Building a network diagram: an example. Production process model

Network scheduling is a set of methods that is designed to manage a project schedule. Network planning allows you to determine, firstly, which of the many works or operations that make up the project are “critical” in their impact on the overall calendar duration of the project and, secondly, how to build the best plan for carrying out all work on this project with in order to meet specified deadlines at minimal cost. A network schedule is a graphical representation of the technological sequence of work at a facility or several facilities, indicating their duration and all time parameters, as well as the total construction period. Construction management should be based on a pre-developed model of the process of construction and installation work, from preparatory work to commissioning of the facility. A network diagram is an information model that allows you to display the process of performing a set of works aimed at achieving a single goal.

Distinctive features of the network diagram are:

• - the presence of a relationship between the work and the technological sequence of its implementation;
• - the ability to identify work, the completion of which primarily determines the duration of construction of the facility;
• - the ability to select options for the sequence and duration of work in order to improve the network schedule;
• - facilitating control of construction progress;
• - the ability to use computers to calculate schedule parameters when planning and managing construction.

The network model is depicted as a network diagram (network) consisting of arrows and circles. A network schedule consists of four elements: work, events, expectations, and dependencies.

• 1. Work is a technological process that requires time, labor and material resources and leads to the achievement of a certain planned result. Work on the schedule is indicated by a solid arrow, the length of which may not be related to the duration of the work (if the schedule is not made on a time scale). Under the arrow you can also show the estimated cost of construction and installation work (thousand rubles), the physical volume of work, the performer of the work, etc. Depending on the purpose of the schedule, the content of the given work parameters may change, but the duration and name of the work are always indicated.
• 2. Waiting is a process that requires only time and does not consume any material resources. Waiting, in essence, is a technological or organizational break between jobs that are immediately performed one after another. (an example of a technical expectation is the strengthening of concrete; an example of an organizational expectation is if a team of carpenters is busy with other work, and for this reason work is not carried out on stripping concrete structures).

Waiting is depicted in the same way as work, with a solid arrow indicating the duration and name of the wait.

• 3. Dependency (fictitious work) is introduced to reflect the technological and organizational relationship of work and does not require either time or resources. The dependency is represented by a dotted arrow. It determines the sequence of events.
• 4. An event is the fact of the completion of one or more work, which is necessary and sufficient for the start of the next work. In any network model, events establish the technological and organizational sequence of work. Events are depicted by circles or other geometric shapes, inside of which (or next to) a specific number is indicated - the event code. Events limit the work in question and in relation to it can be initial and final. Start event - determines the beginning of this work and is the final event for previous works. End event - determines the end of this work and is the initial event for subsequent works. An initial event is an event that has no previous activities within the network diagram under consideration. The final event is an event that has no subsequent activities within the network schedule under consideration. A complex event is an event that includes or exits two or more activities.

Network Diagram Symbols

Network diagram is a network model reflecting the technological and organizational relationships of the construction and installation work process, with calculated time indicators. Displayed as a graph consisting of arrows and circles. The construction is based on the concepts of “work” and “event”.

Management responsiveness

Accounting for external work

Accounting for resource perspectives

Easily corrected situation

Peculiarities:

The presence of a relationship between the work and the technological sequence of its implementation

Based on the schedule, it is possible to identify work on the execution of which on time depends on the duration of the entire construction

Possibility of variant development

Makes it easier to make adjustments without changing the end result

Essential elements:

Work is the process itself, which requires time, material resources and leads to the achievement of certain results.

Waiting is a process that requires only time (technological and/or organizational break)

Dependency – is entered to reflect the relationship of work (arrow with a dashed line)

Event - the actual completion of one or more jobs, necessary and sufficient for the start of the next job

Path – a certain sequence from one event to another

The critical path is the complete path that has the greatest length (duration).

№16 Basic provisions for organizing the material and technical base of construction

Material and technical base of construction (MTB) - System of enterprises for the production of construction. materials, parts and structures, enterprises for operation and repair of construction. machines and transport, stationary and mobile production plants, energy and storage facilities, construction. organizations, research, design and other institutions and farms serving construction.

The supplier of tools for construction is the mechanical engineering industry. Materials, products, structures for construction are supplied by the following enterprises: construction. industry, i.e. enterprises in the construction industry that are on an independent industrial balance sheet or structure balance sheet. organizations in the building materials industry and other industries - metallurgical, chemical, forestry and woodworking, etc.

Sources of supply MT supply for construction is carried out under direct contracts with manufacturers or through a diverse network of intermediary trade organizations. Construction industry enterprises include factories and sites for the production of prefabricated concrete and reinforced concrete structures (except for enterprises subordinate to the building materials industry); factories and workshops for construction and technological metal structures, electrical and sanitary equipment, fittings and embedded parts for monolithic reinforced concrete; factories and shops of commercial mixtures. In a construction trust, a distinction should be made between production and production and assembly bases. The first is intended for the manufacture of materials and structures, the second is for increasing the factory readiness of materials and components. With small production volumes, the CMO has a single production and assembly base, and with large industrial scales. activities, both components of the base are separated into separate structures.

Prom. enterprises construction organizations (on-site, local) are intended to supply construction sites remote from the main base. These include small testing grounds (shops) for concrete reinforced concrete products, stationary and mobile installations of commercial mixtures, mechanical repair shops and vehicle fleets.

Wholesale trade of materials and materials is carried out through wholesale bases, commodity exchanges, and wholesale fairs.

Territorial supply bases carry out wholesale purchases and deliveries of all resources needed by construction organizations, as a rule, on the basis of long-term direct contracts.

Wholesale and retail stores serve as the main source of supply for individual developers and small construction organizations.

Cost of materials and equipment:

1. purchase price;2. shipping cost;3. storage cost;4. cost of shortages and losses.

SUPPLY CYCLE:

1. Determination of needs during the design and budgeting period. 2. Development of design characteristics required for a particular product, part, structure. 3. Calculation of the required number of elements and preparation of specifications. 4. Drawing up an application indicating the requirements. 5. Requesting proposals for supply with an indication of price or by organizing a tender. 6. Receipt and consideration of proposals. 7. Issuing a purchase order, concluding a supply agreement, subcontracting or leasing. 8. Preparation and submission by the seller or subcontractor of shop drawings or samples. 9. Review and approval of submitted RFs or samples by the contractor and the owner's representative (architect or engineer). 10. Manufacture of the product by the seller or subcontractor. 11. Packaging, delivery and inspection of delivered products. 12. Acceptance or refusal of acceptance by the owner (or his representative), issuance of guarantees in case of acceptance, making necessary corrections. 13. Storage and preparation for use on the construction site. 14. Preparation for installation, installation and testing in the design position.

