Precast Reinforced Concrete Research Articles

Flexural behavior of high-strength steel-precast prestressed concrete composite beams with grouped demountable bolts under hogging moment

To study the bending behavior of high-strength steel (HSS)-precast reinforced concrete (PRC) slab composite beams with grouped demountable bolts under hogging moment, single-point loading tests were carried out to evaluate the bending behavior of the five prefabricated composite beams, and the key parameters are shear connection degree, shear pocket spacing in the PRC slab, and applying precompression to the concrete or not. The test results indicate that the HSS composite beams have good overall bending behavior, and two failure modes are recorded including the flexural failure, and the concrete damage in the shear pocket region. The prestressing force can effectively increase the anti-cracking performance of the slab and slightly improve the bending behavior, while increasing the shear connection degree from 1.80 to 3.61 or the shear pocket spacing from 360 mm to 800 mm (the limit value in the AASHTO LRFD Bridge Design Specifications is 610 mm) under the same shear connection degree has a limited influence on the bending behavior, and the composite beams still have the effective composite action. The existing formulas are conservative in calculating the bending capacity of HSS composite beams but have a high degree of consistency in stiffness.

Experimental investigation on the horizontal impact response of precast RC bridge piers with grouted sleeve connections considering defects

To investigate the behaviour of precast bridge piers with grouted sleeve connections under horizontal low-velocity impact loads, twelve precast reinforced concrete (RC) bridge pier specimens and two cast-in-place reference specimens were tested to study the effect of grouting defect degree, impact velocity and fabricated method (precast vs. cast-in-place) on the impact response of RC piers. The failure modes, rebar strains, impact forces, displacement, and energy dissipation capacity of both cast-in-place and precast specimens were compared and analyzed. The results indicate that due to inertial effects induced by impact loading, the peak impact forces were three to seven times greater than the peak static loads. Transverse cracks were more likely to initiate in the grout layer for precast specimens, with diagonal cracks extending from the loading position to the pier bottom after impact. As horizontal impact velocity increased, the impact force, maximum displacement, and energy absorption ratio also significantly increased. The impact force-time curves of the pier specimens with grouting fullness ranging from 30 % to 100 % showed minimal differences compared to the cast-in-place specimen. A decrease in grouting fullness led to an increase in the maximum displacement of the pier specimens and reduced the transmission of impact waves between the reinforcement bars.

Impact resistance performance of precast reinforced concrete barriers with grouted sleeve and steel angle-to-plate connections

This study presents the experimental and numerical investigations on the impact resistance of precast reinforced concrete (RC) barriers with grouted sleeve and steel angle-to-plate connections. Four full-sized precast RC barriers were prepared and tested using the pendulum impact facility. Three main parameters, including spacing of grouted sleeves, number of steel angle-to-plate connections and impact energy, were considered in the tests. The failure mode, impact force and lateral deflection of barriers were recorded and analyzed. Under impact loading, the spider-web-like cracks mainly occurred on the rear surface of the barrier, and the presence of the grout sleeve and steel angle-to-plate connections ensured strong anchoring. Additionally, finite element (FE) model was established and calibrated with the test results. With the calibrated models, the dynamic motion process, distributions of stress and strain, and energy absorption of precast RC barrier were analyzed and compared with the cast-in-place barrier. Finally, the influences of impactor mass, impact velocity, grouted sleeve spacing, and steel angle-to-plate connection spacing on the impact resistance were evaluated in the parametric analysis.

Assisting Load Rating Testing of Precast Reinforced Concrete Bridge Slab through Digital Twins and Field Monitoring Data

Assisting Load Rating Testing of Precast Reinforced Concrete Bridge Slab through Digital Twins and Field Monitoring Data

Progressive Collapse Behavior of a Precast Reinforced Concrete Frame System with Layered Beams

