Moderne Bemessungskonzepte für seismisch beanspruchte Hochbauten, wie die Methode der Kapazitäts-bemessung, planen inelastisches Verhalten einzelner Bereiche der Konstruktion beim Entwurf bewußt ein, um so einen Teil der durch das Beben eingetragenen Energie als inelastische Formänderungsarbeit zu absorbieren. Wird bei Akzeptanz inelastischen Verhaltens eine bestimmte Belastungsintensität, die als adaptive Grenzlast oder Einspiellast bezeichnet wird, überschritten, kann es infolge zyklischer Einwirkungen zu einer unbe-grenzten Akkumulation inelastischer Deformationen kommen. Die adaptive Grenzlast stellt damit für zyklische Einwirkungen eine geeignete Kenngröße zur Bewertung der Tragwerksqualität dar, bei der neben der Sicherung des Gleichgewichts ein bestimmtes Schädigungsniveau nicht überschritten wird. Im vorliegenden Beitrag werden die Grundzüge eines Bemessungs- und Nachweiskonzeptes für seismisch beanspruchte Stahlbetontragwerke, das unter Einbeziehung der Grundprinzipe der Kapazitätsbemessung von einem einheitlichen Kriterium zur Beschreibung des Grenzzustandes der Tragfähigkeit auf der Basis der adaptive Grenzlast ausgeht, vorgestellt. Dabei ist die Abschätzung der Verformungen notwendiger Bestandteil des Nachweis- bzw. Bemessungskonzeptes. Bei Druckgliedern ist die Berücksichtigung des Einflusses der Verformungen notwendiger Bestandteil des Bemessungskonzeptes. Entsprechende Erweiterungen der Berechnungsmodelle zur Berücksichtigung des Einflusses geometrisch nichtlinearer Effekte im Sinne einer Theorie II. Ordnung werden vorgestellt.
Die Aufgaben des Bauingenieurwesens sind dadurch geprägt, daß sowohl die Planung als auch die Ausführung von Bauwerken häufigen Änderungen unterliegen. Beschreibt man das Verhalten der Bauwerke und den Bauprozeß im Computer mit Modellen, so ändern sich Umfang und Struktur der Modelle als Folge der Änderung in Planung und Ausführung. Diesen Vorgang nennt man Dynamisierung des Modells. Die Dynamisierung führt zu Veränderungen und Inkonsistenzen in den Modellen der Anwendungen. Die Aktualisierung und Abstimmung von Beziehungen innerhalb eines Modells sowie die Sicherung der Konsistenz der Modelle untereinander sind daher von zentraler Bedeutung für die Lösung von Bauingenieuraufgaben. Seit den letzten 10 Jahren wird die objektorientierte Methode in der Modellierung für Anwendungen im Bauingenieurwesen intensiv entwickelt und eingesetzt. Es hat sich gezeigt, daß die Anwendung dieser Methode in wichtigen Bereichen der Modellierung zu Verbesserungen führt. Gleichzeitig hat sich aber auch herausgestellt, daß die für das Bauingenieurwesen wichtigen Aspekte der Aktualisierung und der Konsistenz nicht zweckmäßig beschreibbar sind. In diesem Beitrag wird eine einfache Modelliermethode in ihrem Konzept und ihrer Realisierung gezeigt, mit der sich die Aktualisierung von Objekten und Modellen sowie die Sicherstellung der Konsistenz in Systemen des Bauingenieurwesens bearbeiten lassen.
It has been shown that symmetries of moment functions of stochastic processes play an important role in identification of systems. They provide the group-theoretic method of choice of the model structure and model parameters. In the first stage the group-theoretic analysis of some fundamental concepts of stochastic dynamics: stochastic processes and functional series of Volterra-Wiener type has been undertaken. The analysis of group representations of the moment functions of order m for stochastic processes is the basic, original concept of the work. The following groups: symmetric Sm, special affine SAff(m), general linear GL(n, R), GL(n,C) and their subgroups play the main role in the models. In the second stage the informational entropy has been introduced as a measure of the randomness in the identified models. The group-theoretic approach underlines the unity of the nonlinear system identification and leads to useful engineering results in the range of the second-order (stochastic) theory.