Not all types of deliveries require the sequence listed above. Having issued, for example, an order for the supply of ready-mixed concrete mix, all you need to do to receive the next batch is call the supplier. At the same time, ordering complex equipment using, for example, intermodal transport, including, for example, sea freight, may require a more complex process than those listed above.

Supply scheduling. Supply is a system interconnected with planning work and monitoring its execution. There are several technical approaches to solving this problem.

The first is to include the stages of the supply process in the overall work plan, CP or SG. The difficulty with this option is that a detailed display of all the steps (14 or more) to provide even a limited set of resources will dominate the schedule and make it difficult to read.

The second approach is to develop a separate supply schedule, but linked to the timing of construction and installation works, the so-called modular schedule (manually or on a computer). For example, in the SG of the construction of an object, the need for delivery by a certain date is indicated by one event or one job “Delivery of a set of doors”, in which all the steps to provide this resource are hidden. Only an early (or late) date can be indicated. A detailed schedule indicating each step should be developed separately in the form of a CP or SG, or in the form of a matrix on paper or in electronic form, listing the product, supplier, cost, start and end of each step before putting it into action, early start of work and time reserve between delivery to the work site and the launch site. But even with the best organization, situations may arise that require corrective action, for example, if some material is required earlier than was provided for according to the agreed schedule. This is where experienced agents play a critical role in finding ways and means to keep construction on schedule. Such alternative solutions could be: attracting additional suppliers, changing delivery methods (instead of rail transport, road, air, etc.).

Ideally, a well-organized flow of materials should ensure that vehicles are supplied for loading directly to the point where it is needed and at exactly the appointed time.

Acceptance of material resources, one of the most important operations in the construction supply process, is carried out by carefully checking the quantity, completeness and quality of incoming products, as well as registering them with the appropriate accounting documentation in the prescribed manner. Compliance of all materials, products, structures and equipment with the requirements of state standards (GOCT), technical specifications (TU) and design documentation is mandatory to ensure the quality of construction products and the durability of buildings and structures.

Accounting and control in supply is achieved by recording the availability, receipt and expenditure of material resources using the current document system. In order to have reliable information about the availability of certain resources, it is necessary to promptly prepare and submit to the accounting department of the construction organization primary accounting documents, receipt and expenditure orders, invoices, invoices, etc. Systematic monitoring has been established over the use of material and energy resources by submission of statistical reports on their expenditure to higher subordinate bodies.

The release of materials for construction and installation works must be carried out on the basis of a limit system. This system is based on a preliminary calculation based on design estimates and approved consumption standards for the amount of materials required for the construction of the facility. Employees of the production and technical department of the construction department enter this data into a limit card, which is a single primary accounting document regulating the release of materials from the beginning to the end of the construction of a given facility. The release of materials in excess of the established limit is permitted only with the permission of the chief engineer of the construction department. Obtaining such permission is associated with checking the reasons for overestimating the limit and, if necessary, recovering from persons who allowed an unreasonable overexpenditure of material.

№17 Organization of production and technological equipment for construction

Technological kitting is the process of synchronous complete provision of objects under construction with prefabricated structures, parts, semi-finished products and materials in strict connection with the pace and technological sequence of work.

The fundamental difference between procurement bodies and the supply authorities operating in most construction organizations is that the procurement department is a combined body whose activities combine three main functions of material support: supply, processing, procurement:

1 supply activity consists of obtaining all material resources, regardless of sources of receipt;

2 industrial activity consists of processing materials and products for preparation for direct use in construction work and the production of non-standard and non-serial structures, parts and semi-finished products;

3, the supply of materials and products consists of their centralized delivery for construction in accordance with the approved work schedules, as the final stage of material support for construction.

The kit places a special requirement on the delivery method, which can be formulated as the principle of unloaded delivery of material to the workplace area.

Bagging

Containerization (and, as a consequence, the introduction of heavy-duty containers to reduce transport costs)

Unified normative and technological documentation for packaging ( UNTDK) construction projects as part of the PPR - this is a set of documents that are a project for the technological configuration of the facility. UNTDK is carried out during the period of preparation for construction for the entire facility as a whole or for the volume of work for the planned year. Taking into account the decisions made in the PPR ensures synchronization of the procurement process with the work schedule. The binding of a standard UNTDK to local conditions or development for an individual object is carried out in the departments of preparation for the production of work of the construction organization or on the order of construction organizations by specialized firms in the technological design of construction. The development of UNTD is associated with the formation of technological, supply, installation and flight kits.

UNTDK is a unified regulatory framework for planning:

1. logistics;

2. manufacturing products and increasing the construction readiness of products in industrial divisions of the SMO;

3. organizing the procurement process, including centralized delivery of resources to the work area.

The initial data for developing the UNTDK system are:

1 design documentation;

2 main PPR decisions regarding the sequence and technology of work execution (CP and technological sections);

3 current standards for the consumption of material resources;

4 information about suppliers, means of transport and container fleet.

Types of kits:

Technological (SC, products, etc., necessary to perform a certain set of works)

Delivery (delivered from 1 plant to the site in accordance with the timing and technology)

Assembly (designed for assembling the assembly unit)

Trip (part of the assembly supplied on 1 vehicle - for 1 trip)

The principle of constructibility: the composition of the equipment is formed so that it is a necessary and sufficient part to ensure the spatial stability of the building and its parts.

The principle of manufacturability: the totality of the kit’s resources ensures the continuity of work in accordance with the PPR

Composition and sequence of development of NTDC

The contents of the UNTDK include the following documents:

1. object details card;

2. schemes for the formation of technological kits;

3. assembly and technological maps; (composition and timing of the formation of kits in accordance with the work schedule; carried out on CL, CM, CD, reinforcement, concrete, etc.)

4. summary complete technological map;

5. table of cost of technological kits;

6. standard schedule for completing the facility by suppliers;

7. transport picking schedule; (included in the UNTDK only when mounted “from wheels”)

8. calculation of steel and concrete;

9. technological maps for increasing the construction readiness of products and materials.

The completion and technological map (CPC) is the main document of the UNTDK, which determines the composition and timing of the formation of kits in accordance with the work schedule.

№18 Organization and operation of a fleet of construction machines

Integrated mechanization is a method of fully mechanized implementation of certain technological processes in construction, carried out by one or more machines. For a large number of operations, the use of a set of machines significantly increases productivity.

