scholarly journals PERCEPATAN WAKTU PELAKSANAAN PEKERJAAN KONSTRUKSI DENGAN METODE CPM DAN TCTO

2019 ◽  
Vol 11 (1) ◽  
pp. 33-40
Author(s):  
Cut Zukhrina Oktaviani ◽  
Ibnu Abbas Majid ◽  
Risdiawati Risdiawati
Keyword(s):  
Completion Time ◽  
Construction Projects ◽  
Critical Path ◽  
Minimum Cost ◽  
Time Cost ◽  
Trade Off ◽  
Project Duration ◽  
Project Completion ◽  
Project Costs ◽  
Total Project

Construction delays are a common and major concern in most construction projects. Construction project delay can indirectly affect of project performance. Delay resolve method is to schedule crashing with various methods. This crashing planning is done by combining the Critical Path Method (CPM) and Time-Cost Trade-Off (TCTO) method for the minimum cost in crash duration calculation. Project A data is used to be a case studi in crash duration calculation and costs increase. Rescheduling with CPM result project completion time 120 days and after crashing project duration becomes 94 days, there was a reduction 26 days project completion time. Crashing programme are do to 18 activities from 30 critical activies rescheduling with CPM result. Total project costs changes is Rp. 19.923.466,- due working time addition (overtime) to reduce project time with Time Cost Trade Off method. Normal condition project costs is Rp. 985,171,182.52 and after duration crash becomes Rp. 1,005,094,648, -.

scholarly journals Bi-Objective Scheduling Optimization for Discrete Time/Cost Trade-Off in Projects

2018 ◽  
Vol 10 (8) ◽  
pp. 2802 ◽  
Author(s):  
Hongbo Li ◽  
Zhe Xu ◽  
Wenchao Wei
Keyword(s):  
Discrete Time ◽  
Large Scale ◽  
Heuristic Algorithms ◽  
Critical Path ◽  
Large Set ◽  
Time Cost ◽  
Trade Off ◽  
Project Duration ◽  
Computational Performance ◽  
Trade Offs

In sustainable project management, time and cost are two critical factors affecting the success of a project. Time/cost trade-offs in projects accelerate the execution of some activities by increasing the amount of non-renewable resources committed to them and therefore shorten the project duration. The discrete time/cost trade-off problem (DTCTP) has been extensively studied during the past 20 years. However, due to its complexity, the DTCTP—especially the DTCTP curve problem (DTCTP-C)—has only been solved for relatively small instances. To the best of our knowledge, there is no computational performance analysis for solving the DTCTP-C on large project instances with up to 500 activities. This paper aims to fill this gap. We present two bi-objective heuristic algorithms for the DTCTP-C where both project duration and cost are minimized. The objective is to obtain a good appropriate efficient set for the large-scale instances. The first algorithm is based on the non-dominated sorting genetic algorithm II (NSGA-II) and uses a specially designed critical path-based crossover operator. The second algorithm is a steepest descent heuristic which generates efficient solutions by iteratively solving the DTCTP with different deadlines. Computational experiments are conducted to validate the proposed algorithms on a large set of randomly generated problem instances.

Time–cost–quality trade-off analysis for planning construction projects

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tianqi Wang ◽  
Moatassem Abdallah ◽  
Caroline Clevenger ◽  
Shahryar Monghasemi
Keyword(s):  
Optimization Model ◽  
Construction Projects ◽  
Present Model ◽  
Construction Project ◽  
Time Cost ◽  
Trade Off ◽  
Content Type ◽  
Project Duration ◽  
Trade Offs ◽  
Project Objectives

Purpose Achieving project objectives in constructionprojects such as time, cost and quality is a challenging task. Minimizing project cost often results in additional project duration and might jeopardize quality, and minimizing project duration often results in additional cost and might jeopardize quality. Also, increasing construction quality often results in additional cost and time. The purpose of this paper is to identify and analyze trade-offs among the project objectives of time, cost and quality. Design/methodology/approach The optimization model adopted a quantitative research method and is developed in two main steps formulation step that focuses on identifying model decision variables and formulating objective functions, and implementation step that executes the model computations using multi-objective optimization of Non-Dominated Sorting Genetic Algorithms to identify the aforementioned trade-offs, and codes the model using python. The model performance is verified and tested using a case study of construction project consisting of 20 activities. Findings The model was able to show practical and needed value for construction managers by identifying various trade-off solutions between the project objectives of time, cost and quality. For example, the model was able to identify the shortest project duration at 84 days while keeping cost under $440,000 and quality higher than 85 percent. However, with an additional budget of $20,000 (4.5 percent increase), the quality can be increased to 0.935 (8.5 percent improvement). Research limitations/implications The present research work is limited to project objectives of time, cost and quality. Future expansion of the model will focus on additional project objectives such as safety and sustainability. Furthermore, new optimization models can be developed for construction projects with repetitive nature such as roads, tunnels and high rise buildings. Practical implications The present model advances existing research in planning construction projects efficiently and achieving important project objectives. On the practical side, the optimization model will support the construction industry by allowing construction managers to identify the highest quality to deliver a construction project within specified budget and duration, lowest cost for specified duration and quality or shortest duration for specified budget and quality. Originality/value The present model introduces new and innovative method of increasing working hours per day and number of working days per shift while analyzing labor working efficiency and overtime rate to identify optimal trade-offs among important project objectives of time, cost and quality.