Dieser Beitrag zeigt einen Ansatz, verschiedene numerische Simulationsaufgaben auf ein gemeinsames und durchgängig dreidimensionales Geometriemodell zu gründen. Hinsichtlich der physikalischen Modelle reicht die Bandbreite der hier vorgestellten Anwendungen von einer ganzheitlichen Betrachtung der Gebäudestruktur in der Strukturmechanik über die raumbezogene, hochauflösende Modellierung konvektiver Raumluftströmungen bis hin zur Simulation des thermischen Verhaltens eines ganzen Gebäudes. Das jeweils zugrunde liegende numerische Verfahren setzt dabei auf einem stets gleichen Zwischenmodell der realen Geometrie der Struktur auf, ohne dabei vereinfachende dimensionsreduzierte Modelle anzuwenden. Nachfolgende Werkzeuge werden derzeit im Rahmen mehrerer Forschungsprojekte an dieses Geometriemodell angeschlossen: Die p-Version der FEM für die Strukturanalyse, ein sog. Mehrzonenmodell für die thermische Gebäudesimulation sowie ein auf dem sog. hybriden thermischen Gitter-Boltzmann-Verfahren (hTLBE) basierender Strömungssimulationscode. Der Import geometrischer wie semantischer Daten eines Bauwerks in das Simulations-Framework erfolgt nach dem Produktmodell der Industry Foundation Classes (IFC), das sich als Quasi-Standard für den Datenaustausch im Bauwesen etabliert hat. Das IFC-Schema dient dabei nicht als Modell zur internen Speicherung von Daten, sondern wird hier als Schnittstelle zur Anbindung unterschiedlicher Programme wie CAD-Anwendungen für Architekten oder anderen Modellierungstools verwendet. Die Implementierung dieser Schnittstelle erfolgt unter Verwendung einer sog. Toolbox, die das Objektschema der IFC auf ein Klassenmodell einer objektorientierten Programmiersprache abbildet und Werkzeuge für den effizienten Objektzugriff zur Verfügung stellt. Damit werden Grenzen zwischen spezialisierten Softwarepaketen, die maßgeschneidert auf spezielle Erfordernisse ausgerichtet sind, aufgebrochen und der Datenaustausch über die Anwendungsgrenzen hinaus unterstützt. Dies ist eine Konsequenz aus einer dem Wunsch nach vernetzt-kooperativen Planung von Bauwerken....
Most of the existing seismic resistant design codes are based on the response spectrum theory. The influence of inelastic deformations can be evaluated by considering inelastic type of resisting force and then the inelastic spectrum is considerably different from the elastic one. Also, the influence of stiffness degradation and strength deterioration can be accounted for by including more precise models from material point of view. In some recent papers the corresponding changes in response spectra due to the P- Ä effect are discussed. The experience accumulated from the recent earthquakes indicates that structural pounding may considerably influence the response of structures and should be taken into account in design procedures. The most convenient way to do that is to predict the influence of the pounding on the response spectra for accelerations, velocities and displacements. Generally speaking the contact problems such as pounding are characterized by large extent of nonlinearity and slow convergence of the computational procedures. Thus obtaining spectra where the contact problem is accounted for seems very attractive from engineering point of view because could easy be implemented into the design procedures. However it is worth nothing that there is not rigorous mathematical proof that the original system can be decomposed into single equations related to single degree of freedom systems. It is the porpose of the paper to study the influence of the pounding on the response spectra and to evaluate the amplification due to the impact. For this purpose two adjacent SDOF systems are considered that are able to interact during the vibration process. This problem is solved versus the elastic stiffness ratio, which appears to be very important for such assemblage. The contact between masses is numerically simulated using opening gap elements as links. Comparisons between calculated response spectra and linear response spectra are made in order to derive analytical relationships to simply obtain the contribution of pounding. The results are graphically illustrated in response spectra format and the influence of the stiffness ratio is clarified.
