules, is not drawn up again, but only adjusted, since its network, reflecting technological connections, remains unchanged.
The use of continuous construction methods requires careful organization of production and its preparation, clear management, uninterrupted supply of labor, materials, machinery and equipment.
Industrialization of construction. In construction practice, there is a continuous transformation of construction production into a process of mechanized continuous assembly of buildings and structures from factory-made structures. Industrialization should be inherent in all stages of construction - from design to finishing of buildings and structures, as a result of which labor productivity increases, the time and cost of work decreases, and their quality improves. Modern industrial construction is characterized by: prefabricated buildings and structures with the production of parts, structures and assemblies in factories and specialized installations, comprehensive mechanization and automation of construction, scientific organization of labor, production flow, normalization and technological design. Each of the listed factors significantly affects the efficiency of construction, but the full technical and economic effect is achieved subject to the comprehensive implementation of all of them in the process of design and construction of buildings and structures.
Prefabrication of buildings and structures. The real conditions for increasing the prefabricability of buildings and structures were created by the industry created in the Russian Federation for the production of precast reinforced concrete. The production of basic building structures was transferred to factory conditions. This achieved a significant reduction in construction costs.
The use of heavy-duty assembly machines makes it possible to enlarge prefabricated elements, which reduces installation operations and speeds up construction.
Integrated mechanization. With this method of carrying out construction work, all technological operations of a certain process are carried out using a set of machines and small-scale mechanization equipment, interconnected by technological purpose, technical level and productivity, which ensures a given pace of work and optimal technical and economic indicators. Each such complex has one or more leading machines, with the help of which the main operations are carried out. The leading machine determines the productivity of the complex, its composition and the organization of the process as a whole.
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