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Research on the application of optimization algorithms in engineering management and its practice in project scheduling

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21 mar 2025

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Introduction

With the continuous development of science and technology, the field of engineering management has ushered in new opportunities and challenges. In engineering management, the application of algorithms and optimization techniques is becoming more and more widespread, providing engineers with more solutions and innovative ideas [1-3]. Optimization algorithms for the realization of a certain goal and find the optimal solution method, it is the product of the intersection of mathematics, computers, information and countermeasures and other fields, can be divided into linear planning, nonlinear planning, integer planning and other categories, which the advanced algorithms, such as genetic algorithms, simulated annealing algorithms, such as phase mountain [4-7]. Optimization algorithms are used in modern urban planning, aerospace technology, engineering design, weather forecasting, financial management and other fields. Through the use of optimization algorithms, the use of resources can be optimized, reduce costs, improve efficiency, reduce energy consumption and so on [8-11].

Project scheduling refers to the process of project implementation, according to the project plan and schedule, the process of reasonable arrangement, coordination and management of various tasks. Project construction scheduling is an important management link of project construction, which plays a key role in the smooth promotion of the project [12-14]. Therefore, in the project construction scheduling process, the need for scientific planning, rational arrangement, comprehensive implementation, and strengthen the communication and cooperation with relevant departments, at any time on the project construction scheduling risk control, to ensure that the project construction scheduling is carried out smoothly. Only in this way can we guarantee the smooth progress of project construction, improve the management level of engineering project construction, and maximize the benefits of project construction [15-18].

In this paper, we design an engineering cost-time control method based on the critical path earned value method and apply it to a bridge for practical scheduling. First, decompose all the work tasks in the project. Estimate the duration of each task and subtask so that each task can be connected to each other to build a network system. Then calculate the longest task route that determines the duration of the entire construction project, i.e. Optimize the route as a critical path. Based on the critical path earned value analysis method, the project budget is calculated, the deviation status of project progress and cost is judged, and corresponding corrective measures are taken in time to achieve accurate and reasonable control of the project.

Engineering cost control methodology based on the critical path earned value approach
Project Cost Management

Project cost management is one of the most important management tasks in a construction company [19]. This refers to the optimization and management of revenues and costs through control throughout the initiation, construction, and completion of a project by a construction company in order to optimize the total construction cost of the project. This includes setting construction responsibility costs, developing cost plans, refining cost targets, performing cost calculations, and evaluating and monitoring the cost management process. The most important thing in project cost management is to correct the deviation, set up a good check point, test and compare the actual cost and target cost according to the time point, if there is a difference between the two, analyze the reason immediately, find out the reason for the deviation to correct the deviation, so as to effectively achieve the goal of project cost management.

Principles of project cost management

The ultimate goal of project cost management is to coordinate the activities of various departments during the construction process to accomplish the objectives of the project at the lowest possible cost, while maintaining quality and quantity according to the schedule. At the same time as possible, minimize the cost of cost management activities. Cost management is one of the three major objectives of engineering project management, which is an important factor affecting the profitability of building construction enterprises. In order to make the project cost management do a good job, first of all, we need to have a special person in the detection point regularly collect and organize the actual cost, use the scientific way to compare the actual cost with the expected target, after analysis to come up with the reasons for the deviation and to take corrective measures, including organization, economy, technology, contract, etc. Reasonable corrective measures can help achieve the high-quality cost target.

General project managers should follow the following principles in cost management.

The principle of comprehensive control: that is, the common management of all project participants and project progress.

dynamic control principle: the project cost is not overnight, but from beginning to end through the entire project, so the cost management of the project needs dynamic monitoring, in the project progress in a cyclical manner, used to monitor the cost of negative fluctuations, and timely detection of deviations from the expected goals, and adjust the management decision as soon as possible, so as to achieve the different stages of the project, to ensure the progress and quality at the same time, the cost control at the optimal level. Cost control at different stages of the project to ensure progress and quality at the same time would be the most ideal level.

