Prestressing Tendons Research Articles

The effect of curing temperature on hardening, thermal, and mechanical characteristics of adhesive for retard‐bonded prestressed tendon

AbstractThe effect of curing temperature on hardening, thermal, and mechanical characteristics of adhesive for retard‐bonded prestressed systems is investigated in detail. To evaluate the degree of hardening of the adhesive, the cone penetration and Shore hardness of two samples are tested throughout the curing process under conditions of 25, 35, 45, 55, and 65°C. The thermal performance and curing reaction are characterized using differential scanning calorimetry and Fourier transform infrared spectroscopy, respectively. The mechanical properties with respect to the cure temperatures are characterized by compression strength tests. Experimental results present that after curing under conditions ranging from 25 to 65°C, the hardness of the samples reached its maximum values (85–90 D). As the temperature increased from 25 to 65°C, there was a greater degree of curing cross‐linking, resulting in an increase in compressive strength from 55 to 72 MPa. Based on Shore hardness–time experimental data, a logarithmic model is proposed for predicting the hardness of adhesives at any given time for engineering applications. Additionally, the time–temperature superposition principle is utilized to extrapolate the curing time of the adhesive under low‐temperature conditions. The research findings are of significant importance for the assessment of adhesive hardening.

Flexural performance of precast segmental continuous box girders with corrugated steel webs

Due to the existence of joints, the flexural performance of segmental assembled girders is different from that of monolithic cast girders. In order to study the flexural performance of precast segmental assembled box girder with corrugated steel webs, a static failure test on a precast segmental assembled continuous box girder with corrugated steel webs and variable cross-section and a monolithic cast continuous box girder with corrugated steel webs of the same size was carried out. The influence of the existence of joints on the deflection, strain, and prestress increment of precast segmental continuous girder with corrugated steel webs was analyzed. The parameter analysis was further carried out by the finite element method. The results showed that, at the initial loading stage, the joint had little effect on the displacement, and the deflection of the segmental assembled girder changed more rapidly than that of the monolithic cast girder. In the monolithic girder, cracks mainly occurred at the middle-support position of the middle span and pure bending sections. In the segmental beam, cracks were concentrated in the concrete on both sides of the joint. The number of cracks was relatively small and concentrated in the concrete on both sides of the joints of the loading segment and the middle support segment. The trends in the strain growth in the segmental beam and MB01 were consistent, and the values were similar. The strain growth trend of the segmental girder and the monolithic girder was consistent, and the values were similar at the initial loading stage. The external prestressed tendons in the segmental girder had a greater role in the loading process than those in the monolithic girder, and the normal stress in the segmental girder increased more rapidly during the bending process. In the ultimate loading state, the external prestressing force of the segmental girder was 2.01% higher than that of the monolithic girder. The number of segments was inversely proportional to the flexural capacity of the structure. Excessive thickness of the adhesive layer would adversely affect the crack resistance of the structure. This study will contribute to the engineering application of continuous composite box girders with corrugated steel webs.

Bending resistance mechanism of prestressed ultra-high performance concrete - reinforced concrete beam based on a full-scale experiment

Ultra-High Performance Concrete (UHPC) is a new type of engineering material with high compressive strength, high tensile strength, and high fracture toughness. Its bending failure mechanism is different from that of traditional concrete beams, which requires a new computational model to describe the bending failure phenomena of the prestressed ultra-high performance concrete - reinforced concrete (UHPC-RC) beam without web reinforcement. Therefore, this paper, through full-scale tests on a 30m prestressed UHPC-RC beam without web reinforcement, captures unique bending failure phenomena, including initial cracking, development of local cracks, and rupture of prestressed steel strands. Considering the tension-compression constitutive relationship of UHPC material, an innovative computational model for bending bearing capacity is proposed. Based on this model, a study on the minimum reinforcement ratio of full prestressed-ordinary steel bars is conducted. The results show that in the bending failure of the prestressed UHPC-RC beam without web reinforcement, excessive tensile strain of steel strands will occur at the local crack location. At this time, the structure does not satisfy the assumption of plane sections, and the introduction of the calculation model of the limit state of external prestressed tendons can effectively match this model, which is highly consistent with the experimental results. The minimum reinforcement ratio of full prestressed-ordinary steel bars is revised to the auxiliary reinforcement ratio of full prestressed-ordinary steel bars, quantifying the minimum reinforcement requirements of ordinary steel bars. The research results of this paper can provide reference for the next step of theoretical research.