The construction industry is suffering form the existence of isolated islands of software applications and bottle neck solutions. The idea of an integrated virtual database that consists of separated platforms, representing various disciplines, depending on the web technology is envisaged to solve the problem of integration. This paper is about the production and use of OIPs (Object Information Packs) as a part of the construction material product in the form of XML files that include all the technical and commercial data of the product, which might be needed by any discipline in its overall life cycle. This object information pack is neutral and independent of any software application. It is assumed to fit in a building product model at the IFC (resource layer). An example of brick - wall aggregation process is used to demonstrate the capability of the technology and the ability of non computer science experts to use it.
Building design, realization, operation and refurbishment have to take into account the environmental impacts as well as the resulting costs over a long period of time. LCA methods had to be developed for buildings because of their complexity, their long life duration and through a large number of actors who are involved. This was realized by integrating life cycle analysis, life cycle costing and building product models in integrated LCA models. However the use of such models leads to difficulties. The principal ones are the uncertainty treatment in LCA models and the lack of experience of practitioners who are not LCA specialists. Answers to these problems are the management of uncertainty and the development of simplified models for building design, construction and operation. This can be achieved with the mean of experimental plans or Monte Carlo simulation. The paper will focus on how these techniques can be used, what are their possibilities and disadvantages, particularly concerning the development of simplified models.
Ein simultanes Lösungsverfahren für Fluid-Struktur-Wechselwirkungen aus dem Bereich des Bauingenieurwesens wird vorgestellt. Die Modellierung der Tragwerksdynamik erfolgt mit der geometrisch nichtlinearen Elastizitätstheorie in total Lagrangescher Formulierung. Die Strömung wird mit den inkompressiblen Navier-Stokes-Gleichungen beschrieben. Wenn Turbulenzeffekte massgeblich sind, kommen die Reynolds-Gleichungen in Verbindung mit dem k-omega-Turbulenzmodell von Wilcox zum Einsatz. Zur Beschreibung von komplexen freien Oberflächen wird die Level-Set-Methode eingesetzt. Die einheitliche Diskretisierung von Fluid und Struktur mit der Raum-Zeit-Finite-Element-Methode führt zu einem konsistenten Berechnungsmodell für das gekoppelte System. Da die isoparametrischen Raum-Zeit-Elemente ihre Geometrie in Zeitrichtung ändern können, erlaubt die Methode eine natürliche Beschreibung des infolge der Strukturbewegung zeitveränderlichen Strömungsgebiets. Die gewichtete Integralformulierung der Kopplungsbedingungen mit globalen Freiwerten für die Interface-Spannungen sichert eine konservative Kopplung von Fluid und Struktur. Ausgewählte Anwendungsbeispiele zeigen die Leistungsfähigkeit der entwickelten Methodik und belegen die guten Konvergenzeigenschaften des simultanen Lösungsverfahrens.