A possible way to improve the structural safety and robustness of precast building structures is to develop effective precast frame systems with layered beams, which combine prefabricated parts with cast-in situ ordinary concrete, high-performance concrete, fiber concrete, or FRP. The paper provides a new type of precast reinforced concrete frame system with layered beams for rapidly erected multi-story buildings resistant to accidental actions. Using a combination of the variational method and two-level design schemes, a simplified analytical model has been developed for structural analysis of the precast reinforced concrete frame system, both for serviceable and ultimate limit states as well as for accidental actions. The proposed model allows for determining shear deformations and the formation and opening of longitudinal cracks in the intermediate contact zone between precast and monolithic parts of reinforced concrete structural elements of the frame, as well as the formation and opening of normal cracks because of the action of axial tensile force or bending moment in these elements. The design model was validated by comparing the calculated and experimental data obtained from testing scaled models of the precast reinforced concrete frame system with layered beams. The paper investigates and thoroughly analyzes the factors affecting the stiffness and bearing capacity of the intermediate contact zone, discusses the criteria for the formation of shear cracks along the contact zone of precast and monolithic concrete, and examines the change in the stiffness and dissipative properties of layered elements at different stages of their static–dynamic loading. The robustness of the experimental models of the structural system was not ensured under the specified load, section dimensions, and reinforcement scheme. Following an accidental action, longitudinal cracks were observed in the contact joint between the monolithic and prefabricated parts in the layered beams. This occurred almost simultaneously with the opening of normal cracks in adjacent sections. A comprehensive analysis of the results indicated a satisfactory degree of agreement between the proposed semi-analytical model and the test data.

Numerical analysis of high-strength centrifugal precast RC hollow pipe columns using grouted corrugated duct connection: Confinement effect and ductility evaluation

High-strength centrifugal precast (HSCP) reinforced concrete (RC) hollow pipe columns using grouted corrugated duct connection (GCDC) is a novel structure form in accelerated bridge construction (ABC). Nevertheless, the confinement effect of the HSCP hollow column core concrete provided by single-layer transverse rebar and its impact on ductility is not clear. Therefore, in this paper, the confinement effect and the ductility of hollow columns is studied using finite element analysis (FEA) method. A modified model is established to evaluate the constitutive relation of the core concrete confined by single layer transverse rebar. Based on the modified model, a simplified fiber model for predicting the hysteric response of HSCP hollow pipe column using GCDC, which considers bond-slip effect in GCDC joint was developed. The results indicate that the confinement effect of HSCP hollow pipe column is sensitive to the wall thickness ratio. When the wall thickness ratio decreases, the ultimate strain of the core concrete significantly decreases, while the effect on strength is not significant. The simplified model which considers confinement effect is more accurate in predicting the ductility of HSCP hollow columns. It proves that the weak confinement effects can lead to early cracking of the inner wall of hollow columns, which leads a significant impact on the ductility of HSCP hollow columns. Based on the parametric analysis, the peak load of the hollow column increases by 16.7% when the wall thickness ratio rises from 0.1 to 0.2, but only slightly changes when the wall thickness ratio is increased beyond 0.2. The wall thickness ratio of HSCP hollow pipe columns should be set above 0.2 to ensure the strength and ductility. In addition, a ductility evaluation method and a design example were developed to guide preliminary ductile design of HSCP hollow columns.

Seismic performance of novel low-damage stair system: Precast reinforced concrete stair isolated with a sliding joint

This research presents a solution that can solve the negative diagonal support effect of the traditional precast reinforced concrete stair with rigid connection (TS) and adverse stress centralization on the fragile reinforced concrete (RC) flight. This innovative low-damage stair system utilizes a sliding joint at the bottom of the precast RC stair (SS). Experimental and numerical investigations were implemented on specimens TS and SS to systematically evaluate the seismic responses of the presented low-damage stair system. Experiment results confirm that specimen SS could effectively eliminate the detrimental diagonal support effect of conventional stair systems and the unexpected overlarge stress concentration of the RC components. Therefore, the RC flight and landing beam of the proposed low-damage stair systems remained undamaged at the inter-story drift ratio up to the final level of 4.00%. Taking advantage of the sliding joint, specimen SS behaves with excellent hysteretic performance and energy dissipation capacity. Furthermore, parametric analysis results reveal that the concrete strength remarkably affects the seismic responses of the innovative stairs, while the impact of the friction factor of the sliding joint on the seismic performance is asymmetric during positive and negative loadings.

Investigation of Precast Reinforced Concrete Structures during the 6 February 2023 Türkiye Earthquakes

On 6 February 2023, two major earthquakes, MW7.7 and MW7.6, occurred in the Kahramanmaraş city region of southeast Türkiye. As a result of the earthquakes that affected the region, around 60,000 people died and thousands of buildings suffered various levels of damage. In this study, the collapse and failure mechanisms of precast reinforced concrete structures, most of which are industrial buildings, and the damages occurred in these structures, were investgated through on-site observations. As a result of the investigations carried out in the field immediately after the earthquake, it was understood that most of the damage was caused by the connection system of the precast structures. The most common damage is the separation of the roof beam from the column due to the weak column–beam connection system. At the end of the paper, studies to strengthen and improve suggestions for this poor behavior will be mentioned. Also, by analyzing a sample structure, the performance levels were determined by comparing it with the damage limit values in TBEC-2018.