Target Control Principle: Whether the cost management reaches the target depends on whether the actual cost is lower than the budget target, i.e. to follow the target control principle. The principle of target management in cost management includes the steps of cost target formulation, decomposition, implementation, review and disposal. In the process of cost management, the formulation of cost management objectives should be scientific, detailed, comparable, and operable.

Project cost management theory

The theory of target cost management

Target cost management refers to the cost management carried out by company managers in order to maximize the company’s profit. First, the target profit must be determined, followed by the target cost. Then, the target cost must be determined according to the company’s current production capacity, operating capacity and market conditions. The principles of implementation can be summarized into three main aspects, first, through price guidance, companies set target cost indicators, usually the change in the average market price minus the expected profit, where the price is determined by the market conditions, and the expected profit is usually determined by the economic conditions of the industry; second, from the point of view of the customer and the product, emphasizing the customer’s requirements for product quality, service, etc.; and, third, the target cost can be controlled by different departments can be controlled through synergies between them. In such a system, each link corresponds to each functional department and can control its target cost individually, thus affecting the overall cost control.

Dynamic cost management theory

Dynamic management refers to a continuous process in engineering practice under the assumption of limited resources and production factors, applying a number of basic theories, such as information theory and operations research theory, to make the project part and the whole realize dynamic equilibrium under the determined control mechanism. It is the result of enterprise research and the basis of economic efficiency. Dynamic cost management is to manage the costs incurred during the stages of bidding, contract signing, visa changes, and project accounting. It compares the actual cost and target cost of the project in time, finds out the reasons for deviation, and subsequently makes adjustments to keep the project cost within a reasonable range.

Theory of Total Cost Management

Comprehensive cost management refers to the implementation of whole-process, dynamic, multi-dimensional and all-round management of enterprise costs according to the characteristics of modern enterprise cost management and the application of cost management methods and principles. Its main purpose is to optimize costs, improve cost structure, and avoid cost risks. Its essence is that the cost management of engineering construction projects not only considers the specific aspects of cost management, but also refers to the comprehensive and integrated management, which is a more advanced cost management theory, which can better adapt to the current market economic environment, improve the efficiency of the cost management of the construction enterprise, improve the effectiveness of the overall cost management, realize the operating efficiency of the engineering construction enterprise, realize the management objectives of the construction enterprise, and provide a reliable management system for construction The development of the enterprise provides a reliable management system guarantee. The basic idea is to decompose the project work, establish work breakdown structure WBS, determine the target cost of each link according to the cost breakdown structure of CBS, control the cost within a reasonable range, and realize the real-time dynamic control of cost management.

Earned value method variables and indicators

The earned value method is a type of cost control method, and its core advantage is that it introduces the intermediate variable "earned value", which converts the input cost into the completed work task for the collaborative analysis of project progress and cost, and combines the calculation results of the budgeted cost and actual cost parameters of the completed work task to fully reflect the project progress and achieve effective cost control [20].

Variables underlying the earned value approach

Budgeted cost of the project’s planned workload

The budgeted cost of the project’s planned workload (PV) refers to estimating the project’s own costs on the basis of covering both price and workload elements.

Actual Cost of Completed Workload of the Project

The actual cost (AC) of the completed workload of the project indicates that the actual price is used as the basis for calculation, which in turn leads to the cost of the existing workload.

Budgeted Cost of Completed Work

The budgeted cost of completed work, also known as earned value (EV), is often the cost that corresponds to the amount of work that has been completed so far.

Earned value method evaluation indicators

Cost Performance Index CPI

The ratio of the earned value EV to the actual cost AC, the significance of which is a method of detecting and predicting the efficiency of the use of resources, can be expressed by the formula: CPI=EV/AC

If CPI < 1, it means that the existing costs have exceeded the budget, resulting in overspending.

If CPI = 1, it means that the efficiency of resource utilization is in line with the plan.

If CPI > 1, it means that the existing cost is far below the budget and there is some saving in cost.

Progress Performance Index SPI

The ratio of the earned value to the planned value, meaning that the project only wants to express the process of time utilization, expressed as: SPI=EV/PV

If SPI < 1, it means that the progress is inefficient, the schedule is delayed, the project is behind schedule, and it is necessary to catch up with the original schedule at this stage of the project.

