Accelerated Bridge Construction Research Articles

Robust localization of shear connectors in accelerated bridge construction with neural radiance field

Accelerated bridge construction (ABC) demands precise alignment of prefabricated members to prevent assembly failure. Conventional methods struggle to localize shear connectors from point cloud data (PCD) generated by structure-from-motion due to its sparsity. This paper introduces a robust method for shear connector localization using PCD generated by a neural radiance field and a three-step narrowing-down algorithm. The PCD exhibits densely populated points for small connectors, allowing the algorithm to pinpoint their locations accurately. The method successfully identified all 72 shear connectors in a mock-up prefabricated girder, with an average error of 10 mm, demonstrating its potential for assessing constructability in ABC projects. Future research may integrate deep learning-based segmentation techniques to enhance efficiency and adaptability in complex geometries and non-standard bridge designs.

Study, Evaluation, and Monitoring of Bridge Bearing in Accelerated Bridge Construction (ABC)

Study, Evaluation, and Monitoring of Bridge Bearing in Accelerated Bridge Construction (ABC)

Fatigue and Ultimate Strength Evaluation of GFRP-Reinforced, Laterally-Restrained, Full-Depth Precast Deck Panels with Developed UHPFRC-Filled Transverse Closure Strips

A depth precast deck panel (FDDP) is one element of the prefabricated bridge element and systems (PBES) that allows for quick un-shored assembly of the bridge deck on-site as part of the accelerated bridge construction (ABC) technology. This paper investigates the structural response of full-depth precast deck panels (FDDPs) constructed with new construction materials and connection details. FDDP is cast with normal strength concrete (NSC) and reinforced with high modulus (HM) glass fiber reinforced polymer (GFRP) ribbed bars. The panel-to-girder V-shape connections use the shear pockets to accommodate the clustering of the shear connectors. A novel transverse connection between panels has been developed, featuring three distinct female-to-female joint configurations, each with 175-mm projected GFRP bars extending from the FDDP into the closure strip, complemented by a female vertical shear key and filled with cementitious materials. The ultra-high performance fiber reinforced concrete (UHPFRC) was selectively used to joint-fill the 200-mm transverse joint between adjacent precast panels and the shear pockets connecting the panels to the supporting girders to ensure full shear interaction. Two actual-size FDDP specimens for each type of the three developed joints were erected to perform fatigue tests under the footprint of the Canadian Highway Bridge Design Code (CHBDC) truck wheel loading. The FDDP had a 200-mm thickness, 2500-mm width, and 2400-mm length in traffic direction; the rest was over braced steel twin girders. Two types of fatigue test were performed: incremental variable amplitude fatigue (VAF) loading and constant amplitude fatigue (CAF) loading, followed by monotonically loading the slab ultimate-to-collapse. It was observed that fatigue test results showed that the ultimate capacity of the slab under VAF loading or after 4 million cycles of CAF exceeded the factored design wheel load specified in the CHBDC. Also, the punching shear failure mode was dominant in all the tested FDDP specimens.

Connections between precast hollow concrete columns and foundations using UHPC and rebar lap splices

Hollow concrete columns (HCC) have been widely used in accelerated bridge construction worldwide. The column-foundation connections are vital in such precast systems to ensure seismic resilience. In this paper, a novel HCC-foundation connection using UHPC and rebar lap splices was proposed, which could facilitate the construction process. Cyclic tests were carried out on four specimens to examine their seismic performance. Test results showed that the proposed connections exhibited satisfying capacities, ductility, and energy dissipation comparable to monolithic connections under lateral cyclic loads. The use of a precast UHPC shell did not deteriorate the performance of the connection with no interface separation observed. The decrease in joint height would, however, bring about anchor rebar slippage and reduce energy dissipation. A validated fiber element model of the specimens was established for efficient seismic modeling of precast systems with the proposed connection in actual projects. Force transfer mechanisms and design methods for the connections were further deduced. The proposed connection has been verified to be comparable to cast-in-place connections and is thus suitable for use in precast column-foundation connections. Several design recommendations were derived for engineering reference.

