Program

Keynote Lectures

Cheol Ho Lee
Cheol Ho Lee (Seoul National University, Korea)

Brief Biography

Cheol Ho Lee received his BS (1983), MS (1985), and Ph. D (1992) degrees from Seoul National University in Korea and conducted his post-doc. research at UC San Diego. His current research interests are in high performance steels, tubular joints, hybrid framing of steel structures, seismic design of nonstructural elements, and structural fire design. Dr. Lee served as the President of Korea Society of Earthquake Engineering and the Vise President of Korea Society of Steel Construction. He, as the director, led the IRCT (innovative and rapid construction technology) project sponsored by the Korea government for six years. He has long worked on several hard core issues on high-strength steel applications with a continued sponsorship from Korean government and POSCO (Pohang Steel Corp.). He has been the recipient of more than 10 honors and awards from Korean academic and professional societies such as National Academy of Engineering of Korea, Korea Society of Steel Construction, Korea Society of Earthquake Engineering, Korean Structural Engineers Association, and Korea Association of Steel and Iron.

Title:
Behavior and Design of Rectangular Hollow Section X-Joints with High Brace to Chord Width Ratio

Abstract

A comprehensive experimental and analytical investigation into chord sidewall buckling and related behavior in rectangular hollow section (RHS) X-Joints with high width ratio is presented in this paper. First, based on up-to-date experimental evidences, it is shown that the borderline brace-to-chord width ratio, beyond which the limit state of chord sidewall buckling should be considered in design, needs to be derived on a mechanical basis. Second, based on test-validated numerical analysis, the effects of initial local and global imperfections on ultimate strength of the full-width RHS X-joints are explored. Third, the borderline brace-to-chord width ratio is mechanistically derived as a function of chord face and chord sidewall slenderness and the yield strength of chord material. Fourth, an improved chord sidewall buckling formula is proposed based on the concept of variable effective column length factor. Finally, incorporating all the findings, a set of improved design recommendations for RHS X-joints under axial compression are proposed up to steel grade S700 under the EC3 framework.
Richard Liew
Richard Liew (National University of Singapore, Singapore)

Brief Biography

Richard Liew is a Professor and Acting Head of the Department of Civil and Environmental Engineering at the National University of Singapore. He received his B.Eng (1986) and M.Eng (1988) degrees from the National University of Singapore and a Ph.D (1992) degree from Purdue University at West Lafayette in USA. He is a fellow of academy of Engineering, Professional Engineer in Singapore, Chartered Engineer in U.K, and Past President of the Singapore Structural Steel Society. Prof Liew is a renowned expert in the field of steel and composite structures. His research focuses on the design and application of high-performance materials in tall buildings and large span structures covering civil infrastructures, protective and security and offshore engineering sectors. He received several research and design awards, including the 2020 NUS Engineering Research leadership award, 2017 best research paper prize from Institution of Structural Engineers ( UK) and the 2013 Structural Excellent Award from the Hong Kong Institute of Engineers. He has been consulted on the design and construction of several iconic buildings in Singapore such as the iconic structures in Changi Jewel and Gardens by the Bay. He is a key person responsible for the development of Singapore’s codes of practices for steel structures.

Title:
Design and Construction of Composite High-rise Buildings Using High Strength Materials

Abstract

Steel-concrete composite structures comprising of structural elements made of steel section acting in composite with reinforced concrete have been used widely in high-rise buildings. Modern building codes provide some guidance on the design of composite members but restricting their uses for normal strength materials due to the lack of understanding on the interactive behavior between high strength concrete and high strength steel section. A lack of research breakthroughs in high strength composite structures has prompted further action from the research group at the National University of Singpaore to conduct a series of large-scale tests on composite columns made of high strength concrete and high strength steel sections. This paper provides the f database from the test programs and propose a unified design method for composite columns with concrete grade up to C150 and steel section grade up to S550. More than 2300 test data collected from the literature on concrete encased and concrete filled tubular members with normal and high strength materials have been analyzed to formulate this design guide. Actual building projects utilizing this design methodology will be highlighted and their implementation in practice will be explained.
Venkatesh Kodur
Venkatesh Kodur (Michigan State University, USA)

