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
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
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
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
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
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
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.