Characterizing the free-vibration response of a two-span rocking bridge with free-standing columns

For accelerated bridge construction (ABC), replacing traditional emulative connections of precast elements with simpler discontinuities may lead to more resilient structures with reduced expected damages after strong seismic events. This paper comprises novel free-vibration tests of a 1:10 scale two-span rocking bridge with free-standing columns with proper geometrical and dynamic similarity. The two spans induced in the model the interaction between frames with different tributary masses, as would be expected for a realistic bridge. To excite the bridge uniformly, the experimental protocol consisted of forty-nine incremental sinusoidal ground motions that were interrupted, letting the bridge vibrate freely to rest. The results were compared with six analytical models. The results showed that the structure remained undamaged for the free-vibration tests after drifts up to 6 % and did not wobble unrestricted. The results were used to obtain the dynamic properties of the system and their variation to displacement increments. Construction imperfections induced the model to rock for all excitations, including low-intensity excitations, and to vibrate with periods different from those of theoretical equations at low displacements. This behavior was critical in the comparison between experimental results and the estimates from analytical models. These findings demonstrate that rocking bridges are a suitable system to control structural damage during seismic events despite the apparent variability of the behavior under realistic conditions. However, the design of these structures must account for the effects of construction imperfections at the rocking surface. The experimental results are openly available for download in the DesignSafe Data Depot using this DOI https://doi.org/10.17603/ds2-znfv-8t55.

Evaluation of retrofitting effect of concrete filling in hollow RC columns using XFEM

Hollow RC columns are widely utilized in the construction of high piers in mountainous regions. Recently, precast hollow RC columns have been increasingly used to enhance transportability and ease of handling, aiding Accelerated Bridge Construction. This paper evaluated the effectiveness of concrete-filling retrofitting measures for hollow RC columns using eXtended Finite Element Method (X-FEM). Our focus was particularly on instances where original hollow sections and post-filled concrete sections don't behave as unified structures. The proposed X-FEM model's reliability was validated through simulations replicating compressive strength tests on molded concrete specimens and previous static loading tests on hollow RC columns conducted to evaluate the efficacy of concrete-filling retrofitting for hollow RC columns. The proposed X-FEM model successfully represents the compressive softening and fracture behavior of concrete under uniaxial compression. It also successfully replicated the lateral load capacity and the crack patterns of hollow RC columns observed in the previous experiments. When comparing the component ratios of bending and shear deformation of the columns, the shear deformation component of the hollow RC column retrofitted with the concrete filling was about 1.5 times larger than that of the solid RC column at each displacement. This result indicates that concrete-filling retrofitting might not enhance the shear capacity of hollow RC columns to the anticipated level in scenarios where the pre-existing hollow portion and the post-filled concrete portion fail to function as unified structures. Based on these findings, this study investigated the efficacy of anchor reinforcement in hollow RC columns filled with concrete to enhance the structural unity of existing and filled portions. The results indicate that anchor reinforcement improved the shear resistance properties by enhancing the structural unity between the pre-existing hollow portion and the post-filled concrete portion.

Shear Performance of Prefabricated Steel Ultra-High-Performance Concrete (UHPC) Composite Beams under Combined Tensile and Shear Loads: Single Embedded Nut Bolts vs. Studs

Ultra-high-performance concrete (UHPC) is widely used in precast concrete-steel composite beams because of its beneficial properties, including reduced structural weight, higher flexural rigidity, and reduced tensile crack formation. In comparison to conventional steel-concrete composite beams, steel-UHPC composite beams exhibit superior characteristics, including reduced structural deadweight, enhanced flexural stiffness, and the capacity to withstand tensile cracking. One successful attempt at meeting the current demands for expedited girder engineering is the development of steel-UHPC composite beams with full-depth precast slabs as key components affecting the overall structural performance using dismountable single embedded nut bolts (SENBs) and widely used studs as competitive alternatives. In contrast, shear connectors are exposed to a combined tensile and shear stress in service life rather than shear only. The corresponding scientific problem is the problem of combined effects under stress in practical applications, but there is currently no relevant research. The shear performance of SENBs in precast steel-UHPC composite beams under tension and shear loads remains unclear. For this purpose, ten push-out specimens and theoretical analyses were performed in this paper, considering the influence of the connector’s type and tensile-to-shear ratio. However, ten specimens were conducted to investigate the tensile-to-shear ratio, and the connector’s type on shear performance is limited. In the future, an increasing number of specimens and test parameters should be considered to investigate the shear performance of precast steel-UHPC composite beams. An increase in the tension-to-shear ratio resulted in a substantial reduction in the ultimate shear capacity, initial shear stiffness, and ductility of the studs. The increase in the tensile-shear ratio from 0 to 0.47 resulted in a 16.9% decline in the ultimate shear capacity, a 30.4% reduction in the initial shear stiffness, and a 21.7% decrease in the ductility of the Series I samples. However, an increase in the tensile-to-shear ratio of the Series II samples from 0 to 0.47 resulted in a 31.3% decline in ultimate shear strength, a 33.2% decline in initial shear stiffness, and a 41.9% decline in ductility. The SENBs demonstrated minimal deviations in ultimate shear capacity compared to their stud counterparts, despite exhibiting notable differences in shear stiffness, and ductility. A lower tensile-to-shear ratio was recommended in practical engineering, which might achieve a larger ultimate shear capacity, stiffness, and ductility. The design-oriented models with enhanced applicability were developed to predict the tension-shear relationship and the load-slip curve of SENBs in prefabricated steel-UHPC composite beams subjected to combined tensile and shear loads. For a tensile-shear relationship model, the point error range was 0 to 0.08, with an average error of 0.03. The square coefficient (R2) was 0.99 for a load-slip curve model. The study findings could offer a credible reference for the shear mechanism of such economical and environmentally friendly precast steel-UHPC composite beams in accelerated bridge construction.