If SPI = 1, it means that the project is in line with the expected schedule.

If SPI > 1, it means that the project is progressing faster than the expected schedule.

Schedule Deviation SV

The difference between the earned value and the planned value is expressed as: SV=EVPV

If SV < 0, it means that the schedule is inefficient, the schedule is delayed, the project is behind schedule, and the project needs to be rushed so that it can catch up with the original schedule at this stage.

If SV = 0, it means that the project is in line with the expected schedule.

If SV > 0, it means that the project is progressing faster than expected.

Cost deviation CV is the difference between the earned value and the actual value and is expressed as: CV=EVAC

If CV < 0, it indicates inefficient utilization of resources and cost overruns.

If CV = 0, it means that the resource utilization efficiency is in line with the plan.

If CV > 0, it means that resource utilization efficiency is higher than the plan and cost is saved.

In the above figure, CV = EVAC, Earned Value and actual cost of completed workload are calculated based on the completed workload, therefore, the difference between EV and PV parameters reflects the current cost deviation of the project.

In SV = EVPV, the earned value and the budgeted cost of the planned project workload are calculated based on the budgeted cost value, so the difference between the EV and PV parameters reflects the current schedule deviation of the project.

Implementation process of the earned value methodology

To cost control a project using the earned value method analysis, the project manager needs to perform the following tasks and parameters as shown in Figure 1:

Figure 1.

Method of earning value method

Decomposition of work objectives

Based on the project master plan and the project itself, the work task decomposition, made into a work structure decomposition (referred to as WBS), that is, the product development project in accordance with the logical relationship between the various R & D professional tasks, broken down into sub-tasks, and then broken down by the sub-tasks into a package of work.

Calculating the critical path of the project development plan

Decompose the decomposed work packages, constraints of work packages, project budget documents, etc. to decompose the total budget cost to the bottom work package.

Prepare a network plan based on the internal logical relationship of the decomposed work packages and the cycle time required to complete the work, fully consider human resources, technical capabilities and other factors, and derive the critical path through calculation.

Earned value parameter calculation

Project managers and technical leaders carry out real-time supervision of progress and cost information, combine the project plan and the actual progress of the project, the costs incurred, the amount of work accomplished and other information, and get the earned value, the planned cost, the actual cost, and then calculate them in accordance with the formula of the Earned Value Method, and get the parameters of the cost deviation, progress deviation, and so on.

Deviation Analysis

Analyze the above parameters, conduct a detailed discussion on schedule or cost deviations to determine the reasons for them. This work needs to be discussed together with the current environment and environmental factors of the project.

Corrective measures

Formulate corrective measures for the causes of product deviation, determine the optimal solution, and implement it according to cost, quality, schedule, market, and other factors. In general, there are four main corrective measures: economic solutions, design tools, organizational structure, and incentives.

Review and summarize

When all project tasks are completed, the application process of the earned value method, the reasons for cost and schedule deviations, and the development and implementation of corrective measures during the R&D process are documented for subsequent projects.

Critical path based earned value analysis
Critical path method

The Critical Path Method (CPM), also known as the Critical Route Method, is a method of project management that utilizes network diagrams and is one of the most basic and critical concepts in project management. It was first used in chemical plants in the 1950s to rationalize the routine maintenance of projects. At that time, there were a lot of complex and large projects that required a lot of human and material resources, which undoubtedly increased the difficulty of project management. Through the introduction of the critical path method, the pain points of project management were solved and good results were achieved. Critical path method divides the whole project into many individual tasks, then predicts the completion date of each task, uses network diagram to describe the logical relationship of each task in the project, and from this, finds out the route with the longest duration in the project plan, which is the so-called critical path. The critical path determines the total time spent on the project, so it is crucial to determine and effectively manage the work on this path during the project implementation process.

For the calculation of the critical path, there are several main steps [21].

