56.03 Methoden im Bauingenieurwesen
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Identification of modal parameters of a space frame structure is a complex assignment due to a large number of degrees of freedom, close natural frequencies, and different vibrating mechanisms. Research has been carried out on the modal identification of rather simple truss structures. So far, less attention has been given to complex three-dimensional truss structures. This work develops a vibration-based methodology for determining modal information of three-dimensional space truss structures. The method uses a relatively complex space truss structure for its verification. Numerical modelling of the system gives modal information about the expected vibration behaviour. The identification process involves closely spaced modes that are characterised by local and global vibration mechanisms. To distinguish between local and global vibrations of the system, modal strain energies are used as an indicator. The experimental validation, which incorporated a modal analysis employing the stochastic subspace identification method, has confirmed that considering relatively high model orders is required to identify specific mode shapes. Especially in the case of the determination of local deformation modes of space truss members, higher model orders have to be taken into account than in the modal identification of most other types of structures.
In this paper, we present an open-source code for the first-order and higher-order nonlocal operator method (NOM) including a detailed description of the implementation. The NOM is based on so-called support, dual-support, nonlocal operators, and an operate energy functional ensuring stability. The nonlocal operator is a generalization of the conventional differential operators. Combined with the method of weighed residuals and variational principles, NOM establishes the residual and tangent stiffness matrix of operate energy functional through some simple matrix without the need of shape functions as in other classical computational methods such as FEM. NOM only requires the definition of the energy drastically simplifying its implementation. The implementation in this paper is focused on linear elastic solids for sake of conciseness through the NOM can handle more complex nonlinear problems. The NOM can be very flexible and efficient to solve partial differential equations (PDEs), it’s also quite easy for readers to use the NOM and extend it to solve other complicated physical phenomena described by one or a set of PDEs. Finally, we present some classical benchmark problems including the classical cantilever beam and plate-with-a-hole problem, and we also make an extension of this method to solve complicated problems including phase-field fracture modeling and gradient elasticity material.
In this study, we propose a nonlocal operator method (NOM) for the dynamic analysis of (thin) Kirchhoff plates. The nonlocal Hessian operator is derived based on a second-order Taylor series expansion. The NOM does not require any shape functions and associated derivatives as ’classical’ approaches such as FEM, drastically facilitating the implementation. Furthermore, NOM is higher order continuous, which is exploited for thin plate analysis that requires C1 continuity. The nonlocal dynamic governing formulation and operator energy functional for Kirchhoff plates are derived from a variational principle. The Verlet-velocity algorithm is used for the time discretization. After confirming the accuracy of the nonlocal Hessian operator, several numerical examples are simulated by the nonlocal dynamic Kirchhoff plate formulation.
Electric trains are considered one of the most eco-friendly and safest means of transportation. Catenary poles are used worldwide to support overhead power lines for electric trains. The performance of the catenary poles has an extensive influence on the integrity of the train systems and, consequently, the connected human services. It became a must nowadays to develop SHM systems that provide the instantaneous status of catenary poles in- service, making the decision-making processes to keep or repair the damaged poles more feasible. This study develops a data-driven, model-free approach for status monitoring of cantilever structures, focusing on pre-stressed, spun-cast ultrahigh-strength concrete catenary poles installed along high-speed train tracks. The pro-posed approach evaluates multiple damage features in an unfied damage index, which leads to straightforward interpretation and comparison of the output. Besides, it distinguishes between multiple damage scenarios of the poles, either the ones caused by material degradation of the concrete or by the cracks that can be propagated during the life span of the given structure. Moreover, using a logistic function to classify the integrity of structure avoids the expensive learning step in the existing damage detection approaches, namely, using the modern machine and deep learning methods. The findings of this study look very promising when applied to other types of cantilever structures, such as the poles that support the power transmission lines, antenna masts, chimneys, and wind turbines.
This study proposes an efficient Bayesian, frequency-based damage identification approach to identify damages in cantilever structures with an acceptable error rate, even at high noise levels. The catenary poles of electric high-speed train systems were selected as a realistic case study to cover the objectives of this study. Compared to other frequency-based damage detection approaches described in the literature, the proposed approach is efficiently able to detect damages in cantilever structures to higher levels of damage detection, namely identifying both the damage location and severity using a low-cost structural health monitoring (SHM) system with a limited number of sensors; for example, accelerometers. The integration of Bayesian inference, as a stochastic framework, in the proposed approach, makes it possible to utilize the benefit of data fusion in merging the informative data from multiple damage features, which increases the quality and accuracy of the results. The findings provide the decision-maker with the information required to manage the maintenance, repair, or replacement procedures.