Radial force analysis of long span bridge with trapezoidally corrugated steel webs

The study numerically and theoretically investigates the radial force effect of long span prestressed concrete (PC) box girders with trapezoidally corrugated steel webs (TCSWs). It reveals that under the influence of radial forces, the curved prestressing tendons in the bottom slab in long span box girder bridges with TCSWs exhibited higher levels of stress and deflection compared to conventional concrete box girder bridges due to the accordion effect of the TCSWs. Furthermore, this study simplifies the radial forces as concentrated forces of PC box girder with TCSWs. Based on this simplification, a formula is derived to accurately calculate the magnitude of these radial forces. Through parameter analysis of the power exponent in the equation defining the curve profile of the bottom slab, it was observed that lower power exponents result in more significant radial force effects. Finally, to eliminate the radial force effect, the study innovatively proposed an optimized structural scheme by adopting horizontal bottom slab at midspan and arranging horizontal diaphragms uniformly across the entire longitudinal span of the bridge. A contrastive study suggested that the horizontal arrangement of internal prestressing tendons in the bottom slab at midspan could effectively eliminate the negative impact of the radial force effects and greatly improve the overall bearing capacity of the box girders with TCSWs.

Effects of Prestressing Magnitude and Position on Seismic Performance of Unbonded Prestressed Concrete Beams

To study the effects of the jacking stress level, height and strength ratio of the prestress tendons (λ) on the seismic performance of unbonded prestressed concrete (UPC) beams, six UPC beams and one reinforced concrete (RC) beam were tested under cyclic loads. The hysteretic characteristics, skeleton curves, ductility properties, energy dissipation capacity, strain distribution of reinforcement and self-centering capability of the specimens were studied and discussed. Numerical parameter analysis was also carried out by using OpenSees. The results indicate that three failure modes of UPC beams under cyclic loading were observed, namely the tension-failure mode involving a broken rebar, the compression-failure mode involving concrete crushing and the balanced failure. By considering the influence of the prestress position and magnitude, the modified reinforcing index ω was proposed to determine the failure mode. The ω is suggested to be less than 0.3 to ensure sufficient ductility. The effective stress level is linearly and positively related to the stiffness from cracking to yield Kcr and the ultimate bearing capacity of the UPC beam under cyclic loading. The stiffness of the UPC beam is slightly larger than that of the RC beam before yielding, and significantly greater than that of the RC beam after yielding. Due to the large strength reserve after yielding, the integrated seismic performance of the UPC beam is similar to that of the RC beam. When the λ was unchanged, the increase in the relative height of the prestressed tendons αh is beneficial for the overall performance factor F, ductility and crack control. The stiffness degradation performance depends on the λ but is independent of the αh. The total energy dissipation of the non-tensioned UPC specimen was 59% higher than that of the RC beam. The cumulative total energy dissipation of the tensioned UPC specimen was only 13% lower than that of the RC beam with the same number of cycles, indicating that the UPC specimen had a considerable energy dissipation capacity.

Investigation of the applicability of infrared thermography detection of grouting voids in prestressed tendon ducts under hydration heat excitation

Infrared thermography (IRT) has been successfully utilized to identify void defects in external prestressed tendon ducts (without concrete protective layers) under hydration heat excitation. Nonetheless, applying IRT technology for the inspection of internal prestressed tendon ducts presents challenges due to the presence of the thicker concrete protective layer, which can significantly influence the detection results. Therefore, this paper proposes a method for detecting void defects in internal prestressed tendon ducts using IRT technology under hydration heat excitation. The influence of the depth, length and compactness of the void on the detection ability is investigated and the influencing factors such as duct materials are analyzed. The results show that under the hydration heat excitation of the grouting material, IRT can detect complete void defects with a depth of 110 mm below and a length of 350 mm. In addition, the detection effects of metal ducts, tubeless ducts and plastic ducts decrease in turn. Finally, this paper recommends that the IRT detection time be 0.5–2 h and 13–23 h after grouting, which can reduce the cost of post-maintenance by timely detection and repair.

