Existing Design Rules Research Articles

Partially loaded areas in reinforced concrete: Experimental campaign and model validation

This paper presents the results of a comprehensive experimental campaign investigating the structural behaviour of concrete blocks subjected to partial area loading. A total of 62 concrete blocks were loaded up to failure by applying a compressive load over a limited area. The campaign focused on plane cases of partial area loading, i.e. the load was applied over the (almost) entire block length and thus dispersed mainly in one direction. The test parameters included (i) the specimen geometry; (ii) the size of the loaded area; (iii) the concrete strength; (iv) the conventional reinforcement ratio, layout, and detailing; and (v) the steel fibre content. Modern measuring techniques were applied to gain insight into the crack development, the reinforcement activation, and the contact pressure distribution over the loaded area. The test results, together with experimental data found in the literature, substantiate the fundamental mechanical behaviour identified in previous theoretical studies by the authors. It is shown that the Dual-Wedge and Dual-Cone stress fields presented in the companion paper can accurately reproduce the influence of the investigated test parameters. Moreover, the bearing capacity predictions by these stress fields correlate significantly better with the experimental data than existing design rules implemented in current design codes.

Austenitic Stainless Steel I‐section Beam‐column Tests and Numerical Modelling

AbstractStainless steel became a relatively common material for load‐bearing structures in corrosive environment or when maintenance is difficult. The existing design rules cover all common cases. However, for some, the experimental or numerical data are very limited. This includes studies on welded I‐section beam‐columns. This paper presents a comprehensive experimental and numerical investigation into the structural performance of welded I‐section members loaded by compression and major axis bending moment. In total, eighteen test specimens were fabricated from grade EN 1.4301 austenitic stainless steel plates using two welding methods, namely conventional and laser welding. The experimental program on pin‐ended long beam‐columns is described in the paper. The loading eccentricities for the tests varied to provide a wide range of bending moment‐to‐axial load ratios. Nonlinear finite element models were developed in ABAQUS software and validated using the test results to simulate the beam‐column behaviour accurately.

Experimental and numerical study of stainless steel channel-to-gusset plate connections

With the advantages offered by stainless steel in terms of sustainability, mechanical performance and superiorserviceability, structural application of stainless steel is prevalent. This paper presents experimental and numerical studies of stainless steel channel-to-gusset plate connections failing by net section fracture. The experimental programme was carried out on 16 stainless steel channel-to-gusset plate connections, with each consisting of a channel section member bolted to two gusset plates by web or flange. The test setup and procedures as well as the key test results, including the failure loads, load–elongation curves, failure modes and strain distribution at critical cross-sections, were reported in detail. The effects of connection length, out-of-plane eccentricity and in-plane eccentricity on net section efficiency were discussed. Following the experimental programme, a numerical modelling programme was performed, where finite element models were firstly developed to replicate the tests and then employed to conduct parametric studies to generate further numerical data over a wide range of cross-section dimensions and connection lengths. Based on the test and numerical data, the existing design rules for stainless steel channel-to-gusset plate connections failing by net section fracture, as given in the European code and American specification, were evaluated. Generally, the European code yields excessively conservative and scattered failure load predictions, while the American specification leads to unsafe and scattered failure load predictions. An improved design approach was proposed and shown to provide substantially improved failure load predictions over the design codes.

Experimental investigation on the flexural behaviour of stainless steel reinforced concrete beams

The durability of reinforced concrete (RC) structures and infrastructure has been the subject of significant attention from the engineering research community in recent years, mainly owing to the deterioration of RC elements due to corrosion of the embedded steel reinforcement. In this context, stainless steel reinforcement can provide an efficient solution to enhance the expected lifetime of concrete structures, reducing the damage due to corrosion of the reinforcement and carbonation and deterioration of the concrete. However, current international design standards for reinforced concrete structures do not include appropriate guidance for stainless steel reinforced concrete (SSRC). In order to investigate the behaviour of stainless steel RC beams, a series of six beam tests was conducted and is discussed herein. The key performance measures for RC beams such as load-deflection response, cracking behaviour and deflections at service load are assessed. The validity and applicability of existing design rules, which were developed for carbon steel RC, are also examined for stainless steel reinforced concrete members. Other recently developed design procedures, based on the Continuous Strength Method and including an accurate material model for the stainless steel bars, are also examined.

