Rolled Steel Sections Research Articles

The behavior of Shear Connectors in Steel-Normal Concrete Composite Structure under Repeated Loads

In today's construction industry, the use of composite beams is becoming more and more important, particularly for long-span bridges that must withstand repeated loads from moving automobiles. This work investigates the behavior of composite beams through experimentation. Six push-out steel-concrete specimens are made and tested with various levels of static and repetitive loading applied. The specimens are made of rolled steel sections that are joined to concrete decks on both sides by stud shear connectors. Two approaches—one static and the other repeating—applied a push-out load to two sets of samples. One has a stud shear connector measuring 16 mm, and the other measures 25 mm. Three specimens were made for each group. To determine the final load, one specimen from each group underwent a static push-out test in the first stage. In the subsequent phase, repeated loads of 0-80% and 25-80% of the maximum static load were applied to the remaining ones. The analysis process measured the variation in slip between the concrete decks and the steel section over several load cycles. It was found that the recorded slip values at the ultimate load increased about four times just before the failure. The recorded values of the residual slip at the end of each load cycle decreased with the increase in load cycle numbers. Also, it was found that the values of the residual slip depend on the values of the lower and upper limits of the load level. Doi: 10.28991/CEJ-2024-010-01-013 Full Text: PDF

Design optimisation for cold rolled steel beam sections with web and flange stiffeners

This paper presents the analysis and design optimisation of the cold rolled steel sections for flexural strength considering the effect of cold working exerted on the section during the roll forming process. The sections included channel and zed shapes with complex longitudinal web and flange stiffeners. Nonlinear Finite Element (FE) modelling was developed to model the flexural strength of the channel and zed beams and validated against the four-point bending experiments for these sections. The material properties of steel at the section's flat parts, corners, and stiffener bends were obtained from tensile tests and were incorporated into the FE simulations to account for the true material properties at these regions due to the cold working during the roll forming process. The strength enhancement at the section corners and stiffener bends obtained from tensile tests were also compared with the predicted values from design standards. The section strength was then optimised using FE modelling results based on the Design Of Experiments (DOE) and response surface methodology. Optimal designs for the channel and zed sections with maximum strength in distortional buckling could be obtained while changing the stiffeners' position, shape, sizes, and considering true material properties at section corners and stiffener bends. It revealed that, for the two sets of channel and zed sections with the depths of 145 mm and 170 mm, the optimal designs provided up to 43% and 39% increase in flexural strength for the channel and zed sections, respectively; however, when the true material properties at the section corner and the stiffener's bend regions was included, the increase in flexural strength increased up to 50% and 41%, respectively. Including flange stiffeners to the sections with longitudinal web stiffeners generally increased further the section strength. However, the levels of increase were largely dependent on the section depths and material properties.

Additive manufacturing of steel components by cold spraying

AbstractDesign of steel structures in the construction industry uses built‐up or rolled steel sections. These are processed as steel elements and connected together at joints. Massive and complex steel nodes such as those in steel frame bridges or truss structures are still manufactured by forging or casting to avoid weld seams in highly stressed areas. Since this is a manual manufacturing process, it results in increased costs and time. Cold spray (CS) technology has recently attracted attention in aerospace and automotive engineering for producing metallic, composite coatings as well as repairing the surface damage of components in service. Additive manufacturing by cold spraying can offer significant advantages with respect to other additive manufacturing methods due to higher material deposition rates (up to 14 kg/h), lower energy consumption, and deposition in solid state. So far cold spraying has not been used for 3D‐printing of typical steel constructions.In the preliminary test campaign, structural steel‐powder was investigated to evaluate their suitability for cold spraying in civil engineering applications. Simple flat specimens were used, and a range of metallographic and mechanical tests were conducted to determine the properties of the deposited coupons, such as the coating quality, layer thickness, the degree of porosity, micro‐hardness, and micro flat tensile test. This paper presents the results of the powder characterisation and the preliminary tests on the printed specimens.

