Structural Design Standards Research Articles

Dowel–bearing behavior of bamboo scrimber for bolted–type joint

Dowel-bearing behavior is one of the key material characteristics in the design of laterally loaded joints with dowel-type fasteners and provides its strength and stability of structures. In this study, the dowel-bearing behavior of bolted joints on bamboo scrimber were investigated by analyzing the effect of specimen size, bolt diameter and loading direction on the dowel-bearing behavior. The estimation formulas of dowel-bearing strengths of bamboo scrimber for engineering utilization were developed based on conducting on 16-group experiments comprising a total of 80 half-hole samples. The results indicate that the initial stiffness was affected by the bolt diameter, sample thickness and loading direction. Dowel-bearing strength was only affected by bolt diameter and it decreased gradually with the increase in bolt diameter, irrespective of specimen sizes and loading direction. The failure mechanisms of the samples loaded in parallel- and perpendicular-to-grain were completely different. The existing empirical expressions was suitable for bamboo scrimber loaded in parallel-to-grain when larger bolts were used, but can under-estimate the dowel-bearing strengths in perpendicular-to-grain direction. Finally, semi-empirical regression-based formulas as functions of compressive strength and bolt diameter were proposed, which exhibited good agreement with the experimental dowel-bearing strength. The findings will be useful for designing safe and efficient bolted joints to promote more widespread use of bamboo scrimber in construction, as well as supplying basic data for systematic development of test and design standards for bamboo structures.

Advances in the study of simultaneous occurrence of strong wind and earthquake and their effects on structures

<p indent="0mm">With the increasing demand for sustainable development of engineering structures, the study of engineering structures under the joint action of multi-hazards is receiving more and more attention from scholars and engineers. Are the simultaneous occurrence of strong wind and earthquake, as two major hazard loads, still uncertain as a coincidental event? To clarify the possibility of simultaneous occurrence of two hazards, this paper summarizes the current research status that strong wind and earthquake can occur simultaneously from two aspects, respectively, strong wind triggers earthquake and earthquake causes strong wind, collects data on the simultaneous occurrence of strong wind and earthquake in some areas from various factors, provides data support for the coupling phenomenon of simultaneous occurrence of strong wind and earthquake, and reviews the current research progress of engineering structures under the simultaneous action of strong wind and earthquake. It reviews the progress of related research on engineering structures under the simultaneous effects of strong wind and earthquake. The results show that: (1) Strong wind can trigger microseismic, slow earthquake, and normal earthquake by affecting waves and geological structures, and earthquakes can trigger strong wind by causing changes in atmospheric temperature and electromagnetic waves, and there is a coupling phenomenon between strong wind and earthquake. (2) The probability of simultaneous occurrence of strong wind and earthquake varies greatly in different regions, and the wind speed surface fitting can better meet the temporal and spatial relationships for collecting data on the simultaneous occurrence of strong wind and earthquake. (3) Engineering structures under the simultaneous effects of strong wind and earthquake are more prone to damage and destruction, and structural design standards should be adjusted or energy-consuming damping devices should be installed to improve their performance. Therefore, it is still necessary to improve the data related to the simultaneous occurrence of strong wind and earthquake and their mechanism of action. The comprehensive consideration of the effects of strong wind and earthquake on engineering structures is an important research direction in this field in the future.

Post-fire local buckling behaviour of cold-formed S700 high strength steel circular hollow sections under axial compression: Experiments, modelling and design

This paper presents experimental and numerical studies of the local buckling behaviour and compression resistances of cold-formed S700 high strength steel circular hollow sections (CHS) after exposure to elevated temperatures. The testing programme included post-fire material tests, initial local geometric imperfection measurements and stub column tests on ten specimens. Then, finite element models were developed to simulate the test structural responses and employed to perform parametric studies to generate further numerical data over a wide range of cross-section dimensions. Given that there are no existing design standards for high strength steel structures after exposure to elevated temperatures, the relevant ambient temperature design rules were evaluated, using post-fire material properties, for their applicability to cold-formed S700 high strength steel CHS after exposure to elevated temperatures, based on the test and numerical data. The evaluation results revealed that (i) the codified slenderness limits were generally accurate when used for cross-section classification of post-fire cold-formed S700 high strength steel CHS and (ii) although the codified design rules resulted in overall relatively accurate cross-section compression resistance predictions, the predicted resistances were conservative for cold-formed S700 high strength steel non-slender CHS after exposure to elevated temperatures of 900 °C and 1100 °C (owing to the high levels of material strain hardening) and those slender CHS (owing to the conservatism of the codified effective width methods).