Für eine Abschätzung des Heizwärmebedarfs von Gebäuden und Quartieren können thermisch-energetische Simulationen eingesetzt werden. Grundlage dieser Simulationen sind geometrische und physikalische Gebäudemodelle. Die Erstellung des geometrischen Modells erfolgt in der Regel auf Basis von Bauplänen oder Vor-Ort-Begehungen, was mit einem großen Recherche- und Modellierungsaufwand verbunden ist. Spätere bauliche Veränderungen des Gebäudes müssen häufig manuell in das Modell eingearbeitet werden, was den Arbeitsaufwand zusätzlich erhöht. Das physikalische Modell stellt die Menge an Parametern und Randbedingungen dar, welche durch Materialeigenschaften, Lage und Umgebungs-einflüsse gegeben sind. Die Verknüpfung beider Modelle wird innerhalb der entsprechenden Simulations-software realisiert und ist meist nicht in andere Softwareprodukte überführbar. Mithilfe des Building Information Modeling (BIM) können Simulationsdaten sowohl konsistent gespeichert als auch über Schnittstellen mit entsprechenden Anwendungen ausgetauscht werden. Hierfür wird eine Methode vorgestellt, die thermisch-energetische Simulationen auf Basis des standardisierten Übergabe-formats Industry Foundation Classes (IFC) inklusive anschließender Auswertungen ermöglicht. Dabei werden geometrische und physikalische Parameter direkt aus einem über den gesamten Lebenszyklus aktuellen Gebäudemodell extrahiert und an die Simulation übergeben. Dies beschleunigt den Simulations-prozess hinsichtlich der Gebäudemodellierung und nach späteren baulichen Veränderungen. Die erarbeite-te Methode beruht hierbei auf einfachen Modellierungskonventionen bei der Erstellung des Bauwerksinformationsmodells und stellt eine vollständige Übertragbarkeit der Eingangs- und Ausgangswerte sicher.
Thermal building simulation based on BIM-models. Thermal energetic simulations are used for the estimation of the heating demand of buildings and districts. These simulations are based on building models containing geometrical and physical information. The creation of geometrical models is usually based on existing construction plans or in situ assessments which demand a comparatively big effort of investigation and modeling. Alterations, which are later applied to the structure, request manual changes of the related model, which increases the effort additionally. The physical model represents the total amount of parameters and boundary conditions that are influenced by material properties, location and environmental influences on the building. The link between both models is realized within the correspondent simulation soft-ware and is usually not transferable to other software products. By Applying Building Information Modeling (BIM) simulation data is stored consistently and an exchange to other software is enabled. Therefore, a method which allows a thermal energetic simulation based on the exchange format Industry Foundation Classes (IFC) including an evaluation is presented. All geometrical and physical information are extracted directly from the building model that is kept up-to-date during its life cycle and transferred to the simulation. This accelerates the simulation process regarding the geometrical modeling and adjustments after later changes of the building. The developed method is based on simple conventions for the creation of the building model and ensures a complete transfer of all simulation data.
Für eine Abschätzung des Heizwärmebedarfs von Gebäuden und Quartieren können thermisch-energetische Simulationen eingesetzt werden. Grundlage dieser Simulationen sind geometrische und physikalische Gebäudemodelle. Die Erstellung des geometrischen Modells erfolgt in der Regel auf Basis von Bauplänen oder Vor-Ort-Begehungen, was mit einem großen Recherche- und Modellierungsaufwand verbunden ist. Spätere bauliche Veränderungen des Gebäudes müssen häufig manuell in das Modell eingearbeitet werden, was den Arbeitsaufwand zusätzlich erhöht. Das physikalische Modell stellt die Menge an Parametern und Randbedingungen dar, welche durch Materialeigenschaften, Lage und Umgebungs-einflüsse gegeben sind. Die Verknüpfung beider Modelle wird innerhalb der entsprechenden Simulations-software realisiert und ist meist nicht in andere Softwareprodukte überführbar.
Mithilfe des Building Information Modeling (BIM) können Simulationsdaten sowohl konsistent gespeichert als auch über Schnittstellen mit entsprechenden Anwendungen ausgetauscht werden. Hierfür wird eine Methode vorgestellt, die thermisch-energetische Simulationen auf Basis des standardisierten Übergabe-formats Industry Foundation Classes (IFC) inklusive anschließender Auswertungen ermöglicht. Dabei werden geometrische und physikalische Parameter direkt aus einem über den gesamten Lebenszyklus aktuellen Gebäudemodell extrahiert und an die Simulation übergeben. Dies beschleunigt den Simulations-prozess hinsichtlich der Gebäudemodellierung und nach späteren baulichen Veränderungen. Die erarbeite-te Methode beruht hierbei auf einfachen Modellierungskonventionen bei der Erstellung des Bauwerksinformationsmodells und stellt eine vollständige Übertragbarkeit der Eingangs- und Ausgangswerte sicher.