IMPACT OF BIDDING ENVIRONMENT ON CHANGE ORDERS

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Bahadir V. Barbarosoglu ◽  
David Arditi
Keyword(s):  
Construction Projects ◽  
Potential Change ◽  
Project Cost ◽  
Change Orders ◽  
Public Building ◽  
Project Duration ◽  
Project Completion ◽  
The Difference ◽  
Dollar Amount ◽  
Total Project

Change orders occur during construction, and usually increase both construction cost and project duration. This paper investigates how change orders are related to the bidding environment. The data used in this study were collected from 74 public building construction projects awarded by the Public Building Commission of Chicago in the seven-year period 2008-2015. The contract values range between $0.3-$70 million, and the total worth of the projects is a little over $1.1 billion. While delay may result in liquidated damages for contractors, increase in project cost can cause financial problems for owners. It is in the interest of owners and contractors to study similar past projects, and to observe how change orders are affected by the level of competition in bidding. Owners must budget for contingencies, and contractors must adjust their resources in anticipation of change orders. It would therefore be quite desirable for owners and contractors to be able to predict the dollar amount and duration implications of potential change orders by making use of past historical data. The prediction of the dollar amount and duration implications of potential change orders before the construction starts can alert construction owners and contractors to potential delays in total project completion time and potential overruns in total project cost. Knowledge about potential change orders creates a predictable environment and improves the relationship between owners and contractors. The results of this study indicate that contractor-driven change orders are positively related to the difference between the lowest and the second lowest bids.

scholarly journals   Project costs planning in the conditions of uncertainty

2012 ◽  
Vol 58 (No. 2) ◽  
pp. 72-84 ◽  
Author(s):  
H. Štiková
Keyword(s):  
Critical Path ◽  
Project Planning ◽  
Fuzzy Approach ◽  
Project Duration ◽  
Planning And Control ◽  
New Information ◽  
Project Costs ◽  
Project Network ◽  
And Control ◽  
Total Project

The fuzzy approach to the project network analysis of the project planning and control is commonly oriented on the fuzzy critical path setting and the project duration monitoring. In the article, this approach is improved by the addition of the project costs perspective to the standard time aspect. The relations for the fuzzy quantity of the total project costs and for its membership function are derived. The example demonstrates the application of the theoretical relations and shows how the enhanced fuzzy approach can be used when different project variants are to be compared. The example also reveals how the fuzzy approach with the project costs monitoring brings new information for the project planning and management and for the risk management.  

STUDI ANALISIS BIAYA DAN WAKTU MENGGUNAKAN METODE TIME COST TRADE OFF (TCTO) PADA PROYEK TELKOM MANYAR-SURABAYA.

EXTRAPOLASI ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 20-29
Author(s):  
Rizal Rosyid ◽  
Gede Sarya ◽  
Michella Beatrix ◽  
Wateno Oetomo
Keyword(s):  
Critical Path ◽  
Working Hours ◽  
Time Cost ◽  
Time Duration ◽  
Project Cost ◽  
Trade Off ◽  
Project Duration ◽  
Network Diagram ◽  
Schedule Compression ◽  
Normal Duration

