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Modification Management for Construction Processes

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Tsinghua Science and Technology 2008年第S1期13卷 185-191页

作者： Wolfgang Huhnt Sven Richter Felix Enge Institute of civil engineering Berlin Institute of Technology

This paper presents an approach to handle different types of subsequent modifications in construction processes. It is focused on a formalized approach with the objective that effects of subsequent modifications are detected automatically. The approach presented in this paper makes use of an existing modeling technique specifically focused on construction processes. The modeling techniques result in a process description where all technological interdependencies between construction activities are considered and where consistency between the sequence of activities and the history of components is guaran-teed. This modeling technique is expanded by an existing concept for handling versions and dependencies between objects. The integration of these different concepts makes it possible to track effects of relevant types of subsequent modifications in construction processes on a formalized basis. Effects of subsequent modifications are detected by algorithms, different versions can be compared by algorithms and different versions are stored so that subsequent modifications are documented. The innovation of the approach presented is the completeness. Effects of different relevant types of subsequent modifications in construction processes are tracked on a formalized basis.

关键词： construction processes process modeling subsequent modifications

Development of site suitability analysis system for riverbank filtration

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Water Science and engineering 2010年第1期3卷 85-94页

作者： Sang-il LEE Sang-sin LEE Department of civil and Environmental engineering Dongguk University

Site selection plays a crucial role in riverbank filtration for sustainable water availability and quality. Choosing the most appropriate from among multiple candidate sites requires a complex procedure, involving many tangibles and intangibles. In this study, the Analytic Hierarchy Process （AHP）, which selects the optimal alternative by hierarchically classifying various attributes and then quantifying the importance of each attribute, was used to prioritize candidate locations for riverbank filtration. A GIS-based computer program was developed to automate the assessment process. The developed software was applied to the Han River in Korea. Analysis of four candidate sites reveals that a site that has better water quality and connectivity to the neighboring purification facility is more suitable than other locations.

关键词： riverbankfiltration AHP site suitability," Han River

Industry Foundation Classes Based Integration of Architectural Design and Structural Analysis

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Journal of Shanghai Jiaotong university(Science) 2011年第1期16卷 83-90页

作者：秦领邓雪原刘西拉 Department of civil engineering Shanghai Jiaotong University

The numerous construction projects in China provide the best environment for the development of information technology applied in building *** commercial CAD/CAE software applications are purchased by design firms for multi-disciplinary design ***,researches on integration and interoperability are seldom *** study pursues a breakthrough point of integration in the architectural and structural domains and expects further development in other aspects.A central building information modeling (BIM) framework based on the industry foundation classes (IFC) is proposed to handle the data exchange between IFC-compatible architectural models and structural models.A central XML(extensible markup language)-based unified finite element model (FEM) is proposed for model conversion among various commercial structural CAE software *** addition to bidirectional data interfaces among IFC-based BIM,XML-based FEM and various commercial FEMs,some other components such as visualization,calculation and model editing/check are also equipped into the prototype system.

关键词： integration industry foundation classes (IFC) building information modeling (BIM)

Performance Investigation of 2D Lattice Boltzmann Simulation of Forces on a Circular Cylinder

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Transactions of Tianjin University 2010年第6期16卷 417-423页

作者：陈同庆张庆河程亮 School of civil engineering Tianjin University Key Laboratory of Harbor and Ocean engineering Ministry of Education of China School of civil and Resource engineering The University of Western Australia

The lattice Boltzmann method (LBM) is employed to simulate the uniform flow past a circular cylinder. The performance of the two-dimensional LBM model on the prediction of force coefficients and vortex shedding frequency is investigated. The local grid refinement technique and second-order boundary condition for curved walls are applied in the calculations. It is found that the calculated vortex shedding frequency, drag coefficient and lift coefficient are consistent with experimental results at Reynolds nu...

关键词： lattice Boltzmann method flow past a circular cylinder large eddy simulation grid refinement secondorder curved boundary treatment drag and lift coefficients

Effect of contact thermal resistance on temperature distributions of concrete-filled steel tubes in fire

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Journal of Harbin Institute of Technology(New Series) 2011年第1期18卷 81-88页

作者：吕学涛杨华张素梅 School of civil engineering Harbin Institute of Technology

To predicate the temperature distribution of concrete-filled steel tubes(CFSTs) being exposure to fire,a finite element analysis model was developed using a finite element package,ANSYS.A suggested value of contact thermal resistance was therefore proposed with the supporting of massive numbers of collected test *** analysis was conducted subsequently towards the cross-sectional temperature distribution of CFST columns in four-side fire,in which the exposure time,width of the cross section,steel ratio were taken into account with considering contact thermal *** was found that contact thermal resistance has little effect on the overall temperature regulation with the exposure time,the width of cross-section or the change of steel ***,great temperature dropping at the concrete adjacent to the contact interface,and gentle temperature increase at steel tube,exist if considering contact thermal *** results of the study are expected to provide theoretical basis for the fire resistance behavior and design of the CFST columns being exposure to fire.