Thermal building simulation based on BIM-models. Thermal energetic simulations are used for the estimation of the heating demand of buildings and districts. These simulations are based on building models containing geometrical and physical information. The creation of geometrical models is usually based on existing construction plans or in situ assessments which demand a comparatively big effort of investigation and modeling. Alterations, which are later applied to the structure, request manual changes of the related model, which increases the effort additionally. The physical model represents the total amount of parameters and boundary conditions that are influenced by material properties, location and environmental influences on the building. The link between both models is realized within the correspondent simulation soft-ware and is usually not transferable to other software products.
By Applying Building Information Modeling (BIM) simulation data is stored consistently and an exchange to other software is enabled. Therefore, a method which allows a thermal energetic simulation based on the exchange format Industry Foundation Classes (IFC) including an evaluation is presented. All geometrical and physical information are extracted directly from the building model that is kept up-to-date during its life cycle and transferred to the simulation. This accelerates the simulation process regarding the geometrical modeling and adjustments after later changes of the building. The developed method is based on simple conventions for the creation of the building model and ensures a complete transfer of all simulation data.
The fire resistance of concrete members is controlled by the temperature distribution of the considered cross section. The thermal analysis can be performed with the advanced temperature dependent physical properties provided by 5EN6 1992-1-2. But the recalculation of laboratory tests on columns from 5TU6 Braunschweig shows, that there are deviations between the calculated and measured temperatures. Therefore it can be assumed, that the mathematical formulation of these thermal properties could be improved. A sensitivity analysis is performed to identify the governing parameters of the temperature calculation and a nonlinear optimization method is used to enhance the formulation of the thermal properties. The proposed simplified properties are partly validated by the recalculation of measured temperatures of concrete columns. These first results show, that the scatter of the differences from the calculated to the measured temperatures can be reduced by the proposed simple model for the thermal analysis of concrete.
Building Information Modeling is a powerful tool for the design and for a consistent set of data in a virtual storage. For the application in the phases of realization and on site it needs further development. The paper describes main challenges and main features, which will help the development of software to better service the needs of construction site managers
The node moving and multistage node enrichment adaptive refinement procedures are extended in mixed discrete least squares meshless (MDLSM) method for efficient analysis of elasticity problems. In the formulation of MDLSM method, mixed formulation is accepted to avoid second-order differentiation of shape functions and to obtain displacements and stresses simultaneously. In the refinement procedures, a robust error estimator based on the value of the least square residuals functional of the governing differential equations and its boundaries at nodal points is used which is inherently available from the MDLSM formulation and can efficiently identify the zones with higher numerical errors. The results are compared with the refinement procedures in the irreducible formulation of discrete least squares meshless (DLSM) method and show the accuracy and efficiency of the proposed procedures. Also, the comparison of the error norms and convergence rate show the fidelity of the proposed adaptive refinement procedures in the MDLSM method.
Different types of data provide different type of information. The present research analyzes the error on prediction obtained under different data type availability for calibration. The contribution of different measurement types to model calibration and prognosis are evaluated. A coupled 2D hydro-mechanical model of a water retaining dam is taken as an example. Here, the mean effective stress in the porous skeleton is reduced due to an increase in pore water pressure under drawdown conditions. Relevant model parameters are identified by scaled sensitivities. Then, Particle Swarm Optimization is applied to determine the optimal parameter values and finally, the error in prognosis is determined. We compare the predictions of the optimized models with results from a forward run of the reference model to obtain the actual prediction errors. The analyses presented here were performed calibrating the hydro-mechanical model to 31 data sets of 100 observations of varying data types. The prognosis results improve when using diversified information for calibration. However, when using several types of information, the number of observations has to be increased to be able to cover a representative part of the model domain. For an analysis with constant number of observations, a compromise between data type availability and domain coverage proves to be the best solution. Which type of calibration information contributes to the best prognoses could not be determined in advance. The error in model prognosis does not depend on the error in calibration, but on the parameter error, which unfortunately cannot be determined in inverse problems since we do not know its real value. The best prognoses were obtained independent of calibration fit. However, excellent calibration fits led to an increase in prognosis error variation. In the case of excellent fits; parameters' values came near the limits of reasonable physical values more often. To improve the prognoses reliability, the expected value of the parameters should be considered as prior information on the optimization algorithm.