CALCULATION OF THE NEED FOR CONSTRUCTION MACHINERY

At the PIC stage, calculations are performed according to standard indicators to determine the need for construction machinery for 1 million rubles. estimated cost of construction and installation work. The requirement standard includes the main types of construction machines for performing work on the own resources of construction organizations, and also takes into account the needs for machines of manufacturing enterprises that are on the construction balance sheet.

At the PPR stage, the need for construction machines is determined based on the physical (estimated) volumes of work to be performed in one of two ways:

1 according to the norms of machine time consumption of SNiP (Part IV “Estimated norms”);

2 according to machine production standards established by the relevant departments, taking into account local construction conditions.

ORGANIZATIONAL FORMS OF OPERATION OF THE CONSTRUCTION MACHINERY PARK

The forms of organization and structure of the construction machinery fleet depend on the form and structure of the construction and installation organization it serves, the types and volumes of work performed, and are determined by the degree of territorial concentration of construction. The listed factors predetermine the possibility of specialization of operating organizations and influence the depth of its development.

Form I - construction machines are on the balance sheet of construction organizations (SMU, PMK, etc.). The maintenance and operation of the machines is managed by the chief mechanic service. Based on requests from line workers, machines are allocated to sites.

Form II - construction machines are part of and on the balance sheet of specialized mechanization units subordinate to construction organizations. Operational management of the distribution and use of equipment and all payments for its operation are carried out by the CMO. Construction departments receive machines on a service, lease or contract basis. Calculations are made at planned prices.

III form - construction machinery and equipment are part of and on the balance sheet of former mechanization trusts or independent mechanization enterprises subordinate to territorial construction associations, plants, etc. The concentration of construction equipment at specialized mechanization enterprises creates the most favorable conditions for its maintenance and service, ensures the ability to maximize the use of machines in accordance with their technical parameters, and also allows you to concentrate, if necessary, a large number of machines in the desired direction.

IV form - leasing of construction machinery and equipment They are on the balance sheet of leasing companies specializing in leasing (renting) their equipment for short-term or long-term use on a contractual basis.

V form - construction equipment is in the possession of an individual private entrepreneur.

1. Mechanization Department

2. Construction mechanization trusts

3. Means of small-scale mechanization

FORMS OF CALCULATIONS AND RELATIONSHIP OF CONSTRUCTION ORGANIZATIONS WITH MECHANIZATION DEPARTMENTS

In the system of relationships between machine operators and builders, the forms of payment are of decisive importance. The amount of work performed by machine operators for builders can be determined in various ways:

according to the volumes actually completed and according to the time the machine was at the disposal of the construction organization at the site.

1. When calculating the actual work performed, natural indicators of the volume of work are taken as the unit of measurement.

2. Calculation based on machine operating time (per time worked). In cases where accurate recording of the volume of construction work performed is impossible or difficult.

CONSTRUCTION MACHINERY PERFORMANCE INDICATORS

The condition for increasing annual output is the commissioning of a listed fleet of machines. This depends on the operational readiness of the machines, the scope of work and the shift.

The quality of park operation is characterized by a number of specific indicators.

Construction vehicle fleet utilization rate over time k n

Machine utilization rate over time k. mung bean

Machine utilization rate by productivity k np

Machine shift coefficient k.cm

Machine utilization rate over time during a shift kusp.cm

№19 Indicators characterizing the degree of mechanization of construction and installation work. Vehicle fleet utilization indicators.

Indicators of mechanization of work, characterizing the degree of mechanization coverage of construction and installation work, are level of mechanization And integrated mechanization works

Level of mechanization of work: kmex = (Vmex /V)*100. (volume of mechanized work to the volume of work performed using machines and manually),%

Level of complex mechanization: kk.mex = (V k. mex / V mex) * 100. (integrated-mechanized to complex), %

Indicators of mechanical equipment characterize the equipment of construction and installation organizations with mechanization means and are defined as an indicator of mechanical equipment of construction or mechanical equipment of labor.

Mechanical strength of construction: Mstr = (C mech / C total) * 100. (book value of mechanization equipment to the total cost of construction and installation work)

Mechanical-to-labor ratio: M tr = (C mech / Pr). (book value of construction machines to the average number of workers employed in construction)

Indicators of power-to-weight ratio are similar in meaning to indicators of mechanical-to-weight ratio. The difference lies in the assessment of mechanization in the energy aspect, characterized by the connection between an increase in the power consumption of machines and an increase in labor productivity.

Energy capacity of construction: E str = (N total / C). (total power of machine engines for the annual cost of construction and installation works). For example, currently 200-300 kW per 1 million rubles

Energy output of labor: E tr = (N o / Pr) . (total engine power, per total number of workers)

Fleet utilization indicators .

The main indicator of the correct operation of the construction machinery fleet is actual annual output in physical terms (physical volume of work), determined from reporting data in comparison with the planned target.

The condition for increasing annual output is commissioning of a listed fleet cars This depends on the operational readiness of the machines, the scope of work and the shift.

Reasons for machine downtime:

Lack of preparation of construction sites

Inconsistency between machine and transport performance

Supply disruptions

Excessive downtime at previous stages

The quality of park operation is characterized by a number of specific indicators:

Coefficient of use of the construction machinery fleet over time: k n = T f /T k. (number of actually worked machine days to the calendar number of machine days for the same period)

Machine utilization rate according to: k mash = T f / T pl. (ratio of actual machine time to planned time)

Machine utilization rate by productivity: kpp = Vf / Vpl. (actual production to planned)

Shift coefficient of machine operation: k cm == T f. h. /(T day *t r.d.). (the ratio of the number of machine hours worked by machines of the same type during the reporting period to the product of the number of days in work and the average duration of a working day)

Machine utilization rate over time during a shift: k usp.cm==Tf.cm. / tcm. (number of machine shifts worked by the machine by the time of the 1st shift)

The assessment of the given indicators is made by comparing the reporting data with the regulatory data on the production of main machines, their use, etc.

№20 Organization of road transport. Calculation of vehicles.

Types of transport:

Automotive (main – 80%)

Railway (up to 15%)

Water (up to 5%)

ORGANIZATION OF VEHICLE TRANSPORT ON CONSTRUCTION

Motor transport serving construction is part of enterprises of different types of ownership and legal status, private, state, municipal, etc., including construction organizations, construction industry factories and mechanization organizations. The main organizational options are similar to the previously discussed forms of operating a fleet of construction machines.

