Requirements Of Eurocode Research Articles

ОСОБЕННОСТИ ПРОЕКТИРОВАНИЯ ВЕРТИКАЛЬНО АРМИРОВАННОГО ОСНОВАНИЯ ПЛИТНОГО ФУНДАМЕНТА

The analysis of experimental and theoretical studies of reinforcement of soil foundations to create an artificial foundation on weak soils is given. The aim of the present work is to develop a design solution of a vertically reinforced base of a slab foundation of a multi-storey building. The study is carried out on the example of the design solution of reinforcement of the foundation of a real object. The novelty of the work consists in determining the optimal parameters of the reinforcement grid and the length of reinforcement of the soil mass to ensure the bearing capacity and reduce the settlement of the slab foundation base. Numerical calculations were carried out by the finite element method using the PLAXIS 3 programme, using the Hardening Soil model, in accordance with the requirements of Eurocode 7. Reinforcement of the soil foundation with rigid vertical reinforcing elements increased the bearing capacity of the foundation and reduced the settlement by 2 times. The use of rolling equipment in the construction of bored vertical reinforcing elements is a promising and reliable method of ensuring the bearing capacity and deformability of the foundation, which significantly reduces the time and costs required for the creation of artificial foundations.

Calculating shear lag in steel-concrete composite beams under combined compression and bending

Long and complex composite steel-concrete structures are becoming common, requiring a deep understanding of the effects induced by the simultaneous action of axial forces and bending. In fact, the axial force generated, for instance, by cable inclination in cable-supported structures can modify the stress distribution within the elements compared to bending scenarios, thereby necessitating a revision of the effective width to be utilized. Nonetheless, current design codes, including Eurocode specifications and others, lack provisions for addressing the combined effects of axial force and bending, as they are exclusively tailored for bending. This limitation can introduce design complexities, necessitating the implementation of intricate Finite Element (FE) models, which impose substantial computational loads and design efforts. The methodology proposed in this paper overcomes these challenges allowing to assess the stress distribution and resistance of composite deck at Serviceability Limit State (SLS) and Ultimate Limit States (ULS) by leveraging results obtained from standard beam models typically used by structural designers or practitioners. A comprehensive parametric analysis using nonlinear finite element models is performed to validate the developed methodology. A comparison with the Eurocode 4 formulations highlights that the proposed method provides superior accuracy in estimating peak stress in concrete slabs under combined compression and bending. Additionally, it facilitates straightforward verification at the ULS in compliance with Eurocode requirements.

Experimental studies on fully demountable P-DBSCs shear connectors in sustainable reinforced concrete beam-slab

To improve the increasingly serious environmental pollution and waste of resources in the construction of traditional buildings, a novel type of shear connector P-DBSCs (Demountable Bolted Shear Connectors with connection Plate) was designed. The shear performance of P-DBSCs in RC beam and slabs were comprehensively evaluated by seven push-out tests and secondary loading. The failure mode, load-slip curve, ultimate shear capacity and ductility of the specimens were carefully discussed. As illustrated by the experimental results, the failure mode of the 7 push-out specimens is bolt fracture with no obvious crack in the beam and slabs, and the demount-ability is excellent after failure. The ultimate slip of all specimens is greater than 6 mm, which meets the requirements of Eurocode 4. The ultimate strength of P-DBSCs shear connectors increased with the increase of steel box thickness and bolt diameter, it decreased with the increase of channel spacing. The ductility of P-DBSCs shear connectors increased with the reducing of channel spacing and bolt diameter. Additionally, the shear performance of P-DBSCs is insensitive to the strength of concrete of slabs. After the first loading, the ultimate shear resistance; ultimate displacement and initial stiffness of the push-out specimen decrease slightly in secondary loading, but the influence code of each parameter remain constant. Finally, a comparison of ultimate strength between the calculated value and the experimental results showed that the theoretical values given by the Eurocode 3, Eurocode 4 and code AISC360–16 were higher than the experimental values, which indicated that the calculations overestimated the shear capacity of connection. Based on this, two formulae were proposed to predict the friction-type shear capacity and pressure-type shear capacity of P-DBSCs and the efficacy of the proposed design formula was proved by the comparison with the test results, which provides a research basis for such shear connectors.