Experimental Study on the Axial Compression Performance of Glued Wood Hollow Cylinders Reinforced with BFRP

The present paper investigates the impact of basalt fiber reinforced polymer (BFRP) on the axial compression performance of glued wood hollow cylinders. This study aims to facilitate the application of BFRP in the field of structural reinforcement of glued wood hollow columns. Ten glued laminated wood hollow columns of the same size were designed and placed into five groups (ZC1 and ZRC2 to ZRC5), of which one group (ZC1), with a total of two pure wooden columns, was not arranged with BFRP, and the remaining two wooden columns in each group were arranged with BFRP at different distances. The destruction mode, ultimate load capacity, load–displacement curve, load–strain curve, and ultimate load capacity–total area of the BFRP paste curve of each specimen were obtained by conducting axial compression tests on five groups of wood columns reinforced with different basalt fiber cloths, which revealed the damage mechanism, the relationship between the ultimate load capacity and total area of BFRP paste, and pointed out the most effective area ratio. The test results show that the destruction mode of axially pressed, glued, laminated wood hollow columns is typical compression buckling damage, mainly manifested as follows: the wood at the middle or end of the specimen under pressure first buckles; then, with the increase in load, the specimen is crushed; at this time, the maximum ultimate bearing capacity of each specimen is in the range of 296.77~375.85 kN, the maximum longitudinal displacement is in the range of 2.77~3.38 mm, and longitudinal cracks appear at the end. It is worth noting that the growth rate of the ultimate bearing capacity varies with the increase in the total area of the BFRP paste. When the total area of the BFRP paste is less than a 3.2 × 105 mm2 range value, the growth rate of the ultimate bearing capacity is faster, and then, the growth rate gradually becomes slower. The optimum BFRP paste area ratio can be taken as k = 0.59. The ultimate bearing capacity after reinforcement increases from 11.06% to 26.65% compared with the pure wood column. According to GB50005-2017, “wood structure design standards” improve the hollow wood column bearing capacity calculation method and fit the BFRP reinforced hollow wood column’s ultimate bearing capacity calculation formula; the errors are within ±10%, which can provide a reference for the practical application of BFRP in the field of reinforcing glued wood hollow cylindrical structures.

Development of a unified design buckling curve for fibre reinforced polymer plates subjected to in-plane uniaxial and uniform compression

Presented are 24 non-dimensional buckling curves to estimate the strengths of Fibre-Reinforced Polymer (FRP) square plates having four simply supported edges and subjected to in-plane uniaxial and uniform in-plane compression. The curves are constructed by the authors from a parametric numerical analysis using ABAQUS® software with changing variables for: material properties; initial geometrical imperfections; laminate lay-ups; and plate thicknesses. These strength curves express relationships for the buckling reduction factor with plate slenderness, and account for post-buckling strength. We observe that regardless of the laminate lay-up (except for purely unidirectional), the choice of FRP material and the magnitude of the initial geometrical imperfection the predicted buckling reduction factors display a meaningful correlation with plate slenderness. Presented is a proposed unified buckling design curve, defined as the lower bound to 18 of the 24 ABAQUS®-generated buckling curves. This new curve is benchmarked by the authors against experimental test results extracted from the literature and it is found that there is a reasonable agreement. The authors recommend that the proposed buckling design curve has the potential to be introduced into structural design standards as a procedure to design the buckling strengths of FRP plates.

Experimental and numerical investigations into S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures

This paper reports experimental and numerical investigations into S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures. A testing programme was firstly conducted and included heating, soaking and cooling of specimens as well as post-fire tensile coupon tests, initial local geometric imperfection measurements and stub column tests. Following the testing programme, a numerical modelling programme was conducted, where finite element models were developed and validated against the test results and then employed to perform parametric studies to generate further numerical data over a wide range of cross-section dimensions. Given that there are currently no available design standards for high strength steel structures after exposure to elevated temperatures, the relevant ambient temperature design rules, as set out in the European code, American specification and Australian standard, were assessed, using post-fire material properties, for their applicability to S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures. The assessment results revealed that the codified slenderness limits for plate elements in compression were generally accurate when used for cross-section classification of S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures up to 700 °C but conservative for higher temperatures beyond 700 °C. Moreover, the codified design rules were shown to provide accurate and consistent post-fire cross-section compression resistance predictions for S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures up to 700 °C but resulted in conservative predictions for higher temperatures beyond 700 °C.

