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In smaller projects with limited resources, schedule updates are often not performed. In these situations, traditional delay analysis methods cannot be used as they all require updated schedules. The objective of this study is to develop a model that performs delay analysis by using only an as-planned schedule and the expense records kept on site.

This study starts out by developing an approach that estimates activity duration ranges in a network schedule by using as-planned and as-built s-curves. Monte Carlo simulation is performed to generate candidate as-built schedules using these activity duration ranges. If necessary, the duration ranges are refined by a follow-up procedure that systematically relaxes the ranges and develops new as-built schedules. The candidate schedule that has the closest s-curve to the actual s-curve is considered to be the most realistic as-built schedule. Finally, the as-planned vs. as-built delay analysis method is performed to determine which activity(ies) caused project delay. This process is automated using Matlab. A test case is used to demonstrate that the proposed automated method can work well.

The automated process developed in this study has the capability to develop activity duration ranges, perform Monte Carlo simulation, generate a large number of candidate as-built schedules, build s-curves for each of the candidate schedules and identify the most realistic one that has an s-curve that is closest to the actual as-built s-curve. The test case confirmed that the proposed automated system works well as it resulted in an as-built schedule that has an s-curve that is identical to the actual as-built s-curve. To develop an as-built schedule using this method is a reasonable way to make a case in or out of a court of law.

Practitioners specifying activity ranges to perform Monte Carlo simulation can be characterized as subjective and perhaps arbitrary. To minimize the effects of this limitation, this study proposes a method that determines duration ranges by comparing as-built and as-planned cash-flows, and then by systematically modifying the search space. Another limitation is the assumption that the precedence logic in the as-planned network remains the same throughout construction. Since updated schedules are not available in the scenario considered in this study, and since in small projects the logic relationships are fairly stable over the short project duration, the assumption of a stable logic throughout construction may be reasonable, but this issue needs to be explored further in future research.

Delays are common in construction projects regardless of the size of the project. The critical path method (CPM) schedules of many smaller projects, especially in developing countries, are not updated during construction. In case updated schedules are not available, the method presented in this paper represents an automated, practical and easy-to-use tool that allows parties to a contract to perform delay analysis with only an as-planned schedule and the expense logs kept on site.

Since an as-built schedule cannot be built without updated schedules, and since the absence of an as-built schedule precludes the use of any delay analysis method that is acceptable in courts of law, using the method presented in this paper may very well be the only solution to the problem.

Delays represent one of the most critical factors that affect the cost of a construction project. They have to be therefore analysed comprehensively using appropriate techniques. The purpose of this paper is to find out the delay analysis techniques (DATs) that are most commonly used in road projects in Sri Lanka, the extent of their usage, the criteria that can be used in selecting them and the technique that is most appropriate for the selection.

The research methodology adopted included an extensive literature review, expert interviews and a questionnaire survey.

In road projects in Sri Lanka, five types of DATs are mainly used. The “As-planned v. As-built Analysis” technique is the most commonly used technique while “Window Analysis” is the least used technique. Out of the nine criteria identified for selecting a DAT, the most important criterion is the acceptability of the technique to courts and tribunals. “Window Analysis” was found to be the most appropriate DAT that can be used in road construction projects in Sri Lanka.

“Window Analysis” can be recommended as the most appropriate DAT for road projects in Sri Lanka.

This study aims to detect the most appropriate delay analysis method in mega airport projects.

First, the criteria affecting the selection of delay analysis methods were detected through an in-depth literature review and an expert panel, which was conducted with 12 experts who have experience in delay analysis domain in mega airport projects. Later, fuzzy VIKOR (VIsekriterijumska optimizacija i KOmpromisno Resenje) approach was conducted by considering the detected selection criteria and the most common delay analysis methods.

Windows Analysis method was detected as the best option for mega airport projects. It was followed by Time Impact Analysis (TIA), collapsed as-built analysis, as-planned vs as-built method and impacted as-planned method, respectively.

Each project has its own characteristics and thus requires specific management techniques; therefore, selecting a delay analysis method without considering the project types and size may cause conflicts between the contracting parties. On the one hand, numerous fruitful studies concerning delay analysis methods have been conducted in the literature, but on the other hand, none of them has considered project characteristics in terms of project size and type while selecting the most appropriate delay analysis method. Moreover, the larger the size of a project is, the more vulnerable it is to encounter with delays. Mega airport construction projects are complex in their nature in that they are large size and involve multi-disciplinary processes; thus, they need special attention in the process of resolving delays. This study intended to fill this gap in the literature by focusing on selection of the most appropriate delay analysis method for mega airport projects, and it is clear that considering the project type and size in the selection of delay analysis methods will provide more reliable outcomes.

