5^th International Conference on Steel and Concrete Structures August 29-30, 2018 Tokyo, Japan

Biography:

Prof. Chao-Hsun Huang is an Associate Professor in Structural Engineering at National Taipei University of Technology, Taiwan. His main research areas include reinforced concrete and masonry structures, seismic assessment and retrofit, and dynamic behaviors of building and other structures. He is the author of several books as well as a number of journal and conference papers. His most current research is mainly on seismic retrofit of concrete buildings using combination of column jacketing and supplemental beams.

Abstract:

To improve the safety of existing structures, the Taiwanese government has been urging the seismic rehabilitation of old buildings in recent years. Among the numerous retrofit approaches, column-jacketing, which builds up building columns with enlarged sections and additional reinforcement, is the most widely used techniques currently in Taiwan. However, with the mechanism dominated by the flexural yielding of column base, the retrofit bonus drops quickly as the height of building increases. To provide additional strength, the concept of supplemental beams is introduced. By constructing additional beams between adjacent columns, the effectiveness of column jacketing could be improved. For verification, a full-scale, quasi-static experiment on three two-story concrete frames was performed in this study. Result of the experiment indicates that this technique can make a great enhancement to the seismic performance of the retrofitted frames.

Biography:

Abstract:

The Shanghai Tower is the tallest structure in China and one of the super tall buildings in the world. The 128 storey building stands approximately 632 meters high.  On May 8th, 2015, an ambient vibration test was performed on this building in its final stages of construction. Nine modes of vibration and associated damping ratios were identified below 1Hz using the Frequency Domain Decomposition (FDD)and Enhanced Frequency Domain Decomposition (EFDD) techniques. To get a quick and direct insight into the overall dynamic behavior of this complex structure, a simple and efficient lumped-mass stick model based on macro beam theory was developed in SAP2000 as the baseline model. This model was first calibrated with a sophisticated finite element (FE) model developed using ABAQUS. By performing the sensitivity analysis, several sets of parameters were selected and then modified with an automated updating procedure.  After model updating, the average difference between the model and measured first nine frequencies was reduced from 28% to 4%, and the average modal assurance criterion (MAC) value was improved from 73% to 87%.  The process of model updating for super tall buildings described in this study can lead an efficient and accurate prediction of their seismic response, and the outputs are reliable for wide range of applications in the area of seismic performance, long term heath monitoring and risk assessment.  

Biography:

Jalal is Assistant Professor of civil engineering at Malayer University from September 2008. He spent about one-year (2006-2007) as a research scholar at University of Florida (UF) in USA. He graduated with Ph.D. from Tarbait Modares University (TMU) in 2008 in Tehran. He received M.Sc degree in the civil engineering field (IUST) in 2002 in Tehran. He got B.Sc degree in the civil engineering field from Bu-Ali Sina University in 1999 in Hamedan.

Abstract:

Wavelet transforms are convenient tools in the structural health monitoring and damage detection fields. However, these methods have encountered some limitations in practical usage. Thus, signal energy analysis was also used as an alternative technique for damage detection. In this research, firstly, comparison between the wavelet and signal energy methods for beam type structures with different support conditions and multiple damage scenarios has been conducted. Then, Discrete Wavelet transforms (DWT) and Teager energy operator (TEO) have been applied on the curvature of mode shapes of the beams, and the locations of the damages have been identified. The results show that in compare with discrete wavelet transform signal energy operator has preference. This superiority in detecting the damages, especially near the supports of the beams, is obvious, and contains enough sensitivities in low damage intensities. Additionally, the damage detection in the cases that the response data is noisy has been investigated. For this purpose, by adding low intensity noises to the curvature of the mode shapes, the abilities of mentioned methods have been evaluated. The results indicate that each method is not individually efficient in recognizing damages in noisy condition, but the combination of them under noisy conditions is more reliable.

