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    <title>Research in Progress (RIP)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Research in Progress (RIP)</title>
      <url>https://rip.trb.org/Images/PageHeader-wTitle-RIP.jpg</url>
      <link>https://rip.trb.org/</link>
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    <item>
      <title>Anchorage Design and Detailing for Fabric-Reinforced Cementitious Matrix Retrofits of Transportation Concrete Structures</title>
      <link>https://rip.trb.org/View/2691724</link>
      <description><![CDATA[The repair and rehabilitation of transportation structures is urgently needed to restore structural capacity, slow deterioration caused by aging, overloading, and environmental stressors, and minimize disruptions associated with large-scale replacement projects. State DOTs and the Federal Highway Administration (FHWA) have implemented several advanced rehabilitation techniques, including fiber-reinforced polymer (FRP) composites, ultra-high-performance concrete, and fiber-reinforced cementitious matrix (FRCM) systems. FRCM consists of an open-grid textile made of FRP or steel strands embedded within an inorganic cementitious matrix. The system offers multiple advantages over traditional FRP, including mechanical compatibility with concrete and masonry substrates, improved fire and elevated-temperature performance, vapor permeability, durability in moist or cold environments, and ease of application in field conditions.

As an externally bonded strengthening system, the performance of FRCM is governed by the ability of the FRCM–substrate interface to maintain composite action and to transfer forces effectively. Premature interfacial slip, end debonding, or localized interface damage are commonly reported for unanchored FRCM systems. These brittle failure modes often occur at loads far below the tensile capacity of the textile, limiting the effectiveness of the strengthening system to 30–60% of its potential and undermining both safety and return on investment. Introducing anchorage mechanisms into FRCM systems provides an engineered means to restrain interfacial slip, delay debonding, promote more favorable failure modes, and enable the textile to mobilize higher tensile strains. However, the existing literature on FRCM anchorage is sparse, fragmented, and lacking in unified, design-oriented guidance. Quantitative provisions addressing anchor geometry, capacity, and interaction with the primary FRCM reinforcement remain absent from current codes and standards.

The primary objective of this research is to advance the understanding, design, and implementation of anchorage systems for FRCM-strengthened concrete members, with the goal of mitigating premature debonding and achieving ductile, and efficient strengthening outcomes. Specifically, the project aims to: (a) synthesize and critically evaluate the current state of knowledge on FRCM anchorage; (b) develop and experimentally validate practical anchorage systems including transverse wraps, mechanical anchors, and spike anchors; and (c) produce a design-oriented framework for selecting, proportioning, and detailing anchorage systems.

Two coordinated experimental programs are proposed: (1) bond-level tests to characterize the effects of anchorage presence and type on joint force transfer, slip response, and failure mechanisms; and (2) flexural tests on reinforced concrete beams strengthened with anchored and unanchored FRCM reinforcement, to evaluate the translation of bond-level behavior to member-level performance and to verify design expressions under combined shear and normal stresses. The proposed research will equip state DOTs with validated anchorage solutions, support cost-effective preservation strategies, and accelerate the adoption of durable composite materials for extending the service life of transportation infrastructure.]]></description>
      <pubDate>Sun, 12 Apr 2026 23:52:50 GMT</pubDate>
      <guid>https://rip.trb.org/View/2691724</guid>
    </item>
    <item>
      <title>Examining the Potential of Thermoplastic FRP Tapes Inside Highly Exothermic Overlays as a New Material for Rapid Bridge Deck Protection</title>
      <link>https://rip.trb.org/View/2633313</link>
      <description><![CDATA[Some scenarios for concrete bridge deck repair involve inadequate bond between overlay and bridge deck leading to various distresses, including slippage, delamination, longitudinal joints failure, fatigue cracking, and rutting. Inadequate bond does not allow the cross-section act as a single monolithic unit. This is detrimental to structural integrity and causes major problems associated with bridge deck failures. Detecting and repairing this damage is often costly and time-consuming due to the inaccessibility of the underlying concrete for direct inspection. To maintain durability over its design life, special attention should be given to the protection of bridge decks to prevent serious damage to the concrete and structural reinforcement. It is of vital importance to develop solutions and investigate alternatives that can not only improve adhesion between overlay and underlying concrete decks and maintain the necessary strength requirements but also reduce maintenance cost throughout its service lifetime.]]></description>
      <pubDate>Tue, 02 Dec 2025 16:11:37 GMT</pubDate>
      <guid>https://rip.trb.org/View/2633313</guid>
    </item>
    <item>
      <title>Strengthening Piers to Resist Vehicular Collision</title>
      <link>https://rip.trb.org/View/2317394</link>