The purpose of this research is to develop a generic framework of a digital twin (DT)-based automated construction progress monitoring through reality capture to extended reality (RC-to-XR).

IDEF0 data modeling method has been designed to establish an integration of reality capturing technologies by using BIM, DTs and XR for automated construction progress monitoring. Structural equation modeling (SEM) method has been used to test the proposed hypotheses and develop the skill model to examine the reliability, validity and contribution of the framework to understand the DRX model's effectiveness if implemented in real practice.

The research findings validate the positive impact and importance of utilizing technology integration in a logical framework such as DRX, which provides trustable, real-time, transparent and digital construction progress monitoring.

DRX system captures accurate, real-time and comprehensive data at construction stage, analyses data and information precisely and quickly, visualizes information and reports in a real scale environment, facilitates information flows and communication, learns from itself, historical data and accessible online data to predict future actions, provides semantic and digitalize construction information with analytical capabilities and optimizes decision-making process.

The research presents a framework of an automated construction progress monitoring system that integrates BIM, various reality capturing technologies, DT and XR technologies (VR, AR and MR), arraying the steps on how these technologies work collaboratively to create, capture, generate, analyze, manage and visualize construction progress data, information and reports.

This paper aims at improving progress tracking and control of repetitive projects by developing a novel framework that automates the documentation of as-built information directly into the project schedule and also introduces enhanced linear scheduling formulation to support project control decisions.

The proposed framework uses e-mail technology to facilitate detailed tracking of daily as-built events of all parties through bidirectional communication between site and head office. It also provides a new formulation for more accurate critical path and linear scheduling computation to accurately update the project's time and cost during construction.

Using a case study of a road project, the paper proves that the proposed framework reduces as-built documentation effort and its schedule updates are more responsive to all as-built events than traditional scheduling techniques.

The proposed method applies to linear projects (e.g. highways) and can be extended to other repetitive projects such as high-rise buildings. It can also be extended to include voice features and procedures for forensic schedule analysis.

The developed methodology presents a low-cost approach to document timely progress information for decision makers of massive linear projects (often associated with infrastructure) to have better control over the execution of projects, save documentation time and cost, and avoid disputes and problems.

This research contributes in improving construction productivity by collecting timely as-built information using affordable communication technologies. It also presents novel advancements to the existing scheduling and control techniques to suit linear projects, which are most challenging.

When construction delays occur, it is necessary to ascertain the liabilities of the contracting parties and to direct the appropriate amount of resources to recover the schedule. Unfortunately, delay analysis and schedule compression are normally treated as separate or independent aspects. This paper examines the feasibility of integrating the delay analysis and schedule compression functions into a broad‐scoped two‐stage process. The main issue is shown to be the kind of delay analysis required for each stage of the process and seven existing techniques are illustrated for use in conjunction with schedule compression. Since the current form and assumptions of delay analysis techniques are unlikely to provide the necessary level of feedback reliability for recovering delays, it is necessary to modify these techniques by incorporating some means of delay type scrutiny, excusable delays updating, and treatment of concurrent delays. The modified delay analysis techniques can serve as a basis for negotiation between the client and contractor and hence improve the interdisciplinary relations.

Prompt and effective responses to incompatibilities between as-designed and as-built drawings prevent cost and time overruns and material waste. This paper aims to provide an efficient framework to handle mismatches between these two models with the least negative impact on the whole project.

First, 11 most frequent mismatches were identified through questionnaires. Also, the respondents were asked to determine the mismatches’ roots and solutions and the impact of applying solutions on the whole project. Afterward, the process to present the optimum solution to one of these mismatches was modeled. After running the application programming interface developed in Navisworks software, decision-makers access a form, showing mismatches, their causes and solutions, as well as the solutions’ effect. To finalize the optimal solution, a platform was provided on whether to accept the system solution or to propose an alternative.

To empirically validate the reliability of the proposed framework, two projects were investigated. Two different approaches to dealing with the same mismatch occurred in these projects were compared in terms of time, cost and material required. The results showed that addressing the mismatches through the proposed framework can efficiently enhance time, cost and material consumption, in comparison with the traditional approach.