The GCM‐FE Method for the Advanced Analysis of Steel Frameworks and Connections

AbstractThe Generalised Component Method (GCM) has recently been formulated for analysing the full‐range nonlinear response of connections, incorporating the elastic and inelastic stiffnesses, the post‐ultimate softening as well as the ductility of each component. In this paper, the GCM is implemented in an FE analysis framework of steel structural frames. The paper explains the key elements of the FE modelling, such as the integration of the connection model with adjoining members, the accurate representation of components, and the automatic modelling technique using Python scripts. The framework, termed the GCM‐FE joint modelling method, is then validated against experimental results for bolted top‐and‐seat angle connections, and used to analyse a two‐storey four‐bay irregular steel frame. The GCM‐FE analysis is shown to provide substantially greater insight into the performance of connections than the simplified joint models used in traditional analysis. It not only provides the ultimate resistance and failure mode of the frame, considering both members and connections, but also accurately predicts the load‐redistribution process inside the connections and the resultant effect on the structural framework. The GCM‐FE analysis presents a major step towards the complete direct design of steel frameworks by advanced analysis, and lays the foundation for the next generation of structural design standards in which the strength and structural safety checks of both members and connections are performed in a single step at system level.

Post-fire behaviour and residual resistance of hot-rolled stainless steel channel sections under major-axis combined loading

This paper presents experimental and numerical investigations into the post-fire local buckling behaviour and residual resistance of hot-rolled stainless steel channel sections under combined compression and major-axis bending. The experimental investigation included heating and cooling of specimens as well as post-fire material testing, initial local geometric imperfection measurements and fourteen eccentric compression tests. A subsequent numerical investigation was performed, where finite element models were developed to simulate the test results and then used to conduct parametric studies to generate additional numerical data over a wide range of cross-section dimensions and loading combinations. Due to the lack of specific design standards for stainless steel structures after exposure to elevated temperatures, the relevant ambient temperature design interaction curves, as set out in the European code and American specification, were evaluated, using post-fire material properties, for their applicability to hot-rolled stainless steel channel sections under major-axis combined loading after exposure to elevated temperatures. The evaluation results revealed that the codified design interaction curves result in conservative post-fire residual resistance predictions, due to the conservative end points and inefficient shapes. Finally, new design interaction curves, with more accurate end points and efficient shapes, were proposed and shown to provide improved design accuracy than the codified design interaction curves for hot-rolled stainless steel channel sections under major-axis combined loading after exposure to elevated temperatures.

Study on the Root Causes and Prevention of Coating Cracks in the Cargo Hold of a Product Carrier

Recently, shipyards have been booming in the product carrier (PC) market of the global shipbuilding industry. Due to the rising market conditions, orders for large container vessels and PCs are also steadily increasing. According to the industry, freight rates for LR tankers (70K) and MR tankers (50K) in the shipbuilding industry have rose to the highest level during the previous year. In order to secure the competitiveness of PCs, various core items are required, and Korean shipbuilders have been leading the market for a long time based on their knowledge of the design and production of low-fuel ships. In recent years, there have been frequent cases of coating cracks in the cargo hold after sea trial. All relevant rules presented by the classification so far are structural design, safety evaluation, and inspection standards, and coating cracks are considered a problem for coating makers. In other words, they must establish a standard coating measure agreed upon by all parties (owner, shipbuilder, and coating maker); therefore, solutions have been proposed by each shipping company. In this study, the causes of coating cracks occurring in the cargo hold of PCs during tank tests in sea trials were analyzed and measures to prevent them were studied. The main point of this study is assumed that coating crack are caused by mechanical load induced by structural behavior, and the numerical analysis methodology is newly introduced. Based on the results of the numerical analysis, it was confirmed that there is a high probability of coating cracks in the critical area where high stress occurs in the cargo hold. Therefore, the results obtained in this study will be useful to prevent coating cracks in future PC designs.