      <description><![CDATA[The need to strengthen existing piers to resist collision forces is being encountered frequently in multiple Florida Department of Transportation (FDOT) districts and a better understanding of strengthening methods with concrete collars, ultra-high performance concrete (UHPC) collars, FRPs or other optimized methods would make those repairs more cost efficient. This project will be a synthesis study of previously completed research with analysis performed to develop design details for strengthening with conventional concrete, UHPC, and CFRP wrap. Finite element methods for evaluating damage to bridge piers with applied impact load are well documented in the literature and can be followed to complete analysis for the three aforementioned repair strategies. The research shall include an appropriate baseline case for comparison. Areas where further research is required to develop design procedures and construction details will be identified.]]></description>
      <pubDate>Mon, 03 Jun 2024 15:02:47 GMT</pubDate>
      <guid>https://rip.trb.org/View/2317394</guid>
    </item>
    <item>
      <title>Determining the Effect of Changing Relative Area on the Galvanic Corrosion Rate of Contacting Dissimilar Metals/Materials</title>
      <link>https://rip.trb.org/View/2335372</link>
      <description><![CDATA[The research objectives are to: (1) Conduct accelerated laboratory testing to predict the impact of changing the relative surface area on the corrosion behavior of contacting dissimilar materials under conditions commonly experienced in Florida Department of Transportation (FDOT) concrete bridge structures (focus on steel/stainless steel, CFRP/stainless steel). (2) Provide specific recommendations for inclusion in the Standard Specifications and Structures Design Guidelines on acceptable quantities/ratios of each material that can be placed in electrical contact with each other as reinforcement in a concrete bridge. (3) Review limitation in the FDOT Structures Design Guidelines on using CFRP and Stainless-Steel in the same element for a target service life of 75 to 100 years.]]></description>
      <pubDate>Mon, 03 Jun 2024 14:58:31 GMT</pubDate>
      <guid>https://rip.trb.org/View/2335372</guid>
    </item>
    <item>
      <title>Evaluation of GFRP Spirals in Corrosion Resistant Concrete Piles</title>
      <link>https://rip.trb.org/View/2250474</link>
      <description><![CDATA[This project will: (1) develop impactor and test setup for pile driving simulation to extend the capabilities of the Florida Department of Transportation (FDOT) Structures Research Center Pendulum; (2) experimentally evaluate the response of CFRP, GFRP and steel ties under impact loading and bending; (3) experimentally evaluate the confinement behavior at a pile cut-off location; (4) develop analytical and numerical models to explain the observed behavior, to provide guidelines for piles that are not experimentally tested; and (5) design GFRP or GFRP/CFRP hybrid ties that meet the loading requirements.]]></description>
      <pubDate>Tue, 19 Sep 2023 07:48:52 GMT</pubDate>
      <guid>https://rip.trb.org/View/2250474</guid>
    </item>
    <item>
      <title>Steel-Free Concrete Bridge Decks (3.18)</title>
      <link>https://rip.trb.org/View/1994581</link>
      <description><![CDATA[In order to realize a potentially transformational improvement in concrete bridge deck durability, the proposed research program intends to validate a deck design by which little to no conventional reinforcement is required. The design relies on the development of so-called arching action to maintain compressive stresses in the concrete thereby minimizing the risk of cracks that adversely affect long term durability. The project will move the technology forward by both validating the structural parameters by which the arching action is invoked, and by developing a suitable concrete mix reinforced with small non-metallic fibers that will meet the structural and long-term durability requirements. The outcome of the project will be a set of guidelines by which a field demonstration project can be developed.]]></description>
      <pubDate>Fri, 15 Jul 2022 15:21:29 GMT</pubDate>
      <guid>https://rip.trb.org/View/1994581</guid>
    </item>
    <item>
      <title>Design of Anchors for Rapid and Durable Strengthening of Bridges with Externally Bonded Carbon Fiber Reinforced Polymer Composites—Phase 2</title>
      <link>https://rip.trb.org/View/1907230</link>
      <description><![CDATA[The beams tested in Phase 1 had sufficient steel stirrup shear reinforcement, which allowed the research team to evaluate the effectiveness of U-wraps in anchoring the longitudinal CFRP reinforcement. However, in practice, an RC beam deficient in flexure may also be deficient in shear, requiring both vertical (shear) and longitudinal (flexural) CFRP reinforcement. Due to the lack of experimental data, the current ACI 440.2R design guidelines do not permit to count on shear U-wrap reinforcement to provide anchorage for the longitudinal CFRP. Thus, the specific objectives of the proposed research program are to determine how effective U-wraps are in:
i. enhancing the shear capacity of shear-deficient RC beams, AND
ii. increasing strain utilization of longitudinal CFRP reinforcement in shear-deficient RC beams.
The primary expected outcome of this work will be more economical FRP strengthening. This will be accomplished by allowing the designer to limit the required area of longitudinal CFRP reinforcement through improved strain utilization (provided by the U-wrap anchorage) while, the same time, being able to consider U-wrap anchors as shear reinforcement.
