03.33: Experimental assessment of tolerances for the fabrication of laser‐cut steel joints

Characterization of moment resisting I-beam to circular hollow section column connections resorting to passing-through plates

As thin walled HSS columns are very flexible, they usually exhibit excessive deformation when resisting a bending moment or transverse loads. Adding exterior/interior diaphragms is one way to remedy the problem. Another option that can significantly increase strength and stiffness is to allow passing plates through the hollow column by means of Laser Cutting Technology (LCT). This solution was tested on CHS columns within the RFCS LASTEICON project. The first outcomes were promising. One of LASTTS new RFCS project's overarching concerns is to enlarge the range of application of the passing‐through solution onto SHS columns.The goal of this research paper is to present the behaviour of I‐beam‐to‐SHS column moment resisting joints using passing‐through plates under opposite bending moments. First, a solid‐based finite element model is presented. This model is used to conduct a sensitivity analysis with different SHS column and passing plates geometry. The failure mode is resulting contribution of both weld/tube‐wall tearing in tension, and chord face crushing in compression. Analytical models are developed in an attempt to ascertain the bending resistance and initial rotational stiffness of this new type of connections.

Circular hollow sections (CHS) offer a variety of constructional and architectural advantages. Up to now, hollow section structures have usually been connected by welding, and more rarely by bolting. However, these established connection methods have disadvantages. Despite its great success in the mobility sector, adhesive bonding is not yet used for joining hollow steel sections in steel construction. Adhesive bonding, however, has significant advantages, especially if combined with classical joining processes. To highlight these advantages, this article presents excerpts from the results obtained in two recently completed research projects. First, a hybrid brace connection for hollow section framework structures is presented which combines welding, bolting and adhesive bonding methods. In addition, the loadbearing behaviour of a novel hybrid grouted connection, which advantageously combines adhesive and grout materials, is analysed and discussed in this paper.

Displacement ductility is one of the parameters used to measure the seismic performance of a structure. This study experimentally determines the increase in displacement ductility of the spun pile with 400 mm of outer diameter and 100 mm of wall thickness using concrete infill cast inside the hollow of the pile. The spun pile and concrete infill's concrete compressive strength was 54.4 MPa and 33.0 MPa, respectively. Loading was conducted with constant axial and reversed lateral flexural loads. A total of six samples were tested with different axial loads of 392 kN (0.08fc'Ag) for S-DB-1, S-DB-2, S-DB-5, and 784 kN (0.16fc'Ag) for S-DB-3, S-DB-4, S-DB-6 with the reverse flexure load applied in the middle span of the pile. The results showed spun piles with concrete infill could resist the flexural load combined with axial loads until the displacement ductility 5.8 for P0 = 0.08fc'Ag, and 3.7 for P0 = 0.16fc'Ag, respectively. Compared with the ordinary spun piles, which had a hollow section, the presence of concrete infill due to the presence of the concrete infill the displacement ductility increased by 18% when loaded with 0.08f'cAg and 42% at 0.16f'cAg of axial loads. In conclusion, according to seismic codes, displacement ductility evaluation showed that tested piles for plastic concept design applications are appropriate for moderate seismic risks category state under axial loads of 0.08fc'Ag. The increasing of the axial load becomes 0.16fc'Ag decreasing the displacement ductility to become less than 4, applicable for low seismic risks category state.

Three-dimensional macro-modeling of beam-to-rectangular hollow section column joints under cyclic loading. Part 1: Modeling of cyclic out-of-plane behavior of single isolated plate element

Development and seismic performance evaluation of New high strength reinforced concrete column and steel beam (New-RCS) joint

Experimental and numerical investigations of tensile behavior of slip-critical blind bolts anchored in concrete-filled steel tubes

As part of the AiF‐FOSTA research project P1020 „Economical welded joints of high‐strength steels”, extensive tests were carried out at the Institute of Steel and Timber Construction at the TU Dresden. Tested were lap joints, cruciform joints and butt joints of steels in grades S500 to S960. The picture shows the flat tensile test specimens made from butt joints with a thickness of 20 mm and a width of 35 mm in the weld area to be tested. Fully and partially penetrated butt welds were tested. In order to determine the strains in the course of the tests, strain measurements were carried out using photogrammetry in addition to inductive measurements. For this purpose, a stochastic pattern of graphite spray was applied to the test specimens and the high‐frequency image recordings were digitally evaluated (s. article pp. 138–149. Foto: TU Dresden, Institute of Steel and Timber Construction).

The study focuses on the structural design and detailing of steel joints for an industrial mixer plant in accordance with guidelines provided by the American Institute of Steel Construction, incorporating provisions from AISC 360 and relevant design guides to ensure safe and efficient performance under demanding industrial conditions. Industrial mixer plants are subjected to complex loading scenarios that include not only conventional dead and live loads but also significant dynamic forces arising from rotating equipment, vibration effects, and cyclic stresses that may lead to fatigue over time. This work addresses these challenges by presenting a comprehensive approach to the design of various types of steel connections, including bolted, welded, shear, moment-resisting, and base plate connections, ensuring that each connection type satisfies strength and stability requirements while also meeting serviceability criteria such as deflection control and vibration resistance. Special emphasis is placed on the behavior of joints under repeated loading conditions, highlighting the need for fatigue-resistant design and the selection of appropriate connection configurations such as slip-critical bolting where necessary. In addition, the study underscores the importance of proper detailing practices, including adequate spacing, edge distances, weld quality, and constructability considerations, to facilitate ease of fabrication and erection. Overall, the design methodology aims to achieve structural safety, durability, and long-term operational reliability, ensuring that steel joints perform effectively throughout the service life of the industrial mixer plant under both static

