Scientific Program

Conference Series Ltd invites all the participants across the globe to attend 4th International Conference on Advanced Steel Structures Singapore.

Day 1 :

Keynote Forum

Xudong Qian

National University of Singapore, Singapore

Keynote: Fracture analysis and assessment: From materials to large-scale steel structures

Time : 09:30 to 10:15

OMICS International Steel Structures Convention 2017 International Conference Keynote Speaker Xudong Qian photo
Biography:

Xudong Qian is currently an Associate Professor in the Department of Civil and Environmental Engineering at the National University of Singapore (NUS), the Director for Centre for Advanced Materials and Structures in NUS and the Co-Director for NUS-JTC (Jurong Town Corporation) Industrial Infrastructure Innovation Centre. His research interest covers ductile and brittle fracture, fatigue and impact for steel/offshore structures, welded connections, steel-concrete-steel composite structures, as well as non-destructive crack detection and sizing, through experimental, numerical and hybrid approaches. He is also a Member of the ASTM E-08 Committee on Fatigue and Fracture.

 

Abstract:

Fracture failure has emerged as one of the most common failure modes in modern large-scale steel structures subjected to cyclic or extreme loads caused by artificial or environmental actions. The integrity assessment of the fracture requires a detailed understanding on the material level fracture resistance. However, the scalability between the material fracture toughness and the fracture resistance in the structural component imposes a critical barrier the fracture assessment and representation in large-scale steel structures. This study first embarks on the innovative approaches to reveal the material fracture resistance, characterized by the material J-R curve, through the experimental approach or the experimental-computational hybrid method. These material level investigations cover the non-conventional specimens including the mixed-mode fracture specimens, surface-cracked specimens and circumferentially welded pipes. Coupling the material fracture resistance curve and the extended η-approach, this study proposes a practical method to embed the material J-R curve in the load-deformation relationship of the critical welded connection, to describe phenomenologically the effect of ductile crack extension and the subsequent unstable fracture failure on the load resistance of the welded joint. The validation of the proposed approach covers two different levels: (1) the true-scale welded connection and (2) large-scale steel frames. The fracture modified load-deformation response predicts successfully the experimentally measured load-deformation response of the high-strength steel welded joints accompanied by ductile crack extension and final brittle failure. Incorporating the fracture-modified load-deformation response in a global frame analysis allows accurate prediction on the global frame response with progressive fracture failure.

Keynote Forum

Hieng Ho Lau

Curtin University Sarawak, Malaysia

Keynote: Behavior of axially loaded back-to-back cold-formed steel built-up channel sections

Time : 10:15 to 11.00

OMICS International Steel Structures Convention 2017 International Conference Keynote Speaker Hieng Ho Lau photo
Biography:

Hieng Ho Lau is currently the Dean of Faculty of Engineering and Science, Curtin University Malaysia. He is a Member of Curtin University Malaysia Campus Community where he has accumulated over 14 years of teaching experience in the field of civil engineering. He is a Professional Engineer with Practicing Certificate registered with Board of Engineers Malaysia (BEM) and also Chartered Professional Engineer with Engineers Australia.

Abstract:

Back-to-back built-up cold-formed steel channel columns are being increasingly used by cold form steel structures, such as trusses, wall frames and portal frames. In such an arrangement, independent buckling of channel-sections can be prevented by using intermediate fasteners, at discrete points along the length. Current guidelines in the North American Standard (NAS) for such back-to-back built-up cold-formed steel channel sections requires the use of a modified slenderness approach in order to take into account the spacing of the screws. This method, however, is well-known to be conservative. This paper presents the results of 60 tests performed on back-to-back built-up cold-formed steel channel sections. Test results are then compared against the design strengths calculated in accordance with AISI and the Australian and New Zealand standard. It is shown that the AISI and the Australian and New Zealand Standards are un-conservative for columns sections failed by local buckling whereas standard under estimate the strength of intermediate and long columns which were failed mainly by overall member buckling for the both the section BU 75 and BU 90 considered in the investigations.