Seismic performance of full-scale prefabricated semi-rigid bolted connection between RC column and composite beam

This paper presents a novel proposal for an assembled bolted joint between precast reinforced concrete (RC) column and steel-concrete composite beams, focusing on its seismic performance. To evaluate the joint's behavior, a comprehensive experimental investigation was conducted on a full-scale RC column to composite beam joint specimen subjected to pseudo-static loading. The study aimed to analyze the joint's failure mode, bearing capacity, ductility, and energy dissipation characteristics. The joint stiffness was assessed by analyzing the bending moment-rotation (M-θ) curve of the beam in accordance with the European standard BS EN 1993-1-8:2005. The experimental results demonstrate that the proposed assembled bolted joint exhibits semi-rigid behavior under positive moments and approaches rigidity under negative moments. To further enhance our understanding of the joint's performance, a finite element model was developed using ABAQUS. The stress distribution in each joint component, as well as the failure mode and ultimate bearing capacity, were analyzed in conjunction with the experimental results. Based on the findings from both the experimental and finite element analyses, an improved joint design is proposed. Additionally, parametric analysis was conducted on the enhanced joint configuration. The study findings indicate that the improved joint exhibits superior damage resistance, seismic performance, and enhanced assembly efficiency compared to the original design. This research contributes to the advancement of assembled bolted joints between precast RC columns and steel-concrete composite beams, offering valuable insights for practical applications in seismic regions.

Flexural performance of precast circular reinforced concrete members with intermediate connection filled with ultra-high-performance-concrete

Precast Reinforced concrete (RC) columns with circular sections are increasingly being utilized in the construction of RC structures. This paper reports investigations into the flexural behavior of precast circular RC members with an intermediate connection filled with Ultra-High-Performance-Concrete (UHPC). Experimental program and results are described of twelve RC circular members tested under four-point loads up to collapse. Of the twelve columns, three of them are solid ones without intermediate connection, while nine of them are precast Normal Concrete (NC) panels connected with UHPC. The studied parameters are the existence of an intermediate connection (with and without connection), the ratio of longitudinal reinforcement (µ) ratio and the length of steel bars embedded in the UHPC connection (Le). Three concrete types are used including Normal Concrete (NC), Strain Hardening Cementitious Composite (SHCC), and UHPC. Test results show that increasing the reinforcement ratio and the embedded length of the steel bars increases the strength and energy absorption of members. Finite element models (FEMs) developed using ABAQUS are presented for capturing the responses of RC columns incorporating different concrete types. The good agreement between computer simulation and experimental results suggests that the FEMs can be utilized to undertake further parametric studies with confidence.

Steel corrosion in precast reinforced concrete column-beam joint with grouted sleeve connections under chloride-rich environment

Due to the existence of pump and vent holes, precast reinforced concrete (RC) structure with grouted sleeve connections may have serious durability issues, which have almost never been studied. In this paper, a precast RC column-beam joint specimen with grouted sleeve (GS) connections, as a comparison of a cast-in-place specimen, was exposed to chloride-rich environments for 4 years. The steel corrosion and its impacts on specimen were investigated by visual inspections, X-ray computed tomography (X-ray CT) and data analysis. The test results showed that the precast RC specimen exhibited porous and loose interfaces between PVC tubes, sleeve and cement-based materials within the GS connections, leading to more severe stirrup corrosion compared to the cast-in-place specimen. In contrast, the sleeve, grouting material and their interfaces were dense so that the longitudinal bars inside had been well protected. Besides, the chloride diffusion coefficient of concrete cover in the two specimens were quantified. The corrosion level of precast RC structures with GS connections was found to grow more rapidly versus service year. On this basis, several precautions for alleviating the negative impact of GS connections on steel corrosion were proposed.