An experimental campaign for assessing the role of tensioned tendons on the shear capacity of half-joints

An important percentage of bridges and viaducts constituting the Italian road infrastructures dates back to the years 50s and 60s and is characterized by prestressed r.c. decks adopting half-joints for obtaining statically determinate schemes. In existing bridges, half-joints are often subjected to degradation phenomena, mostly promoted by water percolation and stagnation, which led to classify the bridge in a high attention class, according to the Italian Guidelines for Risk Classification and Management, Safety Assessment and Monitoring of Existing Bridges. Furthermore, half-joints are difficult to inspect and to maintain. The current safety assessment procedures at ultimate limit state are based on simplified Strut&Tie models that usually neglect the contribution of prestressing tendons anchored in the half-joints on the resisting mechanisms and the ultimate capacity. This work presents the design of an experimental campaign for investigating the shear behaviour and the ultimate capacity of half-joints in which inclined prestressed tendons are anchored. In detail, six laboratory scaled post-tensioned beams are built with half-joints in correspondence of the support regions, dimensioned on the basis of a real bridge girder and numerical 3D finite element nonlinear analyses. The main research goal is to evaluate the influence of tendons on the half-joints capacity by comparing results with those obtained from specimens with non-tensioned tendons and without tendons. Three levels of pre-tensions in specimens characterized by the same reinforcements are considered. In addition, for one level of pre-tension, the effects of different half-joints detailing are investigated. Finally, the role of degradation due to ageing is also addressed by inducing corrosion in one specimen through a galvanic method.

Open issues on the use of carbon composite tendons as prestressed reinforcement of concrete members

In the last decades, fiber-reinforced polymer (FRP) composites gained popularity in the field of structural engineering thanks to their high mechanical properties and limited corrosion in harsh environments. These composites are used as reinforcement of new concrete members as well as for strengthening of existing structures. For existing reinforced concrete (RC) structures, different techniques are available to increase the strength and stiffness of the existing elements. Among them, a promising technology consists in inducing to the element a bending moment opposite to that induced by the applied load by using external prestressed FRP tendons. This technique increases the load carrying capacity of the beams and induces concrete crack closure, thus reducing the exposure of steel bars to the environment.In this paper, a literature review is carried out to investigate the open issues that hinder the diffusion of prestressing made with composite carbon fiber tendons. According to the literature, the main issue is represented by the anchor system that should guarantee high stress level into the composite material avoiding local ruptures. Another open issue is the definition of the maximum stress applied to the composite with respect to its tensile strength. In fact, high levels of stress may induce premature composite failure. Finally, the exposure of CFRP bars to some harsh environmental conditions and high temperatures may negatively affect the reinforcement effectiveness.

Construction Technology and Application of Bonded Pre-stressed Tendons in Wind Turbine Mixed Towers

Construction Technology and Application of Bonded Pre-stressed Tendons in Wind Turbine Mixed Towers

Bending behavior of RC beams with Fe-SMA strip reinforcement

This paper presents an experimental investigation on reinforced concrete beams with different slenderness strengthened with unbonded Fe-SMA strips. The retrofitting system acts as an external prestressed tendon with a mechanical anchorage. In a first step, the strips are positioned against the concrete bottom surface and fixed against the concrete substrate with a direct fastening system. Activation and hence prestressing of the strips is performed with a gas torch and a subsequent temperature control. The concrete elements are afterwards subjected to 4-point bending up to failure. The aim of the investigation is to assess the structural behavior of the retrofitted members as well the additional strain and stress development in the Fe-SMA strips under additional loading after prestressing. Stress increase in the external strip resulting from the flexural loading has a direct influence on the failure mechanism in a sense that the ultimate stress is governed by the anchorage resistance. The experimental investigation for instance shows the effect of the beam slenderness and reinforcement ratio on the failure mode.

Cyclic loading response of precast concrete beam-column connections with partially bonded draped prestressing tendon