Keynote Forum

Lu Deng

Hunan University, China

Keynote: Experimental study on the steel-concrete composite girder joint of a single pylon cable-stayed bridge

Time : 11:15 to 12.00

OMICS International Steel Structures Convention 2017 International Conference Keynote Speaker Lu Deng photo
Biography:

Lu Deng has obtained his PhD degree in Civil Engineering from Louisiana State University in 2009 and worked as a Research Engineer in the Offshore Structure Division at ExxonMobil for 3 years. He is currently a Full Professor in the College of Civil Engineering at Hunan University. He is an Associate Editor of the ASCE Journal of Bridge Engineering and Guest Editor of ASCE Journal of Aerospace Engineering. His areas of expertise include bridge safety evaluation, bridge fatigue and bridge-vehicle coupled vibration. He has published over 100 technical papers, including more than 40 peer-reviewed journal papers in English.

 

Abstract:

Hybrid girder cable-stayed bridges have been widely used around the world due to its advantages including the large-span viability of the main span of steel and the counterweight effect of the side span of concrete. In hybrid girder cable-stayed bridges, the steel-concrete composite joint plays an important role in connecting the steel girder with the concrete girder. Therefore, the performance and reliability of the composite joint is of great importance to the safety of the bridge. In order to examine the performance of the steel-concrete composite joint of a hybrid girder cable-stayed bridge with single pylon, a 1:4 scaled model for the joint was fabricated in the laboratory and static test was conducted. The stress distribution and the relative slip between concrete and steel under the combined action of the axial force and bending moment were investigated. The test results showed that the axial force and bending moment in the steel girder can be transferred uniformly through the joint to the concrete girder with the bearing plate and the multiple parallel perfobond ribs. The transverse stress at the composite joint reduces from the center to the two sides. Along the longitudinal direction, the minimum compressive stresses occurred at the steel-concrete composite section rather than the steel or the concrete section of the girder. The findings from the study provide useful information and guidance for the design and construction of steel-concrete composite joints in hybrid girder cable-stayed bridges.

Keynote Forum

Xuechun Liu

Beijing University of Technology, China

Keynote: Performance and design of an bolted joint connecting H-shaped beams and square hollow steel columns

Time : 12.00 to 13.00

OMICS International Steel Structures Convention 2017 International Conference Keynote Speaker Xuechun Liu photo
Biography:

Xuechun Liu is a Vice-Professor in the Beijing Engineering Research Center of High-rise and Large-span Pre-stressed Steel Structures at the Beijing University of Technology. He has received his PhD in Structural Engineering from the Beijing University of Technology. His research areas include steel structures, prefabricated steel structures and pre-stressed steel structures.

Abstract:

This paper presents a bolted joint to connect H-shaped steel beam to square hollow steel (HSS) column and connect upper and lower columns in a multi-stored modular steel structure. The modular components are welded at the factory, while the assembly is completed on site using high-strength bolts. Moreover, the resulting structure has a desirable seismic performance. Rigid connections or connections with variable stiffness between beams and columns can be achieved by adjusting the number of bolts or the specifications of the bolts. In terms of connection with variable stiffness, the stiffness of bolted connection between beams and columns changes with the applied load. During minor earthquakes, rigid connections can be achieved, while during moderate and major earthquakes, the cover plate slips relative to the beam flange to dissipate energy. In this paper, the model tests and finite element analysis for the seismic performance under cyclic loads was conducted on six full-size connections. Meanwhile, a finite element model of welded connection is compared with bolted connections. The failure mode of the bolted connection and the slippage between the cover plate and the beam flange are analyzed. Seismic performance parameters including hysteretic behavior, skeleton curve, ductility, rotational capacity and stiffness degradation of the connections are obtained. The influence of parameters such as the number of bolts and the cover plate thickness on the mechanical properties is studied, as well as the evolution and distribution of the bolt tension forces. The results show that the large bolt hole on the cover plate and the beam flange can facilitate installation and improve the deformation capacity, ductility and energy dissipation capability without significantly affecting the load carrying capacity of the connection. The proposed bolted connection is suitable for use in structure located in seismic zones.

Keynote Forum

Lin Shaopei

Shanghai Jiao Tong University , China

Keynote: Advances in intelligent design of structures

Time : 15:00 to 15:45

OMICS International Steel Structures Convention 2017 International Conference Keynote Speaker Lin Shaopei photo
Biography:

Lin Shaopei is the Professor at Civil Engineering Department in Shanghai Jiao Tong University; Fellow and Chartered Engineer of the Institution of Civil Engineers (ICE, UK) and CEO of ICE China Education and Training Center. He has been the Chair of AI application panel, Chinese Society of Civil Engineering. His award includes the Government Special Allowance of the State Council PRC in 1991, the Lifetime Achievement Award of PMI (China) in 2012, the Excellent Service Award of ICE in 2015 and the Service Achievement Award of PMI GAC in 2016. He has had a long-term experience in engineering research during past 60 years and had been Research Professor in Cornell University, USA and Hong Kong University and published eight books and nearly 200 papers in domestic and international journals, conferences covering a variety of disciplines, including engineering, economics, system engineering, computational mechanics, IT & computer application, fuzzy mathematics and artificial intelligence applications, etc.

