Due to the inherent risks and increasing complexity of modern construction projects, delays and cost overruns have become common facts in the industry. Researchers and practitioners have used many techniques to assess project delays and apportion delay responsibility among the parties involved. Windows delay analysis has been recognized as one of the most credible techniques for analyzing construction delays. Despite its benefits, windows analysis can produce different results depending on the window size, it does not consider owner and contractor acceleration, it does not systematically consider the impact of several baseline updates made due to changes in the duration and logical relationships of the activities, and it does not consider the impact of the progress events on resource over-allocation and its consequent delays. This study proposes a computerized schedule analysis model that considers multiple baseline updates and resource over-allocation. The model uses a daily window size in order to consider all fluctuations in the critical path(s) and uses a legible representation of progress information to accurately apportion delays and accelerations among project parties. To facilitate its use, the model has been incorporated into a computer tool, EasyPlan, which integrates estimating, scheduling, resource management, and project control. A simple case study has been implemented on the proposed delay analysis model in order to demonstrate its accuracy and usefulness.

Due to the inherent risks and increasing complexity of modern construction projects, delays and cost overruns have become common facts in the industry. Researchers and practitioners have used many techniques to assess project delays and apportion delay responsibility among the parties involved. Windows delay analysis has been recognized as one of the most credible techniques for analyzing construction delays. Despite its benefits, windows analysis can produce different results depending on the window size, it does not consider owner and contractor acceleration, it does not systematically consider the impact of several baseline updates made due to changes in the duration and logical relationships of the activities, and it does not consider the impact of the progress events on resource over-allocation and its consequent delays. This study proposes a computerized schedule analysis model that considers multiple baseline updates and resource over-allocation. The model uses a daily window size in order to consider all fluctuations in the critical path(s) and uses a legible representation of progress information to accurately apportion delays and accelerations among project parties. To facilitate its use, the model has been incorporated into a computer tool, EasyPlan, which integrates estimating, scheduling, resource management, and project control. A simple case study has been implemented on the proposed delay analysis model in order to demonstrate its accuracy and usefulness.

Inadequate or weak preparatory work before starting construction of any structure may cause serious problems during the construction period. For example, projects without sufficient detailed drawings or construction schedules and a disorganized building site can create many problems in the management and completion of the construction works. Consequently, the cost of construction increases digressively, the construction duration of the project extends and the quality of construction is affected adversely. This study dwells on the importance of construction schedules in achieving the aim of producing good quality construction work within the specified duration. Monitoring continuously the interactive relation concerning delays in construction schedules and contractor demands is a complicated process. Here the simplest and basic approach is that, both for owner and contractor, time is money and for this reason construction schedule delays should be analyzed and corrective measures should be taken in a timely manner. The main purpose of this study is to investigate the causes of construction schedule delays and the methods of schedule delay analyses. In this context completion construction works of a covered swimming pool building in Ankara was selected as a case study for analyzing project scheduling and the delays therein. The &ldquo / Time Impact Analysis Method&rdquo / (TIA) was applied to the case study project using PRIMAVERA&reg / software in order to determine the construction schedule delays / to measure the impacts of these delays on the project completion duration / and to allocate responsibility amongst the project participants for preventing delay claims. After the application of the delay analysis it was observed that the delays in the critical activities extended the project duration by 57 days in total i.e. by 15.4 % of the estimated construction period. Fines should have been paid by the contractor because of 31-days non-excusable delays. Also, the contractor should have been given a time extension of 26-days due to 22-days excusable compensable delays and 4-days excusable non-compensable delays which were beyond the control of the contractor. These delays were caused due to organizational deficiencies of the owner, the bureaucracy of the provincial municipality, the lack of detail drawings during the municipality application, the lack of experience of the contractor, problems in material procurement, unforeseeable weather conditions and shortages of qualified employees of the subcontractors. It was observed that of these all except one correspond to the important causes of delays as reported in literature concerning public projects in Turkey.

