Development of Time-Cost Models for Building Construction Projects in Bangladesh

Abstract

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.

Construction time prediction model for public building projects

“…In comparison with the original BTC model (R 2 value of 0.376), the CUB time model (R 2 value of 0.487) has shown an improved result. This conclusion was also confirmed by the previous works,Assefa (2008),Long et al (2009), andRahman et al (2014).…”

“…Besides the validation BTC model, some researchers’ examined the best fitting curve estimation for the time-cost relationship. Rahman et al (2014) have shown that the exponential regression model has generated the maximum values of R 2 for commercial projects, while the cubic regression model is for all of the remaining characteristics of projects. Le-Hoai and Dai Lee (2009) also examined a curve fitting time-cost model for various categories of building projects in Korea and found that the cubic regression (CUB) model could be used to forecast the duration for various building projects, while the S -curve regression (SCU) model was suitable for negotiated tender projects.…”

Assessing the Suitability of Bromilow Time-Cost (BTC) Model to Predict Project Time on Road Construction Projects in Botswana

“…Bromilow (1969) Australia T = 211C 0.3 (Public) T = 156C 0.3 (Private) Bromilow (1974) Australia T = 313C 0.3 Chan (1991) Hong Kong T = 152C 0.29 (Unknown) Kaka and Price (1991) United Kingdom T = 398C 0.32 (Public) T = 274C 0.21 (Private) Yeong (1994) Yeong 1994Australia Malaysia T = 287C 0237 (Public) T = 161C 0.367 (Private) T = 269C 0:215 (public and Private) T = 518C 0.352 (Public) Kumaraswamy and Chan (1995) Hong Kong United Kingdom T = 216.3C 0.253 Public) T = 250C 0.215 (Private) T = 486.7C 0.205 (Public) Mak et al (2000) Australia T = 131C 0.131 (All types of project) Ng et al (2001) Australia T = 130C 0.310 (Public & private) Chan (2001) Malaysia T = 269C 0.315 (Public) Choudhry et al 2002Bangladesh T = 149C 0.27 (Private) Endut et al (2006) Malaysia T=303C 0.157( Public) Ogunsemi and Jagboro (2006) Nigeria T = 69C 0.255 (Public) Hoffman et al (2007) USA T = 26.8C 0.202 Zujo and Car-Pusic (2008) Bosnia and Herzegovina. T = 79C 0.41 (Public) Car-Pusic and Miladen 2009Croatia Bosnia Herzegovina T = 88C 0.54 T=70C 0.52 (New Construction) Le-Hoai et al (2009) Vietnam South Korea T = 94C 0.338 T = 341C 0.175 Ameyaw et al (2012) Ghana T = 3.17C 0.378 (Public) Rahman et al (2014) Bangladesh T = 156C 0.36 (Private) Mačková and Baskova (2014) Slovakia T = 384C 0.263 (Private) Adeyemi and Masalila (2016) Botswana T = 01.18C 0.362 (Gaborone City Council) Adeyemi and Motlakase (2020) Botswana T=14.111C 0.156 (Roads Department) In this study, R-Square is 0.283266. Even though the R 2 compares favourably with what is found in literature that R-squared is usually between 0.205 to 0.850 when BTC are compared among countries (Rahman et al 2014) , this value is rather weak to predict the project time (T).…”

“…T = 79C 0.41 (Public) Car-Pusic and Miladen 2009Croatia Bosnia Herzegovina T = 88C 0.54 T=70C 0.52 (New Construction) Le-Hoai et al (2009) Vietnam South Korea T = 94C 0.338 T = 341C 0.175 Ameyaw et al (2012) Ghana T = 3.17C 0.378 (Public) Rahman et al (2014) Bangladesh T = 156C 0.36 (Private) Mačková and Baskova (2014) Slovakia T = 384C 0.263 (Private) Adeyemi and Masalila (2016) Botswana T = 01.18C 0.362 (Gaborone City Council) Adeyemi and Motlakase (2020) Botswana T=14.111C 0.156 (Roads Department) In this study, R-Square is 0.283266. Even though the R 2 compares favourably with what is found in literature that R-squared is usually between 0.205 to 0.850 when BTC are compared among countries (Rahman et al 2014) , this value is rather weak to predict the project time (T).…”