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    <title>Research in Progress (RIP)</title>
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    <atom:link href="https://rip.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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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>
    <image>
      <title>Research in Progress (RIP)</title>
      <url>https://rip.trb.org/Images/PageHeader-wTitle-RIP.jpg</url>
      <link>https://rip.trb.org/</link>
    </image>
    <item>
      <title>Evaluation of Concrete Specimens Prepared with Corrosion Resistant Reinforcement After Long Term, Greater than 15 Years, Outdoor and Laboratory Exposures</title>
      <link>https://rip.trb.org/View/2384731</link>
      <description><![CDATA[The purpose of the project is to assess the long-term (>15 years for lab samples) performance of CRRs. The samples that will be evaluated have been exposed to field conditions as well as indoor and outdoor laboratory conditions. Evaluate CRRs to identify which types of materials, exposure conditions, and geometries have shown corrosion initiation. In addition, quantify the extent of the corrosion identified. Obtain chloride profiles from in-service bridges constructed with CRR. The evaluation will include analysis of all available data that has been collected over the lifetime of the samples as well as collecting new data as appropriate.]]></description>
      <pubDate>Mon, 03 Jun 2024 14:22:14 GMT</pubDate>
      <guid>https://rip.trb.org/View/2384731</guid>
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    <item>
      <title>Improved Beam End Reinforcement Details for PCBTs with Debonded and/or Draped Strands</title>
      <link>https://rip.trb.org/View/2087372</link>
      <description><![CDATA[Cracks can form in the end regions of prestressed concrete girders as the force in the prestressing strands transfer to the surrounding concrete as the strands are relased, resulting in tensile forces normal to the direction of the prestressing force. This problem can be more prevalent in deeper members and those with draped or larger diameter strands. VDOT requires that cracks wider than 0.002 inch be repaired. Such repairs necessitate additional time, effort, and money. To counteract these cracks, VDOT implemented the design approach recommended in a 2009 VTRC report. However, the reinforcement details that result from this design lead to congestion, which hinders proper concrete consolidation during fabrication, which, in turn, leads to strength and integrity issues during service. 

Unlike VDOT, other DOTs have wider crack limits, or they permit tendon debonding or splayed draped tendons to mitigate end zone cracking. Alternatively, welded grid reinforcement, consisting of smooth horizontal wire welded to deformed vertical bars, can have shorter development lengths that may allow larger reinforcement stresses and enable less congestion in the end region.
 
This project seeks to develop new standard reinforcement details in the end regions of PCBT beams that reduce the current level of congestion while continuing to prevent cracks in these regions during strand release. The expected details should include  tables and drawings for optimized welded grid reinforcement and/or draped or straight debonded tendons that can be used for design, bidding, and construction for the range of PCBT beams in VDOT’s inventory. Additionally, the research should provide guidance regarding increasing the stress limit for the mild reinforcing within this portion of the girders. These objectives will be achieved through a literature review and DOT survey of current practices, finite element modeling, and small- and large-scale tests.     
]]></description>
      <pubDate>Mon, 19 Dec 2022 10:13:16 GMT</pubDate>
      <guid>https://rip.trb.org/View/2087372</guid>
    </item>
    <item>
      <title>An Innovative Reinforcement Approach for Rebar-Free 3D Printing of Transportation Infrastructure</title>
      <link>https://rip.trb.org/View/1904969</link>
      <description><![CDATA[The main objective of this project is to investigate an innovative configuration for a rebar-free
construction 3D printing process for resilient civil infrastructure development. The proposed
configuration includes using a self-reinforced printing material as well as a discontinuous vertical
reinforcement technique which can be fully automated. To this aim, twisted steel fibers will be
used to develop a structural self-reinforced printing material. Inserting steel mini-rods into the
layers will be investigated as an additional strengthening method. These steel rods are designed
to act as vertical reinforcement and to address a possible weak interlayer adhesion and its
influence on the mechanical performance of 3D printed elements. This project will result in
development of a fully characterized printable self-reinforced mixture as well as comprehensive
experimental data on the performance of an alternative reinforcement technique under different
loading conditions.]]></description>
      <pubDate>Thu, 20 Jan 2022 14:24:21 GMT</pubDate>
      <guid>https://rip.trb.org/View/1904969</guid>
    </item>
    <item>
      <title>Resilient 3D-Printed Civil Infrastructure with Ultra-High Performance Engineered Cementitious Composites (UHPECCs)</title>
      <link>https://rip.trb.org/View/1891226</link>
