Ein Lichtmast aus Glas für die Beleuchtung des Marktplatzes in Göppingen

A lighting mast made of glass for the market place in Goeppingen. The paper presents the design and construction details of glass – lighting masts, whose prototype was developed for the shadowless lighting of the market place in Goeppingen. The cross‐shaped mast consists of a 2.0 m high plate‐base made of stainless‐steel and of a 6.0 m high glass column, made of four wings of composite safety glass, screwed on the top of it. The wings are connected to a centrally placed steel core in such a way, that the structure provides in a catastrophe case the necessary residual bearing capacity. Four multifaceted mirrors, placed at a height of 8.0 m, reflect the light‐beams that are projected by projectors, situated at the ground.     

Aussteifung von Gebäudehüllen durch randverklebte Glasscheiben

Stabilisation of building envelopes by the use of circumferential glued glass panels. The pursuit of maximum transparency with increasingly filigree bearing structures fuels the possibility of using the glazing as a load bearing element that is able to transmit both lateral and in plane forces. Space grid structures with rectangular glass panes seem to be very capable for this purpose. In this case the linear bars are normally pin‐joint at nodes to minimise both cross sections and erection cost. It is common to triangulate space grid structures with rods or prestressed steel cables. These bracings could be omitted if the stiffening forces would be transmitted by the glazing. In the here considered system the glass panes are used as shear panels to stabilize the envelope. Therefore, the panes are glued to the space grid members along their perimeter. Details were designed and the load bearing behaviour of the connections and the glass elements were investigated and design rules developed. These rules consider the shear interaction in laminated glass elements, and the interaction of in plane and out of plane loads.     

Stahlglas‐Bauweise – an einer Treppe werden neue Perspektiven im Konstruktiven Glasbau sichtbar

A self‐supporting glass staircase. This staircase is unique in regard to its span and loading capacity so far, was shown at the fair “Glasstec 2004”. Structural engineers are stretched by ambitious load‐bearing structures of glass in two ways. With the material‐appropriate design and the construction of the details of the structure, creativity and profound knowledge of the behaviour of the material and the load‐bearing structure are demanded by them. Well founded knowledge is required to make the load‐bearing structures sufficiently safe and as economic as possible, because there are no design standards. This article reports on the construction and production of the staircase built in a method of construction called “reinforced glass” (termed according to its load carrying effect – compare with “reinforced concrete”). It starts with an abstract of this method of construction including the safety concept, which has been developed at the University of Technology of Hamburg‐Harburg. The proof of the structural safety, for which loading experiments were required as well, will soon be treated in this magazine.     

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.     

Experimental study on seismic performance of L‐shaped partly precast reinforced concrete shear wall with cast‐in‐situ boundary elements

In order to promote industrial production of reinforced concrete shear wall, a typical partly precast reinforced concrete shear wall with both end boundary elements cast‐in‐situ and the other part precast is experimentally studied. In this paper, three L‐shaped specimens of this kind and one completely cast‐in‐situ specimen as a control group are tested under low‐frequency cyclic loading to investigate their safety, applicability, and different characteristics. For the partly precast specimen, the vertical distributed reinforcements of precast part are equivalently spliced by grouting sleeves arranged along the center line of the wall whereas the horizontal reinforcements are directly anchored into the cast‐in‐situ boundary elements. During the test, the axial compression ratio of these specimens is fixed at 0.2, 0.3, and 0.5, respectively. Such test phenomena and test data including failure modes, yielding load and displacement, the skeleton curve, energy dissipation, stiffness degradation, ductility, and so on are observed, analyzed, and compared. Chinese code and American Concrete Institute code are adopted to estimate the bearing capacity. Results show that the partly precast specimens have good integrity. With the increase of axial compression ratio, the bearing capacity of these partly precast specimens increases whereas the ductility decreases. It is also found that the partly precast specimens have slightly lower bearing capacity compared with the cast‐in‐situ specimen as well as excellent deformation capacity and ductility, which indicates the tested partly precast shear wall has good and reliable seismic performance and can be used as a structural element in building construction.     

Tragfähigkeit von Lochleibungsverbindungen vorgespannter Glasscheiben zur Ausbildung von Anschlüssen im Konstruktiven Glasbau

Strength of bearing connections in toughened glass plates for the structural use. In steel structures due to their “infinite'” ductility the bearing connections are standard components of joints. Their design rules are based on simple engineering models. However if analogous bearing connections are subject of glazing structures the requirements on the materials' ductility cannot be met. Therefore interlayers out of mortar etc. in the hole surrounding the bolt have to be introduced such that a ductile load deformation behaviour can be reached reducing stress peaks and avoiding steel‐glass‐contact. On this basis design rules are to be established to predict the load carrying capacity of bolts in glass bearings. The following investigations describe the experimental and theoretical works to derive an engineering model for this purpose.     

