Punktuelles Kleben mit Silikonen

Sizing of structural silicone bondings. Beside the up to now in detail investigated bonding of line‐type extension – e.g. with respect to the application case of glass facades the U‐type bonding geometry which has been chosen for the Herz‐Jesu church – point‐type bonding geometries are of interest for realisation as well. Concerning the term point‐type, not only bonded point supports are considered here but also U‐type, T‐type or flat bonding geometries of short length which are applied as discrete load introduction points on or in glass edges or glass surfaces. It is common to all these bonding applications that the free surfaces allow a significant lateral contraction affecting obviously the load bearing capabilities and properties. Based on experimental results of the research project “Geklebte Verbindungen im Glasbau (Bonded joints in glass constructions)” of the University of Applied Sciences Munich, the functionality and the potential sizing procedures of point‐type bonding geometries will be presented in this report in the context of subsequent theoretical studies.     

Verbundglasplatten – Schubverbund und Membrantragwirkung – Teil I

Laminated glass plates – shear compound and membrane action – Part I. The mechanical behaviour of laminated glass plates is governed by the interlayer shear stiffness and membrane action. The objective of the present work is the analysis of these two parameters and the development of a simple, safe and economic method for determining glass dimensions. In partI a temperature and load‐duration dependant shear modulus is determined for PVB from experimental data. Chapter 3 contains an analytic solution for two side supported laminated plates, based on sandwich theory and describes the creep‐buckling problem of compression elements. The part II (No. 2/2005) investigates the non‐linear behaviour of laminated plates. The load‐stress diagrams show that the curves for plates with a flexible shear interlayer are quite close to, or even exceed, the curve for a layered configuration with no interaction between panes. For this reason an overall boundary curve is developed, which applies conservatively to all the configurations. Owing to the flexibility of shear transfer between the glass panes, non‐linear action is exhibited at an earlier stage than with a monolithic condition. This flexibility significantly influences the actual strength of laminated glass units: when the shear transfer is poor – i.e. at high temperature or long load duration the strength lost in bending action is compensated by gains through membrane action.     

Verbundglasplatten – Schubverbund und Membrantragwirkung – Teil II (Fortsetzung aus Heft 1/2005 und Schluß)

Laminated glass plates – shear compound and membrane action. The mechanical behaviour of laminated glass plates is governed by the interlayer shear stiffness and membrane action. The objective of the present work is the analysis of these two parameters and the development of a simple, safe and economic method for determining glass dimensions. In partI a temperature and load‐duration dependant shear modulus is determined for PVB from experimental data. Chapter 3 contains an analytic solution for two side supported laminated plates, based on sandwich theory and describes the creep‐buckling problem of compression elements. The part II investigates the non‐linear behaviour of laminated plates. The load‐stress diagrams show that the curves for plates with a flexible shear interlayer are quite close to, or even exceed, the curve for a layered configuration with no interaction between panes. For this reason an overall boundary curve is developed, which applies conservatively to all the configurations. Owing to the flexibility of shear transfer between the glass panes, non‐linear action is exhibited at an earlier stage than with a monolithic condition. This flexibility significantly influences the actual strength of laminated glass units: when the shear transfer is poor – i.e. at high temperature or long load duration the strength lost in bending action is compensated by gains through membrane action.     

Eine Vollglaskonstruktion – Möglichkeiten und Probleme

An All‐Glass construction – possibilities and problems. Presented are the design and realisation of a consequent self bearing glass construction without steel framing or safety elements. No column or girder should derogate the transparent appearance of the face, which lead to realizing those parts in glass as well. The structural elements are glued together. Glue also connects the glass structure with the neighbouring building. Local loading at the bearing glass plates without any additional constructive elements is tested numerically and experimentally. The experimental construction was built to test constructive solutions and to gain substantiated experiences in the usage and erection of such kind of buildings.     

Möglichkeiten der Bemessung von Bauteilen aus Glas

Methods for design of structural elements made of glass. The application of structural elements made of glass became more common and nowadays appear to be standard. For the design of such elements legal conditions and background have to be obeyed. In addition knowledge about design rules and – for special problems – alternative methods and technical background is necessary. In this paper the past and present regulations and related questions for design of structural elements of glass are presented. Finally an outlook for future design methods and regulations in context with the modern concept of partial safety factors is given.     

点支式中空夹层玻璃的抗弯设计方法

使用有限差分方法,在点支式中空及夹层玻璃抗弯设计方法的基础上探讨点支式中空夹层玻璃的抗弯设计方法.在点支式中空玻璃抗弯设计中考虑宽厚比等尺寸因素的影响,且同时考虑因气温、气压变化而产生的荷载;在点支式夹层玻璃的抗弯设计中适当考虑了PVB(聚乙烯缩丁醛)层的作用.将中空夹层玻璃视为包含着夹层的中空玻璃,从而得到其抗弯设计方法.该设计方法计算结果与试验结果在一定程度上吻合,具有一定的实用价值.     