Design optimisation of welded I‐beams made of high strength steels

AbstractNowadays, hot rolled steel sections are used in practice. The cross‐sectional dimensions are therefore fixed and catalogued by the steel manufacturers. However, when the span of the members and/or the applied load becomes significant, such hot rolled steel sections can no longer meet the ultimate and/or service design criteria and the use of a built‐up welded I‐beam should be considered. They are typically made of three steel plates welded together to form a monolithic I‐beam. By varying the dimensions of these plates, an infinite amount of cross‐section geometries can be defined. But face to this high variability of solutions, the designers encounter difficulties in identifying the most appropriate combination of geometrical and mechanical properties for the constitutive plates.To study and optimise these profiles, a MATLAB® routine has been developed at the University of Liege. It allows, for different load cases, to find suitable cross‐sectional dimensions that minimise the weight and/or the total cost of the element. This routine follows the current recommendations prescribed in prEN1993‐1‐5 and evaluates the possibility of using transverse stiffeners along the web to further reduce the weight and cost of the element. The so‐developed routine is presented in the present paper. Also, the advantage of considering the use of high strength steels for such structural members is discussed to propose recommendations to the designers for the selection of the most appropriate steel grade.

Post-fire behaviour and improving the performance of hot rolled open sections subjected to standard fire exposure

This paper presents an experimental and numerical analysis considering the effect of standard fire conditions on the post-fire strength of hot rolled hollow steel sections, where the influence of passive protection, cooling conditions and micro structural changes were also analysed with precision. Square, rectangular and circular shaped specimens were considered for the investigation. Cementitious perlite coating was used to improve the fire resistance of sections exposed to elevated temperature following the ISO 834 standard fire curve. Investigations were performed to evaluate the influence of fire conditions on the axial load capacity, deformation, stress-strain behaviour, yield stress, ultimate stress, and elastic modulus of sections. Finite Element Models (FEM) were developed and validated with experimental results. A detailed micro structural analysis was done with keen observation to assess the physical characteristics by scanning electron microscope (SEM) and image analysis. As expected, passively protected specimens show significantly higher post-fire resistance. In the case of water cooling, the post-fire capacity of sections decreased by approximately to 10–15%. Micro cracks were identified along with a greater proportion of pearlite in the micro structures of water cooled specimen

STUDY ON STRUCTURAL DESIGN OPTIMIZATION OF STEEL BUILDING

Pre-Engineered Building which has been gaining popularity over the past few years employs builtup sections for members as against hot rolled steel sections. The members’ section profiles match closely with the bending moment diagram across the frames as the depth of the sections is greatly dependant on the moment across the sections and hence we see tapered section profiles in such building systems. A detailed study is carried out on the final optimized section profiles and the analysis results for the present paper. As a part of research paper “Comparitive Study of Pre-Engineered Building and Truss Arrangement Building for varying spans”, models of industrial pitched roof steel building which were designed as both Pre-Engineered building system and conventional steel truss building system were analyzed and designed for dead loads, live loads and lateral load. The study focuses on the variation of member strength with respect to its dimensions,optimized section profile characteristics for a certain critical load combination and ways to reduce member forces by floating columns, lateral bracings etc

Design Calculation for A (G +10) Building (Encode Steel)

The proposed steel building at Mumbai consisting of G+10 storeys, has a built-up area of about 165m2. The typical floor height is 3m above GL and the total height of the building above GL is 33m.Withreference to given plan, the architectural drawings and structural drawings showing plan, elevation, sectional views and connection drawings are drawn by using AUTOCAD 2017.Design calculations (Dead Load, Live Load, Wind Load, Seismic Load) are calculated manually-As per IS codes which are mentioned in technical details. The rolled steel sections for beam and column has been chosen from IS 12778:2004. High tensile steel grade-E350BR has been used for steel sections. And, the analysis of structure is done by using STAAD.Pro V8i SS5.Design of beam and column are manually calculated-As per IS: 800-2007. And, spread sheet has been created to check the beam and column, whether it is safe or not. The connection designs are calculated-As per IS codes by using Welding-As per IS 9595-1996 and Fasteners-As per IS 3757-1985. Bracings are provided in the ground floor between the column to avoid soft storey failure. The material requirements are mentioned based on the design calculations. The total estimation of the building is 1.11cr.

