In recent years, the frequency and severity of catastrophic events triggered by natural hazards have increased. Meanwhile, man-made hazards, such as terrorist attacks, and their impacts on infrastructure systems have gained increasing attention. These hazards (both natural and man-made) can cause catastrophic physical damage to transportation infrastructure systems that are essential to the wellbeing of the society. Moreover, the direct economic losses (e.g., physical damage to infrastructure) diffuse and expand continually through the disruption of economic activities between different regions and industries, resulting in enormous and complex indirect losses. A comprehensive investigation of total losses, including direct and indirect losses, requires the use of economic impact analysis models. However, most of the economic impact analysis methods and models introduced in the existing literature fail to incorporate the spatially distributed and networked nature of transportation infrastructures. To achieve a comprehensive and a realistic understanding of the economic impacts caused by the disturbances to the transportation infrastructure, the spatial distribution and the networked nature of transportation systems has to be accounted for, and realistic and locally relevant hazard scenarios must be incorporated into the economic analyses. This paper first provides a detailed account of the status-quo in economic modeling associated with impact analysis of transportation disturbances to identify the gaps in this domain. Next, focusing on the commuting related economic impacts of transportation disturbances as an example, the paper introduces a multidisciplinary framework designed to demonstrate an understanding on how to address the gaps. Preliminary results from a Los Angeles case study are presented.
The frequent natural hazards and their significant impacts in recent years have repeatedly highlighted the vulnerability of urban infrastructure systems and their lack of system resilience. The ever increasing interdependencies between urban infrastructure systems have further complicated the situation, causing considerable risks of failure propagation. Considering that the properties of urban infrastructure systems including their level of resilience are mainly determined at the design stage, the authors aim to propose a Quality Function Deployment ( QFD) based conceptual framework for designing resilient urban infrastructure system of systems ( SoS). As a preliminary effort towards this goal, this paper mainly focuses on developing the first matrix in the QFD based framework. Steps to identify resilience criteria and principles are presented, the questionnaire-based method to determine the main body of the first matrix is described, and the approach to work out practical design schemes is explained. Lastly, this paper summarizes the main strength of the proposed framework as well as its limitations, and discusses directions for future research.
Adaptive structures are sensed and actuated to modify internal forces and shape to maintain optimal performance in response to loads. The use of large shape changes as a structural adaptation strategy to counteract the effect of loads has been investigated previously. When large shape changes are employed, structures are designed to change shape as the load changes thus giving the opportunity to homogenize stresses. In this way, the design is not governed by peak loads that occur very rarely. Simulations have shown a significant amount of embodied energy can be reduced with respect to optimized active structures limited to small shape changes and with respect to passive structures. However, in these previous studies, the actuator layout was assigned a-priori. This paper presents a new method to search for an actuator layout that is optimum to counteract the effect of loads via large shape changes. The objective is to design the actuation system allowing the structure to 'morph' into shapes optimized to maximize material utilization for each load case. A combination of simulated annealing and the nonlinear force method is proposed to meet both the actuator placement problem and to determine appropriate actuator commands. A heuristic for near-neighbor generation based on the actuator control efficacy is employed to explore effectively the large search space. Case studies show the proposed method converges to the global optimum for simple configurations and generally produces actuator layouts enabling shape control even with a low number of actuators.
Construction, maintenance, and renewal of underground utilities ( e. g. gas, water and sewer pipes, and electrical and telecommunication cables) impose a large lifecycle cost on utility companies and the citizens of urban areas. Integrating all the utilities in a Multi-purpose Utility Tunnel ( MUT) can reduce post-construction costs of accessibility, inspection, maintenance, protection, and social costs. Although the high construction cost is an obstacle for promoting MUTs, post-construction cost savings make MUTs an economic alternative solution considering the total lifecycle costs. On the other hand, sharing the lifecycle cost of MUTs is another issue, particularly for the high initial investment in construction. Public-Private Partnership ( PPP) is a promising approach for sharing the lifecycle cost of MUTs among public and private investors and facilitating the development of MUT projects. This paper aims to develop a model for PPP financing and cost-sharing of MUT projects using game theory. The PPP investors need to investigate different scenarios for lifecycle cost-sharing and choosing the best strategy considering their financial situation. The proposed model is based on three steps: ( a) selection of MUT cost allocation method for MUT lifecycle phases, ( b) cost adjustment based on risk and benefit cost factors, ( c) game model of MUT cost-sharing based on an entity covering a part of the MUT construction cost using loans/bonds with a penalty that is used as a reward to the other entity. The results show that this model can improve the fairness of MUT cost allocation and be used as an analytical tool for the MUT project stakeholders to choose appropriate financing strategy based on anticipated lifecycle benefits and costs.
When using Building Information Modeling (BIM), it is expected to increase interorganizational collaboration in the construction industry. To reach this goal, it is necessary to use open standards for model exchange such as the Industry Foundation Classes (IFC). The non-profit organization buildingSMART defines this standard. IFC provides object types and attributes, which describe properties of objects. The IFC standard do not address possible values for attributes; but beside coordinated names for object types and attributes, coordinated values for attributes are required. This is necessary for the evaluation of digital models for different purposes. Several approaches in the fields of ontology and classification systems address this issue. However, at present time there is no clear distinction between prerequisites that modeled objects have to fulfill and products, which satisfy these requirements. Suppliers or construction companies at the interface between planning and construction propose products for the modelled requirements of the planning process. This paper describes an approach that bases on a dictionary, which provides standardized object types, attributes and values. A project database and a database with products, called supplier database, use this dictionary as a basis. Resulting from the modeling phase, the project database is ultimately mapped with the supplier database to propose products that fulfill the requirements. The approach presented in this paper can be regarded as a next step in using a standard that already exists: the buildingSMART Data Dictionary.
