Constitutive Behavior

Mesoscale Design Theory and Innovative Structural System of UHPC Bridges

---

Abstract

The comprehensive studies from materials properties to structural innovations have been conducted aiming at combining the fundamental theory and structural analysis and applications using ultra high-performance concrete (UHPC). Firstly, experimental and theoretical investigations on fiber-UHPC interfacial behavior were performed and two new indices were proposed to evaluate the fiber-matrix interfacial bond behavior from the structural perspective. A mesoscale constitutive model was then proposed, taking into account uniform distribution, embedment length, and orientation of fibers for the multi-scale mechanics analysis. A theoretical method, termed the mesoscale fiber-matrix discrete model (MFDM), was developed to calculate the shear strength of UHPC beams based on the concept of effective fiber distributed region where fibers were efficient at providing shear resistance. The proposed MFDM offered an alternative perspective in understanding the shear behavior of UHPC beams, especially the shear resistance of fibers at a mesoscale level. On the basis of modeling and design methods, five different types of high-performance structural systems for bridges were proposed utilizing UHPC and other innovative construction materials. The structural systems cover various applications including the large stud-UHPC composite structure, light-weight FRP truss-UHPC bridge decks, self-centering precast segmental bridge columns, precast segmental box-girder with large shear key connection. Lastly, some practical engineering applications in China are presented including Vanke pedestrian bridge (the first precast segmental UHPC Arch Bridge in China) and Nanjing 5th Yangtze River Bridge engineering in which the proposed design theory and structural systems were applied

Keywords: mesocale design theory, large studs, FRP truss-UHPC bridge decks, self-centering, precast segmental bridge columns, large shear key connection, composite structure, UHPC

How to Cite:

Wang, J., Yao, Y., Qi, J., Feng, Y., Hu, Y. & Xu, Q., (2019) “Mesoscale Design Theory and Innovative Structural System of UHPC Bridges”, International Interactive Symposium on Ultra-High Performance Concrete 2(1). doi: https://doi.org/10.21838/uhpc.9730