Delay is the most common problem in the construction industry. It has many negative effects on project's success in terms of time, cost, quality, and safety. From the literature review, a total of thirty-five factors of delay were selected. These factors were divided into seven groups related to materials, manpower, owner, consultant, contractor, construction, and external problems. This study was carried out to identify the main causes of delay for a construction project through their importance level. The importance level was determined based on the frequency of occurrence and severity of impact. The structured questionnaire has distributed to the respondents who have much experience in construction management in Bangladesh. The results of analysis indicated that top five factors of construction delay according to their level of importance are: (1) price of construction materials increased very rapidly, (2) political situation (revolution/ public strikes), (3) shortages of skilled workers, (4) poor site management and supervision by contractor, (5) incompetent/ immature subcontractors. These findings of this study are expected to be significant contributions to Bangladesh construction industry in controlling current performance of project on time overrun.

Estimating time and cost is an important mission in the early phase of a construction project, especially in feasibility study. It provides a foundation for making decision whether or not the project is performed on schedule and within budget. Thus, reliability of this estimate plays a key role in measuring the success of a project. This study was carried out to investigate the timecost relationship in building construction projects in Bangladesh. The mathematical equation used in this study is based on Bromilow's equation. The research data were collected from sixty-three completed building projects through questionnaire survey. Type of clients, type of projects, and tender methods are the project characteristics considered in this study. The results of analysis indicated that the Bromilow's time-cost (BTC) models developed for each project characteristic are appropriate due to quite high coefficient of determination and relatively small mean percent errors. Among them, the forecasted model for time and cost according to tender methods is the best fit model. It is concluded that the BTC model could be applied in building construction project to predict its time and cost in Bangladesh. Four different regression models were also developed in this study. The results of BTC model between some selected countries were compared to gain the comprehensive view.