Abstract:

We are facing a knowledge economy and digital era. What is the process of an engineering design? It can be understood as the designer under the design requirements “to make a series of decision under uncertain design environment” in order “to do the right design”; “to do the design right” as well as “to get the design right implementation”. The designer needs to go through system analysis; i.e., to review past design alternatives in their mind (experiences) and make a comparison among them for satisfying design requirements; “To do the right design”. Secondly, “To do the right design” is guaranteed by engineering rules and specification as the design constraints and the third one “To get the design right implementation” means the design should be well treated through acceptability to the related stakeholders. The intelligent design methodology needs to follow designer’s intelligence during design processes through simulation by artificial intelligence technology, among them, first of all is the designer’s fuzzy reasoning processes of comparing his past design samples (experience) in their mind with the assigned design requirements. According to above statements, the available Computer Aided Design (CAD) nowadays is no longer CAD, but CAG, for there will have no design parameters from the fuzzy reasoning by computer, but the heuristic considerations from the designer and input to the drawing machine for the engineering drawing. As the emergence of digital era, characterized by “Softening of theory” and “Hardening of the experience”, the theorem are going more and more softened by uncertain mathematics such as fuzzy logic for accommodating to the changeable environment; on the contract, the experiences are going more and more hardened and stored in computer as the knowledge base. It provides the theoretical basis and possibility of realizing intelligent CAD (as we prefer to ICAD), a conclusion can be made that Fuzzy-AI model is suitable for intelligent design.

Keynote Forum

Ezzeldin Y Sayed-Ahmed

The American University in Cairo, Egypt

Keynote: New trends in structural engineering education with application to design of steel structures

Time : 17:30 to 18:00

OMICS International Steel Structures Convention 2017 International Conference Keynote Speaker Ezzeldin Y Sayed-Ahmed photo
Biography:

Ezzeldin Y Sayed-Ahmed is a Professor and the Graduate Program Director in the American University in Cairo, Egypt. He has earned his PhD in Civil Engineering in 1995 from the University of Calgary. He is a Fellow of the Academy of Scientific Research and Technology and a RC and Steel Structures Consultant. He was the Acting Director of the Credit Hours Engineering Programs of Ain Shams University and the Associate Dean of the College of Engineering of Qatar University. He is a Member of the Egyptian Code of Practice Committee for FRPs and the Chair of the Subcommittee of the Composite Polymers Structures Code. He holds the State Award in Engineering Sciences (Egypt) in 1999 and Bruce M. Irons Memorial Scholarship (Canada) in 1994. He has a USA patent and has 169 publications and supervised 35 MSc and PhD students.

Abstract:

Components of higher education are students, faculty and curriculum/teaching paradigms. Regarding the students, higher education needs people with desire to improve them; this is a fact. For faculty, in many developing countries, the system of faculty rewards is undeniably well-below the level that can safely support faculty’s social needs. As a result, faculty involve in other non-academic activities to raise their level of income. Every day passes without resolving this issue turn this “secondary” non-academic activity turns to be the faculty’s primary job; the ones who end-up paying the penalty are the students. As for the curriculum, we get the famous phrase “we had the best engineering education”; this is true if we modified to “we had the best engineering education; then” where both the curriculum and teaching paradigms served the need of that era. However, this does not mean that we must fix both for decades. Should not we accept that all what we have shinned-in is currently surpassed by something newer and better? Traditional teaching may kill the best designed curriculum. Our teaching pedagogy must be developed to fit the needs and modes of today’s students. Generation Z students are not interested anymore in passive learning; classes must be switched form teacher-centered to student-centered: The only learning path of this generation is active learning. Innovative teaching techniques for design courses (e.g., structural steel design) have been adopted by the author and proved to be very rewarding. Among these innovative techniques are blended learning and flipped classrooms, which stretch the utilization of technology in our today’s classes. Other techniques such as student-generated examinations, student-generated classes and course competitions are also direct reflection of student-centered education. Herein, these innovative paradigms will be presented. Believing that the true purpose of education is to stimulate creativity and passion of the students and more important to teach them how to master the life-long learning skills, we will come to a conclusion that what-ever we are doing now should be reformed: it is a leap of faith.