SummaryAn efficient component model has been developed that captures strength and stiffness deterioration of steel hollow structural section (HSS) columns. The proposed model consists of two fiber‐based segments at a member's ends along with an elastic segment in between. The fibers exhibit nonlinear uniaxial stress–strain behavior, which is explicitly defined by uniaxial monotonic tensile and cyclic round coupon tests. The postbuckling behavior of an HSS column is traced through a proposed uniaxial effective stress–strain constitutive formulation, which includes a softening branch in compression and an energy‐based deterioration rule to trace the influence of cyclic deterioration in the inelastic cyclic straining. These may be inferred by uniaxial stub‐column tests. The component model captures the coupling between the column axial force and flexural demands. Consistent model parameters for a number of steel materials used in the steel construction in North America and Japan are proposed along with the associated model calibration process. The efficiency of the proposed model in predicting the hysteretic behavior of HSS columns is demonstrated by comparisons with physical steel column tests subjected to various loading histories, including representative ones of ratcheting prior to earthquake‐induced collapse. The proposed model is implemented in an open‐source finite element software for nonlinear response history analysis of frame structures. The effectiveness of the proposed model in simulating dynamic instability of steel frame buildings is demonstrated through nonlinear response simulations of a four‐story steel frame building, which was tested at full‐scale through collapse. Limitations as well as suggestions for future work are discussed.

Purpose Concrete-filled hollow section (CFHS) is widely used in steel construction. The combination of concrete and steel decreases buckling and deformation of steel. However, studies reveal that using normal concrete increases the dead weight of a structure. Therefore, a lightweight concrete, such as foamed concrete (FC), is proposed to reduce the weight of the structure. The purpose of this study is to determine the strength of modified fibrous foamed CFHS (FCFHS). Design/methodology/approach Steel and polypropylene fibres were used with rice husk ash, and short column fibrous FCFHSs were tested under compression load. Greased and non-greased methods were adopted to determine bond strength and confining effect between steel and concrete. Findings Results indicate that the use of fibre in FCFHSs improves the strength of CFHS from 9% to 11%. The non-greased method confirms that an interaction exists between steel and concrete with a confinement coefficient of more than 2.0. Originality/value It can be shown that the modified fibrous foamed concrete can increase the strength of the concrete and can be used as concrete filled in steel construction industry.

Detailing of I-beam-to-CHS column joints with external diaphragm plates for seismic actions

Experimental and numerical study of double-through plate connections to CFST column

The risks of failure by brittle fracture, fatigue and other failure modes are greatly influenced by the presence of weld defects. Three principal forms of cracking associated with welds can occur in the fabrication of off-shore structures in ferritic steels, namely, weld metal solidification (hot) cracking, hydrogen-induced cold cracking in the heat affected zone (HAZ) and weld deposit, and lamellar tearing in the parent plate. The paper discusses the incidence and nature. Of these cracking types in relation to offshore structures such as pipelines and platforms. The risks of each type of cracking must be considered during design, as well as at the fabrication stage. This approach can lead to considerable savings both of cost and time in avoiding subsequent difficulties. Recent findings concerned with the way in which materials and welding consumables influence the risk of cracking are considered in relation to this dual approach. Test techniques to aid selection of materials and welding processes at the design stage are outlined, together with typical results. Finally, advice is given on the avoidance of cracking in fabrication. 1 INTRODUCTION When fabricating offshore structures such as platforms or pipelines, a number of potential cracking problems can arise in welded joints of ferritic steels. Welder defects such as lack of fusion, slag entrapment etc are outside the scope of this paper, the main purpose of which is to show that an understanding of the factors controlling the incidence of the different cracking types can bring about considerable cost savings. Much can be done at the design stage to select steel compositions and processing routes, as well as welding processes, consumables, procedures and joint details which can minimise the risk of cracking and the need for expensive repairs. Undetected cracks at the fabrication stage may result, of course, in premature failure in service by either brittle fracture, fatigue, stress corrosion or other failure modes and the consequential costs of a major failure of this type, including possible environmental damage, can be enormous. It should be remembered, however, that some welding defects including cracks may be of no significance as regards service performance, a subject deart)with in another paper in this Conference.1 The three forms of weld cracking which are of most concern in offshore structures arehydrogen-induced cracking in the heat-affected zone (HAZ) or weld metal,weld metal solidification cracking andlamellar tearing in the HAZ and parent material. In following sections these threecracking types will be described and the factors controlling their incidence -discussed. In a final section, the implications as regards specification of steel type, consumables and welding process will be consideredin terms of minimising t weld cracking.

Cold Formed Steel (CFS) is one of the materials that recently used in building structures. There are many advantages of CFS compared with other materials, such as lightweight, high tensile strength, and fast construction. Hollow Structural Sections (HSS) is the most commonly used as beam and column CFS sections. The purposes of this study are determining the behavior and capacity of CFS beam column joint under lateral load with manual calculation, numerical analysis and experimental. The test specimens used 1 mm thick, 4x4cm HSS for column and 2x4cm HSS for beam. Beam and column connected by two single angle plates placed above and below the beam sides. Both parallel and staggered fastener configurations used in this experiment. Four 4 mm diameter bolts used in this connection. Monotonic static loading applied on beam for modelling the lateral load. The experimental results show the behavior and the capacity of the beam column joint with parallel fastener configurations. The numerical results show that the staggered fastener configuration has better performance compared with the parallel fastener configuration. The CFS beam column joint are adequate to resist the lateral load and feasible to be apply as structural components in building structures.