Biography:

Veerarajan selvakumar currently doing PhD at National Taipei University of Technology, Taiwan. He did Master of Engineering project under the guidance of DM. Pukazhendhi, Principal Scientist at Fatigue and Fracture Laboratory, CSIR – Structural Engineering Research Center, Chennai, India.

Abstract:

The loading on the piping component in nuclear power plant is predominantly bending in nature which is accompanied by some torsional loading during the operation. The pipe experiences higher crack growth rate due to the torsional loading along with bending. The numerical simulations were carried out 170 mm outer diameter SA312 Type 304 LN stainless steel straight pipe using Finite Element based ABAQUS software. Pipe and loading arm were modeled separately and assembled according to the torsion and bending loading. The stress intensity factor values were obtained for every 0.5 mm incremental crack depth and the numbers of cycles were calculated using Paris’ law. In addition to the numerical simulation, the experimental fatigue test was carried out on 170 mm outer diameter stainless steel straight pipe subjected to torsion and bending loading. The crack depth was monitored using Alternating Current Potential Drop technique. The numerical results compared well with the experimental results.

Biography:

Xiaoxiong Zha is a third-level professor and doctoral tutor at Harbin Institute of Technology, President of 7^th and 8^th China Association of Steel Concrete Composite Structures (CASCCS), Executive Director of China Steel Structure Association, Member of the China Steel Structure Association Expert Committee, Expert of steel structure of China Construction Metal Structure Association, Shenzhen high-level talents, Director of Shenzhen Container Modular Housing Innovative Engineering Laboratory, Director of Shenzhen Carbon Storage Cement-based Materials Engineering Laboratory, Expert of Shenzhen Construction Industrialization Association, Nanshan District, Shenzhen pilot talent, Reviewers of international publications

Abstract:

The application of concrete pillar in cooling towers has become more common. However, the CFST(Concrete Filled Steel Tube) pillar have no relevant applications and researches in cooling towers. In order to research the CFST pillar, we will analyze the optimization of the parameters of the CFST pillar first. In CFST pillar, the parameters that can be optimized are: The position of the intersection (above, below, or in the middle), the cross angle, the tilt angle of the CFST pillar, the form of the intersection, the form of the pillar section, etc. Changes in these parameters can also cause a large change in the CFST pillar internal force. The purpose of this paper is to obtain the optimal value range of “intersection position, cross angle, and CFST pillar tilt angle” in the CFST pillar parameters through theoretical calculations, and to provide parameters selection suggestions for cooling tower engineering design. The main theories adopted are: classical structural mechanics (eg: force method, displacement method, moment distribution method, graph multiplication, etc.), moment distribution method of space rigid frame, and transformation rule of space coordinates. We analyze the CFST pillar by three-dimensional structural mechanics and use Matlab to obtain the optimized results of CFST pillar parameters. Conclusion: The position of the intersection point is better above the middle of CFST pillar, the range of ratio λ is 0.2~0.35; the optimal value of cross angle α is 18°~22°; the optimal range of CFST pillar tilt angle β is 74°~78°.

Biography:

Dr. Lin’s research is in the fields of structural and earthquake engineering, and focuses on the improvement of the seismic design and performance of buildings, bridges and infrastructure systems. In addition to her research expertise, she has extensive practical experience in the design of buildings and bridges. She is a licensed engineer registered in the province of Ontario, Canaad. She has received two teaching excellence award.

Abstract:

Since the real records from strong earthquakes are not available for almost all parts of Canada, they are often selected from other countries having similar characteristics of ground motions. For example, for the time-history analysis of structures in western Canada (e.g., Vancouver) records are normally selected from earthquakes in California through PEER (Pacific Earthquake Engineering Research Center) database. However, for eastern Canada researchers and practitioners always have difficulties in choosing accelerograms for the seismic analysis. Given this, the objective of this study is to compare the bridge responses based on different types of the spectrum-compatible ground motions, and to make a recommendation on the use of the accelerograms for the nonlinear time history analysis of bridges in eastern Canada.

