Alpenquerende Tunnel: Prüfsystem für Betonmischungen beim Gotthard‐Basistunnel

Gotthard Base Tunnel: Testing System for Concrete Mixtures AlpTransit Gotthard is a future‐orientated project for a high speed railway through the Swiss Alps. The base tunnel under the St. Gotthard massif – with 57 kilometre the world's longest tunnel – is the core structure of the new transalpine Gotthard railwayline. This 21st century project will significantly improve passenger travel and freight transport in the heart of Europe. The main features of the project and the processing of the excavated material will be presented. The applied testing system for concrete mixtures, the contractual conditions and the implementation on site will be explained. The construction of the Gotthard Base Tunnel will produce approx. 24 million tonnes of excavated rock. This huge amount of material has a large potential to be converted into concrete aggregates. Already in 1993 an innovative testing programme for concrete mixtures was launched in order to prove that high‐quality concrete can be produced using TBM‐excavated material. The permanent testing on site ensures, that the produced concrete will meet the high requirements in tunnel construction.     

Instandsetzung von Spannbetonbrücken bei laufender Schadensanalyse

Bei der Instandsetzung von zwei etwa 30 Jahre alten Spannbetonbrücken traten eine Reihe von Problemen auf, die einer raschen Klärung bedurften, um unter den komplizierten Randbedingungen das Vorhaben fortführen zu können. Dies betraf unter anderem sofortige Materialanalysen und Erarbeitung von Lösungen zu den Themen Abdichtung/Aus kris talli sa tionen mit etwaigen Treibreaktionen bzw. gefährdeter Betonzusammensetzung und Rissen sowie ganz besonders zu den Lagern, Betonschäden an Endquerträgern und Auflagerbänken. Ein weiterer Schwer punkt war die Instandsetzung von Spann gliedern, da Mängel bei der Endverankerung festgestellt wurden. Die nötigen Unter suchungen nebst Lösungen der Pro bleme werden dargestellt. Repair of prestressed concrete bridges with continuous failure analysis. During the reinstatement of two 30 year old pre‐stressed concrete bridges a great range of problems occurred. These problems required a rapid clarification to be able to continue the project under the complicated boundary conditions. This concerned among others immediate material analyses and development of solutions to the topics sealing/crystallizations with possible expansive reactions or endangered concrete composition and cracks as well as in particular bearings, concrete damages to end transversal girders and bridge seats. A further main focus was the repair of tendons because there were detected defects at the end anchorage. The necessary investigations together with the solutions of the problems are illustrated.     

Analysis and prediction of TBM performance in blocky rock conditions at the Lötschberg Base Tunnel

This paper focuses on the analysis of the TBM performance recorded during the excavation of the Lötschberg Base Tunnel. The southern part of the tunnel was excavated by two gripper TBMs, partly through blocky rock masses at great depth. The jointed nature of the blocky rock mass posed serious problems concerning the stability of the excavation face. A detailed analysis has been carried out to obtain a relationship between the rock mass conditions and the TBM performance, using the Field Penetration Index (FPI). In blocky rock conditions, the FPI is defined as the ratio between the applied thrust force and the actual penetration rate. A database of the TBM parameters and the geological/geotechnical conditions for 160 sections along the tunnel has been established. The analysis reveals a relationship between the FPI and two rock mass parameters: the volumetric joint count (J_v) and the intact rock uniaxial compressive strength (UCS). Through a multivariate regression analysis, a prediction model for FPI in blocky rock conditions (FPI_blocky) is then introduced. Finally, other TBM performance parameters such as the penetration rate, the net advance rate and the total advance rate are evaluated using FPI_blocky.     

Airfield pavement construction using basalt aggregate

75,000 m³ oc concrete were required for the Fast Exit Taxiway and Apron works for development of Wideawake airfield on Ascension Island. Locally available construction materials were used wherever possible because of the remote location. The pavement contractor obtained some 250,000 tonnes of concrete aggregate by quarrying basalt from aa lava flows associated with highly vesicular basalt scoria ejected during Strombolian-type eruptions. The methods used for ground investigation, material assessment and development include the innovative use of geostatistical techniques for resource evaluation.     

