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I.C. Wu, A. Borrmann, E. Rank, U. Beißert & M. König

A Pattern-Based Approach for Facilitating Schedule Generation and Cost Analysis in Bridge Construction Projects

Abstract: The paper presents a computational method to help in automating the generation of time schedules for bridge construction projects. The method is based on the simulation of the construction works, taking into account the available resources and the interdependencies between the individual tasks. The simulation is realized by means of the discrete-event based simulation software originally created for plant layout in the manufacturing industry. Since the fixed process chains provided there are too rigid to model the more spontaneous task sequences of construction projects, a constraint module that selects the next task dynamically has been incorporated. The input data of the constraint module is formed by work packages of atomic activities. The description of a work package comprises the building element affected, the required material, machine and manpower resources, as well as the technological pre-requisites of the task to be performed. These input data are created with the help of a 3D model-based application that enables to assign process patterns to individual building elements. A process pattern consists of a sequence of work packages for realizing standard bridge parts, thus describing a construction method which in turn represents a higher level of abstraction in the scheduling process. In the last step, the user specifies the available resources. The system uses all the given information to automatically create a proposal for the construction schedule, which may then be refined using standard scheduling software.

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Full text: content.pdf (384,072 bytes) (available to registered users only)

Series: w78:2009 (browse)
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Jiwen Zhang, Tim Taylor, Roy Sturgill, Gabe Dadi and Nikiforos Stamatiadis

Predictive Risk Modeling of Differential Bridge Settlement

Abstract: Differential settlement between the roadway pavement resting on embankment fill and the bridge abutment built on more rigid foundation often creates a bump when driving from roadway to bridge, and vice versa. This paper studies the problem at a macroscopic level by determining a method to predict the levels of approach settlement to assist designers in developing remediation plans during project development to minimize the lifecycle costs of bridge bump repairs. A macro method considering a combination of maintenance times, maintenance measures, and observed settlement was used to classify the differential settlement scale as minimal, moderate, and severe. A set of project characteristics including approach, abutment type, embankment, foundation, and traffic volume that may influence the formation of differential settlement were identified and used as parameters to develop a model to predict the settlement severity for a given approach. Logistic regression analyses were implemented to identify the relationships between the levels of differential settlement and the input variables for a sample of 600 randomly selected bridges in Kentucky. Geographic region, approach age, average daily traffic, and the use of approach slabs are identified as the four most predominant factors that can significantly affect the formation of differential settlement. Based on the performance of bridge approaches in Kentucky, how those parameters interacted in the prediction model is illustrated in the logistic regressions.

Keywords: Differential Settlement, Logistic Regression, Prediction Model

DOI: https://doi.org/10.24928/JC3-2017/0060

Full text: content.pdf (338,728 bytes) (available to registered users only)

Series: jc3:2017 (browse)
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Lavrencic,Darko

THE INTRACRANIOVERTEBRAL VOLUMES, THE CEREBROSPINAL FLUID FLOW AND THE CEREBROSPINAL FLUID PRESSURE, THEIR HOMEOSTASIS AND ITS PHYSICAL REGULATION

Abstract: Preface. After publication of the presented hypothesis some predictions were verified independently by other authors: (1) Monro-Kellie "four compartments" doctrine, (2) relation between CSF formation and CSF removal in physiological phase as presented with illustrative curves, (3) hypovolemia during intracranial hypotension syndrome, (4) increased CSF proteins in decreased CSF flow and (5) influence of neuro-vegetative system on CSF pressure. The predictions not yet verified: (1) turning points B-low and B-high that represent physiological borders, (2) pathophysiological self-sustaining phases of low and high CSF pressure with corresponding minimal or maximal CSF volume (maximal dural sac collapse or distension) and no CSF transport, (3) compensated and de-compensated conditions. None of the predictions were disproved yet. The purpose of this presentation on the INTERNET is to promote further discussions about unverified predictions and to encourage clinical research and experimenting in this direction. Summary. Physiological and pathophysiological processes in the intracraniovertebral space are specific because of its rigid and constant volume (Monro-Kellie doctrine). The hypothesis presents how the homeostasis of the intracraniovertebral compartments' volumes, cerebrospinal fluid (CSF) flow and CSF pressure is physically regulated. The hypothesis takes into account the quantitative and qualitative relations regulating CSF formation and CSF removal on which the homeostasis is based.