      <description><![CDATA[The advent of construction 3D printing (3DP) technology has opened the possibility of
revolutionizing construction productivity worldwide. However, one important barrier for broader
adoption of construction 3DP in civil infrastructure is the difficulty to provide printed structural
components with reinforcement to achieve sound structural performance under different loading
conditions. As such, the implementation of intrinsically reinforced cementitious materials has the
potential to address this barrier and yield significant benefits such as an enhanced structural
capacity, durability, and resiliency. For this reason, novel ultra-high strength highly ductile
cementitious composites such as Ultra-High Performance Engineered Cementitious Composites
(UHP-ECCs) are excellent candidates for the 3DP of structurally sound civil infrastructure. This
project proposes the development of UHP-ECC materials with rheological characteristics
tailored specifically for construction 3DP application. Furthermore, this project aims to conduct a
comprehensive evaluation of the hardened properties of printed UHP-ECC.]]></description>
      <pubDate>Wed, 10 Nov 2021 08:36:19 GMT</pubDate>
      <guid>https://rip.trb.org/View/1891226</guid>
    </item>
    <item>
      <title>Developing High-Performance Nanocomposite Coating for Steel Reinforcement Protection in Chloride-Rich Concrete</title>
      <link>https://rip.trb.org/View/1856472</link>
      <description><![CDATA[Anti-corrosion coating is one of the most widely used technologies to mitigate corrosion of steel reinforcement in chloride-contaminated concrete. The durability of epoxy-coated reinforcement commonly used is of great concern due to its failure record in high chloride environments and localized corrosion conditions. In this context, this project aims to design a long-lasting, high-performance rebar coating that increases the service life of the rebar in concrete by reducing corrosion at the interface between the rebar and the surrounding chloride-contaminated concrete. A two-layer coating will be applied on steel rebar, with an inhibitor-loaded epoxy nanocomposite coating as the primer and a minerals-loaded epoxy-polyurethane nanocomposite coating as the top coat. Electrochemical corrosion tests, surface analyses, and mechanical tests will be conducted to assess and elucidate the effect of different constituents on the protective performance of such novel epoxy-based nanocomposite coatings.]]></description>
      <pubDate>Sat, 05 Jun 2021 16:31:24 GMT</pubDate>
      <guid>https://rip.trb.org/View/1856472</guid>
    </item>
    <item>
      <title>Resilient 3D-Printed Infrastructure with Engineered Cementitious Composites (ECC)</title>
      <link>https://rip.trb.org/View/1751182</link>
      <description><![CDATA[Conventional construction of reinforced-concrete structures is slow, labor-intensive, and expensive. 3D-printing holds great potential to assist engineers and architects in the construction of fast and economical, yet complex representational infrastructures. One of the biggest barriers to broader adoption of concrete 3D-printing in civil infrastructure is the difficulty of providing printed structural components with reinforcement to achieve sound structural performance under different loading conditions. Hence, it is essential to design a concrete which can be utilized as a rebar-free material through considering both strength and ductility. Recently, the development of Engineered Cementitious Composites (ECC) has neared the possibility to achieve both strength and ductility in the concrete structures without embedding steel reinforcement. ECC has been offered to enhance the problem related to the ductility and low tensile strength of traditional concrete and Fiber Reinforced Composite (FRC). As such, the implementation of intrinsically reinforced cementitious materials has the potential to address this barrier in reinforcement of 3D-printed concrete and yields significant benefits such as an enhanced structural capacity, durability and resiliency. This project proposes the development of ECC materials utilizing readily available ingredients in Region 6 with rheological characteristics tailored specifically for 3D-printing applications. Furthermore, the project aims to conduct a comprehensive evaluation of the hardened properties of 3D-printed ECC specimens, including mechanical tests.]]></description>
      <pubDate>Wed, 11 Nov 2020 09:44:47 GMT</pubDate>
      <guid>https://rip.trb.org/View/1751182</guid>
    </item>
    <item>
      <title>Guidelines for the Design of Prestressed Concrete Bridge Girders Using FRP Auxiliary Reinforcement</title>
      <link>https://rip.trb.org/View/1707219</link>
      <description><![CDATA[State departments of transportation (DOTs) have been investigating alternative reinforcement materials such as fiber reinforced polymers (FRP) to extend the service life of highway structures especially in aggressively corrosive environments. In the effort to further facilitate the use of these materials, the American Association of State Highway and Transportation Officials (AASHTO) adopted the AASHTO Guide Specification for the Design of Concrete Bridge Beams Prestressed with Carbon Fiber-Reinforced Polymer (CFRP) Systems and the AASHTO LRFD Bridge Design Guide Specifications for GFRP-Reinforced Concrete. Herein, both are referred to as AASHTO FRP guide specifications.