An emulative precast concrete beam-column connection consists of prefabricated columns, T-shaped composite beams with partially bonded post-tensioned (PT) tendon, and cast-in-place (CIP) core region is proposed in this study. Experimental study was carried out to examine the hysteretic behavior of four full-scale beam-column connections under a high axial compression ratio (μ = 0.4). The specimens included a precast interior connection (PC1), a precast exterior connection (PC2), and two corresponding conventional CIP control specimens (RC1 and RC2). Performance assessment of the suggested connection was conducted by evaluating various factors, including failure mode, hysteresis curve, deformation, stiffness, and energy dissipation capacity. Test results revealed that all specimens fulfilled the design objective of strong column-weak beam with flexural failure showed at beams ends. In comparison to RC1, PC1 exhibited a 6.4 % increase in peak load-carrying capacity in the positive loading process and a 7.1 % decrease in the negative loading process. On the other hand, PC2 demonstrated approximately 11.9 % higher load-carrying capacity in the positive loading and a 2.0 % lower capacity in the negative loading when compared to RC2. The ductility coefficients of PC1 and PC2 was 3.39 and 2.64, respectively, which were slightly higher than that of RC1 and RC2 (3.01 and 2.43). All specimens exhibited good deformation restoring capacity and plump hysteretic loops, demonstrating satisfactory energy dissipation capacity. Overall, the proposed connection with partially bonded PT tendon showed comparable seismic performance with their CIP counterparts, indicated its promising potential for use in practical engineering applications.

Effects of unbonded prestressing steel tendons and slit dampers on the seismic behavior of precast concrete beam-column joints

This article proposes a novel precast concrete (PC) beam–column joint that uses prestressing steel reinforcement tendons and external steel slit dampers (SSDs) to provide self-centering and energy dissipation capabilities. The SSDs are steel plates cut to a desired shape installed under the beam ends to control their yield through energy dissipation. Three exterior beam–column joint specimens were investigated through quasi-static reversed cyclic loading tests. The specimens included a PC beam–column joint with only an SSD and two PC beam–column joint specimens using unbonded prestressing steel tendons (two in one specimen and four in the other) and an SSD. A fiber-based model using the software Ruaumoko and a code-based design were developed and validated against the experimental results. The test results showed that without the tendon, the specimen was significantly damaged, whereas using unbonded prestressing steel tendons with an SSD endowed the beam–column joint with a higher lateral load capacity of up to 40%. In addition, the ductility improved significantly up to 1.88 times. The developed model and the code-based design were in excellent agreement with the experimental results. Overall, this innovative connection type offers an alternative for seismic-resistant PC structures, and its design enables easy repair after an earthquake.

Seismic behavior of precast columns with unbonded prestressed tendons and energy-dissipating bars: physical and numerical investigations

The study of the strength and failure modes of construction components has become increasingly important with the advent of industrialized construction. Recently, because of the need to promote the survivability of both structures and persons, it has encompassed failure modes associated with seismic threats. This study reports the seismic behavior of precast segmented columns designed with both unbonded prestressed tendons (UPTs) and energy-dissipating (ED) bars. A physical specimen was subjected to a quasi-static cyclic test; this permitted the evaluation of the damage mode and behavior of the energy dissipation mechanism, and permitted the establishment and verification of a fiber beam element simulation model. The model was then used to evaluate the effects of the variation of the design parameters on the behavior of precast assembled columns. The test specimen exhibited stable energy dissipation and a pinching effect during cyclic loading. An analysis using the fiber beam element model with varying design parameters revealed that high-strength concrete could mitigate the concrete damage and residual deformation after an earthquake, and that the concrete strength and steel bar strength should be matched when enhancing the seismic resilience of precast columns with high-strength steel bars. It was determined that increasing the prestress mechanism, namely the ratio of the UPTs, could greatly improve the residual deformation, while the ratio of ED bars is the key factor in enhancing the energy dissipation capacity of the precast columns. Suitable ratios of UPTs and ED bars are the keys to ensuring stable energy dissipation and low residual drifts. Moreover, an increased axial load ratio and prestress level are able to restrain the joint opening and improve the bearing capacity of the precast columns; however, an excessive axial load or prestressing force would result in the rapid degeneration of the carrying capacity and larger residual displacements.

Experimental Study on Secondary Anchorage Bond Performance of Residual Stress after Corrosion Fracture at Ends of Prestressed Steel Strands

In order to explore the secondary bond anchorage performance between prestressed tendons and concrete after the fracture of steel strands in post-tensioned, prestressed concrete (PPC) beams, a total of seven post-tensioned, prestressed concrete specimens with a size of 3 × 7ϕ15.2 mm were constructed firstly, and the steel strands at the anchorage end were subjected to corrosion fracture. Then, the pull-out test of the specimens was conducted to explore the secondary anchorage bond mechanism of the residual stress of prestressed tendons experiencing local fracture. Moreover, the influences of factors such as the embedded length, release-tensioning speed, concrete strength, and stirrup configuration on anchorage bond performance were analyzed. Finally, the test results were further verified via finite element analysis. The results show that the failure of pull-out specimens under different parameters can be divided into two types: bond anchorage failure induced by the entire pull-out of steel strands and material failure triggered by the rupture of steel strands. The bond anchorage failure mechanism between steel strands and the concrete was revealed by combining the failure characteristics and pull-out load–slippage relation curves. The bond strength between prestressed steel strands and concrete can be enhanced by increasing the embedded length of steel strands, elevating the concrete strength grade, and enlarging the diameter of stirrups so that the specimens are turned from bond anchorage failure into material failure.