Seismic response analysis of reinforced masonry core walls with boundary elements

The seismic design of mid- and high-rise reinforced masonry (RM) structures necessitates a reliable seismic force resisting system (SFRS) that provides adequate capacity and ductility. Core walls are commonly used as the SFRS for counterpart reinforced concrete buildings due to the convenience of locating the elevators and staircases inside it. This study introduces reinforced masonry core walls with boundary elements (RMCW+BEs) as a potential SFRS alternative to rectangular reinforced masonry shear walls (RMSWs) with and without boundary elements given their enhanced structural and architectural characteristics in typical RM buildings. A macroscale nonlinear numerical model was developed using the Extreme Loading for Structures software (ELS) to evaluate the seismic performance of RMCW+BEs. A nonlinear time history analysis (NLTHA) was carried out for three archetype RM buildings with 10-, 15-, and 20-story heights designed according to the CSA S304-14 and located in a North American moderate seismic zone. The results showed that utilizing RMCW+BEs as the main SFRS system adequately controlled the seismic demands on RM buildings subjected to typical North American ground motions. However, the 20-story building showed a shear demand exceeding the nominal flexural resistance of the core wall at the plastic hinge region at the base, which was attributed to the adverse effect of the higher modes of vibration effects on the seismic demand parameters. Therefore, the three buildings were redesigned using a dual plastic hinge (DPH) design approach. The numerical results demonstrated that using the DPH reduced the shear demand and mitigated the effect of the higher modes of vibration on the seismic response of the core walls. The findings of this study highlight the need to integrate a new shear demand magnification factor to account for the higher mode effects in estimating the seismic demand of ductile RMSWs in the next generation of the North American design standards for masonry structures.

Direct Design of Stainless Steel Frames: Recommendations and Case Studies

AbstractAcknowledging the potential of system‐based design approaches, most international design standards for steel structures include preliminary versions of such alternative design methods. The Direct Design Method (DDM) is one of these approaches, which allows designing steel structures directly using advanced numerical analyses without requiring further member checks. This paper presents the DDM design (and verification) procedure and summarizes the key aspects of the advanced finite element model necessary for the determination of the system strength, with an emphasis on cold‐formed stainless steel portal frames. Through the design of two frames, the DDM design procedure is illustrated and the resulting cross‐sections are compared with those derived using the traditional two‐step design approach in the Eurocode and ASCE design frameworks. The results demonstrate that the DDM verification process is simpler and more direct, and that lighter structures are obtained when designing using the DDM for strength considerations. Finally, this paper also highlights that allowing larger deformations in the ultimate limit state design for the DDM does not have additional negative effects on the serviceability requirements if compared to the traditional two‐step design approach.

Numerical Modelling of the World's First Metal 3D Printed Bridge

AbstractRecent disruptive technological advances, including wire arc additive manufacturing (WAAM) and the concept of digital twins, have the potential to fundamentally transform the way in which we design, build and manage structures. WAAM is a method of metal 3D printing that is well suited to the price‐sensitive construction industry and has been used to manufacture the MX3D bridge – the world's first metal 3D printed bridge. The intricate geometry, undulating surface finish and particular material properties rendered the bridge outside the scope of any existing structural design standards; hence, physical testing and advanced numerical modelling were carried out for its safety assessment. The key features of the finite element model of the bridge, and its validation against in‐situ structural tests, are described herein. Subsequent numerical studies undertaken to verify the structural performance of the bridge under various loading scenarios are presented, while the basis for the development of the smart digital twin of the bridge is also introduced. The presented research provides insight into the use of advanced computational simulations for the verification and ongoing assessment of structures produced using new methods of manufacture.

Experimental and numerical studies on post-fire behaviour of S700 high strength steel circular hollow sections under combined compression and bending

The present paper reports experimental and numerical investigations into the post-fire local buckling behaviour and residual resistances of S700 high strength steel circular hollow sections (CHS) under combined compression and bending. A testing programme was firstly conducted and included heating and cooling of specimens as well as post-fire material tensile coupon tests and eccentrically loaded stub column tests. Following the testing programme, a numerical modelling programme was carried out, where finite element models were developed to replicate the test results and then employed to perform parametric studies to generate further numerical data over a wide range of cross-section dimensions and loading combinations. Due to the absence of design standards for high strength steel structures after exposure to fire, the codified ambient temperature design interaction curves for high strength steel CHS under combined compression and bending were assessed, using post-fire material properties, for their applicability to post-fire S700 high strength steel CHS. The assessment results revealed that the design interaction curves in the European code and American specification yield a satisfactory level of accuracy and consistency when used for post-fire S700 high strength steel CHS, while the design interaction curves in the Australian standard provide slightly conservative residual resistance predictions.