基于国内外标准的结构用玻璃构件承载性能设计对比

目前,各国结构用玻璃设计标准相对其他传统建筑材料仍欠成熟,且其中关于玻璃构件承载性能的设计方法也存在较大的差异.为此,对比分析了我国与美、澳、英、欧等国家和地区结构用玻璃设计标准在适用范围、设计理论以及构件承载性能设计模型的异同.结果 表明:JGJ 113-2015《建筑玻璃应用技术规程》中对结构用玻璃设计标准的适用范...     

Interactive instabilities of thin‐walled laminated composite pultrusion box columns

The problem of interactive buckling and post‐buckling of intermediate length thin‐walled columns built of laminated plate elements subjected to compressive load has been proposed and solved analytically. Pultrusion columns have wide‐range applications in high‐rise building due to their low weight and high load carrying capacity. Classic stability theory and laminate theory were implemented to prove the existence of mixed‐mode buckling in thin‐walled pultrusion columns. Interactive stability modes can result in lower loading capacity of most compressive members and affects their post‐buckling behaviour in major proportions. Interactive buckling load analysis has been performed by means of a simplified theoretical model and verified by means of numerical analysis. The calculations were carried out for commonly used square section thin‐walled composite columns dimensions. The post‐buckling performance of selected sections has been investigated and an optimum layup configuration criterion for each section has been extracted according to pre‐ and post‐critical behaviour. Copyright © 2010 John Wiley & Sons, Ltd.     

带构造柱混凝土砌块墙体受压承载力有限元分析

利用ANSYS软件,对构造柱与混凝土砌块组合墙体进行竖向均布荷载作用下的受力性能非线性有限元分析,研究了不同因素如构造柱间距、纵向钢筋配筋率、层高及砌体弹性模量等,对构造柱荷载分配系数与组合墙体承载力的影响,提出了设置构造柱砌块组合墙的受压承载力计算公式。     

Zeitabhängige Traglaststeigerung von Pfählen am Beispiel der Elbphilharmonie

Time‐dependent set‐up of piles considering as example the Elb‐philharmonica. The extension of the Kaispeicher in the Hafencity Hamburg to the Elb‐philharmonica leads to a local load increase of the existing pile foundation. To determine the load bearing behaviour of the existing piles and the need for any extension of the foundations pile load tests on three piles have been performed. A comparison of the results with the data of three old pile load tests from the construction of the building in 1963 reveals that the bearing capacity as well as the stiffness of the piles have increased significance. A finite‐element‐analysis of the pile load tests based on additional measurements shows that the capacity increase can be partly explained by different boundary conditions of the load tests like e.g. pre‐loading, but that a big part of the increase must be due to other time‐dependent mechanisms. Most plausible explanations for this set‐up effect is the relaxation of hoop stresses around the pile after installation as well as a densification of the sand at the pile shaft due to cyclic ground water fluctuation.     

Experimental investigation of the influence of joint connection details between existing buildings and added new frames on failure mode of retrofitted slabs for the vertical expansion of old buildings: Part II

Dismantling entire existing buildings can be circumvented by adding additional frames to provide more residence, thus avoiding the need to reconstruct buildings. The alternatives are to construct new frames on old apartment buildings in order to avoid entirely dismantling existing buildings. The conventional wall frames for super structures added onto existing buildings are replaced by frames consisting of composite beams and steel columns to minimize beam depth and weight of the load from the added frames. This paper studied joint connection types for the rehabilitation of old buildings to withstand lateral loads. Details of the joints between newly added steel columns and existing slabs are presented in this paper. The structural behaviors of anchored joints between the new 3‐story composite frames and an existing 15‐floor building were significantly investigated through extensive experiments. Complex failure modes were identified based on the test of the wall foundation types and the anchor types connecting the base plates to existing slabs. The authors previously reported that the flexural load‐bearing capacity of slabs was the dominant load‐resisting capacity. The column–slab joint connections introduced with experimental demonstrations in this study are expected to contribute to enhancing the lateral capacity of the extended buildings.     

Experimental and numerical investigation of a full‐scale multistorey RC building under dynamic loading

A structural scheme of a typical precast multistorey reinforced concrete building incorporating flat‐slab and braced frame systems is presented. The building has been designed for seismic zones. First its dynamic parameters have been determined experimentally. Than the structure has been subjected to resonance vibration and impulse loads in order to yield cracking and other damage in the load‐bearing elements and their joints. The obtained experimental results have been interpreted from the seismic resistance viewpoint. The dynamic parameters and the structural elements damage nature for that building were the main subject of the experiments. Further theoretical investigation has been focused on examining the response of the building to real earthquakes. The experimentally obtained response of the building to vibration loading and the numerically calculated structural behaviour under real earthquakes have been compared. It was concluded that the building satisfies the seismic code requirements for zones with peak ground accelerations (PGA) less than 0·3 g. In order to adapt the building to seismic zones with higher PGA without any changes in the load‐bearing elements and their joints, it was proposed to use a base isolation system. Numerical simulation shows that the base‐isolated building represents a safe response to real earthquake records with PGA equal to 0·3 g. Hence the structure can be recommended for seismic zones with that PGA. Copyright © 2005 John Wiley & Sons, Ltd.     