AbstractTime cost trade off is a schedule compression to get projects that are more profitable in terms of time (duration), costs, and income. The aim is to compress the project to an acceptable duration and minimize the total project cost. The reduction in project duration is done by selecting certain activities. The analysis begins by preparing a network diagram (network diagram) using Microsoft Project. After that the crashing process is done using the addition of workers and additional hours of work contained in the critical path. Next do the calculations with the time cost trade off method to find the value of the crash cost and cost slope contained in the critical path. From the results of the analysis, the normal duration of the project is 639 calendar days after the process of crashing, adding work hours to 622 days and labor to 623 calendar days and the initial project cost of Rp. 250,320,084,731 after the process of crashing activities with an alternative addition to labor obtained a fee of Rp. 250,559,140,422 and additional working hours in the amount of Rp. 252,734,398,495. So that it can be concluded with the time cost trade off method there is a reduction in the duration and increase in costs.AbstrakTime cost trade off merupakan kompresi jadwal untuk mendapatkan proyek yang lebih menguntungkan dari segi waktu (durasi), biaya, dan pendapatan. Tujuannya adalah memampatkan proyek dengan durasi yang dapat diterima dan meminimalisasi biaya total proyek. Pengurangan durasi proyek dilakukan dengan memilih aktivitas tertentu. Analisa dimulai dengan melakukan penyusunan jaringan kerja ( network diagram ) dengan menggunakan microsoft project. Setelah itu dilakukan proses crashing menggunakan penambahan pekerja dan penambahan jam kerja yang terdapat pada jalur kritis. Selanjutnya melakukan perhitungan dengan metode time cost trade off untuk mencari nilai crash cost dan cost slope yang terdapat pada jalur kritis. Dari hasil analisa yang dilakukan diperoleh durasi proyek normal 639 hari kalender setelah dilakukan proses crashing kegiatan penambahan jam kerja menjadi 622 Hari dan tenaga kerja menjadi 623 hari kalender dan biaya proyek awal sebesar Rp. 250.320.084.731 setelah dilakukan proses crashing kegiatan dengan alternatif penambahan tenaga kerja diperoleh biaya sebesar Rp. 250.559.140.422 dan penambahan jam kerja sebesar Rp. 252,734,398,495. Sehingga dapat disimpulkan dengan metode time cost trade off terjadi pengurangan durasi dan peningkatan biaya. 

Assessing the Time-Cost Trade-Off of Construction Projects

2011 ◽  
Vol 243-249 ◽  
pp. 6394-6399
Author(s):  
Wei Lo ◽  
Ming En Kuo
Keyword(s):  
Construction Projects ◽  
Resource Efficiency ◽  
Linear Quadratic ◽  
Trade Off ◽  
Project Completion ◽  
Proposed Model ◽  
Project Costs ◽  
Adjustable Range ◽  
Completion Times

By using Genetic Algorithms (GAs), a resource-integrated model is presented to identify the relationships between project time and cost in consideration of the changes in resource efficiency under different working durations. Under the assumption of a non-linear quadratic relationship between resource efficiency and working duration, the minimum and maximum project costs for different project completion times are easily identified and the trade-off relationships between the project time and cost are clearly presented by using the proposed model and a case study. The research results logically suggest that the greater the adjustable range of activity durations, the lower the minimum project cost for a specific project’s completion time will be, and the greater the value of an activity is, the later the activity will be adjusted.

A new framework for time-cost trade-off considering float loss impact

2017 ◽  
Vol 22 (1) ◽  
pp. 20-36 ◽  
Author(s):  
Sameh Monir El-Sayegh ◽  
Rana Al-Haj
Keyword(s):  
Optimization Technique ◽  
Time Cost ◽  
Trade Off ◽  
Deterministic Optimization ◽  
Content Type ◽  
Project Duration ◽  
Trade Offs ◽  
Project Objectives ◽  
The Impact ◽  
New Framework

Purpose The purpose of this paper is to propose a new framework for time–cost trade-off. The new framework provides the optimum time–cost value taking into account the float loss impact. Design/methodology/approach The stochastic framework uses Monte Carlo Simulation to calculate the effect of float loss on risk. This is later translated into an added cost to the trade-off problem. Five examples, from literature, are solved using the proposed framework to test the applicability of the developed framework. Findings The results confirmed the research hypothesis that the new optimum solution will be at a higher duration and cost but at a lower risk compared to traditional methods. The probabilities of finishing the project on time using the developed framework in all five cases were better than those using the classical deterministic optimization technique. Originality/value The objective of time–cost trade-off is to determine the optimum project duration corresponding to the minimum total cost. Time–cost trade-off techniques result in reducing the available float for noncritical activities and thus increasing the schedule risks. Existing deterministic optimization technique does not consider the impact of the float loss within the noncritical activities when the project duration is being crashed. The new framework allows project managers to exercise new trade-offs between time, cost and risk which will ultimately improve the chances of achieving project objectives.

scholarly journals A Novel Method of Developing Construction Projects Schedule under Rework Scenarios