The first step is to draw a network diagram by using nodes to represent events and arrows to represent jobs. The project begins on the left and ends on the right;

In the second step, the duration (T) required for the construction of each job is labeled;

In the third step, starting from the left, the earliest ending time (EF) for each job task is calculated. EF is equal to the earliest start time (ES) plus the duration of that task;

Step 4, when all calculations are completed, the time required to complete the entire project is the final time obtained;

In the fifth step, starting from the right, a calculation is made for the latest finish time (LF) for each assignment;

Step 6, calculate the latest start time for the job (LS = latest finish time - duration of the job); and

In the seventh step, the difference between the latest start time and the earliest start time or the latest finish time and the earliest finish time is calculated to obtain the time difference for each operational task;

In the last step, the job with zero time difference is on the critical line.

Basic parameters based on critical paths

In order to more accurately grasp the project performance, based on the traditional Earned Value Method, three new basic parameters based on the critical path are proposed: Critical Route Completed Work Budgeted Cost BCWPCP , Critical Route Planned Work Budgeted Cost (BCWSCP), and Critical Route Completed Work Actual Cost ACWPCP, from which four new analysis indicators are derived:

Critical path cost deviation (CVCP): CVCP=BCWPCPACWPCPCP

If CVCP > 0, the work on the critical path has cost savings; if CVCP < 0, the work on the critical path has cost overruns.

Schedule deviation on the critical path (SVCP): SVCP=BCWPCPBCWSCP

If SVCP > 0, the work on the critical path is ahead of schedule; if SVCP < 0, the work on the critical path is behind schedule.

Cost performance index of the critical path (CPICP): CPICP=BCWPCP/ACWPCP

If CPICP > 1, the work on the critical path has cost savings; if CPICP < 1, the work on the critical path has cost overruns.

Critical path schedule performance index (SPICP): SPICP=BCWPCP/BCWSCP

If SPICP > 1, the work on the critical path is ahead of schedule; if SPICP < 1, the work on the critical path is behind schedule.

Application Process of Critical Path Earned Value Approach

Critical Path Earned Value Method (CPEV), is a management method to control project cost and schedule through Earned Value Method combined with Critical Path, its main application process is formed by combining the Earned Value Method and Critical Path both, the application process of Critical Path Earned Value Method (CPEVM) is shown in Figure 2.

Figure 2.

Application Flow Chart of Earned Value Method

The earned value method is applied in the following steps. In the first step, a work breakdown structure WBS is performed for the project.

In the second step, a duty assignment matrix and a construction cost schedule are developed to provide baseline data for the subsequent calculation of earned value.

In the third step, the critical path and non-critical path of the project are calculated, so that the sources of earned value of the project can be clearly distinguished.

In the fourth step, monitoring points are set up to collect the actual costs incurred in the construction execution process, and then the earned value of the project is measured; through the earned value data, the cost and schedule deviation is analyzed.

If the deviation is large and out of the planned range, it is necessary to immediately analyze the causes of the problem and take corresponding measures to correct the deviation. If the deviation is small or zero, each detail can be adjusted. If the deviation is still very large after correction, corrective measures should be made to the project plan in time and the project should be implemented strictly according to the corrected plan.

Analysis of examples
Project Critical Path and Budget
Overview of a bridge project

Geographic characteristics of the project construction and meteorology

A village is located in the southwestern edge of the Yunnan-Guizhou Plateau, the Hengduan Mountain System, the southeast section of the longitudinal valley, the terrain tilted from northwest to southeast, the average elevation of 1430 m. The project area is divided into four distinct seasons, dry in winter, hot and rainy in summer, with an average annual temperature of 13.4 °C.

Project construction scale and total cost estimate

The example is a continuous girder bridge with a total length of 138 m and 6 spans, all of which are concrete prestressed T-beams, which are prefabricated in Mojiang girder yard. The total cost estimate of a bridge is about 25 million yuan. The project is scheduled to start in September 2022 and finish in August 2023, with a total construction period of 350d.

Calculate the critical path for the Project Bridge project

First of all, the work structure decomposition diagram is prepared, and the tasks in the construction project are decomposed layer by layer according to their relationship with each other, until they are decomposed into a number of relatively independent, single-content work units. Then calculate the critical path of the project bridge project. The projected duration of the Project Bridge Project is shown in Table 1.