Defining the suitability of new crushed rock aggregate source areas in the North of Kocaeli Province using GIS

This study evaluated the current crushed rock aggregate resources and defined the suitability of potential crushed rock aggregate resource areas in the north of Kocaeli Province by using the geographical information system (GIS). Evaluation of the current aggregate market showed that almost 80 % of the total annual production (14.35 million tonnes) is supplied by the quarries located in Gebze and 20 % of the total annual production (3.65 million tonnes) is supplied by the quarries located in Hereke. The commercial crushed rock aggregate is totally supplied from the limestone and dolomite type carbonate rocks in the northern Kocaeli region. Defining the suitability of potential crushed rock aggregate resource areas was achieved by using GIS methods. First, an aggregate bedrock potential map was developed by using the geological map of the area and categorized as high, moderate and low bedrock potential areas. The high potential areas, which comprised almost 25 % of the northern Kocaeli region, contain carbonate rocks with varying physical, chemical and engineering properties. Secondly, the suitability of the bedrock potential areas was checked by considering the land-use, distance to the county centres and distance to major roads and highways layers in the weighted overlay function of the GIS. The resulting final map contained not suitable, low suitability and suitable areas for crushed rock aggregate. The suitable areas were grouped into three zones according to their geographic distributions. Further, the most promising crushed rock aggregate areas were defined based on the previous field work and surveys in the suitable areas.     

Vorschlag zur Verformungsberechnung von WIB‐Brücken

Walzträger in Beton (WIB) stellen für einfeldrige Eisenbahnbrücken mit bis zu 25 m Spannweite eine attraktive Lösung dar. Das Verformungsverhalten derartiger Bauwerke wird durch die Rissbildung des Betons wesentlich beeinflusst, was daher rechnerisch realitätsnah erfasst werden muss. Im vorliegenden Beitrag wird ein Näherungsverfahren vorgeschlagen, welches für die Verformungsberechnung einbetonierter Stahlquerschnitte unter Gebrauchslasten geeignet ist. A proposal for the calculation of deformations in concrete – encased steel beams. Concrete‐encased steel beams are attractive solutions for railroad bridges with spans up to 25 meters. By this type of constructions the cracking of concrete is of great importance. In this article a calculation procedure is suggested, which is appropriate for evaluating deformations of steel‐profiles integrated in concrete under service conditions.     

不同再生骨料取代率混凝土柱耐火性能试验研究

为研究不同再生骨料取代率混凝土柱的耐火性能,进行了3个足尺再生混凝土柱在竖向荷载和温度场耦合作用下的升温耐火试验.其中,2个试件再生粗骨料取代率为100％,细骨料为天然砂的半再生混凝土柱;1个试件为再生粗、细骨料取代率均为100％的全再生混凝土柱.在试验基础上,比较分析了各试件的截面温度变化、耐火极限、轴向变形、侧向挠度和破坏形态.研究表明:相同轴压比条件下,半再生混凝土柱的耐火极限随着混凝土强度的提高而降低;混凝土强度变化对温度场分布规律影响较小;半再生混凝土柱与全再生混凝土柱相比,混凝土材料性能退化较慢,耐火性能较好.     

再生混凝土T形截面叠合梁受弯性能试验研究

通过对5根相同断面,相同配筋率,翼缘采用再生粗骨料取代率依次为0%、30%、50%、70%及100%的再生混凝土,腹板采用普通混凝土制备的T形截面叠合梁的弯曲试验,研究了各梁的受弯性能、变形特征及极限破坏形态等。结果表明:再生混凝土T形截面叠合梁的受弯性能和极限破坏形态与普通混凝土T形截面叠合梁类似;梁正截面的平截面假定依然适用;现行GB 50010—2010《混凝土结构设计规范》依然适用于再生混凝土T形截面叠合梁极限承载力的计算。     

