Biography:

Tadeh Zirakian is an Assistant Professor in the Department of Civil Engineering and Construction Management at California State University, Northridge. He received his PhD in Civil Engineering from the University of California, Los Angeles in 2013. He has been lecturing at various institutions and universities within and outside of the United States. He has authored/co-authored numerous papers published and presented in prestigious engineering journals and conferences. In addition, he is a registered Professional Engineer (PE) in the State of California in USA and serves as an Editorial Board Member for the Journal of Steel Structures & Construction.

Abstract:

Stability and performance of steel plates are characterized by geometrical buckling and material yielding. In this paper, the geometrical buckling and material yielding behaviors of low yield point (LYP) steel plates are studied from the point of view of their application in steel plate shear wall (SPSW) systems. Use of LYP steel facilitates the design and application of web plates with improved buckling and energy absorption capacities in SPSW systems. LYP steel infill plates may yield first and then undergo inelastic buckling. Hence, accurate determination of the limiting plate thickness corresponding to simultaneous buckling and yielding can be effective in seismic design of such lateral force-resisting and energy dissipating systems. The limiting thicknesses of plates with different loading and support conditions are determined theoretically and verified through detailed numerical simulations. Effects of use of LYP steel and plate aspect ratio parameter on the limiting plate thickness are investigated as well. In addition, detailed studies are performed on determination of the limiting web-plate thickness in code-designed SPSWs. Some practical recommendations are accordingly provided for efficient seismic design of SPSW systems with LYP steel infill plates.

Biography:

T. Ito has completed his Dr. Eng. at the age of 27 years from The University of Tokyo on 2004. He was assistant professor on The University of Tokyo during 2004-2008, and he is now associate professor on Tokyo Univerisity of Science (TUS). He was a chair, secretariat and member of many research committee on Architectural Institute of Japan. He has already submitted a lot of paper related to structural engineering, and participated the international conference as oral presenter or organized session chair.

Abstract:

Recently, a lot of building structures have been experienced severe natural disasters, and it was reported that various types of terrible collapse mode were occurred. And also, there are many discussions about repairability and recovery on damaged buildings over the world. In particular, there has been focused on new keyword “Resilience” in any field including structural engineering. In Japan, a technical guideline for repairing damaged buildings have been established. However, the applicability and feasibility of repair method and recovery has not been well reported. Herein, to investigate the recovery and ultimate seismic state of repaired steel framed structures, experimental and analytical studies are conducted. Herein, the actual repairing technique for steel framed structure is suggested. During experimental study, the damaged steel member is reproduced by loading tests with consideration of past reports of mega-earthquake disasters. The next, the damaged portion is repaired by proposed method by use of steel-cover plate technique. After this repair process, the loading test is done again. And the recovery of structural performance is estimated by comparison of original and repaired state. From the test results, it is confirmed that the strength and ductility are improved after repair. Furthermore, the analytical model and restoring force characteristics of repaired steel member are suggested by observation of ultimate behavior during loading test. Here, the purpose on seismic design is to guarantee the overall failure mode formation on frames. So, the structural demand of strength and rigidity and column-to-beam strength ratio on repaired state are discussing analytically.

Biography:

Agnes Kelm is in addition to her work as a research assistant at the Teaching & Research Area Construction Management and Construction Industry at the University of Wuppertal project manager in research projects with research funders from industry and the public sector. The research interests include the topics of automation and digitalization of construction-related processes by AutoID technologies, the use of AutoID technologies in occupational safety and the process-oriented design, construction and FM with BIM. She is am member of DIN Working Group on RFID and PSA and the working group BIM data management of VDI. 2007 she has successfully finished the study of electrical engineering with the focus on Mobile Communication, Multimedia Technology and System and Control.

Abstract:

Despite a slight decrease of the number of accidents at work on German construction sites in recent years, prevention activities should be strengthened and started explicitly in addition. In particular, a large number of accidents on construction sites are carried out by the collision of different trades and missing appropriate PPE for workers of adjacent trades. An important potential is seen in the optimization of the safety and health by making available pre-defined information about safety and health throughout the life cycle of buildings. Using this information, preventive measures can be taken faster, more effective, safer and preventive. The method of Building Information Modelling (BIM) forms the basis for a comprehensive building information model or building data model. The definition of national and international standards for enterprise-wide use of BIM method is currently under development. In addition to technical standards, depth of information and information content needs to be redefined. From the perspective of the applicant the method of BIM in conjunction with the Auto-ID-based tracking of actual process data, however, provides additional data to planning data among other OSH-related processes. This data can be used for the further phases of the life cycle of buildings, that is in the building phase, the use phase and rebuilding phase and the decommissioning phase considerable potential, especially for the optimization of occupational safety and health. The primary objective of this research project is to identify, define and standardize health and safety information and provide them for preventive measures with the BIM method.