The project is expected to be in the construction period

Specific project (working package) Planned period
Bridge September 10, 2022, October 20, 2022
Precast beam field September 10, 2022, October 20, 2022
Bridge foundation (punch pile, column, beam) October 20, 2022 ~ April 11, 2023
Hollow plate prefabrication October 24, 2022 ~ March 4, 2023
Box girder prefabrication October 24, 2022 ~ March 4, 2023
Support stone April 11, 2023 ~ April 21
Beam mounting April 22, 2023 ~ May 20
Reaming May 21, 2023 ~ June 5
Bridge dress June 6, 2023 ~ July 5
Expansion joint installation July 6, 2023 ~ July 15
Fence construction June 6, 2023 ~ June 25
Sideway board installation July 6, 2023 ~ July 20
Marking line July 20, 2023 ~ July 25
The bridge is demolished by the way July 26, 2023 ~ August 20

Based on the actual construction sequence of the project, and the specific dates of the start to finish of each job, the duration of each job required for completion under normal conditions was calculated to create a table of the Project Bridge Project work relationships. The Project Bridge Project work relationships are shown in Table 2.

Bridge project work relationship

Job code Job name Preorder Duration/d
A Bridge 42
B Precast beam field 43
C Bridge foundation (punch pile, column, beam) A 175
D Hollow plate prefabrication B 131
E Box girder prefabrication B 135
F Support stone C 12
G Beam mounting D, E, F 26
H Reaming G 18
I Bridge dress H 25
J Expansion joint installation I, K 10
K Fence construction H 23
L Sideway board installation I, K 26
M Marking line J, L 6
N The bridge is demolished by the way M 35

Based on the logical relationship between the work, the calculation of the time for each activity of the Project Bridge is shown in Table 3.

Activity time calculation results

Activity name Node number Earliest starting time Earliest end Late start time The end of the day Total jet lag Free time Critical path
i j ES EF LS LF TF FF
A 2 4 0 39 0 41 0 0 Yes
B 2 3 0 40 43 81 41 2
C 5 8 40 213 40 213 0 0 Yes
D 3 6 40 172 83 214 41 42
E 4 4 40 171 83 216 41 41
F 7 7 215 226 212 226 0 0 Yes
G 9 8 222 252 223 253 0 0 Yes
H 8 10 254 266 252 266 0 0 Yes
I 11 11 267 296 268 296 0 0 Yes
J 11 14 297 304 299 311 4 5
K 10 10 267 287 278 295 10 10
L 12 13 297 309 297 311 0 1 Yes
M 14 15 309 314 311 316 0 0 Yes
N 15 18 315 345 314 344 0 1 Yes

According to the principles of drawing network plan, the network plan of the bridge project is shown in Figure 3. The key route is ①→②→③→⑦→⑧→⑨→⑩→.

Figure 3.

Bridge project network plan

Budget for the Example Bridge Project

This paper controls the direct costs of the example bridge. The direct cost includes labor cost, material cost, machinery use cost and subcontract cost. According to the rolling statistics, the overall budgeted cost of the Calculated Example Bridge is shown in Table 4.

Overall budget cost of the bridge (yuan)

Job code Labor cost Materials cost Mechanical charge Subcontract charge Total
A 605473 520304 767861 1467259 3389434
B 257294 308712 180754 377083 1119964
C 961406 2607521 672386 0 4255290
D 409299 402371 128379 1372563 2276823
E 302136 3207985 197519 2587247 6339379
F 66159 111796 17829 0 137554
G 446764 1700776 843782 0 2967724
H 156520 51294 111419 0 322795
I 208400 809385 77505 0 1076794
J 101399 181768 85429 0 324085
K 300746 308623 140331 528012 1260523
L 82781 36100 56878 0 225736
M 167781 395465 184476 0 711779
N 98412 -11208 125391 0 216151
Project cost control
Calculation of earned value parameters for engineering projects

The three basic parameters, BCWS, BCWP, and ACWP, are the key data information for applying the critical path earned value method to control the cost deviation, and the accuracy of the calculation of these three values plays a very important role in doing the earned value report analysis.