Seismic Performance of an Earthquake Resilient Self-Centering Precast Reinforced Concrete Rocking Wall with External SMA Rods

ABSTRACT This research aims to propose an alternative way to provide a recentering force to a precast unbonded post-tensioned reinforced concrete rocking wall (RW) using shape memory alloy (SMA) bars. The physical and mechanical properties, such as fatigue, corrosion resistance, and large damping capacity, qualify the SMA to be at the forefront of materials used in structural engineering applications. In this study, the SMA bars replace the post-tensioned tendons to minimize the permanent deformation resulting from the system’s exposure to the lateral loading coming from the seismic events. The SMA bars are attached externally to the wall and fixed with the base to facilitate the installation process and reduce the repairing time if a failure occurs under unexpected events. The proposed system shows that the SMA rods can play the same role as the PT tendons to minimize the residual displacement while also providing an acceptable level of energy dissipation to the system.

Structural behaviour of 2D post-tensioned precast beam-column sub-assemblages subjected to column loss scenario

Many previous studies have investigated alternative load path (ALP) mechanisms of 2D reinforced concrete (RC) beam-column sub-assemblages under column removal scenarios. However, how precast and prestressed RC structures respond under a column loss scenario receives far less attention, as evident from a lack of published test data. Herein, five 2D post-tensioned precast RC sub-structures subjected to a middle column loss scenario were tested by multi-point quasi-static loading. In all the specimens, individual precast members such as beams and columns were joined together through wet connection. The study focused on investigating the combined effects of post-tensioned tendon (PT) and wet connection on load-resisting mechanisms and the influence of basic parameters such as unbonded and bonded PT, T-beam effect, and boundary conditions. The test results indicated that both unbonded and bonded parabolic-shaped PT significantly enhanced compressive arch action (CAA) and catenary action (CA) beyond basic flexural capacity, and also changed the plastic hinge mechanism in the precast beams. The specimen with unbonded PT could provide greater residual capacity than bonded PT, but the former was severely damaged by fracture of normal reinforcement and crushing of concrete rather than fracture of the tendon. In addition, the effects of T-beam and boundary conditions are discussed in detail. Finally, new design criteria for precast and post-tensioned concrete structures under column removal scenarios are proposed for structural engineers to take advantage of high-strength tendons and avoid failure at critical locations by precast joints.

Seismic performance assessment of precast RC shear wall structure with lead viscoelastic damper

The precast reinforced concrete (RC) shear wall structure with lead viscoelastic damper is a combination of shear wall with horizontal connectors and vertical energy-dissipating connectors. The lead viscoelastic damper (LVED) is adopted as the vertical wall-wall joint to increase the plastic deformability of shear wall and provide additional strength and energy dissipation. The pore-forming grouted lap-sliced connector is adopted as the horizontal wall-floor joint to ensure the overall seismic performance of the shear wall. Firstly, cyclic loading tests were conducted to investigate the influence of lead and viscoelastic layer thickness on the hysteretic behaviour of LVED, and the theoretical method and finite element analysis model for LVED were also proposed and validated by the test results. Additionally, the seismic behaviour of precast shear walls with and without LVEDs was studied experimentally and numerically. It was shown that better cooperative working performance was observed in the precast shear wall with LVED. Finally, the dynamic responses of precast frame-shear wall structure adopting LVED was investigated based on dynamic time-history analysis.

Evaluation Method for Ultimate Flexural State of Prestressed Precast Reinforced Concrete Beam–Column Connection with Debonded Partial Tendon

In this paper, a prestressed precast reinforced concrete (PC) beam–column connection incorporating posttensioned debonded partial tendons is introduced for PC frame structure. Compared with the conventional cast-in-place frames and many previously proposed connections for PC frames, this connection has the advantage of self-centering and low damage in strong earthquakes. In addition, the debonded partial tendons can reduce the posttensioning demand and further reduce site labor during construction and repair. In order to establish a performance evaluation method for the ultimate flexural limit of the proposed PC connection, an analytical model was developed to accurately reflect the deformation compatibility and force equilibrium conditions of the PC beam and column members, as well as the debonded partial tendons. Based on this, iterative and direct evaluation methods for the strength and deformation of the PC connections, as well as the strains of the debonded tendons, were developed. The proposed methods were verified by cyclic loading test on the beam–column connection subassemblages. It is concluded that the proposed method is sufficiently accurate and simple to be applied in engineering design, and is helpful to guarantee the self-centering and low-damage characteristics of the proposed connection against a strong earthquake.