Numerical study and design rule for axial capacities of pultruded GFRP hollow columns

This article reports the finite-element (FE) investigation on the axial capacities of pultruded fibre reinforced polymer (PFRP) composite hollow columns. The non-linear finite-element model (FEM) was developed by using ANSYS package for glass fibre reinforced polymer (GFRP) composite hollow columns, which included geometric and initial geometric imperfections. The developed FEMs were verfied against an experimental results available in the literature for GFRP hollow columns. The validated FEMs were used to carry out the parametric study comprising 92 FE models to investigate the effect of different geometries, plate slenderness and length of members on the axial capacities of GFRP pultruded hollow columns. The axial capacities predicted by the nonlinear FE analysis were also used to examine the accuracy/applicability of the current design guidelines for GFRP pultruded hollow columns available in the literature. Based on the comparison of results the merits and demerits of existing design rules in literature are discussed. In addition, this article proposed a simplified design approach over the existing strength equations to predict the axial capacity of GFRP pultruded hollow columns. The proposed design equations have closely predict the axial capacities of GFRP pultruded hollow columns, being only 9% conservative to the FEA strengths.

Rate-compatible multi-edge type low-density parity-check code ensembles for continuous-variable quantum key distribution systems

In this paper, we propose a design rule of rate-compatible punctured multi-edge type low-density parity-check (MET-LDPC) code ensembles with degree-one variable nodes for the information reconciliation (IR) of continuous-variable quantum key distribution (CV-QKD) systems. In addition to the rate compatibility, the design rule effectively resolves the high error-floor issue which has been known as a technical challenge of MET-LDPC codes at low rates. Thus, the proposed design rule allows one to implement rate-compatible MET-LDPC codes with good performances both in the threshold and low-error-rate regions. The rate compatibility and the improved error-rate performances significantly enhance the efficiency of IR for CV-QKD systems. The performance improvements are confirmed by comparing complexities and secret key rates of IR schemes with MET-LDPC codes whose ensembles are optimized with the proposed and existing design rules. In particular, the SNR range of positive secrecy rate increases by 1.44 times, and the maximum secret key rate improves by 2.10 times as compared to the existing design rules. The comparisons clearly show that an IR scheme can achieve drastic performance improvements in terms of both the complexity and secret key rate by employing rate-compatible MET-LDPC codes constructed with code ensembles optimized with the proposed design rule.

Design of heat exchanger for the production of synthesis silica

This study aims to analyze and develop a heat exchanger (HE) application for the manufacture of silica nanoparticles synthesis from agricultural waste. This shell and tube-type HE is designed simply, but it still refers to the existing design rules. The design of a shell and tube type HE with one pass shell and tube with turbulence flow. The specifications of the HE apparatus are 1.93 m in shell length, 0.203 m in shell diameter, 0.020 m in inner tube diameter, 0.022 m in outer tube diameter, and 0.016 m in thickness. The results showed an effectiveness value of 66.38% with an impurity factor of 0.01314. This informed that although the shell and tube-typed HE does not meet the requirements and standards for being set in industrial applications, it can be useful as a learning method regarding the design process, working mechanism, and analyzing the performance of the HE.

Flexible Polymer X-ray Detectors with Non-fullerene Acceptors for Enhanced Stability: Toward Printable Tissue Equivalent Devices for Medical Applications.