Reliability evaluation of flexural capacity design provision for UHPC beams reinforced with steel rebars/prestressing tendons

This study investigated the reliability of the flexural capacity prediction models for ultra-high performance concrete (UHPC) beams in various standards, including the Chinese UHPC Code (draft), Chinese standards JGJ/T 465–2019 and JTG 3362–2018, Swiss standard SIA 2052–2016, and French standard NF P18–710–2016. The research was based on two comprehensive databases of 110 reinforced and 47 prestressed UHPC beams. Correlation analysis of the model errors of the flexural capacity formulae was conducted at first. Then, the reliability of the prediction models was analyzed through Monte Carlo simulation (MCS) and first-order second-moment (FOSM) method, considering the design parameters such as material strength, live-to-dead load ratio, longitudinal reinforcement ratio, and prestressing tendon ratio. The results indicated that the prediction model in Chinese UHPC Code (draft) could accurately predict the flexural capacity of reinforced and prestressed UHPC beams among the five specifications, with the mean model errors of 1.06 and 1.02, respectively. The reliability indexes of Chinese UHPC Code (draft), Swiss standard SIA 2052–2016, and French standard NF P18–710–2016 for both the reinforced and prestressed UHPC beams were significantly higher than the specified value of 4.2 in the Chinese standard. The sensitivity analysis showed that the reliability index increased with the increase of live-to-dead load ratio, but it was not significantly influenced by UHPC compressive strength. In addition, the reliability index decreased as the longitudinal reinforcement ratio and prestressing tendon ratio increased. Material partial factor of flexural resistance of the formula in Chinese UHPC Code (draft) was calibrated, and γc= 1.30 was recommended for UHPC beams for safety.

Bond behavior of flexible braided AFRP tendons in high-performance concrete based on pull-out and beam tests

AFRP tendons are manufactured in both rigid and flexible form, where flexible AFRP tendons could be coiled and utilized as external prestressed tendons with significant curvature. This study investigates the bond behavior of flexible AFRP tendons in high-performance concrete (HPC) by examining the effects of tendon types, tendon diameter, concrete types, and test methods. Results show that pull-out failures are prone to occur in specimens with AFRP tendon, whereas splitting failures are prone to occur in specimens with steel tendon. The bond stresses for AFRP tendons reach maximum value within a slippage range of 4.5–10.5 mm, while for steel tendons, the maximum bond stresses occur within a larger slippage range of 17–44 mm. The bond strength of steel tendons is 1.12–1.26 times higher than that of AFRP tendons. Normal concrete (NC) specimens with splitting failure produced maximum 7.1 % higher bond strength compared to HPC. On the other hand, the pull-out failure is determined by the interlaminar shear strength of AFRP tendons, leading to comparable bond strength between NC and HPC. A 5 % difference in bond strength exists between pull-out tests and beam tests with similar failure modes. For AFRP tendons, changing the diameter from 13 mm to 15 mm increases the bonding strength by +6 % to −17 %, which is basically consistent with the existing research that the bonding strength decreases as the diameter increases. This study presented a formula for AFRP tendon bond strength, considering concrete strength, types, tendon diameter, and test methods. The proposed model outperforms existing ones with an average of 0.99 and a variance of 0.13.