The paper analyses the application of 3D gaming technologies in the simulation of processes associated with human resources and machinery on construction sites in order to determine process costs. It addresses the problem of detailing in process simulation. The authors outline special boundary conditions for the simulation of cost-relevant resource processes on virtual construction sites. The approach considers different needs for detailing in process simulation during the planning and building phase. For simulation of process costs on a construction site (contractors view) the level of detail has to be set to high. A prototype for determination of process durations (and hereby process costs) developed at the Bauhaus University Weimar is presented as a result of ongoing researches on detailing in process simulation. It shows the method of process cost determination on a high level of detail (game between excavator and truck) through interaction with the virtual environment of the site.
This paper presents an application of dynamic decision making under uncertainty in planning and estimating underground construction. The application of the proposed methodology is illustrated by its application to an actual tunneling project—The Hanging Lake Tunnel Project in Colorado, USA. To encompass the typical risks in underground construction, tunneling decisions are structured as a risk-sensitive Markov decision process that reflects the decision process faced by a contractor in each tunneling round. This decision process consists of five basic components: (1) decision stages (locations), (2) system states (ground classes and tunneling methods), (3) alternatives (tunneling methods), (4) ground class transition probabilities, and (5) tunneling cost structure. The paper also presents concepts related to risk preference that are necessary to model the contractor’s risk attitude, including the lottery concept, utility theory, and the delta property. The optimality equation is formulated, the model components are defined, and the model is solved by stochastic dynamic programming. The main results are the optimal construction plans and risk-adjusted project costs, both of which reflect the dynamics of subsurface construction, the uncertainty about geologic variability as a function of available information, and the contractor’s risk preference.
This paper presents a new design environment based on Multi-Agents and Virtual Reality (VR). In this research, a design system with a virtual reality function was developed. The virtual world was realized by using GL4Java, liquid crystal shutter glasses, sensor systems, etc. And the Multi-Agent CAD system with product models, which had been developed before, was integrated with the VR design system. A prototype system was developed for highway steel plate girder bridges, and was applied to a design problem. The application verified the effectiveness of the developed system.
Individual views on a building product of people involved in the design process imply different models for planning and calculation. In order to interpret these geometrical, topological and semantical data of a building model we identify a structural component graph, a graph of room faces, a room graph and a relational object graph as aids and we explain algorithms to derive these relations. The application of the technique presented is demonstrated by the analysis and discretization of a sample model in the scope of building energy simulation.
Many problems related to data integration in AEC can be better tackled by an approach that takes into account the heterogeneity of tasks, models and applications but does not require continuous consistency of the evolving design data, at each data management operation. Such an approach must incorporate adequate services that can facilitate reintegration of concurrently modified data at reasonably selected coordination points. In this paper we present a set of methods which, used in combination, can achieve that goal. After a description of the principal envisaged cooperative work scenario each of these methods is discussed in detail and current observations drawn from their software realisation are given. Whilst the suggested approach is valid for any EXPRESS-based data model, the practical focus of work has been on facilitating IFC-driven integration.
Integrated structural engineering system usually consists of large number of design objects that may be distributed across different platforms. These design objects need to communicate data and information among each other. For efficient communication among design objects a common communication protocol need to be defined. This paper presents the elements of a communication protocol that uses a mediator agent to facilitate communication among design objects. This protocol is termed the Mediative Communication Protocol (MCP). The protocol uses certain design communication performatives and the semantics of an Agent Communication language (ACL) mainly the Knowledge and Query Manipulation Language (KQML) to implement its steps. Details of a Mediator Agent, that will facilitate the communication among design objects, is presented. The Unified Modeling Language (UML) is used to present the Meditative protocol and show how the mediator agent can be use to execute the steps of the meditative communication protocol. An example from structural engineering application is presented to demonstrate and validate the protocol. It is concluded that the meditative protocol is a viable protocol to facilitate object-to-object communication and also has potential to facilitate communication among the different project participants at the higher level of integrated structural engineering systems.
Physically Based Modeling and Multi-Physical Simulation System for Wood Structure Fire Performance
(2004)
This research is devoted to promoting the performance-based engineering in wood structure fire. It looks into the characteristic of the material, structural composing and collapse detecting to find out the main factors in the wood structure collapse in fire. The aim of the research is to provide an automatic simulation platform for the complicated circulation. A physically based model for slim member for beams and columns and a frame of multi-physical simulation are provided to implement the system. The physically based model contains material model, structural mechanics model, material mechanics model, as well as geometry model for the compositive simulation. The multi-physical simulation is built on the model and has the capacity to carry out a simulation combining structural, fire (thermal, CFD) and material degradation simulation. The structural and fire simulation rely on two sophisticated software respectively, ANSYS (an FEA software) and FDS (with a core of CFD). Researchers of the paper develop system by themselves to combine the two existing ones. The system has the capability to calculate the wood char to find out the loss of cross-section and to detect the collapse caused in different ways. The paper gives a sample of Chinese traditional house to show how this simulation system works.
