Method for Base Estimation of Construction Time for Linear Projects in Front-end Project Phases

Even though horizontally linear projects have low complexity schedules, they are still not successful in meeting planned time. The deadlines are mostly based on estimations done in front-end project development when limited data are available. Early time estimation models in literature rely on few variables and, almost in all cases, one of them is the estimated cost. Early cost estimations can significantly deviate from actual costs and thus lead to unreliable time estimation. Time estimation models based on neural network and other alternative methods require databases and software, which complicates the process of time estimation. The purpose of this paper is to bridge the gap of scarce time estimation models and unreliable time estimates by developing a new method for time estimation. This research has been done on one large sewer system project. The case study shows how to extract several continuous activities for a pipeline project chosen from a sewer system. Moreover, a new algorithm for the calculation of project duration is devised based on the existing equation related to the linear scheduling method, and this algorithm works with continuous activities. The new method for construction time estimation is based on the extraction of linear continuous activities, usage of the algorithm for identification of minimal buffer between activities, and calculation of the project duration. To verify the algorithm, this method is used on another pipeline project from a sewer system. The limitation is that this method can be used only for base estimation. Further research needs to be done to include uncertainties and risks in the method

Internal and external risk based assesment and evaluation for the large infrastructure projects

The level of sensitivity to project success of large infrastructure projects is significantly greater in front-phase than in execution phase. Yet, due to focus on execution phase, methods for project assessment and on-going evaluation during front phases are insufficiently developed. On the other hand, risk management approaches has been moved from risk management towards holistic uncertainty management which is the most beneficial in front end phase of the project. This research identifies that majority of methods and techniques available does not support uncertainty management concept. The purpose of this paper is to develop and new method for risk based project assessment and evaluation inte­grating risk impact modelling using cumulative distribution curves (CDC) and multi-criteria project evaluation approach. Research is based on in-depth risk analysis of 15 large infrastructure projects using risk model of components and char­acteristics. The conclusion of the paper is verification and validation of method that combines qualitative and quantita­tive analysis using risk components, risk breakdown structure, AHP method and risk impact modelling using cumulative distribution curves (CDC) for internal and external risk based assessment and evaluation of large infrastructure projects

Method for Base Estimation of Construction Time for Linear Projects in Front-end Project Phases

Even though horizontally linear projects have low complexity schedules, they are still not successful in meeting planned time. The deadlines are mostly based on estimations done in front-end project development when limited data are available. Early time estimation models in literature rely on few variables and, almost in all cases, one of them is the estimated cost. Early cost estimations can significantly deviate from actual costs and thus lead to unreliable time estimation. Time estimation models based on neural network and other alternative methods require databases and software, which complicates the process of time estimation. The purpose of this paper is to bridge the gap of scarce time estimation models and unreliable time estimates by developing a new method for time estimation. This research has been done on one large sewer system project. The case study shows how to extract several continuous activities for a pipeline project chosen from a sewer system. Moreover, a new algorithm for the calculation of project duration is devised based on the existing equation related to the linear scheduling method, and this algorithm works with continuous activities. The new method for construction time estimation is based on the extraction of linear continuous activities, usage of the algorithm for identification of minimal buffer between activities, and calculation of the project duration. To verify the algorithm, this method is used on another pipeline project from a sewer system. The limitation is that this method can be used only for base estimation. Further research needs to be done to include uncertainties and risks in the method