Relationships between transport workers and builders are determined by contracts establishing the rights and obligations of the parties, and are based on the norms of the civil code. In a market economy, the content of contractual relations has changed. In addition to the function of transportation to its destination, the transport company bears financial responsibility for the quantitative and qualitative safety of the cargo, as well as the timeliness of its delivery. Upon arrival at the site, the contractor must check the compliance of the arrived cargo with the accompanying documents.

Schemes for organizing the transportation of construction goods are associated with the technology of construction production: pendulum, shuttle or shuttle-pendulum.

At pendulum scheme, the vehicle (tractor with a trailer or a car without a trailer) is at the site until unloading.

Shuttle scheme provides the ability to operate the tractor without downtime during unloading. For this purpose, depending on the duration of the transport being unloaded and the length of the transportation arm, several trailers are allocated for each tractor.

Shuttle-pendulum scheme is a special case of the previous scheme, when the unloading time is equal to or a multiple of the cargo delivery time.

Shuttle and shuttle-pendulum are preferable, because this allows you to reduce transport costs (unloading time), as well as when transporting large SCs (installation “from the wheels”, i.e. without organizing a warehouse)

CALCULATION OF THE NUMBER OF VEHICLES

N= P\(T*n cm *P),

where N is the number of machines, T is the time of transportation of a certain load, P is the mass of a certain load, P is the productivity of machines, n cm is the number of shifts

At the PIC stage, calculations are performed according to standard indicators to determine the need for vehicles for 1 million rubles. estimated cost of construction and installation work per year. The requirement standard includes all types of vehicles and takes into account the total demand for vehicles, regardless of the subordination of the vehicle fleet.

At the PPR stage, the need for means of transport is determined in the following order: the need for transportation is identified, freight flow diagrams are drawn up; calculate cargo turnover by calendar periods of work (shift, day, week, month, etc.); select types of vehicles; determine the productivity of the transport unit; calculate the need for vehicles by type and draw up a transport (assembly and transport) schedule or a request for transport.

The work of transport in construction is characterized by the volume of transportation and cargo turnover.

Transportation volume is the amount of cargo to be transported, in tons per unit of time.

Freight turnover is the volume of transport work in ton-kilometers (T-KM) per unit of time.

Freight flow is part of the freight turnover in a certain direction.

Network planning Planning is a method of planning work in which operations, as a rule, are not repeated (for example, the development of new products, the construction of buildings, the repair of equipment, the design of new work).

To carry out network planning, you first need to divide the project into a number of separate works and draw up a logical diagram (network graph).

Job- these are any actions, labor processes, accompanied by the expenditure of resources or time and leading to certain results. On network graphs, work is indicated by arrows. To indicate that one job cannot be performed before another, fictitious jobs are introduced, which are represented by dotted arrows. The duration of the fictitious work is assumed to be zero.

Event- this is the fact of completion of all the work included in it. It is believed that it occurs instantly. In a network graph, events are depicted as vertices of the graph. No job coming out of this event can begin until all jobs included in this event are completed.

WITH original event(which has no previous work) the project begins. The final event(which has no subsequent work) the project ends.

After constructing the network graph, it is necessary to estimate the duration of each work and identify the works that determine the completion of the project as a whole. It is necessary to assess the resource requirements of each job and revise the plan taking into account the provision of resources.

A network graph is often called network diagram.

Rules for constructing network diagrams.

1. There is only one final event.

2. There is only one initial event.

3. Any two events must be directly connected by no more than one arrow work. If two events are associated with more than one activity, it is recommended to enter an additional event and a dummy activity:

4. There should be no closed loops in the network.

5. If to perform one of the jobs it is necessary to obtain the results of all the jobs included in the event preceding it, and for another job it is enough to obtain the results of several of these jobs, then you need to introduce an additional event reflecting the results of only these last jobs, and a fictitious work that connects a new event with the previous one.

For example, to start work D, it is enough to finish work A. To start work C, you need to finish work A and B.

Critical path method

The critical path method is used to manage projects with a fixed completion time.

It allows you to answer the following questions:

1. How long will it take to complete the entire project?

2. What time should the individual start and end?
work?

3. What work is critical and must be completed at a precisely defined time schedule so as not to miss the established deadlines for the project as a whole?

4. How long can non-critical work be deferred so that it does not affect the project deadline?

The longest path of the network diagram from the initial event to the final one is called critical. All events and activities on the critical path are also called critical. The duration of the critical path determines the duration of the project. There can be several critical paths on a network diagram.

Let's consider the main time parameters of network diagrams.

Let's denote t (i, j)- duration of work with the initial event i and the final event j.

Early date t p (j) of event j- this is the earliest moment at which all work preceding this event is completed. Calculation rule:

t р (j) = max ( t р (i)+ t (j))

where the maximum is taken over all events i, immediately preceding the event j(connected by arrows).

Late date t n (i) of the event i- this is such a limiting moment, after which there remains exactly as much time as is necessary to complete all the work following this event.

Calculation rule:

t n (i) = min ( t n (j)- t (i, j))

where the minimum is taken over all events j, immediately following the event i.

Reserve R(i) events i shows the maximum permissible period for which the completion of an event can be delayed i without violating the deadline for the completion event:

R(i)= t n (i) - t p (i)

Critical events have no reserves.

When calculating a network diagram, we divide each circle depicting an event into 4 sectors by diameter:

Managing projects with uncertain lead times

In the critical path method it was assumed that we know the time it takes to complete the work. In practice, these terms are usually not defined. You can make some assumptions about the time it takes to complete each job, but you cannot foresee all possible difficulties or delays in completion. For managing projects with an indefinite execution time, the most widely used project evaluation and review method, designed for the use of probabilistic estimates of the time required to complete the work provided for by the project.

For each job, three estimates are entered:

- optimistic time- the shortest possible time to complete the work;

- pessimistic time b- the longest possible time to complete the work;

- most likely time t- expected time to complete the work under normal conditions.

By a, b And T find expected completion time:

And variance of expected duration t:

Using values t,find the critical path of the network diagram.

Network diagram optimization

The cost of completing each job plus additional expenses determines the cost of the project. With the help of additional resources, you can achieve a reduction in the time it takes to complete critical work. Then the cost of these works will increase, but the total time of the project will decrease, which can lead to a decrease in the total cost of the project. It is assumed that the work can be completed either within the standard or minimum time frames, but not in between.

