A cost study of common surface finish systems for steel structures

This paper presents part of a study aimed at finding a suitable, yet cost-effective, surface finish for a steel structure subject to the car washing environment and corrosive chemicals. The initial, life cycle and average equivalent annual (AEAC) costs for surface finishing methods were calculated for a steel structure using the LCCC algorithm developed by American Galvanizers Association (AGA). The cost study consisted of 45 common surface finish systems including: hot-dip galvanization (HDG), metallization, acrylic, alkyd and epoxy as well as duplex coatings such as epoxy zinc and inorganic zinc (IOZ). The results show that initial, life cycle and AEAC costs for hot dip galvanization are the lowest among all the other methods, followed by coal tar epoxy painting. The annual average cost of HDG for this structure was estimated about €0.22/m2, while the other cost-effective alternatives were: IOZ, polyurea, epoxy waterborne and IOZ/epoxy duplex coating.

Analysis and guidelines for implementation of EN 1090-2 Standard to assist execution class assignment of steel structures

Finnish design and consulting companies are delivering robust and cost-efficient steel structures solutions to a large number of manufacturing companies worldwide. Recently introduced EN 1090-2 standard obliges these companies to specify the execution class of steel structures for their customers. This however, requires clarifying, understanding and interpreting the sophisticated procedure of execution class assignment. The objective of this research is to provide a clear explanation and guidance through the process of execution class assignment for a given steel structure and to support the implementation of EN 1090-2 standard in Rejlers Oy, one of Finnish design and consulting companies. This objective is accomplished by creating a guideline for designers that elaborates on the four-step process of the execution class assignment for a steel structure or its part. Steps one to three define the consequence class (projected consequences of structure failure), the service category (hazards associated with the service use exploitation of steel structure) and the production category (manufacturing process peculiarities), based on the ductility class (capacity of structure to withstand deformations) and the behaviour factor (corresponds to structure seismic behaviour). The final step is the execution class assignment taking into account results of previous steps. Main research method is indepth literature review of European standards family for steel structures. Other research approach is a series of interviews of Rejlers Oy representatives and its clients, results of which have been used to evaluate the level of EN 1090-2 awareness. Rejlers Oy will use the developed novel coherent standard implementation guideline to improve its services and to obtain greater customer satisfaction.

Fatigue damage modelling of steel structures

In the present work a constitutive model is developed which permits the simulation of the low cycle fatigue behaviour in steel framed structures. In the elaboration of this model, the concepts of the mechanics of continuum medium are applied on lumped dissipative models. In this type of formulation an explicit coupling between the damage and the structural mechanical behaviour is employed, allowing the possibility of considering as a whole different coupled phenomena. A damage index is defined in order to model elastoplasticity coupled with damage and fatigue damage.

Structural shapes; information and tables for architects, engineers and designers of buildings and other steel structures.

Cover-title: Bethlehem manual of steel construction.

Automated formulation of optimisation models for steel beam structures

Over 70% of the total costs of an end product are consequences of decisions that are made during the design process. A search for optimal cross-sections will often have only a marginal effect on the amount of material used if the geometry of a structure is fixed and if the cross-sectional characteristics of its elements are property designed by conventional methods. In recent years, optimalgeometry has become a central area of research in the automated design of structures. It is generally accepted that no single optimisation algorithm is suitable for all engineering design problems. An appropriate algorithm, therefore, mustbe selected individually for each optimisation situation. Modelling is the mosttime consuming phase in the optimisation of steel and metal structures. In thisresearch, the goal was to develop a method and computer program, which reduces the modelling and optimisation time for structural design. The program needed anoptimisation algorithm that is suitable for various engineering design problems. Because Finite Element modelling is commonly used in the design of steel and metal structures, the interaction between a finite element tool and optimisation tool needed a practical solution. The developed method and computer programs were tested with standard optimisation tests and practical design optimisation cases. Three generations of computer programs are developed. The programs combine anoptimisation problem modelling tool and FE-modelling program using three alternate methdos. The modelling and optimisation was demonstrated in the design of a new boom construction and steel structures of flat and ridge roofs. This thesis demonstrates that the most time consuming modelling time is significantly reduced. Modelling errors are reduced and the results are more reliable. A new selection rule for the evolution algorithm, which eliminates the need for constraint weight factors is tested with optimisation cases of the steel structures that include hundreds of constraints. It is seen that the tested algorithm can be used nearly as a black box without parameter settings and penalty factors of the constraints.