There is growing interest in the development of novel materials and devices capable of ionizing radiation detection for medical applications. Organic semiconductors are promising candidates to meet the demands of modern detectors, such as low manufacturing costs, mechanical flexibility, and a response to radiation equivalent to human tissue. However, organic semiconductors have typically been employed in applications that convert low energy photons into high current densities, for example, solar cells and LEDs, and thus existing design rules must be re-explored for ionizing radiation detection where high energy photons are converted into typically much lower current densities. In this work, we report the optoelectronic and X-ray dosimetric response of a tissue equivalent organic photodetector fabricated with solution-based inks prepared from polymer donor poly(3-hexylthiophene) (P3HT) blended with either a non-fullerene acceptor (5Z,5'Z)-5,5'-((7,7'-(4,4,9,9-tetraoctyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(benzo[c][1,2,5]thiadiazole-7,4-diyl))bis(methanylylidene))bis(3-ethyl-2-thioxothiazolidin-4-one) (o-IDTBR) or a fullerene acceptor, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Indirect detection of X-rays was achieved via coupling of organic photodiodes with a plastic scintillator. Both detectors displayed an excellent response linearity with dose, with sensitivities to 6 MV photons of 263.4 ± 0.6 and 114.2 ± 0.7 pC/cGy recorded for P3HT:PCBM and P3HT:o-IDTBR detectors, respectively. Both detectors also exhibited a fast temporal response, able to resolve individual 3.6 μs pulses from the linear accelerator. Energy dependence measurements highlighted that the photodetectors were highly tissue equivalent, though an under-response in devices compared to water by up to a factor of 2.3 was found for photon energies of 30-200 keV due to the response of the plastic scintillator. The P3HT:o-IDTBR device exhibited a higher stability to radiation, showing just an 18.4% reduction in performance when exposed to radiation doses of up to 10 kGy. The reported devices provide a successful demonstration of stable, printable, flexible, and tissue-equivalent radiation detectors with energy dependence similar to other scintillator-based detectors used in radiotherapy.

Design of direct-formed square and rectangular hollow section beams

A complementary experimental study showed that the flexural member design rules in the North American steel design standards (AISC 360–16 and CSA S16-19) can be excessively conservative for direct-formed regular- and high-strength steel square and rectangular hollow sections (hereinafter collectively referred to as RHS). It was also found that post-production hot-dip galvanizing can further improve member flexural behaviours through effective reduction of cold-forming-induced residual stresses. In this study, the experimental results of 22 full-scale beam tests from the complementary experimental study are used to validate non-linear finite element (FE) models. The FE models are developed using previously measured stress-strain relationships, residual stresses, and geometric imperfections. A subsequent parametric study including 788 beam models is performed to cover extended ranges of cross-sectional dimensions. The applicability of the existing slenderness limits and flexural design formulae are examined using the experimental and numerical data. The results justify the use of less stringent slenderness limits and higher design curves for direct-formed regular- and high-strength RHS beams (untreated and galvanized). Modifications to the existing design rules are proposed. Based on reliability analyses, the modified approaches are proven accurate and provide adequate safety margins.

Buckling capacities of Double-T-Box Girders – A numerical approach

Owing to the increase in the applications of the built-up Cold-Formed Steel (CFS) sections in the construction industry, there exists an immediate demand in standardisation of the design rules to use built-up sections as structural members. This paper presents a numerical approach to estimate the capacities and structural buckling behaviour of mono-symmetric stiffened built-up CFS homogeneous and Hybrid Double-T-Box Girders (DTBGs and HDTBGs) subjected to uniform static flexure. The geometry of these built-up sections is unique and has the combined advantages of an open 'T' section girder that offers greater resistance against flexural buckling moment and a closed box region, which resist against lateral-torsional bucking. A verified and validated Finite Element Analysis (FEA) parametric study on 120 ideal FE models of I-DTBGs and I-HDTBGs are performed using ABAQUS software. The overall non-dimensional member slenderness (λLT) considered in this study is ranging up to 1.80. This study captured the three primary modes of failures: local, distortional and lateral-torsional buckling and two interaction modes of failures viz, local plus distortional and distortional plus lateral buckling and their sub kinds. For, the DTBGs and HDTBGs with λLT <0.4 say in short to medium span local and distortional buckling is predominant and in the case of larger span girders of with λLT >0.4 exhibits lateral buckling failure. The bending capacities of the girders and their varying buckling modes are dependent upon the increase of member slenderness and plate element stiffness. The obtained flexural capacities of these girders from FEA have been compared against the Effective Width Method (EWM) design equations as suggested in Eurocode standards. This research study identifies that there exist notable differences while assessing the buckling capacities of these DTBGs and HDTBGs using the existing design rules and their relationships. Henceforward, a new simplified and appropriate design equation is formulated, and its corresponding buckling curve is illustrated in this study. The arrived equation is, χLT = 0.13 λ 2LT − 0.65 λLT + 1.11 that is also found to be satisfactory as per reliability analysis.