Strength and Deformability of Structural Steel for Use in Construction

The purpose of the study is an experimental determination of the stress-related characteristics of the structural steel produced in the Republic of Kazakhstan for use in conventional and earthquake-resistive construction. Since 2015, the construction industry has been using European regulatory documents—Eurocodes—as a statutory framework. In particular, the Eurocode 1993 for steel structures and the Eurocode 1998 for the design of earthquake-resistant structures However, the study of stress-related properties of structural steel using experimental methods of ISO standards has not been performed. Therefore, in the construction industry of the Republic of Kazakhstan, steel-work structures have been used in fairly limited volume since 2015. The experimental studies were conducted on 7 types of structural steel with thicknesses of 8, 10, and 20 mm manufactured by Arcelor Mittal. The yield strength, ultimate tensile strength (breaking stress), and tensile strength at break were studied. The experimental studies were carried out on the basis of ISO standards. In each test run, 5 samples were used. In two series, 20 samples each were tested, which made it possible to estimate the yield strength and strength distribution functions. The correlation relationships between Brinell hardness and yield and strength limits have been studied. As a result of experimental studies, it was found that the strength and deformability parameters fully comply with the requirements of Eurocode 1993. Based on the application of the Student's test, it is revealed that the distribution functions of yield strength and resistance correspond to the normal law (Gaussian function). The calculation of a three-story, two-span residential building with box section columns for construction in an area with a seismicity of 8 points is performed by the finite element method. The work results will significantly increase the scope of Kazakhstani structural steel use in seismic and conventional areas of the Republic of Kazakhstan. Doi: 10.28991/CEJ-2024-010-03-09 Full Text: PDF

Building response to two local earthquakes

Instrumental records of two earthquakes with foci in the Almaty territory were obtained, recorded during one month on February 02, 2018, and February 15, 2018. The local seismic events registered in February 2018 in the Almaty territory are analyzed. These are 2 – 4 magnitude earthquakes with foci on the city’s territory. Using the AT 1105 sensors and the RSM-8 recorder, station No. 1 “Institute” recorded instrumental readings of accelerations in the basement and the four-story frame-brick building roof. For the first time, an instrumental recording was obtained, on which two groups of waves were identified. Spectral curves β are plotted. Effective duration is insignificant 0.12 – 1.74 sec. New results have been obtained regarding the behavior of a building under the influence of two earthquakes of different intensities. The absence of significant values of the spectral curves of the two earthquakes was noted. There is an increase in the intensity and number of local earthquakes in 2018 compared to 2007 – 2014. The results can be used to design earthquake-resistant buildings, taking into account the requirements of Eurocode 8.

Ultimate capacity and stability of topologically optimised shear plates in compliance with structural Eurocodes

Topology optimisation (TO) is increasingly used to assist metallic parts manufacturing in automotive, aerospace, and biomedical sectors. A similar trend is observed in civil engineering structures, particularly in steel construction joints representing crucial steelwork components. Yet, the widespread adoption of TO to steel members in structural engineering has been hampered by difficulties complying with code requirements and challenges in utilising cutting-edge software in real, heterogeneous, and complex cases. To fill this research gap, a methodology is developed in the current study to implement the requirements of Eurocode 3 in the TO process. Nonlinear Finite Element Analyses (NLFEA) are performed on the web cover-plates of a well-known bolted splice connection between segments of a steel beam to validate the code-compliant methodology. Results show that it is possible to reduce up to 87.5% of the plate initial volume while keeping the connection original capacity. Also, it has been found that the initial volume can be reduced up 20% without affecting the original plate capacity, and up to 60% while ensuring that the ultimate plastic displacement is larger than that of the original plate. Based on extensive buckling analyses, critical loads exceed ultimate loads from 9.3 to 12.4 folds, thus ensuring excellent stability performance. The results of this study demonstrate that validation with NLFEA is a crucial step for achieving actual code-compliant optimised steel joints, and that the linear elastic TO could not satisfy the safety requirements. Moreover, encouraging findings regarding stability and ductility of (extremely) optimised parts suggest the adequacy of TO for designing steel connections. The volume of topologically optimised solutions significantly decreased, contributing to the decarbonisation targets for steel construction.