Using historical tropical cyclone climate datasets to examine wind speed recurrence for coastal Australia

Likelihood estimates of extreme winds, including those from tropical cyclones (TCs) at certain locations are used to inform wind load standards for structural design. Here, wind speed average recurrence intervals (ARIs) determined from TC climate data dating back to the 1970s in two quantile–quantile adjusted reanalysis datasets (ERA5 and BARRA [1990]), and best-track observations for context, were compared with Standardized ARIs (AS/NZS) across seven tropical and two subtropical Australian inland coastal regions. The novelty of this work lies in determining TC-wind speed ARIs from a range of datasets that are not typically used to evaluate this metric. Inherent differences between the data used to determine the Standard ARIs (large sample size allow for larger extrapolations; GEV function) and TC data ARIs (smaller sample size and less certain data; the more asymptotic Lognormal/Weibull functions are used) led to the use of different extreme value functions. Results indicated that although these are two distinct ways of determining design wind speeds, when they are considered equivalent, there was a moderate reproduction of the ARI curves with respect to the Standard in both reanalysis datasets, suggesting that similar analyses using climate model products can provide useful information on these types of metrics with some caveats. Trends in TC wind strength affecting coastal Australia were also analyzed, indicating a potential slight downtrend in tropical West coast TC wind strength and slight uptrend for tropical East coast TC wind strength, noting considerable uncertainty given the short time period and limitations of data quality including over longer time periods. Such trends are not only limited to the relationship between TC intensity and anthropogenic warming, but also to regional changes in TC frequency and track direction. This could lead to significant trends emerging in regional Australian TC wind gust strength before several decades of warming have occurred. It is hoped that climate models can provide both longer-term and a more homogenous base for these types of evaluations and subsequent projections with respect to climate change simulations.

Numerical simulation and evaluation of the world’s first metal additively manufactured bridge

Recent disruptive technological advances, including wire arc additive manufacturing (WAAM) and the concept of digital twins, have the potential to fundamentally transform the way in which we design, build and manage structures. WAAM is a method of metal 3D printing that is well suited to the price-sensitive construction industry and has been used to manufacture the MX3D bridge – the world’s first metal additively manufactured bridge. The intricate geometry, undulating surface finish and particular material properties rendered the bridge outside the scope of any existing structural design standards; hence, physical testing and advanced numerical modelling were carried out for its safety assessment. The key features of the finite element model of the bridge, and its validation against in-situ structural tests, are described herein. Subsequent numerical studies undertaken to verify the structural performance of the bridge under various loading scenarios are presented, while the basis for the development of the smart digital twin of the bridge is also introduced. The presented research provides insight into the use of advanced computational simulations for the verification and ongoing assessment of structures produced using new methods of manufacture.

Local and global instabilities of rolled T-section columns under axial compression

The resistance capacity of rolled T-section columns comprising slender webs is investigated in this paper. Both (i) cross-sectional behavior influenced by local buckling and (ii) member behavior influenced by global buckling are investigated through extensive numerical analyses. Regarding cross-section resistance, current design rules rely on the traditional cross-section classification system and the Effective Width Method (EWM), while local–global coupled instabilities in members with slender plate elements are usually addressed through the EWM combined with flexural–torsional buckling curves, which leads to conservative and scattered predictions for T-section members, mainly because the effects of torsional buckling are considered twice: through the EWM and through the member buckling curves. To overcome these shortcomings, an Overall Interaction Concept (OIC) approach is proposed in this paper, providing a more economic and simple design method for both T-section members. The load resistances predicted by the OIC, Eurocode 3, the American Specifications and the Australian Standards are compared with numerical and experimental results. Overall, the results show that the OIC-based approach provides more accurate and consistent predictions than current design recommendations and is suitable to be included in current steel structural design standards.

Extreme Wind Variability and Wind Map Development in Western Java, Indonesia

Wind-related disasters are one of the most frequent disasters in Indonesia. It can cause severe damages of residential construction, especially in the world’s most populated island of Java. Understanding the characteristics of extreme winds is crucial for mitigating the disasters and for defining structural design standards. This study investigated the spatiotemporal variations of extreme winds and pioneered a design wind map in Indonesia by focusing on western Java. Based on gust data observed in recent years from 24 stations, the extreme winds exhibit a clear annual cycle where northwestern and southeastern sides of western Java show out-of-phase relationship due to reversal monsoons. Meanwhile, extreme wind occurrences are mostly affected by small-scale weather systems, regardless of seasons and locations. To build the wind map, we used bias-corrected gust from ERA5 and applied the Gumbel method to predict extreme winds with different return periods. The wind map highlights some drawbacks of the current national design standards, which use single wind speed values regardless of location and return period. Beside a fundamental improvement for wind design, this study will benefit disaster risk mapping and other applications that require extreme wind speed distribution.