Biography:

Dr. Hantouche’s research focuses on structural resistance to extreme loads, particularly Earthquake and Fire. He has experience in the analysis and design of both steel and concrete structures and has worked on projects related to building frames and bridges. His research has both computational and experimental aspects and is focused on the development of improved design standards for structural resistance to extreme loads. His work has been published in prestigious international journals and has been presented at conferences in the U.S., Canada, Europe, and Asia.

Abstract:

The finite element (FE) simulations and the experimental results are used to develop a mechanical model to predict the beam axial force-temperature and rotation of top and seat angle connections with and without web angles when exposed to elevated temperatures. First, FE models are developed and validated against experimental results available in the literature at elevated temperature. Second, FE models are developed to conduct an extensive parametric study to investigate some major geometric parameters such as load ratio, beam length, angle thickness, gap distance, that impact the behavior of these connections when exposed to fire. Third, a mechanical model, that considers the major geometric and material properties, is developed to predict the thermal axial force and rotation response. The mechanical model consists of multi-linear and nonlinear springs that predict each component stiffness, strength, and rotation. The beam stiffness is included in the proposed model to predict beam-column connection assembly rotation and thermal axial forces and their effect on the connection response. The proposed model provides important insights into fire-induced thermal forces and deformations and their implications on the design of steel bolted top and seat angle connections with and without web angles under fire.

Biography:

Abstract:

As the threat of terrorist attacks or explosive accidents increases, interest in designing and construction of blast resistant structures has increased. Recently, the blast reinforcement for existing buildings which were not designed to resist blast loading has been issued, and the demands for blast protective materials are continually growing. In this study, a new blast resistant panel consisting of top and bottom steel plates with infilled nano-composite was proposed and blast resistant performance of the composite panels was investigated using explicit dynamic finite element analysis program, LS-DYNA. Since blast loading causes dynamic response of the structure, dynamic properties of the materials used in the analysis are required to conduct the blast analysis. Johnson-Cook constitutive models were introduced to simulate the dynamic response of the steel plates, and the results of several uniaxial tension experiments were used to determine the dynamic properties of nano-composite. Variables of the analysis are the thickness of steel plates and nano-composite. From the analysis result, the effect of the thickness of steel plates and nano-composite for blast resistance was verified, and a method for assessing the blast resistance of the composite panels was derived.

Biography:

Yong jae Lee is a candidate for PhD in Korea University. He did research in the diagrid node experiments and analysis from 2010 to 2012. He has studied the seismic performance evaluation of the diagrid structure. His research topic is modified IDA method used by various earthquake data

Abstract:

As the number of the high-rise buildings increase, it shows new trends such as freeform shape (twisted, tapered, tilted). As a structural solution for the new trend buildings, the diagrid structural system was developed that are used in high-rise buildings. Diagrid structural system consist of brace and beam member without vertical columns. So, diagrid structural system is more safety from progressive collapse. When the structure member has damaged, brace-beam structure is more easy to load-transfer than column-beam structure. But it is required to be reviewed for stability of lateral loads, such as wind loads and seismic loads, because it is difficult to investigate the load transfer mechanism of the diagrid nodes due to their combination of various structural members. Because of these problems, FEMA (Federal Emergency Management Agency), proposed to carry out seismic performance evaluation through the IDA (Incremental Dynamic Analysis) for structures such as the diagrid structure. The FEMA P695 method has suggested a 22 earthquake data for performing an IDA. These data are corresponding to the earthquake ground motions in high seismicity regions. However, in the case of low-to moderate seismicity region such as Korea, the effective ground acceleration(s) is under 0.2 g. According to the effective ground acceleration, the Korea region is represented in a low-to-moderate seismicity region. Therefore, the seismic performance evaluation from FEMA method were over-designed. In this paper, the seismic performance of the diagrid structures was evaluated by IDA. IDA was used for 12 earthquake data in a low-to-moderate seismicity region.

Biography:

WonHo Lee has completed his Master’s degree at the age of 24 years from Korea Advanced Institute of Science and Technology. At present WonHo Lee is a PhD program student at civil and environmental engineering department of Korea Advanced Institute of Science and Technology.