Modellverwaltungssysteme sind eine geeignete technologische Basis zum Management digitaler Bauwerksmodelle bei Planungstätigkeiten für den Neubau als auch für die Revitalisierung von Bauwerken. Die Unterstützung von Revitalisierungsprozessen impliziert für den Entwurf integrierter Planungsumgebungen spezifische Anforderungen wie die Repräsentation von Informationen, die mit verschiedenen Typen von Vagheit behaftet sind, die Notwendigkeit, den Soll- sowie den Ist- Zustand des Bauwerks abzubilden und die Fähigkeit des Umgangs mit temporal inkonsistenten Modellzuständen. Die erforderliche Dynamik der Domänenmodelle und die erforderliche Nutzbarkeit in Virtual Enterprises stellen weitere Ansprüche an die Realisierungsbasis der Modellverwaltungssysteme. Zur Implementierung derartiger Systeme erweist es sich als vorteilhaft, Eigenschaften objektorientierter Programmiersprachen mit nichtstatischen Typsystemen auszunutzen, da diese durch die vorhandene Metaebene sowie Introspektions- und Reflektionsmechanismen eine effiziente Realisierungsbasis bereitstellen. Zur effektiven Unterstützung synchroner kooperativer Planungstätigkeiten innerhalb einzelner Fachdisziplinen wurde ein Benachrichtigungsmechanismus realisiert, der an das Modellverwaltungssystem angekoppelte Fachapplikationen über nebenläufig vorgenommene Modifikationen am zugehörigen Domänenmodell oder an Projektinformationen informiert. Weiterhin existiert ein Mechanismus zur vereinfachten Anbindung von existierenden Applikationen, die auf statischen Partialmodellen beruhen oder standardisierte, modellbasierte Austauschformate unterstützen. Abschließend wird eine aus einem zentralen Projektserver, Domänenservern und Domänenclients bestehende hybride Systemarchitektur vorgestellt, die geeignet ist, unter den Randbedingungen kooperativer und geographisch verteilter Arbeit bei Revitalisierungsvorhaben in Virtual Enterprises eingesetzt zu werden.
The research of the best building design requires a concerted design approach of both structure and foundation. Our work is an application of this approach. Our objective is also to create an interactive tool, which will be able to define, at the early design stages, the orientations of structure and foundation systems that satisfy as well as possible the client and the architect. If the concerns of these two actors are primarily technical and economical, they also wish to apprehend the environmental and social dimensions of their projects. Thus, this approach bases on alternative studies and on a multi-criterion analysis. In this paper, we present the context of our work, the problem formulation, which allows a concerted design of Structure and Foundation systems and the feasible solutions identifying process.
The paper presents a general map-based approach to prototyping of products in virtual reality environments. Virtual prototyping of products is considered as a consistent simulation and visualization process mapping the source product model into its target visual representations. The approach enables to interrelate formally the product and visual information models with each other by defining mapping rules, to specify a prototyping scenario as a composition of map instances, and then to explore particular product models in virtual reality environments by interpreting the composed scenario. Having been realized, the proposed approach provides for the strongly formalized method and the common software framework to build virtual prototyping applications. As a result, the applications gain in expressiveness, reusability and reliability, as well as take on additional runtime flexibility...
In current AEC practice client requirements are typically recorded in a building program, which, depending on the building type, covers various aspects from the overall goals, activities and spatial needs to very detailed material and condition requirements. This documentation is used as the starting point of the design process, but as the design progresses, it is usually left aside and changes are made incrementally based on the previous design solution. These incremental small changes can lead to a solution that may no longer meet the original requirements. In addition, design is by nature an iterative process and the proposed solutions often also cause evolution in the client requirements. However, the requirements documentation is usually not updated accordingly. Finding the latest updates and evolution of the requirements from the documentation is very difficult, if not impossible. This process can lead to an end result, which is significantly different from the documented requirements. Some important requirements may not be satisfied, and even if the design process was based on agreed-upon changes in the scope and requirements, differences in the requirements documents and in the completed building can lead to well-justified doubts about the quality of the design and construction process...
The processes in the life cycle of buildings are characterised by highly distinct teamwork. The integration of all the distributed working participants, by providing an environment, which especially supports the communication and collaboration between the actors, is a fundamental step to improve the efficiency of the involved processes and to reduce the total costs. In this article, a link based modelling approach and its “intelligent” link management is introduced (1). This approach realises an integration environment based on a special building model that acts as a decision support system. The link-based modelling is characterised by the definition and specialisation of links between partial models. These intelligent managed links enable a very flexible and task specific data access and exchange between all the different views and partial models of the participants.