Experimental study on seismic performance of post-tensioned precast segmental piers designed with multiple joint openings

In accelerated bridge construction (ABC), precast segmental piers (PSPs) have shown significant progress in shortening the construction period and reducing the cost. By combining multiple segments with post-tensioned (PT) tendons, the desired self-centering ability can be introduced; however, this may lead to a lower energy dissipation (ED) capacity and concentrated damage. To address this concern, the present study proposes a design concept that promotes multiple joint openings to achieve a better energy dissipation capacity and decentralized damage without compromising the self-centering ability. Two main approaches for this objective are discussed in detail. The first approach incorporates different arrangements of ED rebars at various joints, while the second introduces innovative damage control rubber joints (DCRJs) with varying stiffness beneath each segment. Four scaled specimens designed using these two approaches were quasi-statically tested. The observed damage, final failure mode, energy dissipation capacity, resilience index, and damage decentralization were further examined. The results revealed that for PSPs designed using the first approach, the joint openings were successfully decentralized only up to a certain level, after which they were still predominantly concentrated at a single joint, leading to strength degradation and damage concentration. PSPs designed using the second approach demonstrated decentralized joint openings, improved displacement ductility, and damage mitigation, resulting in both superior seismic and post-seismic performance.

Multi-factor analysis and optimization on seismic behavior of precast pier-footing socket connection considering different connection parameters

Accelerated bridge construction technology, with its various connection methods, has experienced extensive global usage. Common methods include post-tensioned, cast-in-place joint, sleeve, and socket connections. Each method has its advantages and limitations, such as the energy dissipation issue in post-tensioned connections and the on-site challenges of cast-in-place joints. Precast pier-footing socket connections have emerged as a promising solution due to their rapid construction and durability. However, previous research has predominantly focused on the minimum embedded length, overlooking critical factors such as grouting material strength, shear key configuration, and axial compression ratio during service. Furthermore, existing studies often isolated individual factors, neglecting their interconnected effects. This study addressed these gaps by testing two specimens and analyzing thirty-eight models through experimental and numerical methods. The results indicated that an embedment depth of at least 1.0 times the diameter (bc) of the precast pier was recommended. Furthermore, to ensure optimal seismic performance, it was essential to enhance the stiffness of the footing sidewalls beyond this depth. Additionally, while shear keys improve bending resistance, their effectiveness decreases with greater embedment depth (>1.5 times the diameter). This study highlights the importance of considering the interplay of multiple factors to ensure project safety and cost-effectiveness.