Keywords: cerebrospinal,fluid,intracranial,hydrodynamics,formation,production,reabsorption,pressure,hypothesis,flow,homeostasis,physical,CSF,hypotension,hypertension,circulation,dural,sac,sinuses,venous,sinuses,extradural,epidural,chorioideus,plexus,hypovolemia,hydrocephalus,subarachnoidal,space,ventricles,arachnoidal, villi,granulations,cribriform,plate,canalis,centralis

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Full text: content.lavrenč (696,205 bytes) (available to registered users only)

Series: other (browse)
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Lottaz C, Stouffs R, Smith I

Increasing Understanding During Collaboration Through Advanced Representations

Abstract: Efforts to provide support for collaborative work in the AEC industry have resulted in systems that offer various levels of assistance. Although some systems support information transfer in a wide range of formats, they offer little in terms of decision support such as conflict management and negotiation. Other systems provide more decision support but require strict formats for information input and transfer. Nearly all current proposals offer very limited facilities for viewing information. The objective of this paper is to present an environment which has been specifically designed for multiple ways to represent and manipulate information. Several representations, when coupled with appropriate visualization techniques, lead to opportunities for increasing understanding of AEC project characteristics. More specifically, when a numerical constraint solver (SpaceSolver) is integrated within a document-centric collaboration environment (ICC), synergies between information exchange and solution space exploration contribute very positively to the quality of projects. In particular, the ICC environment provides a framework for representing and visualizing information structures that are created during collaboration. Conceptually, an information architecture and visualization techniques to support the virtual AEC enterprise are emphasized. A plug-in architecture allows for the addition of process- specific functionality. The constraint solver SpaceSolver presents a complementary collaborative approach, with strict semantics to support decision making and conflict management. The use of solution spaces during collaborative negotiation avoids premature decisions in the design process, allows detection of conflicting project requirements at early stages of the project, and increases the designers' understanding of hidden relations between design parameters. Together, the ICC environment supports the management of an information space that, when linked to a constraint satisfaction problem, can explain important restrictions and decisions for an effective negotiation. The combination of a flexible framework with more rigid modules, such as constraint solvers, provides a useful compromise and, thus, comprehensive support for a range of AEC projects. Two recently completed construction projects are used to validate the approach

Keywords: collaboration, negotiation, electronic document management, information architecture, information visualization, feedback.

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Full text: http://www.itcon.org/2000/1 (available to registered users only)

Series: itcon:2000 (browse)
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Manu Venugopal, Charles Eastman, Rafael Sacks, Ivan Panushev, Vahideh Aram

Engineering Semantics of Model Views for Building Information Model Exchanges Using IFC

Abstract: The data schema of the Industry Foundation Classes (IFC) schema is generic, designed to support the full range of model exchanges needed in the construction industry. While it has a rich ontology of building part entities and relationships, it does not impose any fixed structure on the ways in which entities should be aggregated or represented, with the exception of the project-building-space containment hierarchy. Thus the IFC model, in and of it-self, is inadequate for ensuring interoperability between software applications. For any given set of use cases for a sub-domain of building construction, a set of model view definitions (MVD) is required to specify exactly what information should be exchanged, and in what form and structure the IFC entities are to be used. Compiling a model view definition, presently based on human intuition of industry knowledge, is challenging. What should be the level of detail to be included in case of geometry, classification and aggregations, and parts and relationships etc.? IFC, which is based on STEP and is represented in EXPRESS language, is known to be good in expressivity but lacks in a formal definition of its concepts. Thus in preparing a set of MVDs, information modellers must determine the appropriate level of meaning to require and they must define the typing structure to be used. If the structure is too simple, the exchanges will only have value for importing software able to apply some level of expert knowledge to interpret the information. If it is too rigid, then it will only be appropriate for a narrow range of use case exchanges and a large number of model view definitions will be required, which also implies that software companies will need to prepare multiple export and import routines. This paper discusses the spectrum of possibilities, using examples from concrete construction in general and precast concrete construction in particular.

Keywords: Industry Foundation Classes (IFC), Model View Definitions (MVD), National BIM Standard (NBIMS), Product Modeling, Process Modeling

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Series: w78:2010 (browse)
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Oloke D A, Edwards D J

An intelligent system for improving plant information management

Abstract: The modern economy is reliant upon the application of mechanisation to sustain economic growth and prosperity. However, plant users must invest substantial and continuing capital resources in order to maximise turnover and profit. An exact quantification of profitability and performance resulting from plant usage can only be achieved through the effective documentation and utilisation of plant records. This paper sought to review existing information management systems for off-highway plant and equipment (e.g. excavators, rigid dump trucks, telehandlers and so on) and determine whether such represent an appropriate solution to modern industrial needs. Pilot study findings reveal paper based and electronic documentation formats resident on PC and local networks; PC being the most common system utilised. Overall, information management systems employed within the off-highway plant sector compare rather poorly to more technological advanced industries (e.g. rail and aviation). Based upon these findings, a new Internet based 'intelligent, multi-user functional' application is proposed that essentially consists of an integration of three core components, namely: (i) a web-based Relational Database Management System (RDBMS); (ii) a dynamic Model Base Management System (MBMS); and (iii) a Knowledge Base Management System (KBMS). The paper concludes with direction for future work that aims to model aspects of plant history file data collected.