Experimental and Finite Element Study of Polymer Infilled Tube-in-Tube Buckling Restrained Brace

This study presents a tube-in-tube buckling-restrained brace (BRB) infilled with lightweight and rapid hardening polymer. The proposed BRB consists of a circular or square tube core encased with a tube of similar shape and polymer infill. The tube-in-tube arrangement minimizes the filler material volume and enables the use of rolled steel section as opposed to welded profiles commonly utilized when large BRB axial strength is required, although welded profiles suffer from low assembly accuracy resulting from welding deformation. The infilled polymer has a density of approximately half that of mortar and requires a curing time of 24 h, enabling weight and fabrication time reduction. The stability and inelastic deformation capability of the BRB were investigated through brace and subassembly tests of six circular and four-square full-scale specimens, followed by finite element analysis. The test results show that circular BRB designed with a Pcr/Py ratio of 1.46 exhibited a stable hysteresis up to 1.42% and 1.06% core strain in tension and compression, respectively. Circular and square specimens designed with Pcr/Py ratios ranging from 0.82 to 1.06 exhibited stable hysteresis before failing by global buckling at compressive core stains ranging from 0.86% to 1.09%. The slot weld detail adopted for welding core projection stiffener displayed a stable performance in circular BRB specimens, while it resulted in large plastic strain demand in square BRB specimens, leading to core fracture at tensile core strains ranging from 0.64% to 0.71%.

Numerical Investigation on Cold Formed Steel Angle Section Portal Frames

Cold formed steel portal frames are widely used as alternative to traditional portal frames made from hot rolled steel sections. Load-displacement response of cold formed steel single C-section portal frames is available. C- section portal frames undergo significant deformation before reaching their ultimate loads. In this study, cold formed steel angle portal frame is analyzed using finite element analysis in order to find the load-displacement response. Bolt pressure is applied at the location of physical bolts in ANSYS.
 Keywords- Cold formed steel portal frames, fasteners, bolts, connections, Numerical modelling

Performance assessment of high strength concrete two-sided corbels with embedded stiffened web-rolled steel

In this work, a new proposal of composite corbels has been suggested based on incorporating a stiffened rolled steel in the RC corbel. The enhancement in response have been investigated in terms of tracking the map of crack propagation at failure, history of loading, cracking and failure load, failure mode, ductility index, toughness value, and rate of crack widening. Ten specimens have been tested experimentally with two values of shear span/depth (a/d) ratio; 0.70 and 1.0. Two RC corbels are considered as control specimens and eight encased corbels with tapered WT- or WF- rolled steel sections, without or with stiffeners. Moreover, a theoretical proposal has been suggested to estimate shear capacity of the composite encased corbels.It is found that for a/d = 0.7, composite corbels with the stiffened elements yielded same cracking load as for RC corbel. For a/d = 1.0, stiffened composite corbels yielded relative increments of (11%–33%). Moreover, it is obtained that for a/d = 0.7, specimens with stiffened rolled steel yielded a relative capacity of (95–105)% to the RC corbel while for a/d = 1.0 the failure load ranged in (93–104)%.Significant enhancements in ductility have been noticed. For a/d = 0.7, the relative values ranged in (85%-150%) with highest value with stiffened tapered WT-steel. For a/d = 1.0, specimen with non-stiffened rolled steel yielded relative ductility index of 152%. Regarding toughness, Relative values are (203%- 278%) have been obtained for a/d = 0.70, with highest value for that with stiffened tapered WT-steel. For a/d = 1.0, Relative values of (123%-154%) are obtained with highest value for that with non– stiffened WF-steel.