Gantt chart

Sometimes it is useful to visually depict the available time reserve. For this purpose it is used Gantt chart. Every job is on it ( i, j) is depicted by a horizontal segment, the length of which on the appropriate scale is equal to the time it takes to complete it. The beginning of each work coincides with the earliest date of completion of its initial event. The Gantt chart is very useful in scheduling work. It shows working hours, downtime and relative system load. Pending work can be distributed to other work centers.

The Gantt chart is used to manage work in progress. It indicates which work is running on schedule and which is ahead or behind schedule. There are many possibilities for using the Gantt chart in practice.

It is worth noting that the Gantt chart does not take into account the variety of production situations (for example, breakdowns or human errors that require repetition of work). The Gantt schedule should be regularly recalculated when new work appears and when the duration of work is revised.

The Gantt chart is especially useful when working on a project with unrelated work. But when analyzing a project with closely interrelated activities, it is better to use the critical path method.

Resource allocation, resource schedules

Until now, we have not paid attention to resource limitations and assumed that all the necessary resources (raw materials, equipment, labor, funds, production space, etc.) are available in sufficient quantities. Let's consider one of the simplest methods for solving the problem of resource allocation - the “trial and error method”.

Example. Let's optimize the network diagram for resources. The available resource is 10 units.

The first number assigned to the graph arc means the time it takes to complete the work, and the second number means the required amount of resource to complete the work. Work does not allow interruption in its execution.

Finding the critical path. We are building a Gantt chart. In brackets for each job we indicate the required amount of resource. Using the Gantt chart, we build a resource schedule. We plot time on the x-axis, and resource requirements on the y-axis.

We believe that all work begins at the earliest possible date for completion. Resources are added up for all work performed simultaneously. We will also draw a limit line for the resource (in our example this is y = 10).

From the graph we see that on the interval from 0 to 4, when work B, A, C are simultaneously performed, the total need for resources is 3 + 4 + 5 = 12, which exceeds the limit of 10. Since work C is critical , then we must shift the deadlines for either A or B.

We plan to complete work B from the 6th to the 10th day. This will not affect the timing of the entire project and will make it possible to remain within resource limitations.

Work parameters

Let us recall the notation: t (i, j)- duration of work ( i, j); t r (i)- early date of the event i; tn(i)- late date for the completion of the event /.

If there is only one critical path in the network diagram, then it can be easily found by critical events (events with zero time slack). The situation becomes more complicated if there are several critical paths. After all, both critical and non-critical paths can pass through critical events. In this case, you need to use critical jobs.

Early start date (i, j) coincides with the early date of the event i: t p n (i, j) = t p (i).

Early completion date (i, j) is equal to the sum t r (i) and t (i, j):t p o (i, j) = t p (i)+ t (i, j).

Late start date (i, j) equal to the difference tn(j)(latest date of the event j) And t (i, j): t pn (i, j) = t p (j) - t (i, j).

Late work completion date (i, j) coincides with t n (j): t by (i, j) = t p (j).

Full time reserve Rn( i, j) works (i, j) is the maximum amount of time by which the start of work can be delayed or its duration can be increased, provided that the entire complex of work is completed within the critical period:

Rn( i, j)= t n (j) - t p (i) - t (i, j)= t by (i, j) - t p o (i, j).

Free time reserve R c ( i, j) work (i, j)- this is the maximum margin of time by which one can delay or (if it began at an early date) increase its duration, provided that the early deadlines of all subsequent work are not violated: R with ( i, j)= t p (j) - t p (i) - t (i, j)= t p (j) - t p o (i, j).

Critical jobs, like critical events, do not have reserves.

Example. Let's see what the work reserves are for the network schedule.

We find t r (i), t n (i) and make a table. We take the values ​​of the first five columns from the network diagram, and calculate the remaining columns using these data.

Job (i, j)	Duration t (i, j)	t r (i)	t r (j)	tn(j)	Start date
t p n (i, j) = t p (i)	t pn (i, j) = t p (j) - t (i, j)
(1,2)						6-6 = 0
(1,3)						7-4 = 3
(1,4)						8-2 = 6
(2,4)						8-2 = 6
(2,5)						12-6 = 6
(3,5)						12-5 = 7
(4,5)						12-4 = 8

Job (i, j)	Completion date	Working time reserves
t p o (i, j) = t p (i)+ t (i, j)	t by (i, j) = t p (j)	Full Rn ( i, j)= = t by (i, j) - t p o (i, j)	Free R with ( i, j)= = t p (j) - t p o (i, j)
(1,2)	0 + 6 = 6		6-6 = 0	6-6 = 0
(1,3)	0 + 4 = 4		7-4 = 3	4-4 = 0
(1,4)	0 + 2 = 2		8-2 = 6	8-2 = 6
(2,4)	6 + 2 = 8		8-8 = 0	8-8 = 0
(2,5)	6 + 6= 12		12-12 = 0	12-12 = 0
(3,5)	4 + 5 = 9		12-9 = 3	12-9 = 3
(4,5)	8 + 4=12		12-12 = 0	12-12 = 0

Critical work (work with zero reserves): (1, 2), (2,4), (2, 5), (4, 5). We have two critical paths: 1 - 2 - 5 and 1 - 2 - 4 - 5.

Network planning and management methods allow you to focus on the most important aspects for project implementation. In this case, it is required that the work be mutually independent, that is, within a certain sequence of work, it is possible to start, pause, eliminate work, and also perform one work independently of another work. All work must be performed in a certain sequence. Therefore, network planning and management methods are widely used in construction, aircraft and shipbuilding, as well as in industrial sectors with rapidly changing trends.

Skepticism about network planning and management methods is often based on their cost, which can amount to about 5% of the total project cost. But these costs are usually fully offset by the savings achieved through more accurate and flexible schedules, as well as shorter project completion times.

More information on this topic HERE.

Work schedule (schedule), of course, is the key document of the PPR. The success of the project implementation largely depends on the quality of its development. The schedule plan is a model of construction production in which a rational sequence, priority and timing of work at the site are established.

Scheduling

The essence of scheduling, its role in construction

Scheduling is an integral element of organizing construction production at all its stages and levels. The normal progress of construction is possible only when it is thought out in advance in what sequence the work will be carried out, how many workers, machines, mechanisms and other resources will be required for each work. Underestimating this entails inconsistency in the actions of the performers, interruptions in their work, delays in deadlines and, naturally, increased construction costs. To prevent such situations, a calendar plan is drawn up, which serves as a work schedule within the accepted construction duration. Obviously, the changing situation at a construction site may require significant adjustments to such a plan, however, in any situation, the construction manager must clearly understand what needs to be done in the coming days, weeks, and months.