Keywords: off-highway plant, information technology, information management, internet and intelligent decision support

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Full text: content.pdf ( bytes) (available to registered users only)

Series: itaec:2003 (browse)
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Petrovic I

Integrative knowledge-based design systems: a view

Abstract: The paper describes a recent project which objective was the redesign of GIMSEX- PERT, an existing architectural knowledge-based design system developed in 1987. Its critical generative problems appeared to be the rigid structure and limited evaluation criteria. The project's outcome is DESTOOLS, based on the "object-oriented-methodology", inspired by the traditional trial-and-error approach. It includes a set of interchangeable design methods that can be applied interactively by any desired sequence, producing or transforming a GIMS Building System object. Such "moderately-loose" sys- tem structure offers flexibility in use, avoids pitfalls of knowledge-based design systems with rigid structure, and is applicable in design research, education and practice.

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Full text: content.pdf (1,088,336 bytes) (available to registered users only)

Series: w78:1991 (browse)
Cluster: papers of the same cluster (result of machine made clusters)
Class: class.software development (0.024168) class.education (0.021297) class.man-software (0.016427)
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Permission to reproduce these papers has been graciously provided by Eindhoven University of Technology.


Raimondi A, Salvioni G

A construction product browser

Abstract: The World Wide Web contains a wealth of information from manufacturers of building products which needs to be gathered and reorganized in order to be used by designers. Currently there is a tendency to develop systems based on database architecture that require large amounts of structured data newly compiled from the sources, and it takes great effort to update the data in the database that changes with time. This process can be supported only by large and expensive organizations. In this paper we discuss the requirements and conceptualize an information system that knows where certain pertinent information is and helps the users to find it by means of a retrieval system based on natural and controlled querying language. Our system also helps the user decide between alternatives and lets him select only some information out of all the data that usually comes in a product’s data sheet. The program further allows the user to download the data and use it in his project. In order to allow the producers of building products to give information according to their own layouts without being forced into a rigid standardized layout, we propose an indexing system based on the application of blind labels (tags) to the existing source code (html) which describes the information about a product that is already on the Internet. The tags are based on the Master Lists and EPIC’s construction-product grouping. Each piece of information indexed by its own tag will be handled by a specialized software that will put it in the right place in our newly developed product data sheet. This mechanism avoids the construction of a centralized database, and replaces the need for it by accessing a series of indexed documents containing indexed information already on the Internet.

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Full text: content.pdf (278,398 bytes) (available to registered users only)

Series: w78:1998 (browse)
Cluster: papers of the same cluster (result of machine made clusters)
Class: class.collaboration (0.025719) class.represent (0.016246) class.store (0.013301)
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Permission to reproduce these papers has been graciously provided by Royal Institute of Technology, Stockholm, Sweden. The assistance of the editors, Prof. Bo-Christer Björk and Dr. Adina Jägbeck, is gratefully appreciated.


Rebolj D

Virtual product model

Abstract: "In the cosmos there are no complex laws which would govern some huge monolithic structures. But there obviously are particles/energies and there are some basic laws, which condition the interactions between the particles. Because there exist many combinations of particles the outcome of interactions are not simple to predict. Independently of this fact the many combinations exist and it seems that they form more and more complex structures, which are not very concerned about their own complexity. More and more authors are recognizing the problem of modeling complex structures and many are asking themselves whether an all-including-product-model is a solution for an integrated information environment that should efficiently support the life-cycle of a product. It seems that rich experiences in product modeling in the last decade lead not to better and better models but rather to the awareness that the more complex the product models are, the more rigid and the less usable they become in reality. These recognitions already led to some suggestions for the future integration methods and product modeling. The article introduces a concept of the virtual product model, a network of loosely coupled particle models, interconnected by relatively simple but strong rules (like gravity in the macro-cosmos). The neighborhood of a particle model is defined through a process model, which also determines relations between particles. A special attention has been given to the content harmonization of particle models, which are representing parts of the virtual product model. The mechanism is based on harmonization agents, which are leaving the particles their individuality but also bind them to the whole. The author also doubts about the possibility of ever using a single complex standard for structuring and describing structures of product models, especially in civil engineering and construction, where many different views have to be considered through a product life cycle. Again a bottom-up principle has been used to enable communication between harmonization agents, which share and extend their own knowledge about structures through common dictionaries. Through the concept of the virtual product model it is believed that it is possible to preserve the independence and flexibility of particles - existing island models and applications (without implementing any interfaces) and the simplicity of mastering them, but also to preserve the positive integration effects of complex product models. The reason for this conviction lies in the simplicity of used principles and in their closer relation to natural mechanisms, which does not exclude implicit evolution."

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Full text: content.pdf (249,531 bytes) (available to registered users only)

Series: w78:2000 (browse)
Cluster: papers of the same cluster (result of machine made clusters)
Class: class.legal (0.041034) class.represent (0.034655) class.man-software (0.024636)
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Permission to reproduce these documents have been graciously provided by Icelandic Building Research Institute. The assistance of the editor, Mr. Gudni Gudnason, is gratefully appreciated


T Tiainen, M Heinisuo

Tubular Steel Truss Design Using Semi-Rigid Joints

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Full text: content.pdf (126,572 bytes) (available to registered users only)

Series: w78:2014 (browse)
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