Natural Aggregates at Makkah Governate, Western Saudi Arabia

 Natural coarse and fine aggregates which accumulated along six selected wadis in the region of Makkah were assessed both qualitatively and quantitatively. The six wadis were Numan, Al-Yamanyah, Al-Shamyah, Hwarah, Alaf and Faydah. More than 440 aggregate samples were collected and their physical, mechanical and chemical properties determined. Petrographic studies on the gravel samples were undertaken to characterise the aggregate types. The results were compared with ASTM and British Standard specifications. The aggregates were generally within the acceptable limits for use in concrete although there were the relatively high values of chloride, sulphate and total dissolved salts in the fine aggregates in Wadis Alaf, Hwarah and Faydah. Nine fine aggregate samples representing upstream, midstream and downstream deposits from these saline wadis were washed in distilled waters after which the aggregates were within the acceptable limits for structural concrete. There were indications of material which could cause alkali-silica in the coarse aggregate at Wadi Faydah. The study proved reserves of 12.5 million m³ of coarse aggregate and 23 million m³ of fine aggregate. Received: 27 May 1998 · Accepted: 18 February 1999     

Lime based steam autoclaved fly ash bricks

About 10 million tonnes of fly ash are produced yearly as waste from coal fired thermal power plants in Turkey. Only a small portion of this waste is utilized as a raw material in the production of cement and concrete. In this study, Seyitömer power plant fly ash was investigated in the production of light weight bricks. Fly ash, sand and hydrated lime mixtures were steam autoclaved under different test conditions to produce brick samples. An optimum raw material composition was found to be a mixture of 68% fly ash, 20% sand and 12% hydrated lime. The optimum brick forming pressure was 20 MPa. The optimum autoclaving time and autoclaving pressure were found 6 h and 1.5 MPa, respectively. The compressive strength, unit volume weight, water absorption and thermal conductivity of the fly ash–sand–lime bricks obtained under optimum test conditions are 10.25 MPa, 1.14 g/cm³, 40.5% and 0.34 W  m⁻¹ K⁻¹ respectively. The results of this study suggested that it was possible to produce good quality light weight bricks from the fly ash of Seyitömer power plant.     

高强轻骨料混凝土梁承载力的研究

在6根高强轻骨料混凝土梁、2根高强普通混凝土梁正截面受弯承载力试验的基础上,提出了轻骨料混凝土强度等级提高后的正截面受弯承载力的计算方法;在对110根轻骨料混凝土梁斜截面受剪承载力试验数据分析的基础上,提出了轻骨料混凝土强度等级提高后的斜截面受剪承载力计算公式,为《轻骨料混凝土结构技术规程》的编制提供依据。     

Weathering and aggregate suitability—A case history from the “Victoria” project,Sri Lanka

The Victoria Project under construction near Kandy in Sri Lanka, required 1.7 million tonnes of aggregate to be quarried in slightly weathered gneiss. This paper describes an investigation into the strength and durability of the as-produced aggregate which contained a small proportion of weathered fragments. These tests were carried out before full scale production commenced as part of an aggregate acceptance test programme. A range of laboratory tests and the results of petrographic examination were correlated with simple counts of weathered aggregate fragments in stockpiles. It was found that the properties of the aggregate from normal production differed little from those of completely fresh aggregate, and that there was excellent correlation between all testing methods.     

Sandwichtürme für Windenergieanlagen mit höherfesten Stahl‐ und Verbundwerkstoffen