Abstract:

The analysis and design of a reinforced concrete (RC) structures are generally conducted based on the complete structures. However, the construction of a RC structure is accomplished through a sequential construction, and the change in the structural system during each construction step causes remarkable differences in the structural behavior. This research deals with rigorous analysis of RC frame structures and prediction of exact structural response during the construction.. Time-dependent deformations of concrete such as creep and shrinkage are taken into consideration and the construction sequences are described. The stiffness matrix of a beam element is derived on the basis of the layer approach, dividing a section with imaginary layers, and the iteration method adopted for structure analysis is the combined method. Creep and shrinkage strains at each layer are calculated by using the first order algorithm based on the expansion of creep compliance. Correlation studies with the numerical analysis results of low-rise, medium-rise, and high-rise RC frame structures are conducted to assess the differences in structural responses according to the construction sequences and profile of the structure.

Biography:

Ju-young Hwang has completed his bachelor’s degree in civil and environmental engineering from Korea Advanced Institute of Science and Technology (KAIST). He is doctoral candidate at Structural Design Laboratory in KAIST.

Abstract:

CFT column has a lot of structural advantages due to the composite behavior between in-filled concrete and steel tube. This paper deals with the resistance capacity of CFT columns by numerical method with developed bond-slip model between in-filled concrete and steel tube which can simulate the behavior of CFT without changing mechanical properties. Since the applied axial load to in-filled concrete is delivered to steel tube by the confinement effect and the friction, the governing equation related to the slip behavior can be constructed on the basis of the force equilibrium and the compatibility conditions. Developed model is described behavior of CFT to take into account this effect of bond-slip to calculate confinement effect of in-filled concrete by steel tube. Correlation studies between numerical results and experimental data are conducted to verifying the efficiency of the introduced numerical model and evaluation of resistance capacity for various types of CFT columns are conducted.

Biography:

Sana El Kalash completed her ME degree in Structural Engineering at the American University of Beirut (AUB) and is currently a PhD candidate at AUB. Her research focuses on experimental and analytical studies of steel connections resistance and demand under extreme loads, particularly Earthquake and Fire.

Abstract:

The finite element (FE) simulations and the experimental results are used to develop a mechanical model to predict the beam axial force-temperature and rotation of top and seat angle connections with and without web angles when exposed to elevated temperatures. First, FE models are developed and validated against experimental results available in the literature at elevated temperature. Second, FE models are developed to conduct an extensive parametric study to investigate some major geometric parameters such as load ratio, beam length, angle thickness, gap distance, that impact the behavior of these connections when exposed to fire. Third, a mechanical model, that considers the major geometric and material properties, is developed to predict the thermal axial force and rotation response. The mechanical model consists of multi-linear and nonlinear springs that predict each component stiffness, strength, and rotation. The beam stiffness is included in the proposed model to predict beam-column connection assembly rotation and thermal axial forces and their effect on the connection response. The proposed model provides important insights into fire-induced thermal forces and deformations and their implications on the design of steel bolted top and seat angle connections with and without web angles under fire.

Biography:

Mehmet Fatih Yılmaz is Phd candidate student at Istanbul Technical Univercity. He is resaearch assistent at Istanbul Technical University and Supervising graduation projects of students. He has 2 year design engineering experiance and design large steel and concreate buildings and manage design team. He is researcher at the on going project “ The development of effective and appropriate method for probabilistic seismis assessment of existing railway bridge in Turkey. [(114M332 TUBITAK)- Turkish Science Foundation Project ($300,000/3year)]

Abstract:

There are various approaches and engineering practices to constitute lateral stability against the lateral loads in steel structures. Braced members are one of the widely used approaches and practices. They are used to increase the structural capacity under earthquake effects. Structural capacity of the buildings with braced members is higher than the capacity of conventional steel structures. Concentric and eccentric ones are available for steel structures. Concentrically braced members are most common structural systems using to restrain lateral displacement and constituted lateral rigidity. With development of computer technology, more complex analyses become possible and popular for braced members. Now, various approaches are available to calculate the capacity of the braced members. These approaches are as Finite Element and Physical Theory Methods. Recently, Finite Element Method becomes popular in structural design in many cases despite the fact that it’s computationally complexity. Physical Theory method based on fundamental structural behavior, provides a balance of efficiency and accuracy. Force Analog and Sliding Hinge Methods are the most common ones in Physical Theory Method for determining capacities of braced members. In this study, Finite Element Method and Physical Theory Method as Force Analog Method and Sliding Hinge Method will be considered to calculate the capacity of concentrically braced members. Also design capacities will be calculated based on the valid design codes and specifications. The ultimate capacities, calculated with these methods are compared with each other. Calculated design capacities are compared with ultimate capacities; hence, security coefficient that the specification provides will be evaluated.