Ultra-high-performance concrete (UHPC) continues to attract more researchers, engineers, architects, students and experts across disciplines due to its fascinating material properties.
Over the last decades novelties have been shared in material design, mixing technology, material characterization and application, structural performance and design. While more innovations and novelties have been shared and exciting application examples are being presented, more knowledge gaps, research needs and questions have been raised.
This session will invite national and international research groups, material suppliers and contractors to share new insights in UHPC technology, structural design and applications.
(1) Report on structural seismic behavior;
(2) Recognize UHPC's potential in pumping and spraying;
(3) Explain new placement and rehabilitation methods;
(4) Discuss the restoration potential of UHPC.
Seismic Behavior of Structural Systems with Highly Ductile Concrete Materials
Presented By: Matthew James Bandelt
Description: Ultra-high-performance concrete (UHPC) and similar materials with high strength and ductility have been applied in seismic structural applications to improve the strength, damage tolerance, and ductility of individual structural components. Relatively little, however, is known about how the use of these materials improves the response of entire structural systems from seismic ground shaking. This presentation will present ongoing research related to the seismic response of structural systems using highly ductile concrete materials such as UHPC. The behavior and design of various archetype structures using these materials will be presented along with considerations for structural design. Future research directions on developing seismic design criteria for structures utilizing these new materials will be discussed.
Pumping and Spraying Ultra-High Performance Concrete (UHPC)
Presented By: Michael D McDonagh
Description: Ultra-high-performance concrete (UHPC) has been pumped and sprayed in only limited instances to date due to challenges posed by conventional concrete pumps. Conventional concrete pumps heat up the UHPC and make controlling the material workability very difficult. Steelike, Inc. has invented two UHPC mixing, pumping, and spraying machines that solve this problem, expanding the range of applications of UHPC. In addition to solving the problem of overheating, the new systems are portable, easy to clean, include an integrated chiller to eliminate ice, and can be paired with ready-mix trucks for non-stop pumping and spraying. The pumping feature of the two Steelike™ System for UHPC Placement Acceleration (SUPA™) units can be used to eliminate concrete buggies and to get UHPC into hard-to-reach places, such as steel girder end repairs, without having to go through extreme measures to place it by gravity. The spraying feature of the Steelike SUPA™ units makes durable UHPC repairs of vertical and overhead concrete surfaces practical and has unlimited potential for architectural applications. The two Steelike SUPA™ units will be presented as well as early pumping and spraying applications of the machines.
Under Construction Update: Phase 1 - Delaware Memorial Bridge Deck Rehabilitation
Presented By: Gill Brindley
Affiliation: UHPC Solutions North America
Description: During the 2022 ACI Fall Convention, Phase 1 of the Delaware Memorial Bridge Deck Rehabilitation (DMB) will be under active construction. This estimated $70 million project will be the largest Ultra-High-Performance Concrete (UHPC) project in the United States using 4,700 yd3 covering a total of 550,000 ft2 deck area over 4 lanes of traffic with a length of 10,765 ft. The Delaware River Bay Authority (DRBA) awarded this project to UHPC Solutions and specified rehabilitation of Structure 1 to occur in 3 phases during the Fall of 2022, Spring of 2023 and Fall of 2023. This presentation will provide an active status update from the Phase 1 construction site. Project overview, planning details, material selection, project progress, construction methods, equipment selections, early challenges and insights from a contractor’s perspective will be presented. Hydrodemoltion, surface preparation and design details will be discussed. The experiences learned from of this iconic rehabilitation project will shape future US infrastructure projects especially rehabilitation of large suspension bridges.
Innovative UHPC Placement Techniques
Presented By: Michael D McDonagh
Description: Field mixing and placement of ultra-high-performance concrete (UHPC) on bridges with traditional methods and equipment is often a time-consuming process, involving small batch sizes, the transport of fresh material with concrete buggies, top forming and overfilling deck-level UHPC connections, grinding the cured UHPC overfill, and curing UHPC overlays with plastic sheeting. Steelike, Inc., working with contractors on UHPC projects over the past few years, has introduced a number of new techniques that simplify UHPC construction and reduce time and cost, eliminating some or all of the aforementioned steps. Recent projects that incorporated these techniques will be presented, showing how the innovative techniques saved contractors time and money.
Restoration of Post-Tensioned Box-Girder Bridge Decks Using UHPC
Presented By: Sri Sritharan
Affiliation: Iowa State University, Facca Incorporated
Description: Post-tensioned Box Girder (PBG) bridges are frequently used when spans range from 100 to 250 ft, especially in the western US. Due to aging, environmental factors, and increasing traffic load demands, decks of these bridges experience extensive damage. Replacing the deck in PBG bridges is difficult and costly. Using analytical models representing different types of as-built PTBG bridges from California, this presentation will summarize the effects of full and partial deck removal/replacement in these bridges and their short- and long-term behavior. In addition to showing the significant benefits of partial over full deck replacement in terms of limiting the short- and long-term deflections and stresses, the presentation will discuss the benefits of using UHPC for deck rehabilitation in PBG bridges.