关键词： contact thermal resistance temperature distribution concrete-filled steel tube heal transfer

Analyzing variations in spatial critical gaps at two-way stop controlled intersections using parametric and non-parametric techniques

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Journal of Traffic and transportation engineering(English Edition) 2021年第1期8卷 129-138页

作者： Digvijay S.Pawar Gopal R.Patil Department of civil engineering Indian Institute of Technology HyderabadKandi 502285India Department of civil engineering Indian Institute of Technology BombayPowai 400076India

At two-way stop controlled(TWSC)intersections drivers on minor stream are generally at risk because of the difficulty in judging safe gap between major stream *** misjudgment by the driver while choosing gap may result in a collision with major stream *** paper provides important insights for determining and analyzing spatial critical gaps of drivers at high speed and medium speed TWSC *** critical gap line(CGL)fitted for the accepted and rejected gaps using parametric(binary logit model-BLM)and non-parametric(support vector machines-SVM)techniques gives critical gap values at 15 th,50 th and 85 th percentile *** evaluation of spatial critical gap with respect to major road vehicle(conflicting vehicle)speed makes it easier to understand the impact of variation in speed on spatial gaps accepted by the drivers on the minor *** logit models developed revealed that the probability of accepting gap decreases with increase in the speed of the conflicting vehicle and it increases with increase in the distance of conflicting *** spatial critical gaps estimated using support vector machines were found in close approximation with those estimated using binary logit *** study results showed that SVMs have very good potential to be an alternative tool for the estimation of driver's critical *** spatial critical gaps corresponding to 15 th,50 th and 85 th percentile speeds for medium speed intersections were 32 m,38 m and 46 m respectively and for high speed intersections these values were 64 m,76 m and 104 m *** increase in the magnitude of gap value with respect to the percentile speed clearly states the effect of speed on spatial *** insights from the study can be used to suggest various measures to improve the safety of crossing drivers at uncontrolled intersections.

关键词： Traffic engineering Spatial critical gaps Uncontrolled intersections Logit model SVM Driver behavior

Effects of Temperature Variations on Safety of Reinforced Concrete Structures During Construction

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Journal of Shanghai Jiaotong university(Science) 2014年第2期19卷 139-145页

作者：黄科锋刘西拉 Department of civil engineering Shanghai Jiaotong University

Since 1960s, many research works on the reinforced concrete structure have been published and some concise and practical calculation methods for safety control during construction have been achieved. The reinforced concrete structure during construction is a time-dependent structure which consists of a partly completed structure and a formwork-shore system. Experience shows that the most critical condition of the time-dependent structure may happen when the formwork-shore system is partly removed or reset and accidents may occur. In the present paper, effect of ambient temperature variation between day and night is considered, new structural models for reinforced concrete frames, slab-column systems and shear wall structures are proposed, and a new software named Safety Analysis During Construction Considering Temperature(SACT) is also introduced. Compared with on-site measurements, the software SACT is validated for application on construction site.

关键词： reinforced concrete structure shore system safety analysis construction temperature variation

Analysis and Calculation of Axial Stiffness of Tubular X-joints under Compression on Braces

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Journal of Shanghai Jiaotong university(Science) 2009年第4期14卷 410-417页

作者：邱国志赵金城 Department of civil engineering Shanghai Jiaotong University

This paper introduces the influence factors of axial stiffness of tubular X-joints. The analysis model of tubular joints using plate and shell finite element method is also made. Systematic single-parameter analysis of tubular X-joints is performed using Ansys program. The influences of those factors, including ratio of brace diameter to chord diameter （β）, ratio of chord diameter to twice chord thickness （γ）, ratio of brace wall thickness to that of chord （τ）, brace-to-chord intersection angle （θ）, and chord stress ratio, ratio of another brace diameter to chord diameter, in-plane and out-of-plane moment of braces, etc., on stiffness of tubular X-joints are analyzed. Two non-dimensional parameters-joint axial stiffness factor ηN and axial force capacity factor ωN are proposed, and the relationship curve of the two factors is determined. Computational formulas of tubular X-joint axial stiffness are obtained by multi-element regression technology. The formulas can be used in design and analysis of steel tubular structures.

关键词： tubular structures circular hollow section (CHS) X-joints axial stiffness parameter analysis

Fabrication and Compressive Properties of Expanded Polystyrene Foamed Concrete:Experimental Research and Modeling

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Journal of Shanghai Jiaotong university(Science) 2013年第1期18卷 61-69页

作者：吴震陈兵刘宁 Department of civil engineering Shanghai Jiaotong University

As the construction of high-rise building to expand the product line of lightweight concrete. becomes popular, improvement and innovation are required In this paper, two ways of fabricating lightweight concrete were combined to make a new kind of super lightweight concrete. Normal aggregate is replaced with expanded polystyrene （EPS） granule, while foam is introduced to facilitate fabrication process. As a result, super lightweight concrete denoted as EPS foamed concrete is fabricated, whose bulk density is less than 500 kg/m3. Compressive properties of EPS foamed concrete with bulk density 300--500 kg/m3 were investigated by stress-strain curve. It＇s demonstrated that the compressive strength ranges from 0.7 to 2.5 MPa, which is higher than that of similar products. Furthermore, low elastic module and high residual to ultimate strength ratio ensure its excellent deformation and energy absorption capacity. At last, numerical analysis was performed to interpret the inherent variation of elastic modulus and failure mechanism of this material. The results show that EPS foamed concrete is a kind of super lightweight, easy to fabricate material with excellent compressive property and profound utilization potential.

关键词： expanded polystyrene (EPS) foamed concrete compressive property stress-strain curve