Innovative Betone für Holz‐Beton‐Verbundkonstruktionen

Innovative concretes for timber‐concrete composite constructions. Timber‐concrete composite constructions are currently applied mainly for new buildings or when strengthening existing timber beam slabs. The load bearing capacity of timber‐concrete composite slabs is essentially affected by the material properties of the concrete slab and timber beam itself as well as the efficiency of bond between both parts. As nowadays a wide spectrum of different innovative concretes is available their applicability for timber‐concrete composite constructions has to be verified. In the following the focus is set for self‐consolidating concrete, steel fibre reinforced concrete, structural lightweight concrete, high‐strength and ultra high‐strength concrete. The advantages but also disadvantages of these concretes will be explained considering structural, economic and processing aspects and building physics.     

Experimental study on seismic performance of T‐shaped partly precast reinforced concrete shear wall with grouting sleeves

Prefabricated structure has prominent advantages such as easy control of construction quality, saving fabricating time and natural resources, and reducing environmental pollution and construction noise. The mostly used structural system in high‐rise buildings is reinforced concrete shear wall structure, which has high load capacity and lateral stiffness. Focusing on the connection of reinforcements, three T‐shaped partly prefabricated reinforced concrete shear walls and one cast‐in situ specimen in same dimensions as a control group are tested under low‐frequency cyclic loading to analyze their seismic performances in this paper. During the experiment, the axial compression ratio of specimens is fixed at 0.3, 0.4, and 0.5. Through the observation of phenomena and data analysis, hysteretic curve, skeleton curve, stiffness degradation, ductility, and load bearing capacity are compared and analyzed. The results show that partly prefabricated reinforced concrete shear wall has similar load bearing capacity with the cast in situ specimen, and it also has excellent ductility, stiffness, and energy‐dissipating capacity. The experimental results and analysis indicate that partly prefabricated reinforced concrete shear wall has outstanding seismic performances; under effective and reliable design, it can be used in building structures to play the same role as cast in situ components.     

Umgelenkte Lamellen aus kohlefaserverstärktem Kunststoff für freistehende Spannglieder im Konstruktiven Ingenieurbau

Behaviour of Deviated CFRP‐Strips Carbon fiber reinforced plastic (CFRP) has a number of excellent properties with a wide range of application possibilities in structural engineering. In the last two decades, the use of CFRP‐Strips as a reinforcement for concrete members has emerged as one of the most exciting and promising technologies in structural engineering. These strips could also be used for external prestressing of bridges or for unstrained ceilings in high building structures. Therefore the problematic of the end‐anchorage and the deviation of the strips, due to the sensitivity of the carbon fibers to transverse loads, has to be solved. Several research institutions have already suggested solutions for CFRP‐strip anchorage. In this paper the results of an experimental program of deviated CFRP‐strips at deviation saddle are introduced. The effects of the different parameters on the load bearing capacity, strain responses up to failure and the failure mode of the CFRP‐strip at the deviation saddle are investigated.     

Zum Tragverhalten von Stützen semi‐integraler Brücken

Load‐bearing behaviour of columns of integral bridges – realistic calculation of columns of integral bridges for the ultimate limit state Due to the complex and interactive load‐bearing behaviour, calculation of integral bridges is more expensive than the calculation of bridges with its superstructure uncoupled from the substructure. Apparently conservatively chosen reinforcement ratios lead to increased stiffness of the columns and thus inherently increased the constraining forces. Therefore, a greater reinforcement ratio is not imperatively connected with a better load‐bearing behaviour of the columns. To better understand the load‐bearing behavior of integral bridges, it is necessary to consider the physical non‐linearity in the calculation. In this contribution, the non‐linear behaviour of integral columns is examined by varying the cross section dimensions and the reinforcement ratios. The results are analyzed with regard to the columns ductility and the constraining forces. Finally, this contribution offers conceptual proposals, which can be used for the dimensioning of integral bridges.     

