E. Mirambell

On the calculation of deflections in structural stainless steel beams: an experimental and numerical investigation

Abstract This paper focuses on the flexural behaviour of stainless steel beams and on the determination of deflections. A series of experimental tests on stainless steel beams is presented. The experimental program includes tests to determine the stress–strain relationship of the material, considering the effects of cold work. The experimental tests are performed on six simply supported beams loaded centrally and six continuous beams loaded symmetrically at mid-span. These beams have square hollow sections and rectangular hollow sections from a cold-formed process, and hot-rolled H-sections. A comparative analysis between the experimental results of deflections and those results derived from a numerical model considering material non-linearity is done. Likewise, deflections obtained using rules specified in Eurocode 3, Part 1.4 “Supplementary rules for stainless steel” are presented and are also compared with both experimental and numerical results. Several conclusions are made on the calculation of deflections in stainless steel beams considering the effects of the material non-linearity, the effective cross-section and the variation of Youngs modulus along the length of the beam.

Effects of construction process and slab prestressing on the serviceability behaviour of composite bridges

Abstract The study presented in this paper aims to evaluate the structural response under service conditions of composite bridges when considering different construction processes. Short and long-term stresses and strains, deflections and cracking of the concrete slab are analysed. The study, made over a real structure, has been divided into two parts. First, four construction sequences are considered in order to analyse the structural response of the bridge in each case. The second part is focused to study the effectiveness of post-tensioning the concrete slab to generate long term pre-compression. A numerical model, previously developed for the non-linear and time-dependent analysis of segmentally constructed three-dimensional concrete and composite frames, has been used as the simulation tool. As the results show, the model has been proved to be capable of capturing the structural effects of the phenomena influencing the service behaviour of composite bridges. Consequently, relevant conclusions are obtained that lead to the most suitable construction solution depending on the most restrictive design criterion of the project.

Wireless Sensor Networks for Strain Monitoring during Steel Bridges Launching

In this paper, an experimental test performed on a hybrid steel plate girder was subjected to concentrated loads at the end of an unstiffened panel is presented. This load was intended to produce a typical reaction of the piers while launching steel girders in bridges. In this test, strain measurements were taken with conventional pre-wired gauges as well as with newly developed wirelessly connected strain-measuring system. Both measurements were carefully compared and the accuracy of the developed system was demonstrated. Results were also compared with numerical simulations deployed with FE models and on such a basis; the reliability of the developed wireless system was proven. Finally, suggestions of potential research trends in this area are provided.

Hybrid steel plate girders subjected to patch loading

Hybrid girders have proven to be an economical alternative to homogeneous girders since they provide a greater flexural capacity. One of the potential applications of hybrid steel plate girders is their usage in bridge construction. One of the potential constructive methods of these bridges is the push launch method, in which patch loads may condition the design. The aim of this paper is to present advanced conclusions of a research work dealing simultaneously with these two fields; the hybrid typology when subjected to the particular case of patch loading. The most remarkable results of the research work are pointed out. On the one hand, it is shown that the influence of the fyf/fyw ratio (namely, the hybrid grade) is negligible for girders with largely spaced transverse stiffeners. On the other hand, it is shown that this influence can be significant if the transverse stiffeners are closely spaced. Suggestions for considering these findings on design codes are provided at the end paper.

A model for the analysis of concrete dams due to environmental thermal effects

In this article, an analytical model is presented for the simulation of the thermal behaviour of dams that are subjected to environmental thermal action during service. The method of solution adopted, as well as the evaluation of the different parameters, is described in detail. Also, the theoretical results that are predicted by the model are compared with experimental results obtained through the monitoring of temperature in several dams in Spain. The dams considered are currently in use, of different types and in distinct locations.