Die Leistung und Größe von Windenergieanlagen sind in den letzten Jahren immer weiter angestiegen. Damit erhöhen sich zwangsläufig auch die Anforderungen an die Turmkonstruktionen, die bislang als Stahlrohr‐, Spannbeton‐ oder Fachwerkturm zur Ausführung kommen. Als Alternative dazu wurden am Institut für Stahlbau der Leibniz Universität Hannover mehrere Varianten von Sandwichtürmen untersucht, mit denen die Schalenstabilität und Tragfähigkeit gesteigert werden können. Eine einzelne Sandwichturmsektion besteht dabei grundsätzlich aus einem stählernen Innen‐ und Außenrohr, die durch einen dazwischen liegenden Verbundwerkstoff vollflächig ausgesteift werden. Als Verbundwerkstoffe können pumpfähige Elastomere, Epoxidharze und Vergussmörtel dienen, die vom Turmfuß aufsteigend in den Ringspalt gefüllt werden. Das Sandwichsegment ist dabei nur im unteren Turmbereich vorgesehen, in dem hohe Schalenstabilitäten und große Blechdicken erforderlich sind. Mit dem alternativen Einsatz einer zweischaligen Turmkonstruktion aus dünneren sowie höherfesteren Stahlrohren reduziert sich deutlich das Schweißvolumen gegenüber der herkömmlichen Bauweise. Für Turmsektionen mit einem Durchmesser D > 4,3 m wird ein neues Fertigungskonzept mit längsorientierten Teilschalen beschrieben, womit nicht nur das Transportproblem über Land gelöst, sondern auch die Anzahl der Rundnähte minimiert werden kann. Ferner wird eine neue Verbindungstechnik zwischen den Turmsektionen vorgestellt, die ohne ermüdungskritische und aufwändig geschraubte Ringflansche auskommt. Sandwichtowers for wind turbines with high strength steel and core materials. The performance and the dimensions of wind energy converters have been increased significantly within the last few years. Thus, the requirements on tower constructions will also increase following the development of bigger turbines. Usually tubular steel and pre‐stressed concrete towers are chosen as support structures for wind turbines. The structural design of tubular steel towers is mainly driven by ultimate and fatigue limit state. Especially shell buckling leads to large dimensions and thicknesses for the steel sections. Therefore, a new kind of tower, the so called sandwichtower, has been developed as an alternative solution with the aim of increasing the shell stability. The sandwich tower consists of an inner and outer steel shell which are bonded together with a core material between them. That works as a full space stiffener. As a result of the investigations a combination of steel and sandwich‐section is favoured where the sandwich is only planned for the lower tower section to get higher stability simultaneously with thinner shells. Therefore, the effective welding time can be decreased when the shells are made of high strength steels. Especially for tower sections with D > 4.3 m a new fabrication concept with longitudinal partial shells is developed to offer the transportation onshore and to minimize the number of critical circumferential welds. Furthermore, a new kind of connection between the tower sections is presented without bolted ring flanges.     

Sicherstellung der Dauerhaftigkeit von Großbrücken aus Beton unter besonders korrosiven Einwirkungen

Brücken aus Stahl‐ und Spannbeton werden heute i. d. R. für Nutzungsdauern von 100 Jahren geplant. Insbesondere bei Großbrücken liegen häufig Bedingungen vor, die besondere Lösungen erfordern, wie z. B. bei außerordentlichen korrosiven Beanspruchungen. Beispielhaft wird in diesem Aufsatz die Situation von Pfeilern im Meerwasser näher beleuchtet, die einem ständigen Chloridangriff unterliegen. Soll die Dauerhaftigkeit beispielsweise durch besonders hohe Qualität der Betondeckung erreicht werden, so sind besondere Nachweise zu führen, für die in den letzten Jahren interessante probabilistische Bemessungsansätze entwickelt wurden (s. z. B. [1] bis [3]). Ferner kann die Dauerhaftigkeitsprognose durch Einsatz von Monitoringsystemen kontinuierlich zugeschärft werden, so dass durch Anwendung der Sicherheitsbetrachtungen wirtschaftliche Lösungen ermöglicht werden. In dieser Veröffentlichung wird anhand der Pfeiler der mit 36 km längsten Meeresbrücke der Welt gezeigt, wie die Dauerhaftigkeit unter schwierigen Bedingungen über einen geplanten Nutzungszeitraum von 100 Jahren sichergestellt wird. Design for Durability of Large Concrete Bridges Under Severe Corrosive Attack. Nowadays bridges made of reinforced or prestressed concrete are usually designed for a service life‐time of 100a. Especially for large bridges often conditions are present, which require special solutions, as e. g. extra ordinarily corrosive exposure condi tions. In this paper exemplarily the situation of piles in seawater are discussed more in detail, which are subject to permanent chloride attack. If durability shall be achieved e. g. especially high quality of the concrete cover, special proofs have to be verified, which have been developed during recent years e. g. as probabilistic approaches (see e.g. [1]—[3]). Additionally the prognosis for durability can be updated continuously by using corrosion monitoring systems, allowing economic solutions by using special safety considerations.     

