A bayesian belief networks approach to risk control in construction projects

Although risk control is a key step in risk management of construction projects, very often risk measures used are based merely on personal experience and engineering judgement rather than analysis of comprehensive information relating to a specific risk. This paper deals with an approach to provide better information to derive relevant and effective risk measures for specific risks. The approach relies on developing risk models to represent interactions between risk factors and carrying out analysis to identify critical factors on which risk measures must focus. To ameliorate the problem related to the scarcity of risks information often encountered in construction projects, Bayesian Belief Networks are used and expert knowledge is elicited to augment available information. The paper describes proposed modifications to the standard methods used to develop Bayesian Belief Networks in order to deal with divergent information originated from epistemic uncertainty of risks. The\ud capacity of the proposed approach to provide better information to support risk related decision making is verified by means of an illustrative application to risk factors involved in the construction of cross passages between tunnels tubes in soft soils

Relevant risk factors associated with the construction of excavated tunnel cross-passages in soft soils

This paper reports on an investigation of risk factors associated with the construction of excavated tunnel cross-passages in soft soils. The investigation focused on excavations where freezing technologies are used to provide temporary support. The relevant risk factors and their associated probabilistic data were gathered from elicitation of experts. A ranking of the most important factors was obtained for an on-going project: Sluiskil tunnel in the Netherlands. This was made possible by modelling the risk factors using Bayesian Belief Networks. Based on the modelling results the project has increased its awareness of the relevant risk factors in the construction of cross- passages and further optimized the associated mitigation measure

Using 4D CAD to visualize the impacts of highway construction on the public

Highway construction activities have a multitude of impacts on the public that change over time and with location. In devising strategies to manage and minimize these impacts, gaining an in-depth understanding about timing and spatial extents of them is crucial. However, in practice gaining such understanding is difficult due to the complex and varying nature of the impacts. To support project planners with understanding a highway construction project's impacts upfront, we developed a 4D modeling method that visualizes the most important attributes of the impacts on the public, namely their spatial extents and their progression over time. By applying the method to support a Dutch highway expansion project, we show that, compared to 2D methods, the proposed 4D modeling method provides an integral perspective of the spatial changes of the project impacts over time that allows for the evaluation of various scenarios with relative ease

A model for the automated generation of earthwork planning activities

A review of techniques used in industry showed that there is an absence of a formalised, systematic approach to earthworks planning. The techniques used tend to be subjective and time consuming with a heavy reliance given to the experience and knowledge of the planner. This absence of a formalised technique can lead to inaccurate planning and makes explanation of the techniques difficult. This paper describes the development of a new automated approach for use by the planners to generate earthworks activities that overcomes such limitations. As well as creating activity sets in a much shorter time, the ability to compare various sets allows the planner more scope when planning earthworks. The model is able to generate activity sets that are comparable to those generated by a project planner.\ud \u

Design of a Human Reliability Assessment model for structural engineering

It is generally accepted that humans are the “weakest link” in structural design and construction processes. Despite this, few models are available to quantify human error within engineering processes. This paper demonstrates the use of a quantitative Human Reliability Assessment model within structural engineering. The model consists of four steps. In the first step the process and its boundary conditions are identified. In the second step, the effect of human error on a single task is defined. In the third step, these effects are combined into an overall effect on the engineered structure. Finally, the structural failure probability is estimated by combining the strength and loading conditions by means of a Monte Carlo simulation. The use of the model is demonstrated using a case study based on the design process of a frame structure. This case study shows that the model has the potential to quantify the effect of human errors within carefully defined boundary conditions.OTB ResearchOTB Research Institute for the Built Environmen