Accelerated Bridge Construction Case: A Novel Low-Carbon and Assembled Composite Bridge Scheme

Modern bridge construction towards a higher degree of low carbonization and assembly has been the general trend, while developing and broadening the low-carbon and assembled-oriented Accelerated Bridge Construction (ABC) technology can better realize the trade-offs between construction quality, efficiency, cost and sustainability. In the current mainstream ABC technologies such as precast-assembled concrete bridge and assembled steel bridge schemes, it is difficult to achieve an excellent balance between the above multicriterion trade-offs. To this end, this paper proposes a novel low-carbon and assembled composite bridge scheme as an innovative case of ABC technology based on a 26.7 km-length urban viaduct project in China with urgent environmental protection and assembly demands. Construction sustainability, the comprehensive economy and low-carbon performance are well balanced by the collaborative application of new steel–concrete composite structures, the rapid assembly interface design and low-carbon material technologies. The proposed scheme has been applied to a completed real-scale bridge, and the whole construction process only experienced 105 days of effective time, accompanied with slight environmental interference and construction noise and a small amount of labor and equipment input. In addition, the safety of the bridge, the rationality of the design concept and the calculation method have been verified by the static and dynamic loading tests of the real-scale bridge.

Cyclic Tests and Analysis of Corroded Precast Concrete Column-to-Footing Connections Constructed with Accelerated Bridge Construction Methods

Cyclic Tests and Analysis of Corroded Precast Concrete Column-to-Footing Connections Constructed with Accelerated Bridge Construction Methods

Evaluation of seismic performance and damage characteristics of column-footing joints with shallow socket connection

In the background of the high demand for accelerated bridge construction (ABC), more detailed research is still needed on the connection method of prefabricated columns in high-intensity areas to facilitate on-site construction and reduce costs. Therefore, this study proposed a shallow socket connection method suitable for column-footing joints and the Ultra High-Performance Concrete (UHPC) is filled with the gap between the column and footing. A shallow socket connection column and a shallow socket-corrugated pipe hybrid connection column were constructed with a socket depth of 0.6 times the column diameter, and a quasi-static test was conducted to investigate their seismic capability. As a comparison specimen, a cast-in-place (CIP) specimen was also tested, and the scale ratio of all specimens is 1:2. Finally, to predict the damage mode and capacity of the shallow socket column, a simplified strut-and-tie model was developed through mechanical analysis. The proposed shallow socket-corrugated pipe hybrid connection column has the seismic performance not weaker than that of the CIP column and shallow socket connection column, and even performs slightly better in terms of energy dissipation capacity, making it more suitable for moderate and high-intensity areas based on experimental results. The established model of the socket joints could reflect the force characteristics of the shallow socket column and calculate the lateral forces of the column under different damage conditions to determine the modes of failure.

Bond-slip behavior of steel reinforcing bars in ultra-high performance concrete for field-cast connection of precast bridge decks

In Accelerated Bridge Construction (ABC), Ultra-High Performance Concrete (UHPC) is often used for connecting precast concrete bridge components, including deck portions of the Deck Bulb-T girders. An alternative low-cost non-proprietary UHPC has been proposed for use in place of the proprietary UHPC for connecting the precast components. The pullout behavior of steel reinforcing bars in closure pour with typical range for embedment lengths is studied for both proprietary and non-proprietary UHPC materials.

Reliability, sustainability, resiliency, and performance investigation of an embedded splice-sleeve connector at high velocity semi-trailer impact

Presently, dynamic impacts occurrences caused by car crashes have been frequently reported. Statistical results from different articles indicate that vehicle crashworthiness of bridge pier supersedes the other events. However, majority of the published articles focusses on sustainability and finding severity of distressed pier due to impact correlating faster construction methods, like accelerated bridge construction (ABC). This article is an attempt to examine post impacted behavior of a commonly used connector in ABC for resisting short duration shock. Static and dynamic performance analyses of a connector embedded within a coupler system has been examined. A representative ABC pier with the standardized and selected material properties collected from manufacturer’s data has been utilized. Coupler composite materials consisting of a hollow uniform cross-section cast iron cylinder filled up with specified concrete grout conforms higher strength. The performance examination has been conducted by numerical modeling using finite element method (FEM). A commercially used software ANSYS has been utilized for carrying out the simulations. To investigate the post impact dynamic behavior, mesh-independent studies seems inevitable and hence are executed to evaluate dynamic impact factor (DIF). Sensitivity studies are carried out for validating results in precision. The DIF of the main reinforcing tensile steel embedded into the grout placed inside the connector has been determined. Results captured from simulations to identify material properties at plastic stage in sustaining such load have been conducted. The results provide significant information that aids opting for selecting suitable connectors for attaining help the design offices.

