A displacement-based method of seismic design (DBSD) is presented with particular reference to the design of reinforced concrete shear wall buildings. For preliminary design, approximate estimates of the yield and ultimate displacements are obtained, the former from simple empirical relations, and the latter to satisfy the following criteria: (1) satisfy code-specified drift limits, (2) ensure stability under P-Delta effects, and (3) keep the ductility demand within ductility capacity. For a multi-storey building the structure is converted to an equivalent single-degree-of-freedom (SDOF) system using an assumed deformation shape that is representative of the first mode. The required base shear strength of the SDOF system is determined from the inelastic demand spectrum corresponding to the ductility demand, which is the ratio of ultimate to yield displacement. The base shear is distributed across the height using an assumed pattern, such as the one given by the National Building Code of Canada, and the structure is designed for the moments produced by the estimated shears. (Abstract shortened by UMI.)
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International Conference on Tubular Structures : May 9-10, 1996, Vancouver, British Columbia
Author: American Welding Society, Welding Institute of Canada. | Size: 14.5 MB | Format:PDF | Quality:Scanner | Publisher: American Welding Society | Year: 1996 | pages: 229 | ISBN: 0871714817
Proceedings
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Seismic Design and Detailing of Reinforced Concrete Structures Based on CSA A23.3 - 2004
Murat Saatcioglu PhD,P.Eng.
Professor and University Research Chair
Department of Civil Engineering
The University of Ottawa
Ottawa, ON
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Murat Saatcioglu PhD,P.Eng.
Professor and University Research Chair
Department of Civil Engineering
The University of Ottawa
Ottawa, ON
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Rapid Screening of Buildings for Seismic Retrofit Assessment Report
Murat Saatcioglu PhD,P.Eng.
Professor and University Research Chair
Department of Civil Engineering
The University of Ottawa
Ottawa, ON
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1. INTRODUCTION
1.1 General
Traditional fatigue analysis of welded components is based on the use of nominal stresses and catalogues of classified details. A particular type of detail is assigned to a particular fatigue class with a given S-N curve. Such a method is used in the IIW fatigue design recommendations (1). This nominal stress approach ignores the actual dimensional variations of a particular structural detail, which is an obvious drawback.
Moreover, the form of a welded component is often so complex that the determination of the nominal stress is difficult or impossible. This is true even if the finite element analysis (FEA) method is used for the stress analysis.
In the context of potential fatigue failure by crack growth from the weld toe or end, the structural hot spot stress approach goes one step forward. Here the calculated stress does take into consideration the dimensions of the detail. The resulting structural stress at the anticipated crack initiation site ('hot spot') is called the structural hot spot stress. Structural stress includes the stress concentrating effects of the detail itself but not the local non-linear stress peak caused by the notch at the weld toe. This notch effect is included in the hot spot S-N curve determined experimentally. This is reasonable because the exact geometry of the weld will not be known at the design stage. The variation in the local geometry of the weld toe is one of the main reasons for scatter in fatigue test results. By using the lower-bound characteristic S-N curve, lower bound quality of the weld toe is incorporated into the analysis. A single S-N curve should suffice for most forms of structural discontinuity, providing the weld toe geometry is always the same.
An obvious reason for introducing the structural hot spot approach is the availability of powerful computers and software, which make detailed FEA possible for most design offices. However, the approach is also a valuable tool for choosing the locations of strain gauges when validating design by field-testing prototype structures. Moreover, finite element analyses make it possible to produce parametric formulae in advance for easy estimation of structural stresses at various hot spots. The hot spot approach was first developed for fatigue analysis of welded tubular joints in offshore structures. Corresponding fatigue design rules were published by the American Petroleum Institute, the American Welding Society, Bureau Veritas, UK Department of Energy, etc. A review of this topic can be found in Ref. (2). There is now an increasing demand for application of the approach to be extended to all kinds of plated structures. Some progress has been made in doing this, but at present there are differences in the methods recommended for estimating the structural hot spot stress. The first general design rule to include the structural stress (referred to at the time as the geometric stress) approach was the European pre-standard ENV 1993- 1 - 1 (3) (Eurocode 3) but only limited guidance was given. Later, the International Institute of Welding (IIW) published new recommendations containing four fatigue design approaches, including the hot spot approach (1). A background document was also published focusing on definitions and the determination of stresses used in the fatigue analysis of welded components (4).