Brief Biography

Dr. Venkatesh Kodur is a University Distinguished Professor in the Department of Civil and Environmental Engineering at Michigan State University (MSU). He also serves as Director of the Centre on Structural Fire Engineering and Diagnostics at MSU. His research interests include: Evaluation of fire resistance of structural systems through large scale fire experiments and numerical modeling and Characterization of materials under high temperature. His research contributions has lead to the development of fundamental understanding on the fire behavior of material and structural systems and also resulted in numerous design approaches and innovative and cost-effective solutions for enhancing fire-resistance of structural systems. He has published over 400 peer-reviewed papers in journals and conferences, and has given numerous invited key-note presentations. He is one of the highly cited authors in Civil Engineering and as per Google Scholar, he has more than 13,500 citations with an "h” index of 64. The methodologies, techniques and design guidelines, resulting from his research, have been incorporated in to various codes and standards, as well practical applications, in the US and around the world and are instrumental in minimizing the destructive impact of fire in the built infrastructure.

Prof. Kodur is a Fellow of the Canadian Academy of Engineering and a Foreign Fellow of Indian National Academy of Engineering. He is a professional engineer, Fellow of American Society of Civil Engineers, Fellow of Society of Fire Protection Engineers, Fellow of Structural Engineering Institute, Fellow of American Concrete Institute, Associate Editor of Journal of Structural Engineering, Past Chairman of ACI Fire Protection Committee, Chairman of ASCE-29 (Fire) Standards Committee and a member of UK-EPSRC College of Reviewers. He has won many awards including Fulbright Scholar Award, American Institute of Steel Construction Faculty Fellowship Award, MSU Distinguished Faculty Award, NRCC (Government of Canada) Outstanding Achievement Award and NATO Award for collaborative research. Dr. Kodur was part of the FEMA/ASCE Building Performance Assessment Team that studied the collapse of WTC buildings as a result of September 11 incidents.

Title:
Advanced Analysis for Tracing Fire Induced Progressive Collapse of Steel Framed Buildings by Kodur V.K.R. and Venkatachari S.

Abstract

A steel-framed building, when exposed to a severe fire, can experience instability at a local or global level and this can lead to progressive collapse of a part or the entire structure. The fire performance of a steel-framed building depends on many factors including the geometry of the structure, load level, intensity and severity of fire exposure, the extent of fire spread (number of compartments or floors burning), connection configurations, and high-temperature properties of steel. The current fire design provisions for steel framed buildings is mainly based on sectional or member level analysis and this type of analyses does not fully take in to account realistic load, fire characteristics, material properties, and restraint conditions, as present during a fire exposure. In order to evaluate realistic fire performance of a steel framed building, an advanced analysis is to be carried out at system level, with due consideration to all influencing factors.

The presentation will focus on the application of advanced analysis for tracing the fire induced progressive collapse of steel framed buildings. An approach for incorporating full effects of transient creep, restraint conditions, local instability, and different failure limit states in fire resistance analysis will be outlined. The evolution of temperature-induced instability, leading to progressive collapse, in a fire exposed steel framed building will be discussed. Results from a set of numerical studies will be utilized to recommend guidelines for minimizing the onset of fire induced instability, as well as progressive collapse, in steel framed structures.
Akira Wada
Akira Wada (Tokyo Institute of Technology, Japan)

Brief Biography

Dr. Akira Wada, recipient of the 2011 Fazlur R. Khan Lifetime Achievement Medal and Professor Emeritus of the Tokyo Institute of Technology, is considered to be a Japan’s leading expert in structural engineering with a specific focus on seismic structural design, base isolation and damping. Dr. Wada’s contributions to the field of science and technology and connections in Japanese academic and government circles make him uniquely qualified to lead and consult on a wide variety of projects. Since becoming Professor at the Tokyo Institute of Technology in 1989, Dr. Wada has held a number of important positions, including serving as chairing the CTBUH Japan Chapter since its formation in 2010. In 2014, he was elected President of the Japan Seismic Isolation Association. He also has served as President of the Architectural Institute of Japan (AIJ, 2011.6-2013.5), Member of Science Council of Japan (SCJ, 2005.10-), Representative Director of Japan Academic Network for Disaster Reduction (JANET-DR, 2016.1-).