Effect of member orientation on static strengths of cold-formed high strength steel tubular X-joints

Rotation of brace and/or chord members has a significant effect on the static strengths of tubular joints. Brace-rotated and bird-beak tubular joints are obtained by rotating the brace and/or chord members along their respective longitudinal axes by angles corresponding to their cross-sectional diagonal planes. This paper presents an experimental investigation of 29 cold-formed high strength steel (CFHSS) brace-rotated (BR), square bird-beak (SBB) and diamond bird-beak (DBB) tubular X-joints. The tubular members were made of S960 steel, having a nominal yield strength of 960 MPa. An axial compression load was applied through the braces of brace-rotated and bird-beak tubular X-joints. The welds connecting braces and chords of brace-rotated and bird-beak tubular X-joints were laid using the automatic gas metal arc welding process. The measured values of brace-to-chord width ratio (β) ranged from 0.33 to 0.83, effective brace-to-chord width ratio (β’) ranged from 0.25 to 0.87, brace-to-chord thickness ratio (τ) ranged from 0.67 to 1.28 and chord width-to-chord thickness ratio (2γ) ranged from 25.3 to 39.1. Three failure modes were observed in this study, namely chord face failure by plastification, a combination of this with chord sidewall failure (i.e., combined failure), and chord crown failure by plastification. Nominal strength prediction methods, from prior studies on member-rotated tubular joints as well as from the prEN 1993-1-8 (2021) and CIDECT (2008, 2009), were evaluated against the static strengths obtained from the tests. Reliability analysis was also performed to check the reliability levels of the existing design rules. For the range of tests undertaken, it was found that the current design rules of RHS-to-RHS, CHS-to-RHS and CHS-to-CHS tubular X-joints given in the CIDECT (2008, 2009), when used in conjunction with a material factor of 0.80, were found suitable and reliable for the design of CFHSS BR, SBB and DBB X-joints, respectively. In addition, the effect of change of member-rotation on the joint strengths and load–deformation curves was also assessed by comparing the structural performance of member-rotated tubular X-joints with the those of corresponding identical traditional RHS-to-RHS X-joints (Pandey and Young [1]).

Self‐compacting high‐performance fiber concrete for foundations: Part 1 ‐experimental verification and design considerations

AbstractAn investigation is carried out into the applicability of self‐compacting high‐performance fiber concrete (HPFC) in foundations. A concrete mixture has been designed with a concrete cube strength of about 110 MPa. The concrete contains 60 kg/m3 steel fibers. The properties of the HPFC developed are very suitable for structural applications, especially because the post‐cracking tensile strength, provided by the fibers, is higher than the axial tensile strength of the concrete so that hardening in tension occurs after crack formation, often characterized by multiple cracking. This not only results in a high bearing capacity but as well in substantial durability. As a potential application foundation elements are considered. Experiments have been carried out to determine the pre‐ and post‐cracking strength properties, the shear resistance of short beams with loads near to the supports, the anchorage length of reinforcing bars, and the shear capacity of pile caps. The results of the tests are used for verification of the applicability of the general design rules for fiber concrete, as found in the fib Model Code 2010, to the HPFC developed. The HPFC developed is characterized by high strength and ductility, is durable and self‐compacting. The research program showed that the design of structures with the HPFC considered can be based on existing design rules with some extensions.

Behaviour of Ferritic Stainless Steel Bolted T‐stubs Under Tension‐Part 1: Experimental Investigations

AbstractResearch on stainless steel structures has primarily focused on the structural response and design of individual members, whilst the response of joints has received far less attention to date. Recently, a series of experimental tests has been conducted on austenitic and duplex stainless steel moment resisting connections which highlighted both the excellent ductility and significant overstrength exhibited by such connections as well as the severe conservatism of current design rules specified in EN 1993‐1‐8 when applied to stainless steel joints. A comprehensive experimental study on the structural behaviour of stainless steel T‐stubs fabricated from EN 1.4003 ferritic stainless steel grade is reported in this paper. The tested configurations included both single and double bolt rows and have been assembled with A4‐80 stainless steel bolts. In order to determine the material characteristics of the T‐stubs and the connecting bolts, tensile coupon tests were performed and the material anisotropy exhibited by ferritic stainless steel has been quantified. The ultimate resistance, plastic deformation capacity and failure mode of each T‐stub were obtained and are reported herein. The obtained results are utilised to assess the accuracy of existing design rules and to validate the numerical model discussed in the companion paper.