Physical-based model for exposure coefficient and its validation towards the second generation of Eurocode EN 1991-1-3 for roof snow loads

In standards for structural design, models for snow loads on flat roofs generally provide the basis for determination of snow loads on any roof shapes. They are typically derived from ground snow loads and the predicted effects of exposure of flat roofs primarily due to wind, often conveyed through the exposure coefficient. The paper provides background information on the revision of the model for exposure coefficient in the second generation of the Eurocode on snow loads on structures, prEN 1991-1-3:2020. With the aim to provide an easy-to-use procedure with a minimum amount of input data, but to cover the main physical phenomena, a new formulation is proposed in prEN reflecting up-to-date scientific findings and the model provided in ISO 4355:2013. The prEN model corrects the main deficiency of the model in EN 1991-1-3:2003 where no account for wind velocities expected at the site during a snow season is taken. The prEN formulation additionally requires information on mean wind velocity for the coldest month at the site, that is commonly easily accessible.The contribution starts off by introducing the prEN model. To validate the new model, a parametric study is presented, considering plausible ranges of the main parameters influencing the determination of exposure coefficient in Europe. The outcomes of the new simplified prEN formulation are then compared with an advanced theoretical model. The prEN model is further applied considering detailed meteorological data representative for various climates. The results obtained by the prEN provisions are critically compared with those based on the advanced theoretical model and meteorological data, and with the estimates of the models in ISO 4355:2013 and in the JCSS Probabilistic Model Code.The presented validation demonstrates that the prEN model reflects well typical European snow and wind climates. The model captures a clear decreasing tendency of exposure coefficient with an increasing mean wind velocity. Mean wind velocity in the coldest month of 4.5 m/s appears to provide a reasonable threshold to make distinction between normal and exposed conditions.

Composite overwrap repair of pipelines-reliability based design framework

Considering the ages and need for repairment of the gas and oil transmission pipes in the world, in the past years, lab and field experiments were performed on fiber reinforced polymer (FRP) wrapping to steel pipes. Although this technology has widely been employed for decades, further improvement on the design guidelines is still needed. In this context, this study proposes a reliability structural design framework for the repairment of corroded pipelines using FRP composite wrapping. To be consistent with international structural design standards, reliability-based design framework is to be proposed within a semi-probabilistic approach by calibrating safety factors to account for the associated uncertainties in capacity and load effects to best meet the cost-safety balance in design. Currently, the repair design practice for corroded pipelines is based on a deterministic approach, and it cannot ensure the proper consideration of uncertainties and meeting a consistent level of target reliability in design. This study involves comprehensive experiments of FRP materials under two different environmental conditions for onshore and offshore pipes, which were used to propose the best-fit statistical models to the design parameters to realistically represent the random variables in the proposed safety factor based structural design framework. Through extensive reliability analyses, the values for the safety factors for composite and steel have been proposed according to the target reliability indices and the corrosion rate. The proposed design framework for corroded steel pipes with FRP overwrap repairment is expected to improve the current design practice and optimize the cost and safety by meeting the target reliability level.

In-plane structural response and design of steel I-section beam-columns at elevated temperatures

In this paper, the behaviour and design of steel I-section beam-columns in fire are explored. Finite element models capable of mimicking the behaviour of steel beam-columns in fire are developed. Results from fire experiments on steel I-section beam-columns from the literature are utilised for the validation of the finite element models. Extensive structural performance data are generated on the response of steel I-section beam-columns through numerical simulations, considering different cross-section shapes, elevated temperature levels, member slendernesses and loading conditions. The accuracy and safety of the beam-column design methods provided in the current European structural steel fire design standard EN 1993-1-2 and its upcoming version prEN 1993-1-2 are explored. A new fire design method for steel beam-columns that is compatible with the room temperature beam-column design method provided in the European room temperature structural steel design standard EN 1993-1-1 is put forward. The proposed design rules enable the establishment of a consistency between the beam-column design methods of the European structural steel room temperature and fire design standards (i.e.EN 1993-1-1 and EN 1993-1-2), which is currently lacking. The higher accuracy, safety and reliability of the proposed fire design rules for steel beam-columns relative to those given in EN 1993-1-2 and prEN1993-1-2 are verified.