Dr. Wada received the AIJ Grand Prize 2019 as International collaborative research and development on the seismic design of architectural structures

Title:
Forecast Based Engineering for Big Cities

Abstract

Architects and engineers are basically optimists and build big cities in Asian countries including many large structures. We need everyday electricity, water, gasoline, vegetables, information through the internet or mobile phones, houses, offices, universities, hospitals, government buildings, and complicated transportation systems. In our modern age, these all-sophisticated systems have to be rationally working. Then, we can enjoy modern life. Architects and engineers cannot know new hazards and new disasters that happened before. The next severe disasters will happen sure in the big city. Galileo Galilei said the big structure would be weak comparing the small structures made by the same materials. I would like to discuss we need forecast-based engineering for big cities.
Seokkwon Jang
Seokkwon Jang (LERA Consulting Structural Engineers, USA)

Brief Biography

Seokkwon Jang, Ph.D., P.E., is a Partner at LERA Consulting Structural Engineers. He holds a Ph.D. in structural Engineering from Lehigh University in Pennsylvania, and received his Bachelor and Master of Science at Hanyang University. He has expertise in wide range of building types from high-rise buildings to security related designs. In addition, he has made research related projects in the firm. Since 2009, he has worked on a series of Korean research projects in collaboration with POSCO research Center. He was leading a LERA’s role to assist in the development of the use of very high strength steel in tall buildings by focusing an attention on the primary vertical and lateral load resisting systems of tall buildings. His study extends to research and develop the use of very high strength steel in other applications such as platform structural system to be built above railways or highways, long span truss system, composite structures of mega bracing system, alternative flooring system, etc. that may maximize potential advantage of the high-performance steel materials in cost effectiveness as well as constructability. Currently, he has lead the structural design of the projects in Korea, including Cheongna International City Tower (CICT), Hyundai Global Business Center (GBC), HDC Central Park in Busan, etc., and was involved in the peer review of New York’s Freedom Tower, and involved also in the design of the award-winning 4 WTC on the World Trade Center.

Title:
Design Development of Cheongna International City Tower (CICT)

Abstract

The Cheongna International City Tower (CICT) is 448 meters tall, with 31 stories above ground within four different zones consisting of Lower Zone, Middle Zone, Upper Zone and Crown. The tower is mixed use, with retails, restaurant, and observation deck at the Lower Zone and sky walk, sky garden and observation deck at the Upper Zone. The primary tower structural system has been developed with the core and perimeter mega-structure system that has been selected as the lateral load resisting structural system. This system contains higher structural efficiency than comparable system such as belt truss and outrigger system, and its inherent coordination with the crystalline shape of the tower. The structural floor framing within the core is designed with reinforced concrete and the floor framing outside of the core is composite steel and concrete framing. Between floors with a height greater than 9.0meter, steel framing for catwalk and/or façade supporting framing is considered. These two systems are designed to be constructed alternatively with 4.5meter space. The spire structure above elevation 396meter is designed to be constructed with a system of steel space trusses. The spire has three sub-systems consisting of a triangular pyramidal top, a horizontal ring and six lower perimeter trusses.
Yiyi Chen
Yiyi Chen(Tongji University, China)

Brief Biography

Prof. Yiyi Chen received his Bachelor Degree from Tongji University of China (1983), and Doctor Degree of Engineering from University of Tokyo, Japan (1994). He served as Professor at Department of Structures of Tongji University till the end 2020, and now shifts to Shanghai Sanda University. His current research interests are in seismic performance of steel frames, steel structural joints including tubular joints, progressive collapse behavior of steel structures, and prefabricated steel-composite structures. Prof. Chen served as the Vice- President of China Steel Construction Society, the Executive Committee of China Civil Engineering Society. He has long worked as chief-editor and of the Journal of Building Structures, executive-chief-editor of the Journal of Frontiers of Structural and Civil Engineering, and the member of editorial board of ISSS and other journals. He has been awarded several Chinese National Awards for Science and Technology Progress.

Title:
Mechanical Model and Experimental Investigation of an Innovative Damper with Cast Steel

Abstract

This study explores the feasibility of applying the casting technology into the steel damper for enhancing the seismic performance of structures. The paper proposes an innovative cast damper with a set of yielding plates. By changing the number and dimension of the yielding plates, the behavior of the damper would be modulated. Thus, two types of damper (S1 and S2) are designed for comparison. A mechanical model is presented first to get a better understanding of the behavior of the damper. Then the experimental investigation follows, and it starts with the tensile test of bar samples. The material tests showed stable and sufficient yield and ultimate strength and satisfied elongation. Then, the hysteretic tests are carried out on the cast damper, indicating that all dampers have reasonably good seismic behavior with full hysteresis loops. Finally, the applicability of proposed mechanical model is discussed by comparing with test results.
Amit H. Varma
Amit H. Varma (Purdue University, USA)

