Development Of Steel Structures Research Articles

Development of Steel Structure with Rigid Connection Subjected to Horizontal Cyclic Load By Using Rubber Washer

An earthquake is a dangerous natural phenomenon that exposes buildings to collapse and human life to danger. Due to the weakness and cost of design and implementation by seismic design requirements. Therefore, a way must be found to reduce the impact of the earthquake risk, by using the smart joints technology in steel structures. Two experimental models were analyzed theoretically, The results showed a great convergence between the experimental and theoretical programs. The case study is a numerical study containing four rigid specimens that were analyzed in the ABAQUS / CAS (2017) program with applied a horizontal quasi-static cyclic load. The difference between these samples is the difference in thickness of the rubber washer used in the specimen where it is placed under the bolt head in the beam-column connection of the rigid steel frame. Two bolts connect the column with the angle, and the beam with the angle at the top, bottom, in both sides, and two bolts that connect the beam with the shear tab (ST), and in both sides too. Thus, the total number of bolts is twenty and the total number of rubber washer are forty. The results showed that the resistant load of the model containing rubber washer with the thickness (1,2,3 mm) in the beam-column connection increased by (11.5%, 33.8%, and 47.3%), respectively, as well as a significant improvement in the cumulative energy, the ductility residual displacement, The ductility index, The drift ratio, and the equivalent viscous damping compared to the model without rubber.

Research advances in HSS structures at Tsinghua University and codification of the design specification

AbstractIn Memoriam of Prof. Dr. Bernt JohanssonOwing to the advantages in economy, environmental protection and energy efficiency, high‐strength steel (HSS) has represented an important trend in the development of steel structures and has been adopted in numerous building and bridge structures. This article summarizes engineering applications for HSS structures and comprehensively reviews the recent research advances in HSS structures at Tsinghua University. Investigations were conducted into the behaviour and performance of HSS materials, sections, members, connections and structural systems. Based on the research results, the mechanical behaviour of HSS structures could be improved compared with ordinary strength steel structures. In order to update the current design codes so that they are applicable for HSS structures, a new specification in China, the ”Standard for Design of High‐Strength Steel Structures“, is undergoing codification, with Tsinghua University as the chief editorial institute. The outline of the specification, as well as the new design methods included in it, is introduced in this paper.

Experimental study of earthquake-resilient PBCSC with double flange cover plates

Prefabricated steel structure systems have become new trends in the development of steel structures. Meanwhile, earthquake-resilient steel structures have also become a hot issue in structural seismic performance research. Based on the idea of damage control, this study proposes a new type of earthquake-resilient prefabricated beam-column steel connection (PBCSC), which is formed by a circular tube steel column with a cantilever beam, an independent beam segment, and a connection component. The thickness of the flange cover plates, distance between bolts, and some other parameters could be adjusted suitably to obtain a proper connection stiffness so that sliding of the bolts and plastic deformation of the flange cover plates could dissipate energy and prevent the beam and column from plastic collapse. Quasi-static tests, tests of repaired connections, and fatigue tests were performed on six specimens. The influences of several factors, such as thickness of the cantilever beam flange, weakened form of the flange cover plate, retrofit by adding brass friction plates, and repair after earthquake, were investigated to assess the seismic behaviour of the connection. The experimental results showed that the new type of PBCSC could dissipate energy through the plastic deformation and slip friction of the flange cover plate. The plastic damage of the PBCSC was mainly concentrated in the replaceable plates, which was beneficial to the earthquake resilience of the connection. The bearing capacity and the energy dissipation capacity of the connections remained stable after repair. The stable performance of the connection under low-cycle fatigue load showed that it could be used as a displacement-control damper.

Design theory of earthquake-resilient prefabricated sinusoidal corrugated web beam-column joint

Prefabricated steel structure systems have become a new trend in the development of steel structures. In particular, earthquake-resilient steel structures have become a hot issue in the field of structural seismic research. Based on the idea of damage control and a new kind of energy-saving, material-saving and environmentally friendly sinusoidal corrugated web, this paper put forward a new type of earthquake-resilient prefabricated sinusoidal corrugated web beam-column joint (PSCWJ). Then, its constitution, its mechanics mechanism and its seismic design requirements are introduced. After considering the influence of the bolt binding coefficient, the overall bending of the binding section and the overall instability of the flange cover plate, the design theory of the earthquake-resilient PSCWJ is established. Through 55 examples of PSCWJs, the rationality of the design theory proposed in this study is verified, and a reasonable value range of the middle bolt interval on the flange cover plate is determined. During the process of theoretical derivation, the influences of many design parameters are considered, such as the section parameters of the sinusoidal corrugated web beam and cantilever beam, the thickness of the flange cover plate, the material properties of the flange cover plate, the diameter of bolts, the middle bolt interval and the weaken rate of the cover plate. Research shows that the design theory proposed in this paper can predict the yield load of PSCWJ accurately and effectively control the ultimate bearing capacity of PSCWJ. The PSCWJ designed through this theory has good bearing behaviour and ductility, which can make sure the main members, such as the beam and the column, remain in an elastic range and meet the requirements of earthquake resilience.