Subsequently, further research has led to improved procedures for determining the structural hot spot stress, particularly using FEA (5,6), and the provision of background fatigue test data from which to derive suitable design S-N curves (7-10). Furthermore, the ability to establish through-thickness stress distributions using FEA has enabled a method to be developed that uses this information to calculate the structural hot spot stress. Previously attention has focussed on use of the surface stress distribution, approaching the weld in question, and determination of the structural hot spot stress using an extrapolation procedure. Use of the through-thickness stress distribution instead should avoid the need for extrapolation.
The goal of the present document is to help design engineers and stress analysts to implement the structural hot spot stress approach in practice. Symbols and terms are defined as they are used but symbols are also defined in Appendix 1.
Practical examples of the application of the methods described are given in the form of Case Studies in Sections 6 and 7. Moreover, the document should serve as a reference when detailed guidelines for design are developed for particular welded products. The recommendations given here are intended for design of general welded structures subjected to fatigue loading. The document is mainly focused on plated structures, such as bridges, cranes, earth moving machinery, ship hulls, etc. Specific rules are already available for certain fields of application, including tubular structures (1 l), ship hulls (12,13) and pressure vessels (14).
In view of the scope of current experience and the availability of relevant fatigue test data, the recommendations presented in this document are only intended for plate thicknesses above 4 mm.
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EWM Welding consumables - The logical consequence
The whole world of welding technology from one single supply source:
• Unbeatable benefi ts for the users of EWM Welding consumables
• One point of contact for all system components
• Consultation and service for the whole process chain
• Accelerated availability and delivery times
The responsibility for the complete process chain is carried by one single system partner:
EWM!!
Certifi ed welding with EWM welding consumables
The complete spectrum of EWM welding consumables are produced to EWMs stringent specifi -
cations. Detailed analysis of every single production charge ensures perfectly consistent quality
and welding results.
Further to this, (we will take our solid wire as an example), , we control the winding, coating
quality, percentage of draw lubricants, feed/glide properties (also over long distances) and metallurgical
properties, just to mention a few of the factors effecting quality. All this to ensure the
best possible, reproducible process safety.
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Consumables for mild steels 5
Consumables for low-alloyed steels 87
Consumables for stainless and high-alloyed steels 187
Consumables for aluminium alloys 311
Consumables for nickel-based alloys 339
Consumables for copper-based alloys 365
Consumables for cast iron 381
Consumables for dissimilar materials 389
Consumables for hardfacing 411
Special products 457
Packaging and spool types 471
Storage and handling 481
Quick guide for the selection of welding consumables 485
General information and tables 499
Index 523
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Overview stainless steel consumables 4
Consumable selection by parent material 8
Covered electrodes for MMA welding 10
Solid wires for MIG/MAG welding 42
Welding of exhaust systems. 49
Wires for TIG Welding 50
Orbital-TIG – a great way to join pipes 57
Tubular cored wires for MIG/MAG welding 58
Construction of chemical tankers with cored wires 66
Fluxes for submerged arc welding 67
The stainless steel cladding process 75
Facts about Stainless Steels 76
Corrosion 81
Ferrite in weld metals 82
Joining of Dissimilar Steels 86
Storage and handling 90
Global manufacturing 91
page
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Every day, welders throughout the world encounter the initials OK on the consumables
they use. OK for Oscar Kjellberg, the founder of Esab AB. Oscar
Kjellberg first invented a new welding technique and followed it up with the
covered electrode. These inventions are the origins of Esab.
Oscar Kjellberg qualified as an engineer and worked for several years on
a couple of Swedish steamships. It was during this period at the end of the
1890s that he came across the problem for which there was no effective solution
at that time. The riveted joints on steam boilers often leaked. Attempts were
made to repair the leaking joints with nails which were forged to produce small
wedges which were then pushed into the joints. Simple electrical welding was
already in use, but Oscar Kjellberg had seen electrical welding repairs and the
results were poor, as there were still cracks and pores.
He realized, however, that the method could be developed and was
supported by the leading shipyards. Oscar Kjellberg set up a small experimental
workshop in the harbour in Göteborg.
In the shipyards of Göteborg, the method quickly attracted a great deal of
interest. It was obvious that it could provide tremendous benefits when welding
and repairing ships. Since then, this repair technique has been further
developed and implemented in other segments.
Today, Esab can offer repair and maintenance consumables for most materials
and welding processes.
In this handbook, you will find Esab Repair & Maintenance products and a
number of applications in which these products are used. The products shown
for each application are general recommendations and should only be used as
a guide.
For further product information, please refer to the ESAB Welding Handbook
or to your local Esab dealer.
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