部分再生混凝土T形截面叠合梁抗弯性能试验研究

通过4根部分再生混凝土T形截面叠合梁和1根普通混凝土T形截面叠合梁受弯试验结果的对比分析,研究了各试验梁荷载作用下跨中正截面的受荷性能及极限破坏形态。试验结果表明,部分再生混凝土T形截面叠合梁的受力性能及破坏机理与普通混凝土类似;混凝土梁正截面的平截面假定依然成立;随再生骨料取代率的增加,试验梁的开裂荷载及极限承载力均略有降低。     

Instandsetzung der Druckrohrleitung des Kraftwerks Cleuson‐Dixence,Schweiz — Eine Herausforderung an den Stahlbau

Das Kraftwerk Cleuson‐Dixence in der Schweiz mit 1269 MW Nennleistung zählt zu den eindrucksvollsten Wasserkraftanlagen Europas. Die technischen Leistungen vereinigen einige Weltrekorde: Die größte Leistung pro Pelton‐Turbine mit 423 MW, die größte Pol‐Leistung je Wechselstromgenerator und die größte Fallhöhe von 1883 m — aus welcher eine Druckrohrleitung mit dem bisher höchsten Innendruck von 2070 m Wasserhöhe resultiert. Ein Schadensfall an der bestehenden Druckrohrleitung im Jahre 2000 setzte das gesamte Krafthaus Bieudron für fast ein Jahrzehnt außer Betrieb. Der Schaden wurde offenbar durch einen Kaltriss in einer mangelhaft geschweißten Werksschweißnaht ausgelöst, welcher auch bei der original durchgeführten zerstörungsfreien Werkstoffprüfung nicht ausreichend detektiert werden konnte. Basierend auf den Ergebnissen der eingehenden Untersuchungen wurde beschlossen, dass der gesamte Druckschacht mit einer Länge von über 4 km erneuert werden musste. Diese Rehabilitation sah vor, dass in dem bestehenden Druckschacht eine zusätzliche Stahlpanzerung (= Druckrohrleitung) eingebaut werden muss. Der Nominal‐Ringraum zwischen der bestehenden und der neuen Stahlpanzerung wurde so klein wie möglich mit 130 mm definiert. Dieser Ringraum muss nach der Montage sukzessive mit Beton hinterfüllt werden. Dieses Konzept war Grundlage für die Auftragserteilung im Jahre 2006. Die Auswahl der Fertigungs‐ und Montageverfahren stellte aufgrund der Geschichte dieses Superlativ‐Projektes eine Herausforderung dar. Rehabilitation of the penstock of the power plant Cleuson‐Dixence, Swiss — Challenges for the steel constructor. The power plant Cleuson‐Dixence in Swiss with its 1269 MW nominal capacity is one of the most impressive hydroelectric power plants all over Europe. Three world records are held of this plant: the highest output per Pelton‐turbine with 423 MW, the highest pole‐output of each AC generator and the highest head of 1883 m — resulting in a penstock of a designed internal pressure of 2070 m water column. An accident on the existing penstock in the year 2000 has led to a stop of operations for almost a decade. The damage was apparently caused by a cold crack in a shop weld seam, which couldn’t be detected properly during the originally performed NDT. Based on the results of detailed investigations it had been decided, that the entire penstock over its more than 4 km length had to be renewed completely. The concept of the rehabilitation was the construction of an additional penstock, inserted in the existing one. The nominal gap between the existing and the new penstock should be as small as possible and was defined with 130 mm. The gap shall be backfilled with concrete continuously after installation. This concept was the basis for the award of the construction contract in the year 2006. The selection of the most proper fabrication‐ and installation procedures was a challenge in this project of superlatives.     

