Day 1 :
Concordia University, Canada
Time : 15:45-16:15
Lan 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 bridges. She is a licensed engineer registered in the province of Ontario, Canada. She has received two teaching excellence award from Concordia University.
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, 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 accelerograms 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 a time-history analysis of bridges in eastern Canada.
Director, INSPIRE University Transportation Center at Missouri University of Science and Technology, USA
Time : 9:30-10:00
Dr. Chen received his PhD in 1992 from Civil Engineering at State University of New York at Buffalo. He is Professor and Abbett Distinguished Chair in Civil Engineering, and Director of the federal-funded INSPIRE University Transportation Center at Missouri University of Science and Technology. He has published more than 150 papers in reputed journals in the field of structural health monitoring, structural control, and multi-hazard assessment and mitigation. He has been serving as an associate editor of the Journal of Civil Structural Health Monitoring, an section editor of Sensor, and an editorial board member of 5 reputed journals.
Traditionally, strain data are difficult, if not impossible, to obtain from steel structures in fire due to their harsh environment and temperature measurements are limited to the locations of thermocouples. This paper presents high temperature measurements using a Brillouin scattering based (distributed) fiber optic sensor and the application of the measured temperatures and material parameters recommended in building codes into the enhanced thermo-mechanical analysis of simply-supported steel beams subjected to combined thermal and loading effects. The distributed temperature sensor captures detailed, non-uniform temperature distributions that are compared locally with thermocouple measurements by less than 5% at 95% confidence level. The simulated strains and deflections are validated using measurements from a second distributed fiber optic (strain) sensor and two linear potentiometers, respectively. The results demonstrate that the temperature-dependent material properties specified in the four investigated building codes lead to strain predictions with less than 13% average error at 95% confidence level, and that the EN1993-1-2 building code provided the best predictions. However, the implicit consideration of creep in the EN1993-1-2 is adequate up to 600°C. More recently, the distributed sensing technology for temperature and strain measurements was applied into small- and large-scale composite floor specimens of a reinforced concrete slab on one or two I-shaped steel beams. The temperature measurements in the reinforced concrete slab were compared with those from limited thermocouples. This paper completes with an experimental investigation on the potential change in neutral axis of the concrete-steel composite section at elevated temperature.
Construction Engineering Technology
University of North Texas, USA
Cheng Yu is a professor in the Construction Engineering Technology program at the University of North Texas. He completed his Ph.D. in Civil Engineering from the Johns Hopkins University. He is the author of a number of articles on cold-formed steel behavior and design and serves on the AISI Committee on Specification and Framing Standards
Recent researches have proved cold-formed steel shear wall with corrugated steel sheathing a promising lateral force resisting system for buildings in high wind and seismic zones. Extensive experimental investigations, including monotonic and cyclic tests on cold-formed steel shear walls with corrugated steel sheathing, were recently completed at University of North Texas. This paper summarizes recent research results on the new shear wall system including experimental and finite element analysis on shear strength and collapse probability analysis on seismic performance. Recommended shear resistance of the corrugated steel sheathing shear walls under wind load and seismic load was given in tabular form. A closed-form approach for calculating the story drift was developed. A set of seismic performance factors were proposed based on a compressive incremental dynamic analysis on six building archetypes.
Director of Research & Development, SidePlate Systems, Inc. USA
Dr Behzad Rafezy, PhD, PE is the director of Research and Development Department at SidePlate Systems, Inc. an Innovative Steel Connection Design Company. Dr Rafezy has more than 20 years of combined industrial and academic experience in structural engineering. Prior to SidePlate, Dr Rafezy held the position of visiting professor of Structural Engineering at UCLA, Lecture at Cardiff University, UK and the Associate Professor of Structural Engineering at Sahand University of Technology where he led research at all levels from MSc, through PhD to nationally sponsored research. Dr Rafezy has authored and co-authored over 70 peer-reviewed research papers and multiple patents. As a structural engineer, Dr Rafezy had the privilege of working for more than 15 years as a lead structural designer and consulting engineer on over 100 steel and concrete projects, covering commercial, residential and industrial projects.
An innovative special moment frame connection using the SidePlate moment connection technology was developed and tested at the Powel Laboratories at the University of California, San Diego (UCSD). This connection uses two interconnecting parallel plates that sandwich and connect the beam(s) to the column and features a physical separation, or gap, between the face of the column flange and the end of the beam, as shown in Figure 1. The load is transferred from the beam to the column through a series of connecting plates and angles all of which are welded in the shop and then bolted in the field. The tested connections comprised of Wide-flange, Built-up Box and HSS (Tube) Columns and rolled and built-up wide-flange beams with three different configurations, namely Standard, Narrow and Tuck. The test specimens were loaded in a displacement control mode using hydraulic actuators in accordance with the Chapter K of the AISC 341-16, Seismic Provisions for Structural Steel Buildings. Tested connections exhibited predictable, ductile behavior and met the established AISC’s requirements for special moment frame (SMF) connections with average 50% additional deformation capacity.
The following techniques were employed and lessons were learned in the development of the connection and the successful conduction of the tests:
1. The panel zone regions are substantially strengthened to force plastic hinging into the beam.
2. The additional side plate extensions cause the beam to hinge further out from the column face, which acts to effectively dissipate more energy without increasing the beam size.
3. The configuration requires only welds parallel to the direction of load providing maximum possible ductility in the welds.
4. Substantial finite element analyses were conducted to optimize weld hold-backs and weld-end profiles to reduce stress concentration at the points of load transfer from the beam to the connection. This results in a balanced and smooth load transfer according to the test results.
5. Only fillet welds are used in the configuration, ensuring that there is no notch effect in the root of the welds.
6. Every detail in every part of the connection was thoroughly studied to make sure that there is neither a high triaxial stress state nor notch effects.
Thorough finite element analysis is conducted if there are any changes or new features to the specification/construction of the connection.