Analysis of Pre-Engineered Buildings with different types of bracings – Using STAAD Pro Connect

Every year 1.86 billion metric tons of steel produced and the construction industry accounts to half of its consumption. Steel is an extremely versatile material that is not only easily available, cheap and easy to work with but also 100 % recyclable. This property of steel makes it a very viable solution to the ongoing environmental problems and even a better alternative to the conventional building materials. There are various types of steel available in the industry. It includes hot rolled steel sections that are already manufactured at certain pre-determined sizes. The properties of the hot rolled sections are already studied and readily available as tables. The other type of steel section is cold form steel which is differentiated by the process of production. The last and most commonly used type of steel section is the structural steel. Structural steel is prefabricated according to the design requirements of the project. Pre-Engineered Steel Building System is broadly accepted across the world as a competent alternative to conventional steel buildings. Pre-Engineered Buildings (PEB) are a type of steel structures that can be constructed easily and quickly. Pre-Engineered Buildings are nothing but steel buildings in which surplus steel is evaded by tapering the sections as per the necessity of bending moment. Though it has many advantages, it is not widely used in India due to the lack of awareness. In Conventional steel structures, both the time and cost will be more, thus making it uneconomical. Thus, in pre-engineered buildings, the complete design is done and the detailed drawings are sent to the factories, and where the elements and members are pre-fabricated and then transported to the construction site. As they are already pre-fabricated according to the design the erection process will only take 2 to 6 weeks depending on the immensity of the project. Pre-Engineered Buildings have bolted connections and later can also be reused after dismantling. It is the most affordable and flexible building system ideal for any low or high rise industrial, institutional or commercial applications. The other advantages include low cost, environment friendly, easy erection, aesthetic appeal, flexibility and high durability. All these advantages make it the most suited after construction practice in the world. In India, Pre-Engineered & Pre-Fabricated building industry is growing swiftly. The paper involves analysis of the Pre-Engineered Building with different types of bracing and finding the most economical bracing. It also includes achieving economy by tapering the sections based on the bending moments.

Structure Analysis of Cold-Formed Steel Roof Truss Post Office Branches Loa Janan

Steel is one of the most widely used construction material for structural systems in modern construction. In recent years, Cold formed steel (CFS) sections-which is being another major type of steel sections and found to be an alternative to the familiar Hot rolled steel sections. The purpose of this research is to choose the best CFS products in terms of strength and safety which use for Loa Janan post office. This study begins by collecting primary and secondary data. Then look for references in CFS products in the field. In this study there is 4 CFS brands (Taso, Cici, Truss, and Kaso product). Than the sample of product will be testing in the laboratory. The loading is carried out guide [1]. Than to analyse of the CFS frame use [2]. For model using SAP 2000 application. The material used in this study were steel profile C 75 75 0.75 to tension members. From the results of the analysis. it can be concluded that of the 4 steel materials being studied all can withstand the load. However, the CFS brand Taso has the highest maximum stress of 46.27 KN. while the smallest Truss brand is 0.17 KN.

Seismic Analysis of Steel Structures with and Without Bracings in Different Seismic Zones

In the present study four G+5 steel structures were modeled without bracings and having X, V bracings and diagonal bracings with foundation depth of 2m support conditions are assumed to be pinned at the bottom or at the supports/footings, seismic loads are applied as per IS:1893-2002 The structures having length = 28.2 m, width = 17m and height = 20m. The structures modeled in STAAD.Pro“structural analysis and design software by considering various loads and load combinations by their relative occurrence are considered the material properties considered are” Fe250 rolled steel sections structures were considered in seismic zones 2, 3, 4 and 5 X type bracings systems are observed to better in high seismic zones.