Experimental and numerical studies on lateral torsional buckling of welded Q460GJ structural steel beams

With the development of steel structures, high performance GJ steel has been applied in many large scale projects, such as National Olympic Stadium (Birds Nest), new CCTV Headquarters and Canton Tower in China. In this study, a series of experimental tests and numerical modelling were conducted to investigate the global stability behaviour of Q460GJ structural steel beams. A total of eight doubly symmetric welded beams with lateral restraints at the mid-span were tested under a concentrated load. Finite element analysis (FEA) models considering initial geometric imperfections and residual stresses were also established and verified by experimental results. By using the validated FEA models, parametric studies were carried out as well. The data obtained from parametric studies were compared with the design buckling curves from Chinese steel structure design codes (GB50017-2003, GB50017-201X), American code (ANSI/AISC360-10) and Eurocode 3 (EC3). It was found that the global stability design methods in GB50017-2003 and ANSI/AISC360-10 may not be conservative for GJ structural steel beams with lateral restraints at the mid-span. The design methods in GB50017-201X and EC3 for rolled sections or equivalent welded sections are more appropriate for the overall stability design of GJ structural steel beams.

Local buckling of steel equal angle members with normal and high strengths

Steel angle sections have been widely accepted with the development of steel structures, and such members made by high strength steel (HSS) sections are also increasingly used in buildings and bridges, and especially in transmission towers and long span trusses. Compared to normal strength steels, HSS exhibits different mechanical properties, which can cause different local buckling behavior. A finite element analysis (FEA) was performed in this paper to investigate the local buckling of steel equal angle members with different strengths under axial compression, where the residual stresses and the initial geometric imperfections of specimens were accurately described. Through this work, the relationship of the ultimate local buckling stress of steel equal angle members under axial compression as a function of steel strength and width-to-thickness ratio was established. By comparing the FEA results with the international design specifications (ANSI/AISC 360-10 and Eurocode 3), a modified design formula was developed and corresponding design suggestions were proposed, to take into account the effects of steel strength.

The Classification and Application of Interior Wall-Board in Steel Structure Building

Protection wall system is the key to promote the development of steel structure building to standardization and industrialization. On the market,there are many different kinds of wall materials, but some do not apply to steel structure buildings. In this part, it is discussed the adaptability of wall-board in steel structure, and introduce several common interior wall-board of the classification and application in practical engineering.

Tests and finite element analysis on the local buckling of 420 MPa steel equal angle columns under axial compression

Local buckling can be ignored for hot-rolled ordinary strength steel equal angle compression members, because the width-to-thickness ratios of the leg don't exceed the limit value. With the development of steel structures, Q420 high strength steel angles with the nominal yield strength of 420 MPa have begun to be widely used in China. Because of the high strength, the limit value of the width-to-thickness ratio becomes smaller than that of ordinary steel strength, which causes that the width-to-thickness ratios of some hot-rolled steel angle sections exceed the limit value. Consequently, local buckling must be considered for 420 MPa steel equal angles under axial compression. The existing research on the local buckling of high strength steel members under axial compression is briefly summarized, and it shows that there is lack of study on the local buckling of high strength steel equal angles under axial compression. Aiming at the local buckling of high strength steel angles, this paper conducts an axial compression experiment of 420MPa high strength steel equal angles, including 15 stub columns. The test results are compared with the corresponding design methods in ANSI/AISC 360-05 and Eurocode 3. Then a finite element model is developed to analyze the local buckling behavior of high strength steel equal angles under axial compression, and validated by the test results. Following the validation, a finite element parametric study is conducted to study the influences of a range of parameters, and the analysis results are compared with the design strengths by ANSI/AISC 360-05 and Eurocode 3.

Tests and finite element analysis on the local buckling of 420 MPa steel equal angle columns under axial compression

Local buckling can be ignored for hot-rolled ordinary strength steel equal angle compression members, because the width-to-thickness ratios of the leg don\'t exceed the limit value. With the development of steel structures, Q420 high strength steel angles with the nominal yield strength of 420 MPa have begun to be widely used in China. Because of the high strength, the limit value of the width-to-thickness ratio becomes smaller than that of ordinary steel strength, which causes that the width-to-thickness ratios of some hot-rolled steel angle sections exceed the limit value. Consequently, local buckling must be considered for 420 MPa steel equal angles under axial compression. The existing research on the local buckling of high strength steel members under axial compression is briefly summarized, and it shows that there is lack of study on the local buckling of high strength steel equal angles under axial compression. Aiming at the local buckling of high strength steel angles, this paper conducts an axial compression experiment of 420MPa high strength steel equal angles, including 15 stub columns. The test results are compared with the corresponding design methods in ANSI/AISC 360-05 and Eurocode 3. Then a finite element model is developed to analyze the local buckling behavior of high strength steel equal angles under axial compression, and validated by the test results. Followingthe validation, a finite element parametric study is conducted to study the influences of a range of parameters, and the analysis results are compared with the design strengths by ANSI/AISC 360-05 and Eurocode 3.

The development of steel structures in Portugal — the influence of Patrick Dowling

The paper describes the influence of Professor Patrick Dowling in the authors career and in the development of steel structures in Portugal based on university research and teaching and the creation of the Portuguese Association for Steel and Composite Construction.

Performance of Steel Beam-To-Column Connections with Weld Defects under Inelastic Cyclic Loading

This study concerns the development of steel structures so that the connections can deform plastically without brittle fracture during an earthquake. Under earthquake loads, welded beam-to-column connections containing crack-like defects in the weld region have been studied using 3-D nonlinear finite element analyses. The effect of the connection type used for a welded steel structure and of the dynamic loading nature on the stress-strain distribution has been examined, as well as the fracture behaviour of the whole structure. Nonlinear finite element analyses were repeated for various frequency values for the different loading cases in order to study the effect of the strain rate.