Construction duration is assigned, as a rule, according to standards (SNiP 1.04.03-85* Construction duration standards...) depending on the size and complexity of the objects under construction, for example, the area of ​​irrigation systems, types and capacities of industrial enterprises, etc. In some cases, the duration of construction may be planned to differ from the standard (most often in the direction of tightening deadlines), if required by production needs, special conditions, environmental programs, etc. For facilities constructed in difficult natural conditions, an increase in construction duration is acceptable, but this should always be properly justified.

In construction practice, simplified planning methods are often used, when, for example, only a list of works is compiled with deadlines for their completion without proper optimization. However, such planning is only permissible when solving small current problems during construction. When planning large work projects for the entire construction period, careful work is required to select the most appropriate sequence of construction and installation works, their duration, the number of participants, and it is necessary to take into account the many factors mentioned above. For these reasons, various forms of scheduling are used in construction, allowing in their own way to optimize the planned progress of work, the possibility of maneuvers, etc.

• linear calendar charts
• network diagrams

In addition, depending on the breadth of the tasks being solved and the required degree of detail in the solutions, there are different types of calendar plans that are used at different levels of planning.

When developing schedules in PIC and PPR, the best results are achieved when several options for the schedule are drawn up and the most effective one is selected.

Types of calendar plans (schedules)

There are four types of calendar schedules, depending on the breadth of tasks to be solved and the type of documentation they include. All types of calendar schedules must be closely linked to each other.

Consolidated calendar plan (schedule) in the PIC determines the order of construction of objects, i.e. the start and end dates of each project, the duration of the preparatory period and the entire construction as a whole. For the preparatory period, as a rule, a separate calendar schedule is drawn up. Existing standards (SNiP 12-01-2004 to replace SNiP 3.01.01-85) provide for the preparation of calendar plans in monetary form in the POS, i.e. in thousand rubles with distribution by quarters or years (for the preparatory period - by month).

For complex objects, especially water management and hydraulic engineering, additional summary schedules are drawn up, focused on physical volumes.

When drawing up calendar plans for the construction of hydraulic engineering and water management structures, it is required, as already noted, to carefully link the progress of construction work with the timing of water flows in the river, the timing of blocking the channel and filling the reservoir. All these deadlines must be clearly reflected in the calendar plan. When reconstructing such facilities, minimal interruptions in the operation of the hydroelectric complex or hydraulic structure must be ensured.

At the stage of developing a consolidated schedule, the issues of dividing construction into queues, start-up complexes, and technological units are resolved. The schedule plan is signed by the chief engineer of the project and the customer (as the approving authority).

Object calendar schedule the PPR determines the priority and timing of each type of work at a specific facility from the beginning of its construction to commissioning. Typically, such a plan is broken down by months or days, depending on the size and complexity of the object. The object calendar plan (schedule) is developed by the compiler of the PPR, i.e. the general contractor or a specialized design organization engaged for this purpose.

When developing calendar plans for the reconstruction or technical re-equipment of an industrial enterprise, it is necessary to agree on all deadlines with this enterprise.

Working calendar schedules usually compiled by the production and technical department of a construction organization, less often by line personnel during construction and installation work. Such schedules are not developed for a week, a month, or several months. Weekly-daily schedules are most widely used. Work schedules are an element of operational planning that must be carried out continuously throughout the entire construction period.

The purpose of work schedules, on the one hand, is to detail the site schedule and, on the other, to provide a timely response to all sorts of changes in the situation at a construction site. Work schedules are the most common type of scheduling. As a rule, they are compiled very quickly and often have a simplified form, i.e., as practice shows, they are not always properly optimized. Nevertheless, they usually take into account the actual situation at a construction site better than others, since they are compiled by persons directly involved in this construction. This especially applies to taking into account weather conditions, the peculiarities of interaction between subcontractors, the implementation of various rationalization proposals, i.e. factors that are difficult to account for in advance.

Hourly (minute) charts in technological maps and labor process maps are compiled by the developers of these maps. Such schedules are usually carefully thought out and optimized, but they are focused only on typical (most likely) operating conditions. In specific situations they may require significant adjustments.

Simplified scheduling forms

In short-term planning, as already noted, in construction practice a simplified form of scheduling is often used in the form of a list of works with deadlines for their completion. This form is not visual and is not suitable for optimization, but when solving current problems for the coming days or weeks, it is acceptable due to the simplicity and speed of its preparation. Usually this is the result of an agreement on the timing of work between the performers, which is recorded in the form of minutes of a technical meeting, an order from the general contractor, or another current document.

A simplified form should also include construction planning in monetary form. In this case, some optimization is possible, but it solves such issues only in an extremely general form, since it relates primarily to construction financing. The schedule plan in monetary terms is usually drawn up for particularly large volumes of work, when the planning element is an entire object or complex of objects. Such plans are typical, for example, for PIC.

Linear calendar charts

A linear calendar chart (Ganga chart) is a “work (objects) - time” table in which the duration of work is depicted as horizontal line segments.

Such a schedule provides opportunities to optimize construction and installation work according to a wide variety of criteria, including the uniformity of use of labor, machinery, building materials, etc. The advantage of line graphs is also their clarity and simplicity. The development of such a schedule includes the following steps:

• compiling a list of works for which a schedule is made
• determination of their production methods and volumes
• determining the labor intensity of each type of work by calculations based on existing time standards, aggregated standards or local experience data
• drawing up the original version of the schedule, i.e. preliminary determination of the duration and calendar deadlines for the completion of each work with the display of these deadlines on the chart
• optimization of the calendar schedule, i.e. ensuring a uniform need for resources, primarily in labor, ensuring timely completion of construction, etc., establishing final calendar dates for work and the number of performers.

The results of each stage of development and schedule must be carefully verified, because errors, as a rule, are not compensated for at subsequent stages. For example, if at the first stage the volume of any work is estimated incorrectly, both its duration and deadlines will be incorrect, and the optimization will be imaginary.

When determining the labor intensity of work, it is necessary to pay special attention to the reality of the calculations being carried out and taking into account specific working conditions. The latter may differ significantly from those adopted in the standards, so the schedule designer must be well acquainted with the actual construction conditions.

The main disadvantage of linear schedules is the difficulty of adjusting them if the original deadlines for work are violated or the conditions for their implementation change. These shortcomings are eliminated with another form of scheduling - network schedules.