Sustainability and Resiliency Investigation of Grouted Coupler Embedded in RC ABC Bridge Pier at Vehicle Impact

Increased occurrences of natural and man-made dynamic loading caused by high strain rate dynamic impact load have been recently reported. Different statistical results indicate that vehicular impacts occur more frequently compared to the other dynamic loads. However, existing literature primarily focuses on enhancing survivability and determining damage levels specifically in relation to faster bridge construction methods used as an accelerated bridge construction (ABC). In this context, the present study investigates the dynamic behavior of a commonly used connection type in ABC, namely grouted coupler that connects pre-cast elements like bridge piers and foundations. To execute the research, both the static and dynamic performance of grouted couplers embedded in pier foundation subjected to high strain rate loading incurred by high velocity vehicular impact are examined. A representative non-traditional reinforced concrete (RC) bridge pier is selected for the study with the standardized geometry and selected material properties. The use of splice sleeves as coupler materials and specified cross-sectional hollow cast iron cylinders filled with high strength concrete grout is employed for developing Finite Element (FE) modeling, extracting data from published journals. A commercial software, ANSYS, has been utilized to develop FE models to capture post impact respective static and dynamic behaviors, and the simulation results are then compared with the analytical. This also includes determining material performance via FE simulations. By considering dynamic loading, the dynamic impact factor (DIF) has been evaluated for the reinforcing steel bar adjacent and embedded into the coupler. In addition, dynamic simulations, and material modulus in demand to sustain impact are determined. Thus, the research necessitates mesh-independent sensitivity studies to investigate DIF corresponding to the precise outcomes. The findings of this study manifests valuable information that aids to opt for the suitable coupler connections, considering material properties, and adequate post impact execution. Consequently, it will serve as a useful design tool for design offices, structural practitioners, and forensic structural engineers.

Seismic column-to-footing connections reinforced with steel/GFRP bars and GFRP spirals

Hybrid reinforcement is explored for column-to-footing connections in seismic regions constructed with grouted duct connections as an accelerated bridge construction method. Two 38% scale precast concrete column-to-footing specimens were built; the first column was reinforced with hybrid reinforcement using a combination of mild steel and glass fiber reinforced polymer (GFRP) longitudinal bars, and the second with all-steel longitudinal bars. Double layers of GFRP spirals were used to provide improved concrete confinement for both columns; GFRP spirals exert higher levels of confining pressure on the column concrete core as deformation increases due to their elastic nature compared to steel spirals that yield. An equation was developed for the cross sectional area and pitch of a GFRP spiral to provide the same confining pressure as a steel spiral. The purpose of the cyclic load tests was to show that the column reinforced with hybrid reinforcement could reduce residual displacements using the elastic nature of GFRP bars. Pull-out tests of GFRP bars inside grouted ducts were carried out to determine the minimum embedment depth to achieve GFRP bar tensile strength. The seismic performance of both specimens was examined under quasi-static cyclic loads. The hybrid column reached a drift ratio of 9.0% drift ratio when a GFRP longitudinal bar fractured in compression; the all-steel column reached a drift ratio of 11.0% when two longitudinal steel bars fractured in tension. The elastic nature of the GFRP longitudinal bars provided substantial self-centering ability and reduced the residual displacement of the hybrid column compared to the all-steel column, thus enhancing its seismic resilience.

Experimental investigation of seismic behavior of precast pier‐footing socket connection with different design parameters

AbstractAccelerated bridge construction, with innovative connection details and construction technologies, has been extensively investigated and put into practical application for years. Nowadays, there are three commonly used connection methods of accelerated bridge construction technology, namely, lap‐spliced connection, sleeve connection, and socket connection. Due to the convenience of construction and lower requirements of construction accuracy, the socket connection is more suitable for reconstruction and expansion projects of traffic infrastructure, which could minimize the impact on traffic and accelerate construction progress. According to the structural characteristics of the socket connection, there are some design parameters that may significantly affect the seismic resistance of the structure, such as socket embedment length, fabrication of the shear key, and grouting material strength. To fully study the influence of different design parameters on structural performance, an experiment was carried out to investigate the seismic behavior of the precast pier‐footing socket connections with different design parameters. Five 1:2 scale reinforced concrete precast pier‐footing socket connection specimens with different design parameters were designed and tested under cyclically reversed horizontal loads. The development of hysteresis features, failure mode, load‐bearing capacity, stiffness degradation, structural ductility, energy dissipation capacity, and residual drift are analyzed to reveal the influence of the different design parameters on the seismic behavior of the precast pier‐footing socket connection. The seismic behavior of the precast pier‐footing socket connection was significantly influenced by the embedment length especially when the embedment length was less than 1.0bc. When the embedment length was 0.5bc, the failure mode changed from bending damage at the bottom of the precast pier to the anchorage failure of the precast pier‐footing socket connection. When the embedment length was 1.5bc, the fabrication of the shear key had limited improvement on the seismic performance of the specimen, while reducing the ductility of the specimen. When the embedment length was 1.0bc, the grouting material with a strength grade of C60 could be used in the socket connection between the precast pier and footing. The research presented in this paper provides some design suggestions and a technical basis for evaluating the seismic behavior of precast pier‐footing structures with socket connection.