Mechanical behaviors of the U-girder for urban maglev transit under temperature loads and train loads

The U-girder has been applied to the China’s Fenghuang Maglev Sightseeing Express for the first time around the world, but mechanical behaviors of the U-girder under different loading conditions have not been investigated comprehensively. Firstly, an elaborate finite element (FE) model of the 25 m U-girder considering the longitudinal prestressing tendons and the detailed track structure is built in the paper, and then an in-situ modal test is conducted to validate the FE model. Furthermore, a coupled dynamic model of maglev train-track-girder system is built by the MTS-DCSP distributed co-simulation platform. Secondly, the stress and deformation of the U-girder under the severe temperature gradient loads are analyzed carefully. The results indicate the maximum stresses always appear near the junction between the floor and the track supporting stands, but they are less than the strength of C55 grade concrete. The temperature-induced deflection on the rail can reach 2.91 mm. Thirdly, under jointly the severe temperature gradient loads and maglev train loads moving at 100 km/h, maglev train can run smoothly through the U-girder, deflection and acceleration amplitude of the U-girder are far less than the limits. However, the maximum transverse tensile stress near the junction reaches 3.0 MPa and exceeds slightly the tensile strength, it implies that the U-girder has the cracking risk of concrete.

A Study on the Performance of Prestressed Concrete Containment with Carbon Fiber-Reinforced Polymer Tendons under Internal Pressure.

As the last barrier to preventing nuclear leakage, it is crucial to enhance the load-bearing capacity and cracking resistance of nuclear containment under internal pressure accidents. Currently, fiber-reinforced polymers are widely used in prestressing concrete structures because of their superior performance, but little research has been conducted on fiber-reinforced polymers in the field of nuclear power plants. In this paper, carbon fiber-reinforced polymer (CFRP) is used as a prestressing tendon material instead of traditional steel strands to study the damage mode of the new type of containment under internal pressure and the feasibility of using CFRP as prestressing tendons. In this study, a three-dimensional refinement model is established, employing ABAQUS 2020 software to analyze and quantify the pressure-bearing performance of nuclear containment with CFRP tendons and finally determine the reasonable range of CFRP tendons that can be used as a replacement. The research shows that the containment with CFRP tendons has an obvious strengthening effect in delaying the generation of cracks, restraining the speed of crack development, reducing the plastic damage of the steel liner, and improving the ultimate bearing capacity of the containment.

Shear stress migration in a tapered girder with trapezoidal corrugated steel webs

This study conducted a comprehensive investigation into the shear stress migration of a tapered prestressed concrete (PC) continuous box girder bridge with trapezoidal corrugated steel webs (TCSWs) throughout the entire construction process, including cantilever construction, structural system transformation and external prestressing tendon tensioning. The results revealed that the basic assumptions, which state that TCSWs bear all the shear force and that only the vertical component of the external prestressing contributes to shear stress when considering its contribution, are not valid for the shear design of tapered PC girder bridges with TCSWs. The horizontal component of the external prestressing and bending moments can cause additional shear forces via the Resal effect, which results in the migration of the shear stresses between the curved bottom concrete slabs and TCSWs. This study investigated the mechanism through which the Resal effect and external prestressing influence the migration of shear stress in the entire construction process. The results revealed that within continuous girders, the Resal effect exhibits both positive and negative implications. Specifically, the negative Resal effect exerts an unfavorable influence, resulting in an increase in the shear stress experienced by the TCSWs. Moreover, this study introduced a modified shear method that that takes into account the influence of bending moments and the horizontal component of external prestressing. In contrast to basic shear methods, this approach provides notably heightened accuracy.

Lumped Plasticity Model and Hysteretic Performance of Ultra-High-Performance Concrete Rocking Pier.

Rocking piers using ultra-high-performance concrete (UHPC) have high damage-control capacity and self-centering characteristics that can limit the post-earthquake recovery time of bridges. To study the hysteretic behavior of UHPC rocking piers, a lumped plasticity model is proposed that comprises two parallel rotational springs and which can accurately calculate their force-displacement hysteretic behavior. Three states of the rocking piers, decompression, yield, and large deformation, are considered in this study. The model is verified based on existing experimental results, and the hysteretic characteristics of the UHPC rocking piers, such as strength, stiffness, and energy dissipation, are further analyzed. The research results show that the lumped plasticity analysis model proposed in this study can predict the force-displacement hysteretic behavior of the rocking piers accurately. Moreover, the hysteretic performance of the UHPC rocking piers is better than that of rocking piers using normal-strength concrete. An increase in the energy dissipation reinforcement ratio, pre-stressed tendon ratio, and initial pre-stress improves the lateral stiffness and strength of the UHPC rocking piers. However, the increase in the pre-stressed tendon ratio and initial pre-stress reduces their energy-dissipation capacity.