There is currently no building information modeling-based holistic framework for managing mismatches between as-designed and as-built drawings. The results of this research can help contractors to make the best decision, saving project resources, when setting about a mismatch during construction.

This paper aims to propose an automatic imaging network design to improve the efficiency and accuracy of automated construction progress monitoring. The proposed method will address two shortcomings of the previous studies, including the large number of captured images required and the incompleteness and inaccuracy of generated as-built models.

Using the proposed method, the number of required images is minimized in two stages. In the first stage, the manual photogrammetric network design is used to decrease the number of camera stations considering proper constraints. Then the image acquisition is done and the captured images are used to generate 3D points cloud model. In the second stage, a new software for automatic imaging network design is developed and used to cluster and select the optimal images automatically, using the existing dense points cloud model generated before, and the final optimum camera stations are determined. Therefore, the automated progress monitoring can be done by imaging at the selected camera stations to produce periodic progress reports.

The achieved results show that using the proposed manual and automatic imaging network design methods, the number of required images is decreased by 65 and 75 per cent, respectively. Moreover, the accuracy and completeness of points cloud reconstruction is improved and the quantity of performed work is determined with the accuracy, which is close to 100 per cent.

It is believed that the proposed method may present a novel and robust tool for automated progress monitoring using unmanned aerial vehicles and based on photogrammetry and computer vision techniques. Using the proposed method, the number of required images is minimized, and the accuracy and completeness of points cloud reconstruction is improved.

To generate the points cloud reconstruction based on close-range photogrammetry principles, more than hundreds of images must be captured and processed, which is time-consuming and labor-intensive. There has been no previous study to reduce the large number of required captured images. Moreover, lack of images in some areas leads to an incomplete or inaccurate model. This research resolves the mentioned shortcomings.

A scheduling and progress control system called Photo‐net is introduced where a digital movie of construction activities can be played back along with an animation of as‐built vs. as‐planned performance of these activities. A technique to make time‐lapse digital films of construction activities is used. A method to store a digital film is developed allowing thousands of pictures to be stored and managed in a Windows environment. A program is developed that generates critical path method (CPM) derived bar‐charts. A recording system is devised enabling the user to specify the day‐by‐day progress achieved in construction activities, allowing the program to link the playback film with the progress observed on the construction site. A set of input screens are generated by the system that provide a friendly, intuitive and easy way to enter project data. A case study is presented where the system is used, the performance of the system is discussed and the results are analyzed.

Construction projects commonly encounter complicated delay problems. Over the past few decades, numerous delay analysis methods (DAMs) have been developed. There is no consensus on whether existing DAMs effectively resolve delays, particularly in the case of complex concurrent delays. Thus, the primary objective of this study is to undertake a comprehensive and systematic literature review on concurrent delays, aiming to answer the following research question: Do existing delay analysis techniques deal with concurrent delays well?

This study conducts a comprehensive review of concurrent delays by both bibliometric and systematic analysis of research publications published between 1982 and 2022 in the Web of Science (WoS) and Scopus databases. For quantitative analysis, a bibliometric mapping tool, the VOSviewer, was employed to analyze 68 selected publications to explore the co-occurrence of keywords, co-authorship and direct citation. Additionally, we conducted a qualitative analysis to answer the targeted research question, identify academic knowledge gaps and explore potential research directions for solving the theoretical and practical problems of concurrent delays.

Concurrent delays are a critical aspect of delay claims. Despite DAMs developed by a limited number of research teams to tackle issues like concurrence, float consumption and the critical path in concurrent delay resolution, practitioners continue to face significant challenges. This study has successfully identified knowledge gaps in defining, identifying, analyzing and allocating liability for concurrent delays while offering promising directions for further research. These findings reveal the incompleteness of available DAMs for solving concurrent delays.

The outcomes of this study are highly beneficial for practitioners and researchers. For practitioners, the discussions on the resolution process of concurrent delays in terms of identification, analysis and apportionment enable them to proactively address concurrent delays and lay the groundwork for preventing and resolving such issues in their construction projects. For researchers, five research directions, including advanced DAMs capable of solving concurrent delays, are proposed for reference.

Existing research on DAMs lacks comprehensive coverage of concurrent delays. Through a scientometric review, it is evident that current DAMs do not deal with concurrent delays well. This review identifies critical knowledge gaps and offers insights into potential directions for future research.