BCWS

BCWS, the project monthly BCWS calculation should be based on the monthly project schedule, the budgeted cost is apportioned to each work package in each month, nine months as shown in Table 5.

BCWS in September

Project Labor cost Mechanical charge Materials cost Subcontract charge Total
A 332580 399100 0 597651 1331500
B 0 0 167993 16700 267400

BCWP

In this project, it is based on the multiplication of the budgeted amount and the determined percentage to get the BCWP (Budgeted Cost of Work Performed) that needs to be determined. Using September as an example, the BCWP is shown in Table 6.

BCWP in September

Project Labor cost Mechanical charge Materials cost Subcontract charge Total
A 383520 0 452337 653114 1488971
B 0 189925 0 125262 315187

ACWP

Statistics to calculate the actual cost, taking September as an example. As shown in Table 7.

ACWP in September

Project Labor cost Mechanical charge Materials cost Subcontract charge Total
A 387965 0 463537 659742 1511245
B 195003 130002 325005

The end of January 2023 was chosen as the monitoring deadline, and the earned value reports are now organized as shown in Tables 8 to 12. Among them, Table 8~Table 13 are the earned value reports from September to January respectively.

September earnings report (yuan)

Project Earning indicator Labor cost Mechanical charge Materials cost Subcontract charge Total
A BCWS 337964 0 405557 608336 1351857
BCWP 383520 0 452337 653114 1488971
ACWP 387965 0 463537 659742 1511244
SV 45556 0 46779 44779 137114
CV -4445 0 -11200 -6628 -22273
B BCWS 0 170628 0 113752 284380
BCWP 0 189925 0 125262 315187
ACWP 0 195003 0 130002 325005
SV 0 19297 0 11510 30807
CV 0 -5078 0 -4740 -9818

October earnings report (yuan)

Project Earning indicator Labor cost Mechanical charge Materials cost Subcontract charge Total
A BCWS 265534 0 318652 477978 1062164
BCWP 272265 0 302342 574132 1148739
ACWP 259999 0 328249 589875 1178123
SV 6731 0 -16310 96154 86575
CV 12266 0 -25907 -15742 -29383
B BCWS 0 134064 0 89376 223440
BCWP 0 101564 0 67710 169274
ACWP 0 97501 0 65001 162502
SV 0 -32500 0 -21667 -54167
CV 0 4063 0 2709 6772
C BCWS 0 399790 0 691816 1091606
BCWP 0 421356 0 703985 1125341
ACWP 0 405801 0 662896 1068697
SV 0 21565 0 12168 33733
CV 0 15555 0 41089 56644
D BCWS 0 0 0 377977 377977
BCWP 0 0 0 311473 311473
ACWP 0 0 0 291616 291616
SV 0 0 0 -66503 -66503
CV 0 0 0 19858 19858
E BCWS 0 0 0 521209 521209
BCWP 0 0 0 536471 536471
ACWP 0 0 0 556466 556466
SV 0 0 0 76200 76200
CV 0 0 0 -19995 -19995

November earnings report (yuan)

Project Earning indicator Labor cost Mechanical charge Materials cost Subcontract charge Total
C BCWS 0 705512 0 1220852 1926364
BCWP 0 747013 0 1194311 1941324
ACWP 0 681280 0 1185224 1866504
SV 0 41501 0 -26541 14960
CV 0 65733 0 9087 74820
D BCWS 0 0 0 667016 667016
BCWP 0 0 0 681461 681461
ACWP 0 0 0 669281 669281
SV 0 0 0 14444 14444
CV 0 0 0 12180 12180
E BCWS 0 0 0 822962 822962
BCWP 0 0 0 767074 767074
ACWP 0 0 0 835649 835649
SV 0 0 0 -55888 -55888
CV 0 0 0 -68575 -68575

December earnings report (yuan)