For planning in existing built contexts, the building survey is the starting point for initial planning proposals, for the diagnosis and documentation of building damages, for the creation of objectives catalogues, for the detailed design of renovation and conversion measures and for ensuring fulfilment of building legislation, particularly by change of use and refitting. An examination of currently available IT-tools shows insufficient support for planning within existing contexts, most notably a deficit with regard to information capture and administration. This paper discusses the concept for a modular surveying system (basic concept, separation of geometry from semantic data, and separation into sub-systems) and the prototypical realisation of a system for the complete support of the entire building surveying process for existing buildings. The project aims to contribute to the development of a planning system for existing buildings. ...
At the start of the conceptual design process, designers start to give tangible form to their thoughts by sketching. This helps with reasoning and communicates ideas to other members of the team. Sketches are gradually worked up into more formal drawings which are then passed to the other stages of the design process. There are however some problems with basing early ideas on sketching. For example, due to their ad-hoc nature, sketches tend only to be diagrammatic representations and so designers cannot be sure that their ideas are feasible and what is being proposed meets the constraints described in the client brief. This can result in designers wasting time working up ideas which prove to be unsuitable. Also the process of constraint checking is complex and time consuming and so designers tend limit their search of possible options and instead choose satisfying rather than good solutions. This paper describes the INTEGRA project which examines the role of sketching in early conceptual design and how this can be linked to other aspects of the process and particularly automated constraint checking using an IT based approach. The focus for the work is the design of framed buildings. A multi-disciplinary approach has been adopted and the work has been undertaken in close collaboration with practising designers and clients.
The process of matching data represented in two different data models is a longstanding issue in the exchange of data between different software systems. While the traditional manual matching approach cannot meet today’s demands on data exchange, research shows that a fully automated generic approach for model matching is not likely, and generic semi-automated approaches are not easy to implement. In this paper, we present an approach that focuses on matching data models in a specific domain. The approach combines a basic model matching approach and a version matching approach to deduce new matching rules to enable data transfer between two evolving data models.
This paper describes an ongoing research on the representation and reasoning about construction specifications, which is part of a bigger research project that aims at developing a formalism for automating the identification of deviations and defects on construction sites. We specifically describe the requirements on product and process models and an approach for representing and reasoning about construction specifications to enable automated detection and assessment of construction deviations and defects. This research builds on the previous research on modeling design specifications and extends and elaborates concept of contexts developed in that domain. The paper provides an overview of how the construction specifications are being modele d in this research and points out future steps that need to be accomplished to develop the envisioned automated deviation and defect detection system.
The increased implementation of site data capture technologies invariably results in an increase in data warehousing and database technologies to store captured data. However, restricted use of data beyond the initial application could potentially result in a loss of understanding of site processes. This could in turn lead to poor decision making at production, tactical and strategic levels. Concrete usage data have been collected from two piling processes. These data have been analysed and the results highlighted potential improvements that could be made to existing site management and estimating processes. A cost benefit analysis has been used to support decision making at the strategic level where the identified improvements require capital expenditure.
Information science researchers and developers have spent many years addressing the problem of retrieving the exact information needed and using it for analysis purposes. In informationseeking dialogues, the user, i.e. construction project manager or supplier, often asks questions about specific aspects of the tasks they want to perform. But most of the time it is difficult for the software systems to unambiguously understand their overall intentions. The existence of information tunnels (Tannenbaum 2002) aggravates this phenomenon. This study includes a detailed case study of the material management process in the construction industry. Based on this case study, the structure of a formal user model for information retrieval in construction management is proposed. This prototype user model will be incorporated into the system design for construction information management and retrieval. This information retrieval system is a user-centered product based on the development of a user configurable visitor mechanism for managing and retrieving project information without worrying too much about the underlying data structure of the database system. An executable UML model combined with OODB is used to reduce the ambiguity in the user's intentions and to achieve user satisfaction.