Convenience of scallops in plate structures

In this thesis was performed comprehensive study about the convenience of scallops in plate structures. A literature review was performed and lack of knowledge was fulfilled with fatigue tests performed in the laboratory of Steel Structures at the Lappeenranta University of Technology and with finite element method. The aim of this thesis was to produce design guidance for the use of scallops for different structural details and different loading conditions. An additional aim was to include more precise instructions for scallop design to produce good fatigue resistance and appropriate manufacturing quality. The literature review was performed searching bridge engineering and maritime standards and design guides and studies from scientific databases and reference lists from the literature of this field. Fatigue tests were used to research the effect of using scallops or not using scallops to fatigue strength of bracket specimen. Tests were performed on three specimens with different scallop radii and to five specimens without scallops with different weld penetration depths. Finite element method using solid elements, symmetry and submodels was used to determine stress concentration factors for I-beams with scallops. Stresses were defined with hot spot stress method. Choosing to use a scallop or not in the structure is affected by many factors, such as structural and loading conditions and manufacturability. As a rule of thumb, scallops should be avoided because those cause stress concentration points to the structure and take a lot of time to manufacture. When scallops are not used, good quality welding should be provided and full weld penetration is recommended to be used in load carrying corner weld areas. In some cases, it is advisable to use scallops. In that case, circular scallops are recommended to be used and radius should be chosen from fatigue strength or manufacturing point of view.

A theoretical and experimental analysis of cold-formed steel shapes subjected to bending - Channel and simple lipped channel

Cold-formed steel shapes have been widely employed in steel construction, where they frequently offer a lower cost solution than do traditional laminated shapes. A classic application of cold-formed steel shapes is purlins in the roof panel of industrial buildings, connected to the roof panel by means of screws. The combined effect of these two elements has been the subject of investigations in some countries. Design criteria were included in the AISI Code in 1991 and 1996. This paper presents and discusses the results obtained from bending tests carried out on shapes commonly used in Brazil, i.e., the channel and the simple lipped channel, Tests were carried out on double shapes with 4.5 and 6.0 meter spans, which were subjected to concentrated loads and braced against each other on the supports and at intermediary points in three different load situations. The panel shape was also analyzed experimentally, simulating the action of wind by means of a vacuum box designed specifically for this purpose. The test results were then compared to those obtained through the theoretical analysis, enabling us to extract important information upon which to base proposed design criteria for the new Brazilian code.

Detection of pitting corrosion in steel using image processing

This paper presents an image processing based detection method for detecting pitting corrosion in steel structures. High Dynamic Range (HDR) imaging has been carried out in this regard to demonstrate the effectiveness of such relatively inexpensive techniques that are of immense benefit to Non – Destructive – Tesing (NDT) community. The pitting corrosion of a steel sample in marine environment is successfully detected in this paper using the proposed methodology. It is observed, that the proposed method has a definite potential to be applied to a wider range of applications.

Prediction of defects in steel castings with a multi-physics numerical code

Abstract not available

Corrosion of stainless steel components in seawater reverse osmosis desalination plants-investigations on adapted internal cathodic protection