EXPERIMENTAL INVESTIGATION OF INTERIOR AND EXTERIOR STEEL‐CONCRETE COMPOSITE NPS® BEAM‐COLUMN JOINTS

AbstractThis paper presents the results of an experimental program involving a series of five full scale NPS® (three interior and two exterior) and two moderately ductile reinforced concrete (one interior and one exterior) beam‐column joints, designed per Eurocode requirements. The NPS® System utilizes steel wrapped reinforced concrete columns and composite steel truss concrete (CSTC) beams reinforced with steel truss elements made with bottom plates to double as partial formwork. The specimens were tested under quasi‐static reversed cyclic horizontal loading, with a constant axial load applied to the column. The variables considered were the level of shear reinforcement provided within the joint panel zone and the presence/absence of additional shear reinforcement in the beam end‐regions.

Robustness of Steel Frame Structures Equipped with FREEDAM Dissipative Joints

AbstractIn the framework of a recent RFCS project, innovative joint solutions named FREEDAM were developed with the objective of proposing beam‐to‐column joints able to dissipate the seismic energy with limited or even no damages. The efficiency of the proposed solutions was validated through experimental, numerical, and analytical investigations on moment resisting frames (MRFs) and dual concentrically braced frames (D‐CBFs). However, according to modern design codes, including the Eurocodes, structures subjected to accidental events such as impact, explosion, or loss of a bearing element should not undergo damages disproportionate to the initiating cause. Accordingly, to validate the proposed solutions, it was also required to demonstrate the ability of structures equipped with FREEDAM joints to exhibit an appropriate level of robustness in case of such accidental events. This paper presents the robustness assessment performed on 20 MRFs and D‐CBFs. The loss of a supporting column was considered in full agreement with the Eurocode requirements. Analytical and numerical studies are conducted to demonstrate how the request for robustness influences the design of the joints which were initially tailored for seismic performances.

Design and experimental study of hot rolled shape steel-ultrahigh performance concrete composite beam

A novel lightweight, high-strength and economical hot rolled shape steel (HRSS)-ultrahigh performance concrete (UHPC) composite beam is proposed for short- and medium-span composite bridges. Compared with traditional steel-concrete composite bridges, the new composite bridge has lower self-weight, better economic efficiency, and more constructional feasibility. The flexural and shear behaviors of the HRSS-UHPC composite beam were investigated through four-point bending tests on two scaled (1:2) specimens. The influence of shear-to-span ratio on the behaviors of the HRSS-UHPC composite specimens was revealed, including the failure mode, the crack distribution pattern, the propagating angle of diagonal shear cracks, and the development of crack width. The experimental results showed that the failure mode of the specimens, as well as the morphology of cracks and crack distribution, were strongly dependent on the shear-to-span ratio. In addition, the results of finite element analysis (FEA) and theoretical calculation also demonstrated that the bending and shear resistances of the proposed HRSS-UHPC composite bridge could meet the design requirements of Eurocode [1] at the ultimate limit states (ULS) and the serviceability limit states (SLS). In addition, the influence of concentrated load caused by heavy vehicle on the response of the designed composite bridge at ULS and SLS is also discussed. The calculation results of FE model show that the location of vehicle load (i.e. shear-to-span ratio) has a significant impact on the deformation of the designed composite bridge, internal force of cross section and stress of UHPC web.

Experimental behavior of interior and exterior steel-concrete composite NPS® beam-column joints

This paper presents the results of an experimental program involving a series of seven full scale composite steel-concrete beam-column joints part of the “New Performance System” (NPS®). The NPS® is a novel steel-concrete composite moment resisting frame that utilizes steel wrapped reinforced concrete (RC) columns and steel-concrete composite beams, reinforced with steel truss elements made with bottom plates to double as partial formwork. Prior to this project, no experimental evidence was available to provide insight into the performance of the NPS®.In addition to the four interior and the three exterior NPS® specimens, two moderately ductile reinforced concrete (one interior and one exterior) beam-column joints, designed per Eurocode requirements and intended to serve as reference, were tested in the experimental program. The specimens were tested under quasi-static reversed cyclic horizontal loading, with a constant axial load applied to the column. The variables considered were the moment continuity solution through the beams and joint region, the level of shear reinforcement provided within the joint panel zone, and the presence/absence of additional shear reinforcement in the beam end-regions.The experimental results demonstrated that, if properly designed, the NPS® can achieve adequate strength, stiffness, ductility and energy dissipation, meeting modern seismic performance objectives. The analysis of the experimental results further demonstrated that, if properly detailed, the NPS® can meet or surpass the performance of a traditional Eurocode compliant RC specimen, designed to achieve moderate ductility.