For this purpose, two existing reinforced concrete bridges located in Montreal, which is considered as a moderate seismic hazard zone, are selected for the study. The spectrum-compatible acceleragrams are generated by four different methods. Based on these methods, four sets of accelerograms compatible with the design spectrum for Montreal are selected for the analysis, namely, Set 1: scaled real accelerograms, Set 2: modified real accelerograms, Set 3: simulated accelerograms, and Set 4: artificial accelerograms. Nonlinear time-history analyses are conducted by subjecting the two bridge models to the three levels of the seismic excitations represented by each set of the accelerograms. The deck displacement, expansion bearing displacement, column curvature ductility, and base shear are used to investigate the effects of the selected sets of the accelerograms on the bridge response. Simulated accelerograms are recommended to conduct time-history analysis of bridges in eastern Canada.

Biography:

Abstract:

Biography:

Wan Hamidon Wan Badaruzzaman is currently the Chairman of the Smart and Sustainable Township Research Centre (SUTRA), Universiti Kebangsaan Malaysia. He is also a Professor in Structural Engineering at Universiti Kebangsaan Malaysia. His main research areas in terms of publication output are on composite structures especially on Profiled Steel Sheeting Dry Board (PSSDB), a lightweight structural composite system that has been applied as floor, wall and roof panels in buildings; infilled cold formed steel tube structural elements strengthened with CFRP sheets; and composite plate girders. He has published over 200 journal and conference articles. 

Abstract:

The paper highlights various structural composite construction techniques that finds increasingly wide applications in bridges and buildings throughout the world focussing on the composite systems dealt with by the author. Composite structures are created by combining/binding two or more structural elements to act as a single combined structural unit, where each element behaves in a very structurally efficient manner. Various advantages are achieved by composite structures: higher stiffness and strength, reduced depth and weight of structures, faster construction speed, and structurally more efficient, thus providing an economical solution for a wide range of industrial, residential and commercial buildings and bridges. The paper firstly overviewed the principle of composite construction, followed by an account of the research developments undertaken in the past by the author. Research findings on composite construction that include stiffened in-filled columns, tapered plate girders, CFRP strengthened steel tube beams, and an innovative lightweight composite panel system known as the Profiled Steel Sheeting Dry Board (PSSDB) System applied as flooring, walling and roofing units in buildings are covered. The paper also highlights applications of the PSSDB system in real projects.

Biography:

Jie Liu is a PhD candidate in Southeast University, Nanjing, China, and his research topic is fatigue reinforcement of steel bridges by FRP. Based on his research topic, he made a series of related experiments and field strain measurement of Orthotropic Steel Decks and achieved several test results

Abstract:

The progressive fatigue damage is a common problem for civil infrastructures, such as steel and composite bridges. Under the low-amplitude but repetitive loading, fatigue cracking may often develop in welded bridge decks, resulting in severe damage and considerable maintenance or repair costs. During the past decades, various fatigue repair methods have been proposed and implemented, including the hole drilling, grinding, rewelding, welded steel plates and post-weld treatments.

This paper presents the fatigue test results of seven welded orthotropic bridge decks under pure bending, five of which were strengthened by using the externally bonded fiber reinforced polymer (FPR), as shown in Figures 1. The influence of different materials of FRP, i.e. glass fiber reinforced polymer (GFRP) and carbon fiber reinforced polymer (CFRP), different adhesives, i.e. epoxy resin (ER) and acrylates (AC), and different dimensions of the angles, on the fatigue life of strengthened decks are experimentally investigated.

According to the stress measurements and fatigue life testing, the externally bonded FRP angles can significantly elongate the fatigue lives, and longest one may be up to 4.2 times that of the original life. In all tests of strengthened decks, cracks initiated from the deck-FRP interface, resulting in the debonding of the angle, as shown in Figure 3, followed by the final failure of the decks. Under the same circumstances, the AC adhesive is found to be more appropriate than the ER due to its longer fatigue life and easier construction. Based on the presented work, suggestions for the design of fatigue strengthening of orthotropic bridge decks are given.

Biography:

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