Network graphs

A network diagram is based on the use of another mathematical model - a graph. Mathematicians call graphs (obsolete synonyms: network, labyrinth, map, etc.) “a set of vertices and a set of ordered or unordered pairs of vertices.” In more familiar (but less precise) language for an engineer, a graph is a set of circles (rectangles, triangles, etc.) connected by directed or undirected segments. In this case, the circles themselves (or other figures used), according to the terminology of graph theory, will be called “vertices”, and the non-directed segments connecting them will be called “edges”, and the directed ones (arrows) will be called “arcs”. If all segments are directed, the graph is called directed; if all segments are undirected, it is called undirected.

The most common type of work network diagram represents a system of circles and directed segments (arrows) connecting them, where the arrows represent the work itself, and the circles at their ends (“events”) represent the beginning or end of these works.

The figure shows in a simplified manner only one of the possible configurations of the network diagram, without data characterizing the planned work itself. In fact, the network diagram provides a lot of information about the work being done. Above each arrow is written the name of the work, below the arrow is the duration of this work (usually in days).

The circles themselves (divided into sectors) also contain information, the meaning of which will be explained later. A fragment of a possible network diagram with such data is presented in the figure below.

Dotted arrows can be used in the graph - these are so-called “dependencies” (fictitious work) that do not require either time or resources.

They indicate that the “event” to which the dotted arrow is directed can only occur after the event from which the arrow originates has occurred.

There should be no dead ends in the network diagram; each event should be connected by a solid or dotted arrow (or arrows) with any previous (one or more) or subsequent (one or more) events.

Events are numbered approximately in the order in which they will occur. The initial event is usually located on the left side of the chart, the final event on the right.

A sequence of arrows in which the beginning of each subsequent arrow coincides with the end of the previous one is called a path. The path is indicated as a sequence of event numbers.

In a network diagram, there can be multiple paths between the start and end events. The path with the longest duration is called critical. The critical path determines the total duration of the activity. All other paths have a shorter duration, and therefore the work performed in them has time reserves.

The critical path is indicated on the network diagram by thick or double lines (arrows).

Two concepts are of particular importance when drawing up a network diagram:

Early start of work is a period before which this work cannot be started without violating the accepted technological sequence. It is determined by the longest path from the initial event to the beginning of this work

Late completion of work is the latest deadline for completing work, at which the total duration of work does not increase. It is determined by the shortest path from a given event to the completion of all work.

When assessing time reserves, it is convenient to use two more auxiliary concepts:

Early finish is a deadline before which the work cannot be completed. It is equal to the early start plus the duration of this work

Late start - a period after which the work cannot be started without increasing the total duration of construction. It is equal to the late finish minus the duration of this work.

If an event is the end of only one job (i.e., only one arrow is directed towards it), then the early end of this job coincides with the early start of the next one.

General (full) reserve is the maximum time for which the completion of a given work can be delayed without increasing the total duration of the work. It is determined by the difference between late and early start (or late and early finish - which is the same thing).

Private (free) reserve is the maximum time for which the execution of a given job can be delayed without changing the early start of the next one. This reserve is only possible when the event includes two or more jobs (dependencies), i.e. two or more arrows (solid or dotted) are directed towards it. Then only one of these jobs will have an early finish that coincides with the early start of the next job, but for the rest these will be different values. This difference for each job will be its private reserve.

In addition to the described type of network graphs, in which the vertices of the graph (“circles”) display events, and the arrows represent activities, there is another type in which the vertices are activities. The difference between these types is not fundamental - all the basic concepts (early start, late finish, general and private reserves, critical path, etc.) remain unchanged, only the ways of recording them differ.

The construction of this type of network schedule is based on the fact that the early start of subsequent work is equal to the early finish of the previous one. If a given job is preceded by several jobs, its early finish must be equal to the maximum early finish of the previous jobs. The calculation of late dates is carried out in the reverse order - from the final to the initial, as in the network diagram "vertices - events". For a finishing activity, the late and early finish are the same and reflect the duration of the critical path. The late start of the next job is equal to the late finish of the previous one. If a given job is followed by several jobs, then the minimum value from the latest starts is decisive.

Network graphs “vertices - activities” appeared later than graphs “vertices - events”, therefore they are somewhat less known and are relatively less often described in educational and reference literature. However, they have their advantages, in particular they are easier to build and easier to adjust. When adjusting "completed - work" graphs, their configuration does not change, but for "vertex - event" graphs such changes cannot be excluded. However, at present, the compilation and adjustment of network graphs are automated, and for the user who is only interested in knowing the sequence of work and their time reserves, it does not really matter how the schedule is made, i.e. what type it is.In modern specialized packages of computer programs for planning and operational management, the “top-work” type is mainly used.

Network diagrams are adjusted both at the stage of their preparation and use. It consists of optimizing construction work in terms of time and resources (in particular, the movement of labor). If, for example, the network schedule does not ensure the completion of work within the required time frame (standard or established by the contract), it is adjusted in time, i.e. The duration of the critical path is reduced. This is usually done

due to time reserves for non-critical work and corresponding redistribution of resources

by attracting additional resources

due to changes in the organizational and technological sequence and relationship of work.

In the latter case, the “vertex-event” graphs have to change their configuration (topology).

Adjustment by resources is made by constructing linear calendar graphs based on early starts, corresponding to one or another option of the network schedule, and adjusting this option.

Automated construction management systems usually include computer programs that, to one degree or another, automate almost all stages of drawing up and adjusting network schedules.

References

• SNiP 1.04.03-85 “Norms for construction duration and backlog in the construction of enterprise buildings and structures”;
• MDS 12-81.2007 “Methodological recommendations for the development and execution of a construction organization project and a work execution project.”

Optimizing the work of a company, especially a manufacturing enterprise, is one of the most important conditions for the existence of a company. It is not only competition that requires the uninterrupted flow of the production process. Modern trends in minimizing the cost of manufactured products involve, first of all, the elimination of downtime and the consistency of operations.

To solve these problems, a methodology is used to optimize activities and calculate deadlines for completing work. The developed network schedule allows you to determine the logical sequence of individual operations, the possibility of combining them in time, as well as the timing of the entire production cycle of work.

What is this?

One of the methods for effectively planning the activities of a manufacturing enterprise is the construction of a network diagram. Initially, it was used in construction and determined not so much the sequence of work as the timing of teams of workers of different specialties entering the construction site. It is called a “scheduled work schedule.”

In modern conditions, when large enterprises mass produce products, to facilitate and increase productivity, the entire process is divided into simple operations. Therefore, the network diagram “migrated” from construction to almost all industries.

