Day :
- Structures | Construction Engineering and Management | Earthquake Resistance Design | Reinforced Concrete Structures | Construction | Seismic Performance of Concrete Buildings
Session Introduction
Jing Zhang
Hefei University of Technology, China
Title: Experimental study of demountable shear connectors for composite bridge decks with corrugated steel sheets
Biography:
Jing Zhang has completed her PhD at the age of 30 years from the University of Hong Kong. Now she is an associate professor at the Hefei University of Technology. She has published more than 8 papers in reputed journals and has been serving as the reviewer of several journals
Abstract:
In order to overcome the shortcoming of insufficient shear resistance of traditional concrete bridge decks, a new composite bridge deck formed by corrugated steel sheets and concrete is introduced. Taking the corrugated steel sheets as the baseplate of the concrete, a group of demountable shear connectors with different stud collar size have been push-out-tested based on Eurocode 4 to assess the potential and suitability in terms of replacing welded shear studs for this innovative composite bridge deck design. The ultimate strength and the load-slip characteristics of the demountable shear connectors are investigated. And the properties of those demountable shear connectors such as shear resistance, stiffness, ductility, and failure modes have been compared with the welded shear studs. Finite element (FE) models of push-out test specimens are developed and validated against experimental results, parametric FE analyses are carried out to elucidate the effect of a change in the concrete grades and stud collar sizes on the shear resistance of demountable shear connections of this innovative composite bridge deck.
Dong Yang
Hefei University of Technology, China
Title: Concrete curing process monitoring using intensity-based plastic optical fiber sensor
Biography:
Plastic optical fiber (POF) sensor has emerged as a potential sensing tool for structural health monitoring. The POF sensor provides a new alternative for monitoring the concrete curing processing since the conventional monitoring techniques have many limitations. This paper briefly presents a sensor fabricating process using a carving machine in order to produce grooves in the POF as sensing elements and also presents a new monitoring technique of concrete curing process based on intensity-based POF sensor. The aim of this technique is to monitor the water presence through the scattering of the propagated signal because the concrete curing is accompanied by water evaporation. In this technique, the POF with grooves was embedded in the concrete. By monitoring the intensity of the transmitted light signal, the cement setting rate along all the curing period can be determined. The experimental results verify the practicality of the POF sensing technique for monitoring the concrete curing process. The proposed POF sensor-based monitoring method has the potential to be applied in curing monitoring of concrete structures at early ages.
Abstract:
Dong Yang has completed his PhD at the age of 30 years from Central South University and postdoctoral studies from National University of Singapore School of Engineering. He is Associate Professor in the Hefei University of Technology now. He has published more than 10 papers in reputed journals.
Xuechun Liu
Beijing University of Technology, China
Title: Tension-bend-shearing performance of bolted-flange connection for square steel tube structural column
Biography:
Xuechun Liu is a vice director of the Beijing Engineering Research Center of High-rise and Large-span Pre-stressed Steel Structures at the Beijing University of Technology. He 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. He has published more than 100 papers in reputed journals and gained more than 100 patents.
Abstract:
The connection between columns in high-rise structures, especially the connection at the top of the high-rise structure, may be subjected to the tension, bending moment and shear force under the combination of vertical and horizontal loads. The bolted-flange connection was used for square steel tube structural column in the high-rise structures. To study its mechanical properties, full-scale model tests and finite element analysis were performed on 10 column-to-column connections with different parameters. The mechanical properties of the specimen under the tension-bending-shear combination were obtained. The influence of the flange thickness, flange size, and bolt hole size on the connection performance was obtained. The flange thickness is the main factor affecting the bearing capacity of the connection. As the thickness increases, the yield mechanism of the connection converts from flange yield to bolt yield, and the bearing capacity gradually increases. The size of the bolt hole and the flange has little influence on the carrying capacity of the connection. The finite element models verified by the experiments were used to study the influence of the axial tension ratio of the column (i.e. the axial tension divided by the production of the sectional area and material design strength of the column) on the bearing capacity of the connection. The increase of the axial tension ratio leads to the increase of the bolt tension, which has an adverse effect on the bolt in the tension zone. Based on the yield line theory, the formula of bearing capacity under the combination of tension, bending moment and shear was deduced, which were verified by the tests and finite element analysis.
Biography:
Biao Hu is currently a research associate fellow in the College of Civil Engineering at Shenzhen University, China. He completed his PhD in 2017 from City University of Hong Kong. His research interests involve concrete structures, structural rehabilitation/strengthening by FRP composites, and steel structures. Dr. Hu is accurately a reviewer for several SCI journals, including Journal of Structural Engineering ASCE, International Journal of Geomechanics ASCE, Materials and Structures, and Thin-walled Structures. Dr. Hu has received the 2018 Moisseiff Award from American Society of Civil Engineers (ASCE).
Abstract:
The externally bonded (EB) fiber reinforced polymer (FRP) strengthening technique has become a popular method for improving the structural performance of infrastructures, in which U-wrapping FRP is one of the most popular choices for shear strengthening of reinforced concrete (RC) beams. However, the debonding of EB-FRP U-strips in shear span is the major failure mode, which results in a fracture failure mode with low efficiency of using FRP material. The paper presents an experimental study to investigate the performance of a hybrid bonding (HB) FRP system with mechanical anchors under different targeted vertical pressure levels for shear strengthening of RC beams. The performance of EB- and HB-FRP strengthened beams was compared in terms of the detailed failure process, failure mode, load-deflection response and strain levels in FRP U-strips. Tests results indicate that, compared with EB-FRP system, HB-FRP strengthened beams showed a larger shear capacity and more effective using of FRP material, and that such superiority will be more significant when increasing the vertical pressure applied on anchors. A modified shear strength model considering the mechanical anchor applied on FRP strips was then proposed.