Stainless steel is widely used in seawater reverse osmosis units (SWRO) for both good mechanical and corrosion resistance properties. However, many corrosion failures of stainless steel in SWRO desalination units have been reported. These failures may often be attributed to un-adapted stainless steel grade selection and/or to the particular aggressive seawater conditions in "warm" regions (high ambient temperature, severe biofouling, etc.). Cathodic protection (CP) is a well-known efficient system to prevent corrosion of metallic materials in seawater. It is successfully used in the oil and gas industry to protect carbon steel structures exposed in open-sea. However, the specific service conditions of SWRO units may seriously affect the efficiency of such anti-corrosion system (high flow rates, large stainless steel surfaces affected by biofouling, confinement limiting protective cathodic current flow, etc.). Hence, CP in SWRO units should be considered with special care and modeling appears as useful tool to assess an appropriate CP design. However, there is a clear lack of CP data that could be transposed to SWRO service conditions (i.e. stainless steel, effect of biofouling, high flow rate, etc.). From this background a Join Industry Program was initiated including laboratory exposures, field measurements in a full scale SWRO desalination plant, and modeling work using PROCOR software. The present paper reviews the main parameters affecting corrosion of stainless steel alloys in seawater reverse osmosis units. CP on specific stainless steel devices was investigated in order to assess its actual efficiency for SWRO units. Severe environmental conditions were intentionally used to promote corrosion on the tested stainless steel products in order to evaluate the efficiency of CP. The study includes a modeling work aiming at predicting and designing adapted CP protection to modeled stainless steel units. An excellent correlation between modeling work and field measurements was found.

Structural steel design with BIM technology - interventions on a three buildings block in Deruta (PG)

The aim of this thesis is to use the developments, advantages and applications of "Building Information Modelling" (BIM) with emphasis on the discipline of structural design for steel building located in Perugia. BIM was mainly considered as a new way of planning, constructing and operating buildings or infrastructures. It has been found to offer greater opportunities for increased efficiency, optimization of resources and generally better management throughout the life cycle of a facility. BIM increases the digitalization of processes and offers integrated and collaborative technologies for design, construction and operation. To understand BIM and its benefits, one must consider all phases of a project. Higher initial design costs often lead to lower construction and operation costs. Creating data-rich digital models helps to better predict and coordinate the construction phases and operation of a building. One of the main limitations identified in the implementation of BIM is the lack of knowledge and qualified professionals. Certain disciplines such as structural and mechanical design depend on whether the main contractor, owner, general contractor or architect need to use or apply BIM to their projects. The existence of a supporting or mandatory BIM guideline may then eventually lead to its adoption. To test the potential of the BIM adoption in the steel design process, some models were developed taking advantage of a largely diffuse authoring software (Autodesk Revit), to produce construction drawings and also material schedule that were needed in order to estimate quantities and features of a real steel building. Once the model has been built the whole process has been analyzed and then compared with the traditional design process of steel structure. Many relevant aspect in term of clearness and also in time spent were shown and lead to final conclusions about the benefits from BIM methodology.

Utilização dos eurocódigos na construção metálica

Os Eurocódigos estruturais são um conjunto de normas técnicas que têm como objectivo abranger o projecto e verificação de qualquer tipo de construção para os países membros da União Europeia. O objectivo deste trabalho é sistematizar todos os procedimentos que estão presentes nos Eurocódigos e que são aplicáveis, de uma forma geral, à construção metálica. Foi feito o desenvolvimento de uma solução estrutural para o caso concreto de uma estrutura metálica de uma ponte rolante com o objectivo de se fazer o levantamento dos normativos estabelecidos para o projecto de estruturas metálicas. Este trabalho foi desenvolvido considerando fundamentalmente três Eurocódigos. O Eurocódigo 0 que estabelece o princípio e bases para o projecto de estruturas, o Eurocódigo 1 que define as acções em estruturas e o Eurocódigo 3 que estabelece as regras gerais, de verificação ao fogo, de projecto de ligações e de verificação à fadiga. O trabalho desenvolvido consistiu em projectar a estrutura metálica da ponte rolante considerada e para tal foram feitos os seguintes passos. - Determinação das acções na estrutura e das situações de projecto; - Projecto da estrutura considerando a verificação de cedência ou deformação excessiva dos seus elementos; - Projecto da estrutura considerando a perda de equilíbrio estático da estrutura; - Projecto da estrutura considerando a verificação da sua resistência ao fogo; - Projecto das ligações aparafusadas; - Verificação da resistência à fadiga.

Dimensionamento de um pavilhão industrial misto com fundações indirectas

Trabalho de Projecto para obtenção do grau de Mestre em Engenharia Civil Perfil Estruturas

Dimensionamento de um edifício misto de receção de areias e pirites

Trabalho de Projeto para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização em Estruturas

Dimensionamento de um pavilhão industrial metálico com fundações indirectas

Trabalho de projecto para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização em Estruturas