 
The current AASHTO specifications do not address the design of FRP auxiliary (non-prestressed) reinforcement in prestressed concrete girders. The behavior and the mechanical properties of FRP reinforcement (including carbon, glass, and basalt FRP reinforcement) are different from the traditional steel reinforcement, which is the basis of the current design specifications. Bridge owners, fabricators, designers, and contractors need specifications and guidelines for the design of prestressed concrete girders using FRP auxiliary reinforcement.
 
OBJECTIVES: The objectives of this research were to (1) propose modifications to the AASHTO FRP guide specifications for the design of prestressed concrete girders using FRP auxiliary (non-prestressed) reinforcement and (2) develop guidelines for the design of prestressed concrete girders using FRP auxiliary reinforcement including design examples and training materials to demonstrate the application of the proposed AASHTO FRP guide specifications modifications and guidelines.]]></description>
      <pubDate>Tue, 19 May 2020 20:09:03 GMT</pubDate>
      <guid>https://rip.trb.org/View/1707219</guid>
    </item>
    <item>
      <title>Lateral Loading of Unreinforced Rigid Elements and Basal Stability of Column-Supported Systems (3.12)</title>
      <link>https://rip.trb.org/View/1683419</link>
      <description><![CDATA[The use of rigid column-support to stabilize fill embankments and MSE walls continues to grow in popularity, especially among DOTs and transportation agencies for roadway, railway, and bridge applications because of its distinct advantage in accelerating construction in fill scenarios. However, perimeter columns may be subjected to appreciable lateral loading and excessive tensile stressing in the concrete that may lead to a cessation of the load transfer mechanisms (e.g. arching) and subsequent basal instability.  The objectives of this project are to (i) understand the conditions (e.g. fill scenario, subgrade materials, area replacement ratio) that influence lateral loads and bending in exterior columns and (ii) generate design guidance regarding the necessity of reinforcement in perimeter elements subject to lateral loading near the perimeter of slopes, embankments, and MSE walls. ]]></description>
      <pubDate>Fri, 07 Feb 2020 19:32:31 GMT</pubDate>
      <guid>https://rip.trb.org/View/1683419</guid>
    </item>
    <item>
      <title>High Strength Steel Reinforcement in Critical Regions of Earthquake Resistant Bridges</title>
      <link>https://rip.trb.org/View/1441857</link>
      <description><![CDATA[California Department of Transportation (Caltrans) is considering implementing American Society for Testing and Materials (ASTM) A706 Grade 80 steel reinforcement for seismic applications. A planned research project aims to characterize the stress strain response of Grade 80 steel such that it may be used for design. Grade 80 and ASTM A1035 reinforcement are now allowed by the American Association of State Highway and Transportation Officials  (AASHTO) Load and Resistance Factor Design (LFRD) Specifications to reinforce regions of members that are capacity designed, that is, where plastic hinging will not develop. A reason for not allowing these higher strength reinforcements in regions of bridges where plastic hinges will develop during an earthquake is the knowledge-gap that exists about the cyclic response, of its low-cycle fatigue and tensile development characteristics. The purpose of this research would be to close this knowledge-gap and develop guidelines for capacity protected members constructed using ASTM A 706 Grade 80 steel.]]></description>
      <pubDate>Wed, 04 Jan 2017 10:54:43 GMT</pubDate>
      <guid>https://rip.trb.org/View/1441857</guid>
    </item>
    <item>
      <title>CCTRP 17-01: Development of a Simplified Design Method and Reinforcement Detail for the Acute Corner of Skewed Bridge Decks</title>
      <link>https://rip.trb.org/View/1422701</link>
      <description><![CDATA[In modern transportation projects, skewed bridges are becoming increasingly more common and their degree of skew perceptibly more severe due to more and more restrictive site constraints, especially in urban infrastructure projects. Despite the advantages of skewed bridges, the structural design and construction of the acute corners of skewed concrete slabs present several challenges due to the congested reinforcement details. This may lead to several problems with placing and compacting concrete. At the acute corners of highly skewed bridge decks, the bars perpendicular to the longitudinal axis of the bridge are generally too short to be developed, making them structurally ineffective. In addition, the placement of these bars significantly increases the complexity of construction. Often, as the skew angle increases, large portions of the deck can go unreinforced subjecting them to service issues such as spalling and chipping. The presence of the end diaphragm and an integrated concrete parapet may also have a significant impact on the flexural demand of the deck. In addition, the two-way action of the slab may significantly reduce the flexural demand in acute corners. Hence, an optimal design needs to be developed to account