Project Earning indicator Labor cost Mechanical charge Materials cost Subcontract charge Total
C BCWS 0 729029 0 1261547 1990576
BCWP 0 771914 0 1234122 2006036
ACWP 0 599040 0 1305983 1905023
SV 0 42884 0 -27424 15460
CV 0 172874 0 -71861 101013
F BCWS 5197 337946 6352 383687 733182
BCWP 5023 293721 6140 333477 638361
ACWP 5937 366332 7258 393831 773358
SV -174 -44225 -212 -50210 -94821
CV -914 -72611 -1118 -60353 -134996

January earnings report (yuan)

Project Earning indicator Labor cost Mechanical charge Materials cost Subcontract charge Total
C BCWS 0 282205 0 183649 465854
BCWP 0 292270 0 119431 411701
ACWP 0 173462 0 148991 322453
SV 0 10065 0 -64218 -54153
CV 0 118808 0 -29560 89248
F BCWS 5197 337946 6352 383687 733182
BCWP 5370 313978 6563 333477 659388
ACWP 6348 391597 7757 393491 799193
SV 173 -23968 211 -50210 -73794
CV -978 -77619 -1194 -60014 -139805

Total cost deviation (yuan)

Month September October November December January
Total cost deviation -31598 33372 18141 -13515 -49780

Based on the earned value reports from September 2022 through January 2023, the data was analyzed to summarize the overall monthly cost deviations, and the results are shown in Table 13

By analyzing and organizing the earned value reports of these months, we have initially found out the problems arising from the cost control of the project and the possible causes. The specific analysis is as follows:

Overall situation of cost deviation

From the above table, it can be found that the overall cost deviation occurs in September, December and January projects. In subcontracting costs, good control of processes on non-critical paths can mask the extent of cost overruns on critical path projects. There were cost deviations on both critical paths and non-critical path C.

Preliminary analysis of the reasons for cost deviations

For critical paths A, E, and F, all of which have serious cost deviations, the main reason is overruns in material costs, machinery costs, and outsourcing costs.

In-depth analysis of project deviations

The reasons for cost overruns and schedule delays on the project’s critical path are basically related to the two major modules of materials and subcontracting. After conducting a field investigation, collecting information, communicating with related personnel, and assisting professionals, the reasons for cost deviation were thoroughly identified, which mainly include the following points:

Lack of professional coordination in material procurement

In material procurement, managers did not distinguish between critical and non-critical paths.

Lack of strict management of subcontracting teams

For projects on the critical path, the construction difficulty and the requirements for technology are relatively high, but the managers did not make careful preparations and meticulous planning for the selection of construction teams in advance.

Shortage of skilled labor resources

Critical path E work package, the professional skills of the technicians require high, and the lack of technicians with such professional and technical requirements of the lack of resources to increase the cost of labor, which subcontracting teams to increase the contract price.

Irrational design drawings

The construction drawings of the design appear some errors and part of the unreasonable, need to re-modify and improve the design drawings.

Lack of standardized and unified system for site management

On-site management is not close enough to the engineering construction work process.

Corrective measures for the project

In response to the analyzed reasons, the professional and technical staff and management were exchanged, and after discussion, the management proposed some corrective measures. Specifically as follows:

Sunshine Purchasing

In the later stage, for the purchase of materials on the critical path, when selecting material suppliers, the bidding competition is adopted to select the best among the best.

Strict management of subcontracting team

The management of the subcontracting team is mainly based on the subcontracting contract, subcontracting project quality, project settlement, and other aspects of the layers of control.

Training of technicians

The chief engineer selects technicians with stronger qualifications from the autonomous construction team, and enhances technical training and guidance for personnel.

Strictly supervise the material management process and strengthen the management of construction team

Strictly supervise the material management process, according to the field investigation, the material department will strictly manage the allocation of materials to each construction team and construction stage according to the execution of the project progress, and make a good account registration.

As it takes time for management to rectify the situation, cost control did not improve well in February’s Earned Value Report. From March, we started to implement corrective measures by changing suppliers and strengthening the effective management of subcontracting teams, and the cost deviation and progress deviation in March have been reduced. The earned value reports for these two months have been arranged in Table 14 and Table 15.

From the above data, it can be seen that after the implementation of corrective measures by the management, the cost and schedule have been effectively controlled and there has been great progress. However, some problems still exist.