Mechanical behavior of T-shaped CFST column to steel beam joint

The seismic performance of T-shaped CFST column to H-shaped steel beam joint with vertical rib stiffeners was investigated experimentally and numerically in this study. Specifically, the joint shear deformation, inter-story drift ratio, joint stiffness, and energy dissipation capacity were analyzed. The test results demonstrate that the joint with vertical stiffeners has good seismic behavior and meets the requirements of Eurocode 3 for rigid joints in a braced frame. A finite element model for the multi-cell T-shaped CFST column to H-shaped steel beam joint with vertical rib stiffeners was established to investigate the influences of the following parameters on joint strength and joint stiffness: the width-to-thickness ratio of steel tube, vertical rib dimensions, and the axial load ratio of column. The numerical results indicate that the width-to-thickness ratio of steel tube and vertical rib dimensions play an important role in improving the joint strength and stiffness. A mechanical model for the joint strength was also developed, in which the contributions from the front face and side faces of steel tube and the vertical rib stiffeners were considered. To facilitate the practical design, a simplified design method for joint strength as well as the design suggestions for detailing are proposed based on the mechanical model.

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.

Optimal Design Prediction of a Singly Reinforced Concrete Beam Steel Using Artificial Neural Network

This paper presents the prediction of a singly reinforced concrete beam tension reinforcement design requirements using Artificial Neural Networks (ANN). The method was adopted for cost optimization of the tension reinforcement in the structural element and compared with the requirements of Eurocode 2 design. The code provisions for the design of a singly reinforced beam can vary from place to place. The use of a system immune from the code variation is an excellent means of predicting the reinforcement’s need of a rectangular concrete beam. In this work, an artificial neural network (ANN) is employed to forecast the reinforcement of such a beam. Artificial neural network has the potential to simulate the data that are hard to produce in arithmetical analysis. The scheme was established using the MATLAB tool kit. The design variables were the depth of the beam, the width of the beam, and the moments. A forward pass supervised backward propagation training. The regression analysis of the results is one to one match. The predicted and target values are completely in accord.

Prediction of a singly reinforced concrete beam steel using artificial neural network

This paper presents the prediction of a singly reinforced concrete beam using Artificial Neural Networks (ANN). The method was adopted for cost optimization of the structural element and compared with the requirements of Eurocode 2 design. The code provisions for the design of a singly reinforced beam can vary from place to place. The use of a system immune from the code variation is an excellent means of predicting the reinforcement’s need of a rectangular concrete beam. In this work, an artificial neural network (ANN) is employed to forecast the reinforcement of such a beam. Artificial neural network has the potential to simulate the data that are hard to produce in arithmetical analysis. The scheme was established using the MATLAB tool kit. The design variables were the depth of the beam, the width of the beam, and the moments. A forward pass supervised backward propagation training. The regression analysis of the results is one to one match. The predicted and target values are completely in accord.

Partial factor for local buckling of welded box sections

The accurate consideration of the local (plate) buckling resistance and the determination of the effective width is highly important in the design of civil engineering structures. The current effective width calculation method provided by the EN 1993-1-5 is mainly developed for I-sections subjected to bending. Several previous studies proved that the current design rules can overestimate the plate buckling resistance especially in case of square box sections subjected to pure compression. The purpose of the current study is (1) to investigate the local buckling resistance of welded square box section columns loaded by pure compression and pure bending moment separately, (2) to investigate the applicability of the Winter curve for these worst cases and (3) to provide the necessary partial factor to the application of the Winter curve according to the safety requirements of Eurocode. Another aim of the current study is to investigate the differences between normal strength steel (NSS: S235 – S355) and high strength steel (HSS: S420 – S960) structures on the local buckling resistance. Deterministic and stochastic numerical and experimental research programs are conducted to investigate the effect of residual stresses and geometric imperfections on the local buckling resistance of welded square box sections and the necessary partial factor is determined.

On characteristic values for calculating factors of safety for dyke stability

Various simplified approaches are used to calculate the characteristic values of shear strength properties, which have then been used in deterministic stability analyses of a dyke cross-section. The calculated factors of safety are compared with the 5-percentile ‘system response’ of the dyke cross-section, calculated using the more exhaustive random finite-element method (RFEM), which is consistent with the requirements of Eurocode 7. The simplified methods accounting for variance reduction due to averaging of property values mostly give factors of safety within 10% of the RFEM solution, whereas the factor of safety based on the 5-percentile material properties is significantly over-conservative.