ABSTRACT QUANTIFICATION OF ACCELERATION CLAIMS: A SIMPLIFIED APPROACH Operating a successful business within the construction industry has become more difficult for companies as the profitability margins decreased considerably compared to previous years. Even, global economy has created an environment in which construction firms are enforced to bid projects at or below lowest profit levels. At the same time, owners are demanding more difficult projects without increasing the quality of contract documents. This has placed an added burden on the individual contractor to construct sophisticated projects. Under these circumstances, it is not surprising that the number of disputes within the construction industry continues to increase. Thus, contractors requested additional payments from the owners and the concept of claim and claim management developed. However, implementation of a well developed claim management process is crucial as the consequences and reimbursement depends on this process. The objective of this study is to discuss potential sources of disputes and types of claims in the construction industry by focusing on acceleration claims. Quantification methods for owner directed acceleration are discussed as well as required documentation and claim management strategies for preparation of acceleration claims. Two different methods, namely theoretical approach and simplified approach, are presented here and examined in detail mentioning their advantages and shortcomings. These methods are applied to two different real cases, one in Turkey and the other one is abroad in order to have a better understanding of these approaches. Furthermore, a computer program is developed to carry out the calculations that constitute the necessary steps of simplified quantification method. This study can be considered as a complete guide for young civil engineers about quantification and management of acceleration claims.

Project risk assessment is an effective tool for planning and controlling cost, time and achieving the technical performance of a building construction project. Construction projects often face a lot of uncertainties, which places building construction projects at the risk of cost, time overruns as well as poor quality delivery. Considering the limited resources of developing countries, there is need to complete building projects on-time, on-budget, and to meet optimal quality hence, risk management is an important part of the decision making process in construction industry as it determines the success or failure of construction projects. In line with this need, this research aims to establish a system to improve the time, cost and quality performance of building construction projects in developing countries, through a comprehensive risk management model that ensures the expectations of clients are met. To achieve the aim of this research, a mixed methodological approach was adopted. Through the review of literature, a conceptual risk management framework suitable to elaborate risk assessment of building construction projects especially for developing countries was developed. A questionnaire survey using a nonprobability sampling technique was conducted to elicit information from construction professionals in Nigeria to assess their perception of 79 risk factors identified from literature review based on the likelihood of occurrence and impact on projects using a five point scale. Responses from 343 construction professionals were drawn from 305 contractors and subcontractors and 38 clients (private and public) within the Nigerian construction sector. Response data was subjected to descriptive statistics to depict the frequency distribution and central tendency of responses. Subsequently, the risk acceptability matrix (RAM) was adopted to categorise and prioritise risk factors. 27 critical risks that affect building construction projects were identified. A Bayesian Belief Network (BBN) model was developed by structural learning and used to examine the cause and effect relationship amongst the 27 critical risk factors. The developed BBN model was subjected to validation using a multiple case study of two building construction projects in Nigeria. The result showed the interrelation between the 27 risk factors and how they contributed to cost and time overruns as well as quality problems. The critical risks directly affecting the cost of building construction project were: fluctuation of material prices; health and safety issues; bribery and corruption; material wastage; poor site management and supervision; and time overruns. The critical factors identified to directly affect quality were: supply of defective materials; working under harsh conditions; improper construction methods; lack of protective equipment; ineffective time allocation; poor communication between involved stakeholders; and unsuitable leadership style. Time overruns on building construction projects was directly caused by: quality problems; low productivity; improper construction methods; poor communication between involved parties; delayed payments in contracts; and poor site management and supervision. As a consolidation of the findings of this research, a BBN model for identifying risk factors that directly affect time, cost and quality on building construction projects has been developed which has the potential for assisting construction stake holders to manage risks on their projects. In view of the findings, a best practice system for risk management in building construction projects in Nigeria has been developed with an implementation guide to help building construction practitioners to successfully implement risk management on their building construction projects. Suitable risk responses, also in the form of recommendations have been identified. The strategies include actions to be taken to respond to risks based on their perceived significance or acceptability as well as some positive risk responses, such as exploiting, sharing, enhancing and accepting, and other negative risk responses, such as avoidance, mitigation transfer and acceptance.