Steel Rectangular Hollow Section Columns Research Articles

Stiffness of Loaded Face of Steel Rectangular Hollow Section Columns with and without Concrete Infill in Beam-column Endplate Connections

This paper presents a new analytical approach for calculating the stiffness of the loaded face of a rectangular hollow section RHS column in beam-column connections with and without concrete infill, as well as with flush and extended endplates, to determine the behavior curve of these types of connections. The approach, based on Eurocode 03's component method, offers efficient analytical formulas for accurately determining the loaded face's stiffness. A comparison with existing methods demonstrates its remarkable simplicity and efficiency, allowing a simple beam model to represent the RHS column's behavior with all relevant parameters considered. Comparison of the new approach to existing ones from the literature demonstrates their reliability and efficiency. Furthermore, when compared to 32 experimental tests presenting nearly the entire range of probable connection configurations, as well as attachment techniques commonly used in construction practice, the margin of error does not exceed 12 percent on average and a maximum of less than 25 percent.

Design of cold-rolled stainless steel rectangular hollow section columns

Considering the effects of cold-forming and strain hardening in the design of cold-formed stainless steel columns is an effective way to reduce construction costs. This approach has become a common trend in the revision of relevant design codes. A few studies were conducted in the past on two key aspects: (i) predicting the enhanced material properties in cold-formed stainless steel cross-sections and (ii) modifying the design methods to adapt to stainless steel material characteristics. However, in the existing literature, they had been separately studied, and integration of these two aspects to form a complete design method was rarely reported. In this study, a series of column tests were conducted on 19 stub and 32 long columns in rectangular hollow sections. The measured imperfections, material properties, load-displacement curves, and failure modes were reported. A new design method for columns was developed, which could clearly and accurately determine the column capacity over the space encompassed by member slenderness and cross-sectional slenderness values. The proposed design method and the method laid out in the Design Manual for Structural Stainless Steel were evaluated against the test data. It was demonstrated that the two design methods were both very conservative in predicting the column capacity when material properties in the annealed condition were used. However, their performances improved when the predicted enhanced material properties were used. Generally, the predictions of the proposed design method matched the test data better. Furthermore, a reliability analysis was conducted, and resistance factors were recommended for the corresponding design methods.

Analysis of thin-walled steel RHS columns filled with concrete under long-term sustained loads

The present study is an attempt to predict the time-dependent behavior of concrete-filled thin walled steel RHS (rectangular hollow section) columns by means of a model that is proposed by the ACI Specifications (ACI Committee 209,1992) [1]. A theoretical model of analysis to account for shrinkage and creep effects on concrete-filled steel RHS columns under sustained loading is presented, and is a development of the analysis used for short-term loading (Han et al, 2001a) [2]. A comparison of results calculated using this model shows good agreement with test results. The main objectives of this paper were threefold: firstly, to report a series of tests on the behavior of concrete-filled steel RHS columns under long-term sustained loading, in addition to providing further tests on the static ultimate strength of the composite columns. Secondly, to analyze influence of several parameters, such as changing steel ratio, long-term sustained load level, slenderness ratio, strength of the materials and depth-to-width ratio on the capacities of the concrete-filled steel RHS columns. And finally, to develop formulas for the calculations of the ultimate strength of the concrete-filled steel RHS columns with long-term sustained loading effects are considered, such formulas should be suitable for incorporation into building codes.

Influence of concrete compaction on the strength of concrete-filled steel RHS columns

Abstract Concrete-filled steel tubular columns have better structural performance than that of bare steel or reinforced concrete (R.C.). The use of concrete-filled SHS (Square Hollow Section) and RHS (Rectangular Hollow Section) have become widespread in the past few decades. However, these members are susceptible to the influence of concrete compaction. It is expected that the influence of concrete compaction on R.C. columns and concrete-filled steel tubes is different. For R.C. columns, concrete compaction only affects the mechanical properties of concrete. But for concrete-filled steel tubes, it is well known that the interaction between steel tube and concrete is the key issue to understand the behaviour of this kind of column. The concrete compaction not only affects the properties of the core concrete itself, but also may influence the interaction between the steel tube and its concrete core, and thus influences the behaviour of the composite columns. The present study is an attempt to study the influence of concrete compaction on the strength of concrete-filled steel RHS columns. Tests on 35 concrete-filled steel RHS columns to investigate the influence of concrete compaction methods on the member capacities of the composite columns are reported. The main parameters varied in the tests are: (1) column section depth-to-width ratio, from 1.0 to 2.0, (2) tube depth to thickness ratio, from 34 to 136, (3) load eccentricity (e), from 0 to 31 mm and (4) column slenderness (λ), from 21 to 62. The main objectives of these tests were twofold: firstly, to report a series of tests on composite columns under different concrete compaction methods; and secondly, to investigate the influence of concrete compaction on the member capacities of the composite columns. Comparisons are made with predicted column strengths using the existing codes such as LRFD, American Institute of Steel Construction Inc-1997, AIJ-Architectural Institute of Japan-1997, Eurocode 4-1996 and GJB4142-2000. It was found that better compaction of concrete resulted in higher member capacities in concrete-filled steel RHS columns. The tests showed the importance of good concrete compaction for concrete-filled steel RHS columns.