2019 ◽  
Vol 11 (20) ◽  
pp. 5710
Author(s):  
Guofeng Ma ◽  
Shan Jiang ◽  
Tiancheng Zhu ◽  
Jianyao Jia
Keyword(s):  
Construction Projects ◽  
Development Project ◽  
Real Estate Development ◽  
Design Structure Matrix ◽  
Project Duration ◽  
Project Completion ◽  
Design Structure ◽  
Novel Method ◽  
The Impact ◽  
Critical Chain

Construction projects have faced serious schedule delays caused by rework risks. However, it appears that traditional methods are of limited value in developing applicable project schedules. This study presents an analysis on construction projects schedule development under rework scenarios by a novel method named the improved critical chain design structure matrix (CCDSM). Research data are collected from a real estate development project in China. As a result, predictions of project completion duration and probability have been made. A reliable schedule considering information interactions has been developed and visualized. Rework impact areas of activities have been examined to quantitatively record the impact on project duration. To meet different demands, the method generates two more schedules setting different rework buffers. Furthermore, these activities have the potential of causing rework and have been quantified based on the calculation of two criticalities, providing an identification of rework-intensive works that should be payed close importance to, which have not be realized by previous methods. The results proved the feasibility and effectiveness of this method in developing a schedule for construction projects disturbed by rework, helping practitioners adopt measures to avoid rework-caused schedule delays and achieve sustainable development of such projects.

A Study on Variations in Sewerage Construction Projects

2012 ◽  
Author(s):  
Mohd Azraai Kassim ◽  
Jen Loong Lee
Keyword(s):  
Construction Industry ◽  
Construction Projects ◽  
Site Conditions ◽  
Project Costs ◽  
Research Findings ◽  
Project Characteristics ◽  
Major Factors ◽  
A Company ◽  
Total Project ◽  
Sewerage Network

Perubahan dalam pembinaan telah lama menjadi isu pertikaian antara pelbagai pihak yang terlibat dalam projek pembinaan. Namun, hanya sejumlah kecil kajian yang rasmi telah dijalankan untuk menganalisis sebab-sebab dan kesan-kesannya. Kajian ini tertumpu kepada analisis kekerapan dan keterukan berbagai-bagai faktor yang mengakibatkan perubahan dalam projek pembinaan rangkaian pembetungan. Adalah penting bagi sesebuah syrikat bukan sahaja mengetahui kos perubahan, tetapi juga mengenal pasti perkara-perkara yang perlu diberi perhatian untuk mengurangkan kos-kos sedemikian dalam projek akan datang. Kesemua data dan maklumat yang diperlukan diperolehi dari fail-fail arkib bagi tiga belas projek yang disahkan melalui temubual. Data-data dikategori untuk menganalisis kekerapan dan keterukan faktor-faktor. Jadual dan carta digunakan untuk menunjukkan hasil-hasil kajian. Daripada hasil analisis, keadaan tapak yang berbeza merupakan faktor utama yang mengakibatkan perubahan. Faktor-faktor ini menyumbangkan 49.3% daripada jumlah bilangan perubahan, 56.2% daripada jumlah kos perubahan dan 3.8% daripada jumlah kos projek. Dua ciri projek, iaitu nilai anugerah kontrak dan gred pendaftaran kontraktor dengan Lembaga Pembangunan Industri Pembinaan (mewakili pengkhususan, kedudukan kewangan dan sumber-sumber lain kontraktor) menunjukkan penyebab yang tertentu dengan perubahan. Kata kunci: perubahan; kekerapan; keterukan; pembetungan; rangkaian; pengkhususan Variations in construction have long been a debatable issue among the different participants involved in construction projects. However, only a few formal studies have been carried out to analyse its couses and effects. This study is focused on the frequency and severity of various factors causing variations in sewerage networks construction projects. It is important for a company not only to know the variation costs, but also to identify the most likely areas on which to focus in order to reduce these costs for the future projects. All the necessary data and information are obtained from archival files of thirteen projects and verified through interviews. These data are categorised to analyse the frequency and severity of factors. Tables and charts are presented to show the research findings. From the analysis, differing site conditions appear to be the major factors contributing to variations. They average 49.3% of the total number of variations, 56.2% of the total variation costs and 3.8% of the total project costs. Two project characteristics i.e. contract award value and the contractor´s registration grade with the Construction Industry Development Board (which represents the contractor´s specialisation, financial and other resources standing) show certain causal relationships with variations. Key words: variation; frequency; severity; sewerage; network; specialisation

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