复合筒体结构在钢结构广播电视发射塔中的应用研究

根据钢结构广播电视发射塔的结构特点,外塔身往往作为结构的主要受力构件,井道仅承受自身荷载作用。淮安广播电视发射塔由于其外形方案独特,无法采用传统的高耸结构形式,且采用高层建筑中的"筒中筒"结构难以满足结构刚度和强度的要求,在对结构方案进行分析对比后,提出了钢板核心筒-钢管密柱-预应力柔性拉杆的复合筒体结构。通过采用预应力柔性拉杆和刚性水平支撑联系内钢板筒和外柱,使两者协同工作,共同抵抗水平荷载作用,且减小了外柱的计算长细比,提高了其稳定承载力。分析证明,结构刚度得到了较大的提高,结构周期由8.3 s减小为5.1 s。复合筒体结构在保证建筑外观的同时,可以满足结构受力和加工制作的要求。     

Zur Traglastoptimierung von rechteckigen Verbundstützen aus einbetonierten I‐Profilen – Lohnt sich der Einsatz von hochfestem Beton oder sind konventionelle Modifikationen genauso effizient?

Optimization of the load bearing capacity of rectangular composite columns and beam‐columns of fully encased I‐sections – is it worth to use HSC or are conventional modifications just as efficient? Composite columns and beam‐columns are efficient compression members. The question arises how far the usage of HSC can contribute to an increase of the load bearing capacity or if the restriction to f_ck ≤ 50 N/mm² acc. to current standards is sufficient. The efficiency of HSC and usual strengthening measures are shown and discussed in the following paper.     

Experimental study on seismic performance of concrete‐filled steel tabular frame‐shear wall structure with buckling‐resistant braces

Three specimens of concrete‐filled steel tubular (CFST) frame‐shear wall structures with a scaling ratio of 1:4 were designed and tested in the present study. Two of them were installed with triple‐steel tube buckling‐resistant braces (BRBs). The seismic performances of the specimens were evaluated by testing them under lateral cyclic loading with constant axially compressive load being applied on the tops of the columns and the shear wall. The structural performances, such as failure characteristics, hysteretic behaviour, skeleton curve, strength degradation, stiffness degradation, energy dissipation capacity and strains at different locations of the three specimens, were measured and analysed in detail. The results showed that the load‐bearing capacity, the deformation capacity and the energy dissipation of the CFST frame‐shear wall structure were significantly improved due to the dissipation capacity of the BRBs, with the strength and stiffness degradation being obviously reduced. The results also showed that the CFST frame‐shear wall structure with BRBs has preferable mechanical behaviour and more reasonable failure mode. It was verified that the BRB can be used to improve the seismic performance of the CFST frame‐shear wall structure. Copyright © 2014 John Wiley & Sons, Ltd.     

Entwicklung hybrider Stahl‐Glas‐Träger

Immer höhere Anforderungen an die Transparenz von Bauwerken führen zu einer stetigen Weiterentwicklung von tragenden Glaselementen, wobei dem Glas neben seiner ausfachenden Funktion mehr und mehr konstruktive Aufgaben zugedacht werden. Aktuelle Entwicklungen stellen die hybriden Stahl‐Glas‐Träger dar, bei denen schlanke Stahlflansche und Glasstege mittels geklebter Schubfugen zu einem “I”‐Träger zusammengesetzt werden [1]. Der Vorteil der linienförmigen Verklebung liegt hierbei in der gleichmäßigen Lasteinleitung in das Glasbauteil. Die Wahl des eingesetzten Klebstoffsystems trägt in Abhängigkeit seiner mechanischen Eigenschaften maßgeblich zum Tragverhalten des Verbundquerschnittes bei. Ebenso ist der Fugengeometrie eine große Bedeutung hinsichtlich der Tragfähigkeit und Herstellbarkeit zuzuordnen. Allerdings bestimmen Langzeiteffekte, wie Alterung des Klebstoffs und zeitabhängiges Tragverhalten, die Bemessung. Der Beitrag gibt einen Überblick über das systematische Vorgehen zur Untersuchung des Tragverhaltens und nennt wichtige Kriterien und Anforderungen beim Entwurf hybrider Stahl‐Glas‐Träger in Hin blick auf eine optimierte Ausnutzung der einzelnen Komponenten. Development of hybrid steel‐glass‐beams. Increasing higher requirements for transparent and filigree structures result in continuous development and improvement of load‐bearing glass elements, not only in a classic way being a space enclosing element but also increasingly offering load carrying functions. To realize architectural attractive transparent and lightweight constructions bonded hybrid steel‐glass beams have been developed, composed of slim steel flanges and glass webs which were assembled to ”I”‐beams using adhesives. The adhesive system significantly account for the structural behavior of the bonded composite section. Furthermore the joining geometry is of great importance concerning load carrying capacity and producibility but the design is governed by long‐term effects like ageing, creeping and time dependent load‐carrying behavior. This contribution shows the general systematic approach for the analysis of the load bearing behavior of hybrid steel‐glass beams and introduces important criteria and requirements for the design and its mechanical properties focused on an optimized exploitation of the components.