Recently, many reseraches on active control systems of building structures are preformed based on modern control theory and are installed real buildings. The authors have already proposed intelligent fuzzy optimal active control (IFOAC) systems. IFOAC systems imitate intelligent activities of human brains such as prediction, adaptation, decision-kaking and so on. In IFOAC systems, objective and subjective judgements on the active control can be taken into account. However, IFOAC systems are considered to be suitable for far-field erathquake and control effect becomes small in case of near-field earthqaukes which include a few velosity pules with large amplitudes. To improve control effect in case of near-souece earthquakes, the authors have also proposed hybrid control (HC) systems, in which IFOAC systems and fuzzy control system are combined. In HC systems, the fuzzy control systems are introduced as a reflective fuzzy active control (RFAC) system and imitates spinal reflection of human. In HC systems, active control forces are activated to buildings in accordance with switching rules on active control forces. In this paper, optimizations on fuzzy control rules in RFAC system and switching rules of active control forces in HC system are performed by Parameter-Free Genetic Algorithms (PfGAs). Here, the optimization is performed by using different earthquake inputs. The results of digital simulations show that the HC system can reduce maximal response displacements under restrictions on strokes of the actuator effectively in case of a near-source earthquake and the effectiveness of the proposed HC system is discussed and clarified.
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.
Change management has been the focus of different IT systems. These IT systems were developed to represent design information, record design rationale, facilitate design coordination and changes. They are largely based on managing reactive changes, particularly design changes, in which changes are recorded and then propagated to the relevant project members. However, proactive changes are hardly dealt with in IT systems. Proactive changes require estimating the likelihood of occurrence of a change event as well as estimating the degree of change impacts on project parameters. Changes in construction projects often result from the uncertainty associated with the imprecise and vague knowledge of much project information at the early stages of projects. This is a major outcome of the case studies carried out as part of this research. Therefore, the proposed model considers that incomplete knowledge and certain project characteristics are always behind change causes. For proactive changes, predicting a change event is the main task for modelling. The prediction model should strive to integrate these main elements: 1) project characteristics that lead to change 2) causes of change, 3) the likelihood of change occurrence, and 4) the change consequences. It should also define the dependency relationships between these elements. However, limited data (documented) are only available from previous projects for change cases and many of the above elements can only be expressed in linguistic terms. This means that the model will simulate the uncertainty and subjectivity associated with these sets of elements. Therefore, a fuzzy model is proposed in this research to capture these elements. The model analyses the impact of each set of elements on the other by assigning fuzzy values for these elements that express the uncertainty and subjectivity of their impact. The main aim is to predict change events and evaluate change effects on project parameters. The fuzzy model described above was developed in an IT system for operational purposes and was designed as a Java package of components with their supporting classes, beans, and files. This paper describes the development and the architecture of the proposed IT system to achieve these requirements. The system is intended to help project teams in dealing with change causes and then the change consequences in construction projects.
This paper presents an evaluation system for steel structures of hydroelectric power stations, including hydraulic gates and penstocks, based on Fault Tree Analyasis (FTA) and performance maps. This system consists of fault tree diagrams of FTA, performance maps, design and analysis systems, and engineerin databases. These four modules are integrated by appropriate hyperlinks so that the user of this system can use it easily and seamlessly. A well developed system was applied to some illustrative example cases, and they showed that the developed methodology and system worked well and the users found the system useful and effective for their maintenance tasks at powerstations.
This paper presents results of a study on distributed, or parallel, evolutionary computation in the topological design of steel structural systems in tall buildings. It describes results of extensive experimental research on various parallel evolutionary architectures applied to a complex structural design problem. The experiments were conducted using Inventor 2003, a networkbased evolutionary design support tool developed at George Mason University. First, a general introduction to evolutionary computation is provided with an emphasis on recent developments in parallel evolutionary architectures. Next, a discussion of conceptual design of steel structural systems in tall buildings is presented. Further, Inventor 2003 is briefly introduced as well as its design representation and evolutionary computation characteristics. Next, the results obtained from systematic design experiments conducted with Inventor 2003 are discussed. The objective of these experiments was to qualitatively and quantitatively investigate evolution of steel structural systems in tall buildings during a distributed evolutionary design process as well as to compare efficiency and effectiveness of various parallel evolutionary architectures with the traditional evolutionary design approaches. Two connectivity topologies (ring topology and fully-connected topology) have been investigated for four populations of structural designs evolving in parallel and using various migration strategies. Also, results of the initial sensitivity studies are reported in which two ways of initializing distributed evolutionary design processes were investigated, using either arbitrarily selected designs as initial parents or randomly generated ones. Finally, initial research conclusions are presented.