  • Bridge Engineering | Prestressed Structures | Steel Concrete Composite Structures | Structural Stability | Foundation Engineering | Advanced Structural Analysis
Location: Seletar Room 1 , Level 3
Speaker

Chair

Airong Liu

Guangzhou University, China

Speaker

Co-Chair

Alnuaimi Ali

Sultan Qaboos University, Oman

Speaker
Biography:

Olivia Mirza was a Golden Jubilee Scholarship holder at University of New South Wales in 2000. She has graduated in Bachelors (Civil and Environmental) in 2002. She has worked as a Structural Engineer for 8 years before pursuing her academic career. She has worked for Leighton Contractors, Australia Consulting Engineers and Cardno Group. She is currently a Senior Lecturer in School of Computing, Engineering and Mathematics. She is also Academic Course Advisor for Postgraduate Fire Safety Engineering Program. She has published more than 25 papers in reputed journals and has been serving as an Editorial Board Member of repute.

Abstract:

This research paper investigates an innovative retrofitting technique when an existing steel bridge girder is subjected to fatigue failure. This is an alternative method other than replacing the failed existing bridge structures. The experimental study is focused on rehabilitating steel bridge girders through retrofitting to their original design capacities that have incurred fatigue cracking within the bottom flange. Fatigue is an increasing issue as many steel structures reach the end of their design life each year. Steel structures reaching the end of their design life each year coupled with increased loadings, deterioration due to weathering, climate change and human error also negatively impact the design life. Hence a solution to rehabilitation of the existing steel bridge girders is required to provide a sustainable future. This paper focuses on retrofitting steel bridge girders to further extend their service life. Experimental studies have been conducted on a 120-year-old girder and a new 610UB113 equivalent girder. The results from the experimental test showed that if steel bridge girders have experienced fatigue cracking within the bottom flange, they can be retrofitted with the designed retrofit rehabilitating the girders to their original design loading capacities. Overall it was determined that steel bridge girders can be rehabilitated with the innovative retrofitting technique. Furthermore, this innovative technique enforces that the existing structures do not need to be replaced, instead of using a simple retrofitting technique is sufficient in restoring the existing steel bridge girders to increase their service life to provide a sustainable future.

Speaker
Biography:

P K Gupta is currently working as a Professor of Structural Engineering in the Department of Civil Engineering of Indian Institute of Technology Roorkee, India. He has obtained his Doctoral degree in 2001 from Indian Institute of Technology Delhi, India in the area of Structural Mechanics. His areas of research are: Structural mechanics, finite element analysis, parallel computing, steel-concrete composite and large deformations. He has published more than 130 research papers in international and national journals, conferences. He has experience of organizing short term courses, seminars, workshops and conferences as organizing secretary. Recently, he was awarded with the Endeavour awards of Australian Government.

Abstract:

A nonlinear fiber element analysis method has been presented for predicting the flexural strength of concrete filled steel tubes (CFST). The validation of the method has been done by comparing the results with the actual tested specimens. The fiber element analysis program was developed in Oracle software. Master form has master blocks and a table. Master blocks are used for the input data as well as for calculation work. Table in master form is used to show all required information about each fiber like centroidal distance from neutral axis, strain, stress, force and bending moment of each fiber. The master block section is divided into three parts namely: (1) Input data, (2) Calculation and (3) Results. The input section contains master blocks for material properties, dimensions of the specimen (like length, breadth and depth), steel tube thickness (all four sides) dimensions of concrete core section and the curvature for which results are obtained. To create the fibers, section of the beam is divided into parts as per requirement. Calculation section contains the calculation of centroidal distance of each fiber and other parameters which includes material stress-strain relationship to find neutral axis. Results section provides the printout for centroidal distance from neutral axis, strain, stress, force, bending moment in each fiber. Two rectangular steel hollow tubes having width 120 mm and wall thickness 1.58 mm and depths 140 and 150 mm were filled with concrete having compressive strength 60 MPa and 80 MPa. Both specimens having 1000 mm span were tested under pure bending with four point loading arrangement. A good ductility was observed in the tests. Accuracy of fiber element analysis program is verified by comparing its findings with the counterpart experimental results of both tested specimens and four specimens from literature. It is found that the fiber element analysis technique predicted results within acceptable degree of accuracy.