Automation in the Construction of a 3D-Printed Concrete Wall with the Use of a Lintel Gripper.

Developments in the automation of construction processes, observable in recent years, is focused on speeding up the construction of buildings and structures. Additive manufacturing using concrete mixes are among the most promising technologies in this respect. 3D concrete printing allows the building up of structure by extruding a mix layer by layer. However, the mix initially has low capacity to transfer loads, which can be particularly troublesome in cases of external components that need to be placed on top such as precast lintels or floor beams. This article describes the application of additive manufacturing technology in the fabrication of a building wall model, in which the door opening was finished with automatic lintel installation. The research adjusts the wall design and printing process, accounting for the rheological and mechanical properties of the fresh concrete, as well as design requirements of Eurocode. The article demonstrates that the process can be planned precisely and how the growth of stress in fresh concrete can be simulated, against the strength level developed. The conclusions drawn from this research will be of use in designing larger civil structures. Furthermore, the adverse effects of concrete shrinkage on structures is also presented, together with appropriate methods of control.

Reliability Analysis of a Solid Timber Column Subjected to Axial and Lateral Loading

In this paper, a reliability analysis of a solid timber column of square cross section subjected to axial and lateral loading in accordance with the design requirements of Eurocode 5 is carried out. Compression and bending were the two failure criteria considered in the reliability investigation. The First Order Reliability method was employed to solve the limit state functions formed from the two failure criteria and was coded in MATLAB for quick estimation of the reliability indices. The results obtained showed that both the load and slenderness ratios have effects on the reliability of a solid timber column. The results of the sensitivity analysis carried out on the stochastic variables showed that the reliability indices decreased with increase in slenderness ratio for 3m, 4m and 5m length of column considering both the compression and bending failure modes and decreased with increase in load ratio for 3m, 4m and 5m length of column considering both the compression and bending failure modes. The reliability indices also decreased with increase in length of column mode and decreased with increase in ratio considering bending failure mode. The reliability indices were also found to decrease with increase in load ratio for varying values of axial and lateral loads at constant slenderness ratio and length of column considering compression and bending failure modes. The choice of adequate and suitable dimensions having a lower slenderness ratio will enhance the reliability of the column. Keywords- Reliability analysis, solid timber column, Eurocode 5, failure criteria, slenderness ratio

On characteristic values and the reliability-based assessment of dykes

ABSTRACTA case study involving the assessment and re-design of an existing dyke, founded on a layered soil, has compared deterministic analysis based on 5-percentile property values and a reliability-based random finite element analysis consistent with the requirements of Eurocode 7. The results show that a consideration of the spatial nature of soil variability generally leads to higher computed factors of safety and, for those dyke sections requiring remedial action, to more economic designs. Back-figured characteristic values are shown to be considerably higher than the 5-percentile soil properties; hence, a reduction in over-conservatism is achieved.

Push-out tests on three innovative shear connectors for composite cold-formed steel concrete beams

The composite action between concrete and steel makes the use of composite beams in buildings more economical than the use of typical hot-rolled steel beams. This can be attributed to the beam’s lower depth, which significantly reduces the weight of steel. Composite beams can be constructed by lipped C-channels made from cold-formed steel, concrete, and different shear connectors (which exhibit behaviours that are not yet well understood). In this study, the behaviour of three innovative shear connectors used in composite cold-formed steel concrete beams made of lipped C-channels with profiled metal decking was experimentally examined. Experimental tests aimed to determine the maximum resistance of the proposed shear connectors; these results were then compared with the predicted values and the values for other shear connectors investigated in other studies. Likewise, the ductility and the strength capacity of the shear connectors were investigated. Twelve push-out test specimens were prepared and tested in accordance with Eurocode 4. It was found that a shear connector’s strength capacity considerably depends on its deformation and on the crushing of concrete. The ductile behaviour of all the tested shear connectors satisfied the ductility requirements of Eurocode 4. In this study, it is concluded that the proposed shear connectors were suitable for use in the construction of composite beams, as they were stronger than the standard headed studs and the other available shear connectors; they were also sufficiently strong to perform composite actions.