The method of the finite elements is an adaptable numerical procedure for interpolation as well as for the numerical approximation of solutions of partial differential equations. The basis of these procedure is the formulation of suitable finite elements and element decompositions of the solution space. Classical finite elements are based on triangles or quadrangles in the two-dimensional space and tetrahedron or hexahedron in the threedimensional space. The use of arbitrary-dimensional convex and non-convex polyhedrons as the geometrical basis of finite elements increases the flexibility of generating finite element decompositions substantially and is sometimes the only way to get a clear decomposition...
A Multi-objective Model for Optimizing Construction Planning of Repetitive Infrastructure Projects
(2004)
This paper presents the development of a model for optimizing resource utilization in repetitive infrastructure projects. The model provides the capability of simultaneous minimization of both project duration and work interruptions for construction crews. The model provides in a single run, a set of nondominated solutions that represent the tradeoff between these two objectives. The model incorporates a multiobjective genetic algorithm and scheduling algorithm. The model initially generates a randomly selected set of solutions that evolves to a near optimal set of tradeoff solutions in subsequent generations. Each solution represents a unique scheduling solution that is associated with certain project duration and a number of interruption days for utilized construction crews. As such, the model provides project planners with alternative schedules along with their expected duration and resource utilization efficiency.
The paper investigates accuracy of deflection predictions made by the finite element package ATENA and design code methods ACI and EC2. Deflections have been calculated for a large number of experimental reinforced concrete beams reported by three investigators. Statistical parameters have been established for each of the technique at different load levels, separately for the beams with small and moderate reinforcement ratio.
Efforts to define standards for representing AEC/FM data have been fairly successful. However defining a standard reference process model has not met with the same success. Yet almost every conceptual modelling or software development project starts by defining the business processes to be supported and the related requirements to be satisfied. This paper describes a new process-centred methodology for user requirements capture developed in the ICCI project (IST-2001-33022). Its essence is in recognising user requirements and use cases in the context of the real construction process, identifying the actors and roles for each individual activity and associating these activities with information, communication and standardisation requirements on the basis of a formalised specification, named the Process Matrix. In the paper we outline the history of process matrix development, introduce the basic structure of the matrix and show how it can be further extended and refined. We present also a web-based software implementation of the developed approach, describe how it has been used in ICCI and outline further perspectives.
A comprehensive framework of information management system for construction projects in China has been established through extensive literature survey and field investigation. It utilizes the potential information technologies and covers the practical management patterns as well as the major aspects of construction project management. It can be used to guide and evaluate the design of the information management systems for construction projects in order to make the system to be applicable to a wide variety of construction projects and survive the changes in project management.
The goal of the research is the development of a computer system to plan, simulate and visualize erection processes in construction. In the research construction cranes are treated as robots with predefined degrees of freedom and crane-specific motion planning techniques are developed to generate time-optimized and collision-free paths for each piece to be erected in the project. Using inverse kinematics and structural dynamics simulation, the computer system then computes the crane motions and velocities necessary to achieve the previously calculated paths. The main benefits of the research are the accurate planning and scheduling of crane operations leading to optimization of crane usage and project schedules, as well as improving overall crane safety in the project. This research is aimed at the development of systems that will allow computer-assisted erection of civil infrastructure and ultimately to achieve fully-automated erection processes using robotic cranes...
Buildings require both for construction and, due to their comparatively long life cycle for maintenance, significant raw material and energy resources. So far available knowledge about resource consumption during an entire life cycle of a building is still quite rare, because various criteria affect each other and/or overlay mutually. In this contribution a model based software concept is presented using an integrated approach for life cycle simulation and assessment of buildings. The essential point of the development consists of connecting an IFC compliant product model of a building via the Internet with data bases for the resource and energy requirement of building materials. Furthermore, numerical simulations allow calculating and minimizing the energy consumption, the resource requirement, the waste streams and also the noxious emissions. In the context of this paper we present the first release of software programs for architects and engineers, which help them to evaluate their design decisions objectively in early planning steps. Additionally the usage of the software is demonstrated by a test case study for a real world building. By applying this software in practice a substantial contribution for saving energy and natural resources can be provided in the sense of sustainable and ecological building design.
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 goal of the research is to increase the understanding of dynamic behaviors during the crane operation, and develops computer-aided methods to improve the training of crane operators. There are approximately 125,000 cranes in operation today in the construction industry, responsible for major portion of erection activities. Unfortunately, many accidents occur every year in the U.S. and other countries related to the operation of cranes in construction sites. For example on November 28, 1989 a tower crane collapse during the construction of a building in San Francisco killing four construction workers, one civilian and injuring 28. According to the statistics from Occupational Safety Health Administration (OSHA), there were 137 crane-related fatalities from 1992 to 2001 in the US. A well-known internet website that keeps track of crane-related accidents (craneaccidents.com), reports 516 accidents and 277 fatalities from 2000 to 2002. These statistics show that even though many measures have been taken to decrease the number of crane-related accidents (Braam, 2002), the number of crane related accidents is still very large. It is important to recognize that each construction related fatality is not only a great human loss but also increases the costs of insurance, lawsuits, and the construction budget due to delay of a project (Paulson 1992)...