]]></description>
      <pubDate>Tue, 01 Feb 2022 16:08:41 GMT</pubDate>
      <guid>https://rip.trb.org/View/1907230</guid>
    </item>
    <item>
      <title>Low-Cost Sustainable Engineered Geopolymer Composites (EGCs) for Repair and New Construction of Transportation</title>
      <link>https://rip.trb.org/View/1904905</link>
      <description><![CDATA[Engineered Geopolymer Composites (EGCs) are ductile strain-hardening geopolymer (GP)
based materials that have been recently introduced as an eco-friendly and sustainable
alternative to Engineered Cementitious Composites (ECCs). While EGCs exhibit mechanical
properties exceedingly superior to those of conventional Portland cement concrete (PCC), mass
adoption of these emerging composites is expected to be hindered by their cost, which is mainly
driven by the use PVA reinforcing fibers, silica fume, and manufactured microsilica sand. To
address this key shortcoming, the multidisciplinary team form Louisiana State University and
Texas A&M university will develop and characterize novel low-cost EGC materials for repair and
new construction of transportation infrastructure in Region 6 by evaluating the use of: (1)
calcined clays and fly ash as replacements of commonly used silica fume for GP binders; (2)
low-cost PP fiber, PVA fiber, and hybrid systems of PP and PVA fiber; and (3) natural sand
instead of commonly used manufactured microsilica sand. To achieve this objective, several GP
matrices, and fiber-reinforced GP composites will be developed and comprehensively studied to
identify fundamental relationships between materials composition, properties, and
microstructure. In turn, this will allow for rational material design and optimization.]]></description>
      <pubDate>Thu, 20 Jan 2022 14:56:02 GMT</pubDate>
      <guid>https://rip.trb.org/View/1904905</guid>
    </item>
    <item>
      <title>Multifunctional Composite Sensors for Sustainable Infrastructure Systems</title>
      <link>https://rip.trb.org/View/1482482</link>
      <description><![CDATA[To enhance longevity and structural performance, next generation infrastructure systems must integrate high performance material and structural systems that are durable and safe, and health monitoring systems that can obtain real-time data on the condition of structures and timely detect anomalies in the structural performance. Multifunctional composites that are intrinsically smart and durable can avoid deployment of two separate systems (high performance structural systems and health monitoring systems) to achieve this goal. This project will explore the design, fabrication, and implementation of multifunctional cementitious and polymer composites. The proposed multifunctional composites will exploit intrinsic smart properties of shape memory alloy (SMA) fibers. SMAs are a class of metallic alloys that have unique properties such as high strength, large deformation capability, good ductility and damping capacity, long fatigue life, large electrical resistivity and excellent re-centering ability. Using a multiscale micromechanics-based design approach that has been successfully employed in development of various high performance fiber reinforced cementitious composites, the development of SMA-based multifunctional cementitious composites will be explored to simultaneously achieve strain hardening, self-centering, crack width control, high energy absorption and self-monitoring abilities in a single cementitious composite material. In addition, the use of SMA fibers in a thermoset epoxy matrix and shape memory polymer matrix will be investigated.]]></description>
      <pubDate>Mon, 11 Sep 2017 16:42:17 GMT</pubDate>
      <guid>https://rip.trb.org/View/1482482</guid>
    </item>
    <item>
      <title>Development and Seismic Evaluation of Pier Systems with Pocket Connections and Hollow PT/UHPC Column</title>
      <link>https://rip.trb.org/View/1398654</link>
      <description><![CDATA[Research over the past half a decade has focused on various earthquake-resistant accelerated bridge construction (ABC) connections. The focus of this study is on pocket connections because they have shown promising results while not violating the current seismic codes. Seismic performance of precast columns that are prestressed with unbonded carbon fiber reinforced polymer (CFRP) tendons and connected to the footings and the cap beams using pocket connections is experimentally investigated. Two single columns and one two-column bent will be designed and tested on one of the University of Nevada, Reno (UNR) shake tables. Advanced materials, engineered cementitious composite (ECC) and ultra-high performance concrete (UHPC), will be incorporated in plastic hinge of columns to improve seismic performance.]]></description>
      <pubDate>Mon, 22 Feb 2016 15:45:07 GMT</pubDate>
      <guid>https://rip.trb.org/View/1398654</guid>
    </item>
    <item>
      <title>Design, Construction, Laboratory and Field Testing of the Bridge on the Arnault Branch, Washington County, Missouri</title>
      <link>https://rip.trb.org/View/1231034</link>
      <description><![CDATA[Two innovative FRP technologies will be employed for the rapid and effective replacement of different portions of the structure with a safer and more functional slab type bridge. The design strategies consist of a) helicoidal FRP helixes integrated with longitudinal FRP rebars as slab reinforcement, and b) prefabricated pultruded FRP panels as stay-in-place (SIP) formwork and structural reinforcement.]]></description>
      <pubDate>Thu, 03 Jan 2013 14:10:52 GMT</pubDate>
      <guid>https://rip.trb.org/View/1231034</guid>
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