On the collapse of a post-tensioned reinforced concrete truss bridge during the construction phases

On March 2018 a post-tensioned reinforced concrete (RC) truss bridge, built inside a North American university campus using the Accelerated Bridge Construction (ABC) method, collapsed during the construction phase, while the bars of a diagonal member were being re-tensioned. This process was not part of the scheduled construction phases, but it was decided by the designers after having observed several cracks in the structural nodes.This paper aims to analyse the final design of the bridge useful to determine the hypothetical causes of the collapse. Several numerical analyses have been performed to reproduce the behaviour of the different structural elements during the construction phases. In particular, construction stage analyses have been carried out to obtain the internal actions acting on the structural elements and on the nodes during the different construction steps and in order to analyse in detail the critical phases where the occurrence of the collapse has been hypothesized. The collapse mechanism is identified in the shear failure of a node of the concrete truss during the re-tensioning of a diagonal element. In fact, the reapplication of the post-tension had increased the axial force of the diagonal and consequently the shear action on the node. Moreover, the results obtained have shown that the bridge has never been in safe conditions, mainly because the interface surface of the cold joints had not undergone any type of work and remained smooth.

Seismic performance of Fe-SMA prestressed segmental bridge columns with 3D printed permanent concrete formwork

The integration of digital fabrication technology with prestressed segmental column construction offers significant potential for accelerated bridge construction with material-efficient design. This study aims to explore this potential by developing a novel prestressed segmental column system that utilizes permanent 3D printed concrete (3DPC) formwork for column segment fabrication. Prestressing is achieved in the proposed system by using partially bonded iron-based shape memory alloy (Fe-SMA) reinforcement. Large-scale experiments were conducted on two columns under combined gravity and lateral loading to evaluate the seismic performance and feasibility of the proposed system. The ratio of steel to Fe-SMA reinforcement in the column design was the variable considered in this study. The experimental results showed that the columns could withstand lateral drifts of up to 5% without collapse and the permanent 3DPC formwork showed no premature failure or delamination. Furthermore, the columns exhibited self-centering characteristics, maintaining a residual drift of 1% up to a target drift of 4% when the reinforcement ratio of steel to Fe-SMA rebars was 0.3. The results highlight the potential of the proposed prefabrication concept in designing material-efficient and seismically resilient bridge columns with low damage characteristics.

Repairable Precast Concrete Bridge Columns for Seismic Events

In multispan bridges excited by ground shaking, columns are usually the target ductile members. Although current practice is successful in attaining the no-collapse objective for bridges, columns are usually damaged at displacements associated with this performance level. Minor damage can be repaired, but excessive damage is usually beyond repair. A new design paradigm with minimal damage and repair need is gaining interest. The benefits of such a design can be increased if low-damage technologies are combined with accelerated bridge construction techniques. The main goal of the present study was to develop rein¬forced concrete bridge columns that are fully precast concrete, low damage, and repairable through compo¬nent replacement. To achieve the project objectives, 20 repairable precast concrete alternatives were developed and ranked. Subsequently, the top three candidates were designed at 50% scale, constructed at a precast concrete plant, and tested in a laboratory. The precast concrete columns incorporated different exposed fuses, such as stainless steel bars and steel tendons, advanced materials such as ultra-high-performance concrete, a self-centering mechanism, or an accelerated bridge construction socket connection. A reference cast-in-place concrete column was included for comparison. Each precast concrete column was tested twice. It was found that the repair of the precast ultra-high-perfor¬mance concrete columns with exposed tendons was easy,