The complexity of the relationships between the actors of a building project requires high efficiency in communication. Among other things, data sharing is crucial. The exchange of data is made possible by interfaces between expert programs, which rely on product models. The latter are neutral standards with formal definitions of building objects and their attributes. This paper deals with the state of the art and the research activities concerning product models in the steel construction domain and the advantages provided by this technology for the sector.
Modeling of Freeway Traffic
(2004)
An integrated modeling of freeway traffic is developed, whose implementation in an uniform computer –aided simulation model facilitate comparative evaluation and systematic coupling of several traffic simulations, traffic controls, traffic measurements and traffic scenarios. The integrated modeling of freeway traffic is a basic mapping of freeway networks, control methods, measurements and different simulations of traffic flow...
Particle Simulation and Evaluation of Personal Exposure to Contaminant Sources in an Elevation Space
(2004)
An elevator, which figures a small volume, is normally used by everyone for a short period of time and equipped with simple ventilation system..Any contaminant released within it may cause serious problem. This research adapt a fire and smoke simulation software (FDS) into non-fire indoor airflow scario. Differently from previous research, particles are chosen as a risk evalution unit. A personal and multi-personal exposure model is proposed. The model takes the influence of the human thermal boundary, coughing, inhalation, exhalation, standing position, and the fan factor into account. The model is easy-to-use and suitable for the design of elevator system in practice.
Pre-stressed structural elements are widely used in large-span structures. As a rule, they have higher stiffness characteristics. Pre-stressed rods can be applied as girders of different purpose, and as their separate parts, e.g. rods of trusses and frames. Among numerous ways of prestressing the compression of girders, trusses, and frames by tightenings from high-strength materials is under common application.
The paper summarizes a part of research carried out in ICCI project and provides a current review of ICT infrastructures supporting collaboration. It covers taxonomies, protocols, standards, components, typical subsystems as well as future trends and recommendation for two most important technologies with applications in AEC: (1) EIP (Enterprise information portal) – a single gateway to a company's information, knowledge base, and applications for all actors; (2) RTC (Real-Time Communication and Collaboration technologies) that provide means for asynchronous communication between geographically dislocated people using ICT. Proposed future developments are: orientation towards web services - with building information models, business intelligence, personalization, AEC information retrieval, p2p workspaces and grids.
The highway product model based on the length information of the centerline, and the application system is developed. This paper shows the schema and the modeling process of the product model, which includes geometric elements such as an alignment, lanes, sidewalks, shoulders and sprits, and accessories such as guard fences, plantings and signs. Furthermore, The Highway Sequence Editor (HSE) is developed as an application system to verify the model.
The Priority Programme ‘Network Based Co-operation in Structural Engineering’ of the ‘German Research Foundation’ (DFG) has been established in the year 2000. This paper describes and discusses the main research directions and first results of the workgroup ‘Distributed Product Models’. The five projects of the workgroup have developed completely different solutions for specific application domains. Each solution concept deals with a consistent product modeling and knowledge processing in a distributed environment in the planning process. The individual solution approaches of the projects are described and the underlying basic assumptions are discussed. A unified system architecture is described for all projects of the workgroup. Two different approaches (object-oriented and graph-based models) have been introduced for product and knowledge modeling. The common structure of these models will be explained to fully understand the differences of these modeling approaches. Finally the concepts for co-operative work and conflict management in a distributed environment are described: The solution approaches will be distinguished by classifying the supported co-operation according to time. A final scientific summary describes the state-of-the-art in network based co-operation in structural engineering: The role of research directions like knowledge modeling, standard product modeling and versioning in the distributed planning process will be explained.
An architecture of a distributed planning system for the building industry has been developed. The emphasis is on highly collaborative environments in steelwork, timber construction etc. where designers concurrently handle 3D models. The overall system connects local design systems by the so-called Design Framework DFW. This framework consists of the definition of distributed components and protocols which make the collaborative design work. The process of collaborative design has been formalized on an abstract level. This paper describes how this has been done. A sample is given to illustrate the mapping of concrete scenarios of the ‘real design world’ to an abstract scenario level. This work is funded by the Deutsche Forschungsgemeinschaft DFG as part of the project SPP1103 (Meißner et al. 2003).
The synchronous distributed processing of common source code in the software development process is supported by well proven methods. The planning process has similarities with the software development process. However, there are no consistent and similarly successful methods for applications in construction projects. A new approach is proposed in this contribution.