Analytical approach and design method for evaluation of compressive arch action of precast concrete beams

This paper proposes an analytical approach to predict compressive arch action (CAA) of precast reinforced concrete (PC) beams subjected to middle column removal scenario (MCRS). A beam-column joint with non-seismic detailing is employed in the prototype PC structures, which is a typical joint widely applied in low seismic-risk countries. However, under MCRS, a weaker sagging moment resistance of the precast interface near the removed middle column casts doubts on its structural performance. Based on particular details of the PC beams, the analytical approach is proposed to consider the influences of a potential plastic hinge at the PC interface, various precast interface locations, special precast reinforcing details and horizontal restraint conditions on the mobilisation of CAA. Furthermore, an easy-to-apply design method is developed by assuming linear relationships between bending moment, neutral axis depth and compression force of the PC beam. Reliability of the analytical approach and the design method is verified through comparisons between predictions and FEM simulations of typical two-span PC sub-assemblages with various design details. The comparison study suggests that both the analytical approach and design method can accurately predict the CAA capacity and corresponding displacement, as well as the maximum compression force and bending moment at PC beam ends. Finally, a parametric study is carried out to shed light on the effects of different precast interface locations and various common design details on CAA peak resistance. It is found that when the distance (L3) between the precast interface and the beam end interface does not exceed a threshold value (L3_c), increasing L3 can significantly enhance CAA capacity. However, when L3 exceeds L3_c, CAA cannot be further enhanced due to transformation of CAA mechanism. It also finds that the threshold value L3_c is highly influenced by reinforcement details, span-over-depth ratio and horizontal stiffness of the beam.

Sustainability Impacts of Wood- and Concrete-Based Frame Buildings

The European Commission adopted a long-term strategic vision aiming for climate neutrality by 2050. Lithuania ratified the Paris agreement, making a binding commitment to cut its 1990 baseline GHG emissions by 40% in all sectors of its economy by 2030. In Lithuania, the main construction material is cement, even though Lithuania has a strong wood-based industry and abundant timber resources. Despite this, approximately twenty percent of the annual roundwood production from Lithuanian forests is exported, as well as other final wood products that could be used in the local construction sector. To highlight the potential that timber frame construction holds for carbon sequestration efforts, timber and concrete buildings were directly compared and quantified in terms of sustainability across their production value chains. Here the concept of “exemplary buildings” was avoided, instead a “traditional building” design was opted for, and two- and five-floor public buildings were selected. In this study, eleven indicators were selected to compare the sustainability impacts of wood-based and concrete-based construction materials, using a decision support tool ToSIA (a tool for sustainability impact assessment). Findings revealed the potential of glue-laminated timber (GLT) frames as a more sustainable alternative to precast reinforced concrete (PRC) in the construction of public low-rise buildings in Lithuania, and they showed great promise in reducing emissions and increasing the sequestration of CO2. An analysis of environmental and social indicators shows that the replacement of PRC frames with GLT frames in the construction of low-rise public buildings would lead to reduced environmental impacts, alongside a range of positive social impacts.

Behavior of Confined Headed Bar Connection for Precast Reinforced Concrete Member Assembly

The mechanical performance of precast RC structures relies on the connections, especially the connections of steel bars, between precast RC members. Grouted sleeve splices and grouted spiral-confined overlap connections are widely used in engineering practice in China. Both of these two connection splices require on-site grouting. The process is concealed and invisible, leading to difficult on-site inspection. The unseen defects cause a challenge for detection and repair, which may impair the reliability of precast RC members’ behavior. This paper presents an RC member assembly connection with visible on-site construction quality-monitoring. The proposed confined headed-bar connection (CHBC) consists of two overlapping headed bars and confinement stirrup. With CHBC, the potential construction defects are diminished, and subsequently the construction quality as well as the reliability is upgraded. Experimental investigation on 18 CHBC specimens was carried out; the main parameters considered were overlap length and bar-head size. The failure modes, bearing capacity, stirrup strain development and bond versus slip response are studied. Working mechanism of CHBC is investigated in terms of bond behavior force and concrete compression force at head experimentally and numerically; distributive relationship of these two forces is revealed. The results show that for Φ12 reinforcement, a 90 mm overlap length under test parameters is adequate to reach headed bar ultimate strength in CHBC. Finally, a CHBC-bearing capacity prediction method is suggested based on the superposition method and strut-and-tie model theory.

Quasi-Static Cyclic Flexural Loading Behavior of Precast Reinforced Concrete Tunnel Segments with Glass Fiber-Reinforced Polymer Bars

Quasi-Static Cyclic Flexural Loading Behavior of Precast Reinforced Concrete Tunnel Segments with Glass Fiber-Reinforced Polymer Bars

Construction of Precast Reinforced Concrete

Construction of Precast Reinforced Concrete