February earnings report (yuan)

Project Earning indicator Labor cost Mechanical charge Materials cost Subcontract charge Total
F BCWS 0 305241 0 346556 651797
BCWP 0 344531 0 352467 696998
ACWP 0 363857 0 364420 728277
SV 0 39290 0 5911 45201
CV 0 -19326 0 -11953 -31279

March earnings report (yuan)

Project Earning indicator Labor cost Mechanical charge Materials cost Subcontract charge Total
F BCWS 0 337945 0 383687 721633
BCWP 0 344447 0 376788 721235
ACWP 0 340815 0 374564 715379
SV 0 6502 0 -6899 -397
CV 0 -3632 0 2224 -1408
Project follow-up

Management has added some new management measures to the previous ones:

Assigning additional technicians to each sub-project to supervise and guide the construction to speed up the construction progress;

Give backward scheduling to the work content of each construction team and assign special personnel to conduct assessment.

On this basis, we continue to collect data and analyze the cost and schedule deviation. The Earned Value Report for the month of April is shown in Table 16 below.

April earnings report (yuan)

Project Earning indicator Labor cost Mechanical charge Materials cost Subcontract charge Total
F BCWS 0 327044 0 371310 698354
BCWP 0 344476 0 375446 719922
ACWP 0 326078 0 370279 696357
SV 0 17431 0 4136 21567
CV 0 18397 0 5167 23564
G BCWS 0 149604 0 6029 155633
BCWP 0 160309 0 6448 166757
ACWP 0 139447 0 5871 145318
SV 0 10705 0 419 11124
CV 0 20861 0 577 21438
H BCWS 246592 369889 287691 0 904172
BCWP 247690 369984 291723 0 909397
ACWP 246370 369680 286582 0 902632
SV 1098 95 4032 0 5225
CV 1320 305 5141 0 6766

It can be seen that the progress deviation and cost deviation have been reduced after management has taken corrective measures, but at this rate of progress, there is still more than 90,000 yuan more than the projected cost according to the formula.

The data for the last three months is summarized and organized as shown in Table 17. As can be seen from the data, the costs for the last three months were effectively controlled, savings were realized, and the schedule was completed earlier than scheduled.

Total cost deviation (yuan)

Month May June July
Total cost deviation 19091 23846 48569
Analysis of the effectiveness of project cost and schedule control

Taking October as an example, the Critical Path Earned Value Method is compared with the traditional cost control method to better substantiate the effectiveness of the method. A comparison of the Earned Value Method and the traditional cost control method for October is shown in Table 18.

The earning method is compared to the traditional cost control method

Earning parameter Critical path earning method Traditional cost control method
Completed budget cost (BCWP) 3291297
Actual costs (ACWP) 3257403 3257403
Budget costs (BCWS) 3276398 3276398
Cost deviation 33894 18994
Progress deviation 14899

It is proved that the cost and schedule deviation values are obtained by applying the critical path earned value method in the earned value management of the project in October. The effectiveness of the method designed in this paper is strongly proved.

Conclusion

This paper optimizes the traditional earned value method, proposes a cost control method in engineering management, and applies it to the construction project management of a bridge in southwest China. Under the analysis of the critical path of the project in this paper, the reasons for the cost deviation in the first five months of the construction period are precisely analyzed. Rectification strategies were formulated one by one for problems such as lack of professional coordination in material procurement and lax management of subcontracting teams. The cost of the latter three months was effectively controlled and savings were realized, including a balance of more than 40,000 yuan in July, and the construction period was completed earlier than scheduled. Practice has fully proved that the engineering cost control method designed in this paper based on the critical path earned value method plays a significant role in project scheduling, budget management, etc., which can reduce the cost of engineering projects and realize the reasonable allocation of time and capital under the premise of ensuring quality and schedule.

Język:
Angielski
Częstotliwość wydawania:
1 razy w roku
Dziedziny czasopisma:
Nauki biologiczne, Nauki biologiczne, inne, Matematyka, Matematyka stosowana, Matematyka ogólna, Fizyka, Fizyka, inne