for all these effects to simplify the construction and reduce the costs. This study will use detailed finite element simulation to accurately determine the behavior of skewed slabs. A comprehensive parametric study will be performed to understand the effect(s) of the following parameters on flexural moments and concrete stresses at the acute corner of bridge decks: (1) skew angle, (2) overhang length, (3) girder type, and (4) bridge width and length, (5) end diaphragm, and (6) the presence of an integrated barrier. Concerns about the cost-effectiveness and  adequacy of the current reinforcement detail used for acute corners of skewed decks will be addressed in this study. This research will enable the development of an optimized design method and reinforcement detail to reduce the cost and time of construction, while also increasing the safety of the design. The longevity of the bridge deck will also be improved by preventing cracking of concrete deck that is common in skewed bridges.]]></description>
      <pubDate>Thu, 08 Sep 2016 15:14:28 GMT</pubDate>
      <guid>https://rip.trb.org/View/1422701</guid>
    </item>
    <item>
      <title>Implementation Evaluation of the Rustic Road Geosynthetic-Reinforced Soil-Integrated Bridge System</title>
      <link>https://rip.trb.org/View/1401986</link>
      <description><![CDATA[Deficient small bridges are a significant concern for the nation’s transportation infrastructure, so advancing the implementation of time- and money-saving technology is essential to maintaining a “state of good repair.”

Geosynthetic-reinforced soil-integrated bridge systems (GRS-IBS) technology has the potential to introduce significant time and cost savings on small bridge replacements by removing the need for driven piles. Unfamiliarity with the technical performance and construction operations has impeded implementation.

The goal of this project is to advance the implementation of the technology by evaluating the construction and early service life performance of the Rustic Road GRS-IBS, which was constructed in early 2015, in Boone County, Missouri. This detailed case study was coordinated with the results of a concurrent Midwest Transportation Center effort also focused on advancing implementation of these types of bridge systems.]]></description>
      <pubDate>Fri, 25 Mar 2016 09:59:11 GMT</pubDate>
      <guid>https://rip.trb.org/View/1401986</guid>
    </item>
    <item>
      <title>Strength of Horizontal Shear Reinforcement with Limited Development</title>
      <link>https://rip.trb.org/View/1359422</link>
      <description><![CDATA[The objective of this project is to determine if adequate horizontal shear capacity is provided by the 5-inch concrete deck on slab and box beams, despite lack of reinforcement development. Horizontal cracks between the precast beams and the cast-in-place decks were noticed in several Texas Department of Transportation (TxDOT) bridges. Those cracks could be due to stresses induced by shrinkage or shear forces. In any case, this shows that current TxDOT details might not provide sufficient horizontal shear resistance in those members. The work plan is to first conduct small scale tests to investigate the three major components of horizontal shear resistance: (1) cohesion and/or aggregate interlock, (2) friction between the crack faces, and (3) dowel action of the reinforcement. A simple bar pullout test will also be used to evaluate the influence of the bend curvature on the bond and slip characteristics of the horizontal shear reinforcement. Alternative details for surface roughness and bar geometries will be investigated. The second phase of this research will be testing several full-scale composite box and slab beams with current and proposed alternative details to investigate the overall composite behaviors that may be overlooked in the small scale tests.]]></description>
      <pubDate>Tue, 30 Jun 2015 01:03:05 GMT</pubDate>
      <guid>https://rip.trb.org/View/1359422</guid>
    </item>
    <item>
      <title>Synthesis of Information Related to Highway Problems. Topic 47-01. Control of Cracking in Concrete Bridges</title>
      <link>https://rip.trb.org/View/1353338</link>
      <description><![CDATA[Despite many advances in bridge design, concrete technology, and corrosion-resistant reinforcement, cracking of concrete continues to be a concern for bridge owners; particularly for bridges exposed to severe environments. The presence of cracks provides a direct path for water and chlorides to penetrate the concrete and reach the reinforcement. This in turn, can lead to freeze-thaw damage to the concrete or corrosion of the reinforcement. However, there appears to be little or no correlation between crack width, corrosion, and service life. The American Association of State Highway and Transportation Officials  Load and Resistance Factor Design (AASHTO LRFD) Bridge Design Specifications provides requirements for minimum amounts of reinforcement and maximum spacing of reinforcement to control crack widths. In some cases, these requirements are based on in-depth research, while others are based on experience. Nevertheless, bridge owners find the need to supplement the AASHTO provisions with their own requirements. The