Toward a wire medium endoscope for MRI imaging

This paper shows, numerically and experimentally, that imaging is realizable with a strongly curved wire medium. In a first part, simulation results obtained for various curvatures are presented and sub-wavelength imaging on a wide bandwidth is demonstrated. It is also shown that the collimation phenomenon remains very effective for structures having a cross-section corresponding to about a hundredth of the wavelength. In a second part, experimental results are shown for transmission of a medical image through a 63° curved wire medium in which the receiving antenna has been inserted.     

Numerical study on horizontally curved steel-concrete composite beams subjected to hogging moment

The horizontally curved continuous composite steel-concrete beams, for instance, curved continuous composite bridges, have excellent qualities, such as quick construction, good seismic performance, saving construction formwork and convenience in spatial arrangement etc. At present, the application research of this kind of structures is becoming more of a concern, but very few studies have been conducted to study the mechanical performance of composite beams subjected to combined hogging (negative) bending and torsion. The purpose of the present study is to investigate the effects of curvatures on both elastic and inelastic behaviours of curved continuous steel-concrete composite beams in the interior support regions. Based on the experimental observations in a straight composite beam, a three-dimensional FE model capable of analysing the composite beams subjected to negative bending moment is built. Further numerical studies on curved composite beams with different curvatures are performed in this study. Strength and load carrying capacity, sectional strain distribution and movement of composite neutral axis before and after cracking, as well as the strain results of longitudinal reinforcing bars are investigated. Besides, the interaction equation for ultimate bending and torsional moments is proposed.     

A comprehensive study of externally venting flames—Part I: Experimental plume characteristics for through-draft and no-through-draft ventilation conditions and repeatability

Externally venting flames have been examined during a series of eight full-scale flashover tests. Furniture was used in a burn room larger than a standard one. The purpose of the work has been to investigate the likelihood of external fire spread from a burn room window with standard glass when the external facade is non-combustible. The effects on externally venting flames of internal ventilation conditions and wind have been studied in detail. Secondary fires and glass breakage have been examined. Repeatable experimental data and reliable information on externally venting flames have been generated for numerical model validation and performance-based design code development. In Part I of this two-part paper, the emphasis is on the repeatability of the experimental data on externally venting flames. A new averaging method introduced previously has been used for this purpose. In Part II, extensive comparisons are given with available experimental data and empirical approximations from the literature. Surface fits to the experimental data are also presented for communication purposes.     

新型插盘式脚手架的计算理论与设计公式

本文在试验研究的基础上得到了新型插盘式脚手架的相关计算参数,考虑脚手架立柱的初始弯曲,根据边缘屈曲准则推导了立柱承载力的设计计算公式。计算和分析表明:试验结果、数值计算结果与本文提出的设计公式所得结果间吻合很好。本文工作为新型插盘式脚手架的推广运用提供了实用的设计计算公式。     

Compressive behaviour of laminated structural glass members

Several experimental investigations in the past few years have highlighted the fact that the compressive strength of glass was significantly higher than its tensile strength, allowing new applications of glass in compression members. However, due to the high slenderness of structural glass elements made of thin glass panels, they tend to fail in a brittle manner. A substantial amount of fundamental research has been carried out in the past few years to investigate the stability behaviour of structural glass elements. However, although buckling of glass panels has been quite well studied, a very poor amount of research has been addressed to glass columns, which by contrast represent the most interesting case due to their direct application in buildings. In this paper, the results of ten compressive tests on glass panels and columns are presented and discussed. The main variables considered were slenderness of panels and the shape of the cross-section for columns. The results of six bending tests on monolithic and laminated glass panels are also shown, and the level of connection between the glass sheets was evaluated. A review of the theoretical background is provided and the results achievable with existing analytical models are compared.     

Versuche an Verbindungen für Glaskonstruktionen

Design of connections for glass structures. The paper describes recent developments in structural glass connections. Two types of connections are described – slip‐critical connections and bearing connections – and results of testing and analysis are presented. The paper concludes with one example application. The goal of the tests described above was to establish pilot sets of data to verify the assumptions used in the design of these connections. The tests also revealed several issues related to quality control that have to be carefully checked in order to reach the target strength.     

Granulated foam glass–ceramic material from zeolitic rocks

The objective of this research work was to investigate the production of granulated foam glass–ceramic material from zeolitic rocks. The investigations have shown that grinding raw materials to particle size less than 0.5 mm and adding 13.8% of alkali content provide production of material with the following properties: particle density – 340 kg/m³, strength – 1.6 MPa and water adsorption – 13% at firing temperature of 850 °C. Expanded zeolite with alkali content is a material of glass–ceramic composition with amorphous part of 38.6% and crystalline part of 61.4% that gives higher strength in comparison with sponge glass.     

The Politics of Local Environmental Management

Environmental management on the part of local government is now being accorded a high priority in certain parts of Australia. To date, for example, approximately 25 local councils in Victoria – either singly or jointly – have been involved in the development of Local Conservation Strategies (LCSs), most with some financial assistance from the Government of Victoria's Office of the Environment. The majority of these LCSs relate to urban rather than rural settings. There have been differences of approach depending upon such parameters as the initial professional training of the main officers concerned, the council's level of political commitment to the idea, and the socio-economic make-up of the local community.     