溪洛渡特高拱坝建基面嵌深优化的分析与评价

 对特高拱坝建基面嵌入深度优化的分析与评价是当前水利工程中的重点研究方向之一,具有重要的学术和工程意义,其研究成果可为制定新的优化与评价标准作参考。在分析国内外特高拱坝建基面优化分析与评价研究现状的基础上,总结特高拱坝建基面优化分析与评价的原则与工作步骤。就建设中的溪洛渡特高拱坝建基面嵌入深度的优化设计,采用三维非线性有限元法和三维地质力学模型试验,对3种建基面嵌入深度方案,即可研方案、优化方案和比较方案的坝体应力、整体稳定、超载能力等进行分析评价。论证溪洛渡拱坝基础利用III1级岩体和上部高程部分利用III2级岩体作为大坝基础的可行性;实施中的建基面嵌深采用优化方案。优化方案较可研方案减少基础开挖和大坝混凝土工程量各100多万立方米,节省直接投资约7亿元,经济效益十分显著。     

Aggregate resources inventory in Ontario,Canada

Ontario has an abundance of aggregate resources; however, their location is fixed by nature and they are not always found in the areas of greatest demand. Over 120 million tonnes are produced yearly. Much of this production is in urban fringe areas. Comprehensive planning and resource management strategies, based on an appropriate planning framework and a sound knowledge of the total mineral aggregate resource base, are required to make the best use of available resources. To achieve this, Ontario's Mineral Aggregate Resource Policy requires 1) the Ontario Ministry of Natural Resources to prepare a detailed inventory of the aggregate resources, including location, quality, quantity and extractive activity, and 2) the recognition of aggregate resources in municipal official plans.     

钢筋再生混凝土梁的受弯性能

基于国内外大量相关研究成果,对钢筋再生混凝土梁的受弯性能进行了较为全面系统的分析,主要包括平截面假定对再生混凝土梁的适用性、钢筋再生混凝土梁的破坏形态、极限承载力、变形、刚度以及裂缝等.研究结果表明,与钢筋普通混凝土梁相比,钢筋再生混凝土的破坏形态、极限承载力基本相同,但是钢筋再生混凝土梁的变形较大,刚度低.同时发现平截面假定也适用于受弯的钢筋再生混凝土梁.     

Ein Bemessungskonzept für unbewehrte und faserbewehrte Tunnelinnenschalen

Aufbauend auf geltenden Richtlinien und Normen wird ein Verfahren für die statische Berechnung und Bemessung unbewehrter und faserbewehrter Tunnelinnenschalen vorgestellt. Das Bemessungskonzept erfordert eine iterative Suche nach dem statischen Gleichgewicht des Tragsystems unter Berücksichtigung nichtlinearen Materialverhaltens. Als Ergebnis liefert das Verfahren nebst den herkömmlichen Nachweisen (Tragfähigkeit und Gebrauchstauglichkeit) Aussagen, ob eine unbewehrte bzw. faserbewehrte Ausführung der Innenschale möglich ist. Im Falle der Notwendigkeit faserbewehrten Innenschalenbetons sind Aussagen bezüglich der erforderlichen Nachrisszugfestigkeit möglich. A Design Concept for Plain and Fibre‐Reinforced Final Linings of Tunnels A concept for the design of final tunnel linings on the basis of current standards and guidelines is presented. The proposed method requires an iterative approach towards the equilibrium of the static system considering nonlinear material behaviour in compression and tension. As a result this method returns a design proof either for the unreinforced lining or the fibre‐reinforced lining including the required post crack tensile strength of fibre‐reinforced concrete.