control of cracking for aesthetic, durability, and structural reasons becomes increasingly important as service life goals are extended and higher strength concrete, higher strength reinforcement, and different types of reinforcement are used in bridge construction. The overall goal of the synthesis is to provide a compilation of methods used to control cracking in concrete bridges and the influence of cracking on long-term durability. Specifically, the synthesis will address the following types of cracking: (1) Flexural cracks in nonprestressed members; (2) Shrinkage cracks in nonprestressed concrete bridge decks; (3) Splitting cracks in pretensioned anchorage zones; (4) Vertical cracks in pretensioned beams prior to transfer of the prestressing force; and (5) Reflective cracking in cast-in-place partial-depth decks and overlays. The synthesis will include information related to the use of steel reinforcement with specified yield strengths from 60 to 100 ksi, corrosion-resistant steel reinforcement, and fiber-reinforced polymer reinforcement. The selection of concrete constituent materials and construction methods to reduce the potential for shrinkage cracking will be addressed. Finally, the synthesis will address remedial measures that may be taken after cracks occur. The synthesis will be beneficial to bridge owners and designers and the AASHTO Subcommittee on Bridges and Structures in their Grand Challenges to extend bridge service life and advance the AASHTO specifications.]]></description>
      <pubDate>Wed, 13 May 2015 01:00:32 GMT</pubDate>
      <guid>https://rip.trb.org/View/1353338</guid>
    </item>
    <item>
      <title>Cyclic Behavior of Self-Consolidated Concrete</title>
      <link>https://rip.trb.org/View/1320624</link>
      <description><![CDATA[Self-consolidating concrete (SCC) is an innovative type of concrete technology with significantly enhanced fresh properties that eliminates the need for mechanical vibrations. SCC is characterized by its ability to flow through structural elements under its own weight, filling every corner of the formwork, even in the presence of congested steel reinforcement. Currently, the Nevada Department of Transportation (NDOT) uses SCC mainly for casting drilled shafts. Several federal agencies are currently promoting the expansion of SCC use for all the advantages it provides. This project has two folds. The first fold is sponsored by NDOT where the effects of concrete pumping, tremie use, form shape, local aggregate properties, casting height and/or reinforcement congestion would be investigated. The first fold will conclude with proposing different mixes to be used by NDOT for SCC applications. The second fold will be sponsored by Missouri University of Science and Technology NUTC. The second fold will investigate the cyclic behavior of SCC and will be compared to cyclic behavior of conventional concrete.]]></description>
      <pubDate>Wed, 20 Aug 2014 01:00:38 GMT</pubDate>
      <guid>https://rip.trb.org/View/1320624</guid>
    </item>
    <item>
      <title>Mechanical Characterization of Enamel Coated Steel Bars</title>
      <link>https://rip.trb.org/View/1234587</link>
      <description><![CDATA[Steel bars can be coated with enamels or glass to reduce or eliminate the tendency of steel corrosion in various applications, such as reinforced concrete (RC) decks, beams and columns. The chemical bond between enamel and steel materials is a key to make an enamel-coated steel corrosion free. Therefore, it is essential to characterize the mechanical and bonding properties of enamel-coated steels. To show competitiveness, the performance and cost of enamel-coated steel bars must be compared with those of the current technology such as epoxy reinforcing steel bars. In various applications of an enamel-coated steel bar, potential limit states include cracking and spalling of enamel coatings, surface impact damage of coatings, corrosion of steel components, and debonding of enamel from its coated steel bar. The proposed study is aimed at quantifying the ruggedness of enamel coatings and their bonding with steel and concrete. In a short term, the objectives of this particular study are to demonstrate that enamel-coated steel bars are comparable to conventional steel bars in mechanical properties and demonstrate that they are superior to epoxy bars in field handling and less susceptible to impact damage. The specific scope of work includes: * Cracking and spalling tests of enamel coatings with tensile specimens in order to understand the levels of the tensile deformation in steel bars that correspond to cracking of the enamel materials and their spalling off the steel bars, respectively. * Impact resistance tests of enamel coatings with the projectile impact on enamel coated steel bars and on epoxy coated bars. * Toughness tests of enamel-coated steel bars to document the minimum ratio of bent bars or the minimum number of bending cycles applied on bent bars before cracking. * Thermal tests for the compatibility between enamel and steel with tensile specimens.]]></description>
      <pubDate>Thu, 03 Jan 2013 15:14:56 GMT</pubDate>
      <guid>https://rip.trb.org/View/1234587</guid>
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