用界点分析法计算钢筋混凝土压弯构件的延性系数

本文分析了钢筋混凝土压弯构件的曲率分布规律,将两种工作状态在半跨长上的曲率简化为二段与三段直线分布,并推导出确定段与段之间分界点的公式,提出了适合于手算构件延性系数的方法。本文建议的公式与方法应用于24根钢筋混凝土压弯试件的分析,计算表明能获得满意的结果。本文还根据试验与理论分析对极限压应变的合理取值进行了论述,认为在非约束钢筋混凝土压弯构件的延性分析中取ε_u=0.003是合理的。     

Grout‐Verbindungen von Monopile‐Gründungsstrukturen – Trag‐ und Ermüdungsverhalten

Grouted Joint Connections of Monopile Support Structures – Structural and Fatigue Behaviour. This paper summarises the state of the art for grouted connections of support structures of Offshore Wind Energy Converters (OWECs). Results of numerical and experimental investigations of small and large scale tests of grouted joints which have been carried out within the research project “ForWind – TP V: Fatigue Assessment of Support Structures of Offshore Wind Energy Conversion Systems” at the Institute for Steel Construction, Leibniz Universität Hannover are presented. Furthermore the results of the numerical and experimental investigations are used for an exemplary calculation of a grouted joint connection of an OWEC located in the Baltic Sea. Besides the analysis of grouted joints with plain pipes the effects of an increased mechanical interlock due to shear keys on the fatigue design of grouted connections is demonstrated and fatigue classes for shear keys are presented.     

Structural analysis of FRP reinforced polymer concrete material

The paper deals with a study of precast elements made of polyester polymer concrete (PPC) reinforced with glass fibre rebars (GFRP). The paper describes the properties of the materials, which were tested on a microscopic scale using different experimental techniques such as porosimetry, scanning electron microscopy and petrography. Likewise, characterisation in a macro-scale was carried out to define the mechanical properties of the material (modulus of elasticity, stress–strain curve, ultimate strength and bond). Based on the latter properties, a relatively simple method is presented to estimate the ultimate bearing capacity of beams under bending load. The calculation method has been verified by testing beams and full-scale elements.     

Studies on damage and FRP strengthening of reinforced concrete beams by vibration monitoring

In this paper, modal characteristics of reinforced concrete beam specimens are identified using experimental test data. Nine concrete beam specimens were gradually damaged and the changes of dynamic parameters were monitored from initial to the failure state. Six of the specimens were strengthened with externally bonded CFRP sheets when the load reached approximately half of the predicted failure load. The identification methods based on measured modal parameters were utilized and the efficiencies of these methods were investigated. These methods include frequency changes, Modal Assurance Criterion (MAC), Coordinate Modal Assurance Criterion (COMAC) and modal curvatures. The comparison of the methods shows that the frequency changes are not fully capable of detecting damage and predicting the potency of strengthening. The MAC values can reveal the changes of overall stiffness of the beams during the load steps. The change of stiffness at each degree of freedom of beams evaluated by COMAC and modal curvatures show that the damage identification of the beam specimens is best described by modal curvature method.     

Analytische Lösungen von Rechenmodellen als Voraussetzung zur Überprüfung der Güte der in Rechenprogrammen angewendeten Strahlungsmodelle

Analytical solutions of computational modells as a requirement for verifiing the quality of radiation models applied in computa‐tional programs. The computational capabilities of investigations of the coupled energy transfer due to conduction, convection and radiation are undergoing far‐reaching innovations in last decades. Increasing computational speed and capacity were requirements for numerical modelling heat transfer. New possibilities in solving complex applications – e.g. radiative heat transfer – are available in CFD programs. Questions in surface temperature, temperature and velocity field, gas phase temper‐ature, heat flux due to radiation within absorbing, emitting and scattering media – e.g. in combustions chambers or at glass melting processes – have increased the development of radiation models in CFD. Radiation models are developed for several fields of applications. They were permanently extended and improved. The accuracy of radiation models and the possibility in modelling simple as well as complex radiation processes make them to useful and reliable tools in CFD. However, each of the models has its advantages and limits. The engineer has to choose for a radiation model which is practical and appropriate for the application.     

污秽绝缘表面电导特性的研究

输配电系统中 ,污秽的绝缘外表面在潮湿天气所发生的沿面闪络是引起输电线路故障的主要原因之一。加强对绝缘表面在此种情况下电导特性的基础研究 ,有助于进一步探究表面电导与污秽闪络的关系 ,有利于进行较为准确的绝缘在线监测工作。并可根据研究结果 ,采取相应措施以改进绝缘防污性能、进行有针对性的清洗、检修及更换等 ,以达到减少污闪事故的发生率、保障供电可靠性和安全性的目的。本文以污秽玻璃片为实验对象 ,在人工雾室中对其表面电导特性进行了大量的基础实验 ,得到了相关的实验结果。通过对实验结果的分析和总结 ,得到了一些有益的结论