Brief Biography

Prof. Varma is the Karl H. Kettelhut Professor of Civil Engineering at Purdue University, and the Director of the Bowen Laboratory for Large-Scale CE research. He received his PhD from Lehigh University (’01). Prof. Varma has dedicated his academic and professional life to the development of innovative steel-concrete composite structures for the built infrastructure including commercial, industrial, and safety-related nuclear structures. He has conducted fundamental research leading to the development of design provisions for composite members, connections, and overall structural systems subjected to extreme loading conditions including seismic, fire, blast, and impactive loading. Prof. Varma’s research products are the basis of (and directly cited in) several AISC specifications (AISC 360, AISC 341, AISC N690) for the design of steel-concrete composite structures for building structures and safety-related nuclear facilities. Prof. Varma is the recipient of the AISC Milek Faculty Fellowship Award (2003), AISC Special Achievement Award (2017, 2020), ASCE Shortridge Hardesty Award (2019), and the T.R. Higgins Lecture Award (2021). Prof. Varma is the Chair of AISI/AISC Task Committee 8 on Fire Design, and member of Task Committee 5 on Composite Design. He is also a member of the AISC Committee of Specifications, and ASCE/SEI 7 Standard Committee.

Title:
SpeedCore / Composite Plate Shear Walls: Fire Resistant Design

Abstract

The merits of steel-concrete composite construction have been recognized and leveraged for decades, but they have never been harnessed quite so efficiently as the new SpeedCore system, which consists of composite plate shear walls and composite coupling beams. This system can be used, when needed, in lieu of traditional reinforced concrete core walls / shear walls in commercial, industrial, or nuclear construction. The primary advantages of this composite system stem from the efficient modularization and prefabrication of steel modules, and elimination of rebar cages, formwork, and falsework, resulting in expedited construction schedule, and thus overall project economy. This presentation will summarize the results of recent research, culminating in the development of fire resistant design specifications and guidelines for composite plate shear walls and systems. The presentation will highlight experimental behavior, numerical modeling, and design of composite walls and the SpeedCore system for fire loading conditions. The presentation will cover both the fire resistance rating (in hours) and strength at elevated temperature.
Amit H. Varma
Sumei Zhang (Harbin Institute of Technology, China)

Brief Biography

Sumei Zhang received her BS (1985), MS (1988), and Ph. D (1991) degrees from Harbin Institute of Technology in Harbin, China and conducted his post-doc. research at University of Manchester and London South Bank University, UK. His current research interests are in performance and design of innovative and complex steel-concrete composite structures and steel structures. The application of composite structures in underground infrastructures and assembled structures. Prof. Zhang served as the President of international Association of Steel-Concrete Composite Structures, the General Secretary and Vise President of China Association of Steel-Concrete Composite structures. Her and her research team’s work has been issued the China National Science and Technology Progress Award (1st Class), the Science and Technology Progress Award (1st Class) from China Ministry of Education, and Chin Steel Construction Society. She is currently working at School of Civil and Environmental Engineering, Harbin Institute of Technology, Shenzhen.

Title:
Behavior and Design of Steel-tube-confined Concrete-filled Steel Tube Stubs under Axial Compression

Abstract

The paper aims at investigating the axial compression behaviors of the square and circular concrete-filled steel tube (CFST) stub columns confined externally by circular steel tubes. Apart from strengthening the performance of the existing deficient CFST composite columns, the new configuration is suitable for the application in new structures. Firstly, three series of experimental work were carried out on 70 short composite columns to determine their mechanical properties under axial compression. Secondly, the effect of the outer circular steel tube on the bearing capacity of the inner square CFST and circular CFST were quantitively determined. Then, the superiority of the new member configuration was verified by comparing it with the 6 other types of commonly used composite columns with the same steel ratio. Subsequently, the influence of critical parameters on the mechanical properties of the newly proposed configuration was studied systematically. The considered parameters included the steel ratio of the inner steel tube and outer steel tube, the gap between steel tubes, and concrete strength, etc. Finally, the feasibility of the current designing codes in predicting the compressive strength of the new configuration was evaluated. A satisfactory prediction method was proposed for the circular-steel-tube-confined square CFST.