Today’s building industry not only demands more and more reduced construction time on building site, but also an advanced and mostly construction attendant design phase. Even though there is software available to support design processes in distributed environments, most applications only support simple document based exchange of information. In this paper a knowledge based system is presented to support cooperative, comprehensive design processes in distributed environments. The presented research project is financially supported by the German Research Community (DFG – Deutsche Forschungsgemeinschaft).
Current disaster management procedures rely primarily on heuristics which result in their strategies being very cautious and sub-optimum in terms of saving life, minimising damage and returning the building to its normal function. Also effective disaster management demands decentralized, dynamic, flexible, short term and across domain resource sharing, which is not well supported by existing distributing computing infrastructres. The paper proposes a conceptual framework for emergency management in the built environment, using Semantic Grid as an integrating platform for different technologies. The framework supports a distributed network of specialists in built environment, including structural engineers, building technologists, decision analysts etc. It brings together the necessary technology threads, including the Semantic Web (to provide a framework for shared definitions of terms, resources and relationships), Web Services (to provide dynamic discovery and integration) and Grid Computing (for enhanced computational power, high speed access, collaboration and security control) to support rapid formation of virtual teams for disaster management. The proposed framework also make an extensive use of modelling and simulation (both numerical and using visualisations), data mining (to find resources in legacy data sets) and visualisation. It also include a variety of hardware instruments with access to real time data. Furthermore the whole framework is centred on collaborative working by the virtual team. Although focus of this paper is on disaster management, many aspects of the discussed Grid and Visualisation technologies will be useful for any other forms of collaboration. Conclusions are drawn about the possible future impact on the built environment.
In this paper we present a computer aided method supporting co-operation between different project partners, such as architects and engineers, on the basis of strictly three-dimensional models. The center of our software architecture is a product model, described by the Industry Foundation Classes (IFC) of the International Alliance for Interoperability (IAI). From this a geometrical model is extracted and automatically transferred to a computational model serving as a basis for various simulation tasks. In this paper the focus is set on the advantage of the fully three-dimensional structural analysis performed by p-version of the finite element analysis. Other simulation methods are discussed in a separate contribution of this Volume (Treeck 2004). The validity of this approach will be shown in a complex example.
Current building product models explicitly represent components, attributes of components, and relationships between components. These designer-focused product models, however, do not represent many of the design conditions that are important for construction, such as component similarity, uniformity, and penetrations. Current design and construction tools offer limited support for detecting these construction-specific design conditions. This paper describes the ontology we developed using the manufacturing concept of features to represent the design conditions that are important for construction. The feature ontology provides the blueprint for the additions and changes needed to transform a standard product model into a constructionspecific product model. The ontology formalizes three classes of features, defines the attributes and functions of each feature type, and represents the relationships between features explicitly. The descriptive semantics of the ontology allows practitioners to represent their varied preferences for naming features, specifying features that result from component intersections and the similarity of components, and grouping features that affect a specific construction domain. A software prototype that implements the ontology enables practitioners to transform designer-focused product models into feature-based product models that represent the construction perspective.
A wide variety of behavioural models exist in microscopic traffic simulation. Commercial programms often use closed-source policies and are confined to their respective simulation platforms. Open-source approaches mainly focus on distinctive, highly specialized traffic situations. In the scope of this paper, an open-source framework for developing modular, objectoriented simulation systems is presented, capable of simultaneously accommodating different driving models and enabling the user to modify and extend the catalogue of driving behaviours. The existing driving behaviours and the computational implementation of the simulation are being described.
There exists a big gap between the capabilities of current 3D-CAD applications and their actual usage in practice. Many architects and planners still prefer to draft in 2D because the benefits of 3D modeling are difficult to explain. This presentation offers a basis to view the 3D building model not merely as the source for 2D plan generation. By adding extra dimensions like Time and Cost to the 3D building model it becomes possible to generate dynamic information on building construction progress with regards to used material, resources and cost. These additional benefits are key elements to many planners and contractors and may therefore widen the acceptance of 3D building modeling in general.
Development and Analysis of Sparse Matrix Concepts for Finite Element Approximation on general Cells
(2004)
In engineering and computing, the finite element approximation is one of the most well-known computational solution techniques. It is a great tool to find solutions for mechanic, fluid mechanic and ecological problems. Whoever works with the finite element method will need to solve a large system of linear equations. There are different ways to find a solution. One way is to use a matrix decomposition technique such as LU or QR. The other possibility is to use an iterative solution algorithm like Conjugate Gradients, Gauß-Seidel, Multigrid Methods, etc. This paper will focus on iterative solvers and the needed storage techniques...