So what does this document show? Firstly, all operations necessary for the production of goods (production of services) are listed in detail. Secondly, the logical interdependence between them is determined. And finally, thirdly, not only the deadlines for completing each specific job are calculated, but also the time required to completely complete the production process.

By revealing the internal dependencies of project operations, the network schedule becomes the basis for scheduling the workload of equipment and labor.

The concept of “operation” in network planning

In the network diagram, you can estimate the start (completion) periods of work, forced downtime and, accordingly, the maximum delay time for certain operations. In addition, critical operations are identified - those that cannot be performed behind schedule.

When understanding planning terminology, you need to clearly understand what an operation is. Most often, this is understood as an indivisible part of the work that requires time to complete. Further, we understand that there are costs associated with performing an operation: time and resources (both labor and material).

In some cases, performing some actions does not require resources, only time is required, which takes into account the network schedule. An example of this is waiting for concrete to harden (in construction), cooling time for rolled parts (metallurgy), or simply approving (signing) a contract or permitting documentation.

Most often, operations in planning are given names in the imperative mood (develop a specification); sometimes verbal nouns are used for names (specification development).

Types of operations

When drawing up a network schedule, there are several types of work:

• merge - this operation is immediately preceded by more than one job;
• parallel operations are performed independently of each other and, at the request of the design engineer, can be performed simultaneously;
• A splitting operation assumes that after its completion, several unrelated jobs can be performed at once.

In addition, there are several other concepts necessary for planning. The path is the execution time and the sequence of interdependent operations. And the critical path is the longest path of the entire system of work. If any operation along this path is not completed in a timely manner, the deadlines for the implementation of the entire project will be missed.

And lastly: the event. This term usually denotes the beginning or end of an operation. The event does not require resources.

What does the graph look like?

Any graph familiar to us is represented by a curve located on a plane (less often in space). But the type of network plan is significantly different.

The network diagram of a project can look two ways: one technique involves designating operations in the nodes of the block diagram (DC), the second uses connecting arrows (OS) for this. It is much more convenient to use the first method.

The operation is indicated by a round or rectangular block. The arrows connecting them determine the relationships between actions. Since the titles of the work can be quite long and voluminous, operation numbers are entered in the blocks, and a specification is drawn up for the schedule.

Rules for developing a schedule

To plan correctly, you need to remember a few rules:

1. The graph unfolds from left to right.
2. Arrows indicate connections between operations; they may overlap.
3. Each simple job must have its own serial number; any subsequent operation cannot have a number lower than the previous one.
4. There can be no loops in the graph. That is, any looping of the production process is unacceptable and indicates an error.
5. You cannot use conditions when building a network diagram (an example of a conditional order: “if the operation is completed.., perform the work... if not, do not take any action”).
6. To indicate the beginning and end of work, it is more convenient to use one block that defines the initial (final) operations.

Graph construction and analysis

For each job you need to find out three things:

1. A list of operations that must be performed before this work. They are called preceding in relation to the given one.
2. A list of operations that are performed after a given action. Such works are called the following.
3. A list of tasks that can be carried out simultaneously with the given one. These are parallel operations.

All the information received provides analysts with the necessary basis for building logical relationships between the operations included in the network diagram. An example of constructing these relationships is given below.

A realistic schedule requires a serious and objective assessment of production schedules. Determining the time and entering it into the schedule makes it possible not only to calculate the duration of the entire project, but also to identify the most important nodes.

Graph calculation: direct analysis

The time spent on performing one operation is estimated on the basis of standard labor costs. Thanks to the direct or reverse calculation method, you can quickly navigate the order of work and identify critical steps.

Direct analysis allows us to determine the early start dates of all operations. Reverse - gives an idea of ​​later dates. In addition, using both analysis techniques, it is possible not only to establish the critical path, but also to identify time intervals by which the completion of individual works can be delayed without disrupting the overall project deadlines.

Direct analysis examines the project from beginning to end (if we talk about the compiled schedule, then movement along it occurs from left to right). While moving through all chains of operations, the time required to complete the entire complex of work increases. Direct calculation of the network schedule assumes that each subsequent operation begins at the moment when all its predecessors end. It is necessary to remember that the next job starts at the moment when the longest of the immediately preceding ones ends. At each step of direct analysis, the execution time of the calculation operation is added. This is how we get the early start (ES) and early finish (EF) values.

But you need to be careful: the early end of the previous operation becomes the early start of the subsequent one only if it is not a merge. In this case, the start will be the early completion of the longest previous work.

Reverse analysis

In reverse analysis, the following parameters of the network schedule are taken into account: late completion and late start of work. The name itself suggests that the calculation is carried out from the last operation of the entire project towards the first (from right to left). Moving towards the start of work, you should subtract the duration of each action. In this way, the latest start (LS) and finish (LF) dates for the work are determined. If the project time frame is not initially specified, then the calculation begins from the late end of the last operation.

Calculation of slack

Having calculated the network schedule of work in both directions, it is easy to determine temporary downtime (sometimes the term “fluctuation” is used). The total time of possible delay in the execution of an operation is equal to the difference between the early and late start of a particular action (LS - ES). This is the time reserve that will not disrupt the overall project deadlines.

After calculating all the fluctuations, they begin to determine the critical path. It will go through all operations for which there is no downtime (LF = EF; and accordingly LF - EF = 0 or LS - ES = 0).

Of course, in theory everything looks simple and straightforward. The developed network diagram (an example of its construction is shown in the figure) is transferred to production and implemented. But what is behind the numbers and calculations? How to use possible technological downtime or, conversely, avoid force majeure situations.

Management experts suggest assigning the most experienced employees to perform critical operations. In addition, when assessing project risks, you need to pay special attention not only to these steps, but also to those that directly affect the critical path. If it is not possible to control the progress of work as a whole, then it is necessary to find time to obtain primary information specifically from critical path operations. The point is to talk directly with the performers of such work.

Network diagram - a tool for optimizing the company’s activities

When it comes to the use of resources (including labor), it is much easier for a manager to manage them if there is a network work schedule. It shows all the downtime and busyness of each specific employee (team). Using an idle employee at one facility to implement another allows you to optimize the company’s activities as a whole.

One more practical piece of advice should not be neglected. In reality, project managers are faced with the “desires of higher management” to see work completed “yesterday.” In order to avoid panic and the release of defects, it is necessary to strengthen resources not so much on the operations of the critical path, but on those directly affecting it. Why? Yes, because there is already no downtime on the critical path, and it is often impossible to reduce the production time.