Re‐evaluation and extension of fatigue test data for welded attachments and butt joints

AbstractWelded structures under fatigue loading are widely used in civil engineering. The fatigue strength of components such as welded attachments and butt joints are often determining for the dimensioning of bridges, crane runways or tower constructions. The existing design rules of Eurocode 3, Part 1‐9 are mainly based on experimental data. However, the experimental background of Eurocode 3 Part 1‐9 is partly incomplete. Some fatigue detail classifications are based on numerical modelling and engineering judgement. New findings from experimental research allow a revision of these details, leading to higher fatigue strength classifications in many cases.Firstly an overview of an extensive database for fatigue tests on butt joints and welded attachments is addressed. A method for statistical analysis is presented, which allows the consideration of fatigue tests from different sources by using the design philosophy of Eurocode 3 Part 1‐9 and also meeting the requirements of Eurocode 0.The paper is also going to present some new supplementary experimental investigations on a fatigue detail for transverse end welds of cover plates with blended weld toes, which is traditionally used in German bridge design.Finally a revised and simplified fatigue detail catalogue for welded attachments and butt joints is addressed which is intended as a suggestion for the next generation of Eurocode 3 Part 1‐9.

Cross-section capacity of RHS and SHS at elevated temperatures: Comparison of design methodologies

The accuracy of different fire design methodologies for hollow cross-sections subject to compression and major-axis bending is studied and compared in this paper. For that purpose, a numerical model based on shell finite elements is developed and validated against existing experimental results available in the literature. Comprehensive numerical parametric studies are then carried out by means of the validated numerical model, including different cross-section dimensions, loading conditions, steel grades and temperatures, to obtain a large set of results of the ultimate resistance of hollow sections in fire. Based on these results, the existing design rules of the Eurocode 3 Part 1–2, the AISC 360 specification and the recent design proposals of Couto et al. [1,2] and the Direct Strength Method adapted to fire are assessed in terms of their accuracy for predicting the section capacity, including the resistance against local buckling at elevated temperatures. It is demonstrated that the cross-sectional classification procedure for the case of fire, available in the Eurocode 3 and AISC specifications, results in inconsistencies and should be further investigated and revised in the future. To overcome the Eurocode 3 limitations it is proposed that the design methodology of Couto et al. [1,2] is adopted irrespective of the cross-section classification and for the AISC specification it is suggested the use of a reduced stress based on the 0.2% proof strength until more efficient design methods are developed.

Local stability of normal and high strength steel plates at elevated temperatures

This paper presents an investigation into the local buckling behaviour and design of normal and high strength steel plates at elevated temperatures. The considered high strength steel grades include grades S690 and S460 as well as the normal strength grades S355, S275 and S235 taken into consideration. Shell finite element models of normal and high strength steel plates are created to mimic their local buckling response in fire, whose accuracy is validated against experimental results from the literature. Extensive numerical parametric studies are then carried out by means of the validated finite element models, taking into account different plate slendernesses, elevated temperature levels, edge boundary conditions and steel grades. The accuracy of the design provisions provided in the current European structural steel fire design standard EN 1993–1-2 and its upcoming version prEN 1993–1-2 for the consideration of the local buckling behaviour of normal and high strength steel plates in fire is investigated. It is observed that the existing design rules given in both EN 1993–1-2 and prEN 1993–1-2 lead to rather scattered estimations of the local buckling strengths of high strength steel plates at elevated temperatures. New cross-section classification rules and effective width design equations for the ultimate strength predictions of normal and high strength steel plates in fire are developed. High accuracy and reliability of the proposed design rules are demonstrated.

Experimental and numerical investigations of press-braked stainless steel channel sections under minor-axis combined loading