Speaker
Biography:

Youqin Huang has his expertise in evaluating the dynamic stability of structures. He has constructed a fresh method to investigate the stability of structure subject to arbitrary parametric excitation. He has also studied the stability of long span wind-sensitive roofs under stochastic wind loads or joint actions of wind and snow, and proposed a method to calculate the equivalent static wind load for the stability design in practical engineering.

 

Abstract:

A new method for evaluating the dynamic instability of concrete-filled steel tubular (CFST) column under axial periodic excitation is proposed. The unified equations of dynamic instability of CFST column are explicitly derived based on the differential equations of lateral vibration and the Galerkin method. By employing the theory of Bolotin, the equations of boundary frequencies can be formulated in the format of eigenvalue problem. Subsequently, the regions of dynamic failure can be rigorously constructed by solving the eigenvalue problem. Numerical investigations have been conducted to investigate the applicability and effectiveness of the proposed approach. It is demonstrated that the CFST column, especially those with high slenderness ratios, would become dynamically unstable when the magnitude of the excitation is well below the static buckling load of the column.

Speaker
Biography:

Jaewook Jeong is Country Manager of Singapore at SEN Engineering Group. He has received his PhD from Architectural Engineering at Yonsei University. As a Professional Engineer, he had worked for Kolon Global Corporation in South Korea and he, as a Researcher, also have published several SCI(E) papers about productivity and sustainability on construction industry.

Abstract:

Off-site construction methods such as prefabrication method have been developed to improve productivity in construction and to reduce cost. SEN Engineering Group, a Korea-based structural productivity solution provider, introduces new productivity enhancing construction methodologies, including the Form Prefab Steel Reinforced Concrete (F-PSRC) column and Thin Steel Concrete beam system. This system can dramatically augment on-site productivity by reducing or eliminating the usage of temporary scaffolding works and form-works. The F-PSRC column and TSC beam system has been successfully applied in more than 50 projects in Korea, especially in those involving super-fast-track IT industry factories and offices. In terms of productivity, it was identified through the previous study that F-PSRC columns technology was 42.45% more productive than the conventional SRC columns without increasing of overall cost including fabrication and on-site construction. And now this system is about to be introduced in Singapore through a large-scale inland container deposit project. This system focuses to enhance productivity on site by reducing temporary on-site works and pursuing factory prefabrication. Hence, it is imperative that those in the industry learn about how the F-PSRC column and TSC beam system practices and design are able to shorten the construction periods of projects.

Speaker
Biography:

Mahesan Bavan has completed his MSc in Civil and Structural Engineering from National University of Malaysia, Malaysia. He is a Civil Engineer with 12 years of vast professional experiences in planning, designing and directing the constructions of infrastructure, utilities, geotechnical and structural projects and currently he is enduring the research to read PhD. He has published more than 40 papers in reputed journals and international conferences.

 

Abstract:

An investigation of the buckling behavior of webs in castellated beams of steel-concrete composite beam subjected to combined in-plane negative bending and axial compression is conducted. A Finite Element (FE) model was developed for a steel-concrete composite beam subjected to combined negative bending and axial compression and validated against global and local failure behaviors using experimental analysis in the existing literatures such that the developed FE model can be used for further parametric studies. Subsequently, castellated web panels were modeled in two forms such as square and circle patterns, while the boundary condition and load application of the composite beam were remained same and further investigations have been done on failure behaviors by applying a series of numerical analyses using the three-dimensional finite element modeling. Failure modes in two areas such as local buckling in the web and flanges of castellated steel beam were adopted to predict the ultimate strength of the composite beam, which the predicted ultimate strengths were found earlier with reduction in comparison. Due to the influences of axial compression on mechanical shear connectors, excessive stresses will be induced, which will affect the transmitting shear and accordingly, complexities of interaction analysis techniques should be adopted such that the assessment of existing composite beams and bridge girders in the castellated beams is conservative. It can be concluded in the comparison with the assessment of existing composite beams and bridge girders that this conservative approach may not be warranted as it is often necessary to extract the accurate capacity and stiffness of the beam. This study proposes combined axial loads to predict the failure behavior of steel castellated section composite beam, which is a significant new concept that allows engineers to develop more accurate procedures for determining the strength and endurance of existing composite beams and bridge girders.