Load Bearing Strength of Innovative I-Shapes of Cold Formed Steel Sections

In recent years, cold formed steel sections are used more and more as primary framing components as well as secondary structural systems. The geometry can significantly influence the stability response of cold formed steel members. This reportis an investigation concerning the structural behavior of the cold formed steel beams and their failure modes. The beam profile is cold formed steel section and experimental procedure on cold formed steel section is conducted. Thin sheet steel products are extensively used in building industry, and range from purlins to roof sheeting and floor decking. Generally, these are available for use as basic building elements for assembly at site or as prefabricated frames or panels. These thin steel sections are cold-formed, i.e. their manufacturing process involves forming steel sections in a cold state (i.e. without application of heat) from steel sheets of uniform thickness. Sometimes they are also called Light Gauge Steel Sections or Cold Rolled Steel Sections. The thickness of steel sheet used in cold formed section construction was 3.1 mm. The method of manufacturing is important as it differentiates these products from hot rolled steel sections. Normally, the yield strength of steel sheets used in cold-formed sections is at least 280 N/mm², although there is a trend to use steels of higher strengths, and sometimes as low as 230 N/mm².

Structural features of cold-formed steel profiles

Using capacity of cold-formed steel sections increases thanks to the opportunities which are offered by the developing technology. Low production cost and variety of profiles that can be produce easy, fast, high quality provide to improve its popularity as a structural material. In production, Sulphur and Phosphorous accumulation region occurs at intersection region of flanges and web of hot rolled steel profile. This causes to decrease strength of profile. Other difference between cold-formed and hot rolled steel sections is that mechanical properties of steel material homogeneously distributes throughout the profile. Both in frame and truss systems, cold-formed steel profiles develop both as main and secondary bearing element. These present variety options to the designers with pure, galvanized, aluminized applications. As with many building materials, mechanical behavior of cold-formed steel profile is quite complex due to the nature of thin walled steel sections. Design and analysis methods of cold-formed steel profile are rapidly shaped day by day. The general theory of beams investigated in past studies make possible analyses of cold-formed steel profile. Moreover, in structural systems, using of cold-formed steel profile provide height strength besides sustainable, environmentalist, green building because it requires less material and cost. Although these profiles have many advantages, use of cold-formed steel profiles in our country structures is rather limited unfortunately. New steel construction regulations in Turkey also do not mention cold-formed thin walled steel structure. Main purpose of this study reviews structural specifications of cold-formed steel profiles which are applied world-wide.

08.07: Performance and capacity of composite “mega columns” with encased hot rolled steel sections

ABSTRACTSteel reinforced concrete (SRC) columns are widely used in high‐rise buildings, since they provide larger bearing capacity and better ductility than traditional reinforced concrete (RC) columns. This type of structural system is not currently explicitly addressed in the actual design codes.The paper aims at presenting the behaviour of a new configuration of mega columns – isolated steel reinforced concrete (ISRC) columns. A two‐phase test was conducted on scaled ISRC columns designed based on a typical mega column of a super high‐rise building. Phase 1 of the study includes six 1/4‐scaled ISRC columns under static loads: every two of the specimens are loaded statically with the eccentricity ratio of 0, 10%, and 15%, respectively. Phase 2 of the study includes four 1/6‐scaled ISRC columns under quasi‐static loads: every two of the specimens were loaded under simulated seismic loads with the equivalent eccentricity ratios of 10% and 15%, respectively. A finite element analysis (FEA) was conducted as a supplement to the physical tests to provide a deeper insight into the behaviour of “mega columns”. An extended Plastic Distribution Method is defined to evaluate the capacity of the specimens. The method is based on simplifications similar to those proposed in EC4 [1]. The scope of this latter standard is limited to the consideration of one single steel profile. The method is validated by comparisons with experimental and with numerical simulation results using advanced finite element programs, showing a good accuracy in results.