Global plastic design of stainless steel frames

The use of stainless steel structures has increased during the last decade due to their durability, aesthetics and mechanical properties such as ductility, considerable strain hardening and excellent fire resistance. However, the majority of conducted research works have only focused on single isolated stainless steel members and advances in the analysis of stainless steel frames are limited. EN1993-1-4 does not provide global plastic design rules for indeterminate stainless steel structures, such as frames, despite their proved high ductility. On the other hand, the lack of guidance on plastic design is an obstacle for the optimal design of stainless steel structures, leading to uneconomical design. This paper presents a preliminary study on non-sway stainless steel frames with stocky hollow cross-sections. The study of the behaviour of stainless steel frames is based on numerical parametric studies, considering the nonlinear material behaviour and different stainless steel types (austenitic and ferritic). The paper deals with the redistribution of internal forces and assesses the existing methods based on global plastic design for frames with stocky cross-sections, where alternative design approaches accounting for moment redistribution and strain hardening effects are analysed in addition to traditional plastic design method. Preliminary results demonstrate that including bending moment redistribution and strain hardening effects in capacity predictions is essential for an efficient design of stainless steel structures.

Tests on ferritic stainless steel simply supported and continuous SHS and RHS beams

This is the accepted version of the following article: [Arrayago, I., Real, E. and Mirambell, E. (2016), Tests on ferritic stainless steel simply supported and continuous SHS and RHS beams. Steel Construction, 9: 291–295. doi:10.1002/stco.201610033], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/stco.201610033/full

12.01: Global plastic design of stainless steel frames

The use of stainless steel structures has increased during the last decade due to their durability, aesthetics and mechanical properties such as ductility, considerable strain hardening and excellent fire resistance. However, the majority of conducted research works have only focused on single isolated stainless steel members and advances in the analysis of stainless steel frames are limited. EN1993-1-4 does not provide global plastic design rules for indeterminate stainless steel structures, such as frames, despite their proved high ductility. On the other hand, the lack of guidance on plastic design is an obstacle for the optimal design of stainless steel structures, leading to uneconomical design. This paper presents a preliminary study on non-sway stainless steel frames with stocky hollow cross-sections. The study of the behaviour of stainless steel frames is based on numerical parametric studies, considering the nonlinear material behaviour and different stainless steel types (austenitic and ferritic). The paper deals with the redistribution of internal forces and assesses the existing methods based on global plastic design for frames with stocky cross-sections, where alternative design approaches accounting for moment redistribution and strain hardening effects are analysed in addition to traditional plastic design method. Preliminary results demonstrate that including bending moment redistribution and strain hardening effects in capacity predictions is essential for an efficient design of stainless steel structures.

Shear buckling stress in stainless steel plate girders

Publisher Summary The chapter discusses shear buckling stress in stainless steel plate girders. The main advantage of stainless steel is its natural corrosion resistance which makes it one of the most durables materials in construction, as well as a material with excellent aesthetics and ease of maintenance. The use of stainless steel in construction is becoming increasingly common but due to the lack of knowledge about the actual response of the material, its use as a structural resisting material remains limited. As a relatively new structural material, there are no fully developed design rules included in the standards and in the design manuals that could make a full competitive design of stainless steel structures possible. The chapter presents two series of numerical analyses conducted in panels under a shear to evaluate the influence of the material non-linearity and to investigate the effects of geometric parameters of a stainless steel plate girder on the boundary conditions of the web panel. Results obtained permit to determine shear buckling stress more realistically for a stainless steel webs.

Experimental Investigation On Flexural Behaviour Of Stainless Steel Beams

Stainless steel elements have been increasingly used in the construction industry, especially in architectural applications, due t o its high corrosion resistance, ease of maintenance and aesthetics. The most important limiting factors restraining structural applications of stainless steel are the lack of knowledge about their resistant properties among designers. This factor has inspired researchers to explore the structural behaviour of the material and develop design rules to exploit this material to its full potential in construction. This paper aims to present two experimental programmes on stainless steel beams. Information provided by instrumentation in the tests enables us to observe the non-linear behaviour of stainless steel and to reach some useful conclusions for designing stainless steel structures. Experimental results show that current design provisions for this new construction material are clearly conservative.