This paper presents an in-depth experimental and numerical investigation into the behaviour and resistances of press-braked stainless steel channel sections under combined compression and bending moment about the minor principal axis. The experimental programme adopted two press-braked stainless steel channel sections and included initial local geometric imperfection measurements and ten eccentrically loaded stub column tests. The loading eccentricity was varied to achieve a range of ratios of compression load to minor-axis bending moment. Two types of failure mode, namely ‘C’-orientation failure (indicating that failure specimens bent towards the web) and ‘reverse C’-orientation failure (signifying that failure specimens bent towards the flange tips), were observed upon testing. The experimental programme was followed by a numerical modelling programme; finite element models were developed and validated against the test results and then adopted to perform parametric studies to generate further numerical data over a wide range of cross-section dimensions and initial loading eccentricities. The obtained test and numerical data were then adopted to assess the accuracy of the current codified design rules for press-braked stainless steel channel sections under combined compression and minor-axis bending, as given in the European code, American specification and Australian/New Zealand standard. The assessment results revealed that the codified design rules yield excessively conservative and scattered resistance predictions, owing to the neglect of the favourable material strain hardening of stainless steel and the beneficial stress redistribution within channel sections under combined loading. Improved design rules featuring more efficient interaction curves, anchored to more accurate end points (i.e. cross-section resistances under pure compression and pure bending), were then proposed. The new design proposals were shown to yield more accurate and consistent resistance predictions over the existing design rules. Statistical analyses were also conducted to confirm the reliability of the new design proposals.

Tests of cold-formed steel built-up open section members under eccentric compressive load

An experimental study was performed on cold-formed steel built-up open section members under eccentric compressive load. The specimens with member lengths varied from 300 to 1500 mm were manufactured by composing two identical channels using self-tapping screws. The channels with longitudinal stiffeners were fabricated from the steel grades G500 and G550 zinc-coated sheets with nominal 0.2% proof stresses of 500 and 550 MPa, respectively. A total of thirty-three combined minor axis bending and compression tests were carried out under pin-ended supports to explore the buckling behaviour of the newly designed built-up section members. Six test series with a relatively wide range of axial load-to-moment ratio were included in this study to examine the interaction relationship of the built-up section beam-columns. The test loading capacities, full-history responses and failure modes were obtained for all the test specimens. Since the novel built-up open sections are not covered in the current cold-formed steel design standards, the comparisons of experimental loading capacities with nominal strengths predicted by the North American Specification, Australian/New Zealand Standard, European Code and American Specification were conducted to assess the appropriateness of the existing design rules. The applicability of axial load-moment interactive formulae specified in the aforementioned design standards with the nominal pure compressive resistance and nominal pure bending resistance determined by direct strength method was evaluated for the built-up section beam-columns. It is found that the axial load-moment interactive formulae generally underestimate the strengths of the cold-formed steel built-up open section beam-columns.

Experimental study of ferritic stainless steel bolted T-stubs under monotonic loading

A comprehensive experimental study on the structural behaviour of stainless steel T-stubs in Grade EN 1.4003 ferritic stainless steel and employing A4–80 stainless steel bolts is reported in this paper. A total of 17 ferritic stainless steel T-stubs of various geometric configurations including both single and double bolt rows were tested under monotonic tension. The focus of the tests was on T-stubs failing predominantly in mode 1. Auxiliary tensile tests were performed on coupons extracted from the T-stub flanges in three directions thereby enabling the material anisotropy to be quantified. The ultimate resistance, plastic deformation capacity and failure mode of each T-stub were obtained and are reported herein. The obtained results are utilised to assess the accuracy of existing design rules, which, contrary to austenitic and duplex stainless steels, seem to offer a good prediction of the experimentally determined plastic resistance. Finally, the applicability of recently proposed predictive equations accounting for membrane actions in carbon steel T-stubs to ferritic stainless steel T-stubs has also been assessed.

Fire testing of austenitic stainless steel I-section beam–columns

With the increasing use of stainless steel elements in construction, the need for comprehensive rules to enable their efficient structural design is clear. To date, the fire behaviour of stainless steel I-section beam–columns has been the subject of relatively little research. In particular, there is an absence of experimental data. To address this gap in knowledge, full-scale anisothermal fire tests on six grade 1.4301 austenitic stainless steel I-section beam–columns have been carried out; the test procedure and results are reported herein. The test specimens were subjected to eccentric axial compression with two eccentricity values so as to achieve different combinations of axial compression and uniform minor axis bending. Complementary initial local and global geometric imperfection measurements, room temperature tensile coupon tests and room temperature beam–column tests were also carried out. Based on the obtained experimental results, together with additional numerical results from a previous study, the existing design rules in the European structural steel fire design standard EN 1993-1-2 and the new design method of Kucukler et al. (2021) for stainless steel beam–columns in fire, which will be incorporated into the next version of EN 1993-1-2, are assessed.