Comparative Study of Hot Rolled Steel Sections and Cold Formed Steel Sections for Industrial Shed

Comparative Study of Hot Rolled Steel Sections and Cold Formed Steel Sections for Industrial Shed

EXPERIMANTAL STUDY OF EFFECT OF HEXAGONAL HOLES DIMENSIONS ON ULTIMATE STRENGTH OF CASTELLATED STEEL BEAM

Nowadays, use of castellated steel beams (CSBs) has become very common because of their advantageous implementations in construction of buildings. Castellated Steel Beams (CSBs) are those members that are fabricated from standard hot rolled steel (HRS) I- sections by cutting along its web in "zigzag" pattern and thereafter rejoining the two halves on one another by welding together to form a castellated beam, so that generally the depth of  a section will be increased. This research analyses the experimental results of six specimens of castellated steel beams and compares with control beam (Parent section). The purpose of this study is to investigate the effect of hexagonal hole dimensions on the ultimate strength and stiffens response of the castellated steel beam. Also, the effect of number of holes on the behavior of the castellated steel beams that have the same span and ratio of expansion was investigated. All specimens of the castellated steel beam were fabricated from hot rolled steel section (IPE140) and were expanded to (1.56) times the parent section depth. From the test results, it is observed that best dimension of castellated steel beam was (span length to holes space ratio L/S = 8.0); hole depth to Castellated beam depth ratio is h/H=0.56, and hole space to the castellated beam depth ratio is S/H = 1.03. The ultimate strength of the castellated steel beam was increased about (50%) stronger than the original beam.

Cross Section Optimization of Plane Truss among Different Spans

Cross sectional areas optimization is to be implemented to study the influence of the cross section shape on the optimum truss weight. By the aid of analysis and design engines with advanced finite element analysis that is the steel design software STAAD. Four rolled steel sections (angle, tube, channel, and pipe) which are used in industrial roof trusses are applied for comparison. Many previous studies, use the areas of cross sections as design variables without highlight to the shape of cross section at the start of the process, consequently the result area will be adequate if the designer choose the effective shape than others. Results of this research show that the chosen cross section shape has a significant impact on the optimum truss weight for same geometry of truss type under the same circumstances of loading and supports.

OPTIMIZATION OF ELASTIC BRIDGE TRUSSES / TAMPRIŲ TILTO SANTVARŲ OPTIMIZAVIMAS

The article analyzes the problems of optimizing elastic bridgetrusses, which is a tool for seeking the establishment of theminimum volume (mass) of construction and optimization of thecross-section area and height as well as the structure of the truss.It has been formulated as a nonlinear discrete mathematical programmingproblem. The upper band of the truss works not onlyfor compression but also for bending. The cross-sections of theelements are designed from rolled steel sections. Mathematicalmodels are prepared by using the finite element method and complyingwith requirements for the strength, stiffness and stabilityof the structure. The formulated problems are solved referringto an iterative process and applying the mathematical softwarepackage “MATLAB” along with routine “fmincon”. The ratio ofbuckling is corrected in every case of iteration. Requirementsfor cross-section assortment (discretion) are fulfilled employingthe branch and bound method. Santrauka Darbe nagrinėjami tamprių tilto santvarų optimizavimo uždaviniai, kuriais siekiama nustatyti minimalų konstrukcijos tūrį (masę), optimizuojant strypų skerspjūvius, santvaros aukštį bei tinklelio struktūrą. Jie formuluojami kaip netiesiniai diskrečiojo matematinio programavimo uždaviniai. Santvaros viršutinės juostos elementai ne tik gniuždomieji elementai, bet ir lenkiamieji. Strypų skerspjūviai projektuojami iš plieninių valcuotųjų profiliuočių. Uždavinių matematiniai modeliai sudaromi taikant baigtinių elementų metodą ir atsižvelgiant į konstrukcijos stiprumo, standumo bei pastovumo reikalavimus. Suformuluoti uždaviniai sprendžiamai iteraciniu būdu, naudojant matematinį kompiuterinį paketą MATLAB ir jo paprogramį fmincon. Kiekvienoje iteracijoje koreguojami gniuždomųjų elementų klupumo koeficientai. Skerspjūvių sortimento (diskretiškumo) reikalavimai užtikrinami taikant šakų ir rėžių metodą.