Precast Concrete Piers Research Articles

Numerical parametric study on ultimate load of precast concrete piers with demountable connections

To investigate the flexural capacity of precast piers with demountable steel-concrete composite connection, based on the model test, the refined finite element model was developed. The flexural capacities were compared between cast-in-place (CIP) piers and precast piers with different parameters including the thickness of base steel plate and notched perfobond connector, material strength, open-hole size of base steel plate, height of jacket, and axial compression ratio. The results show that the flexural capacity of concrete precast piers with rationally designed connections should not be lower than that of CIP piers. The cracking load and flexural moment-axial compression ratio curve can be evaluated as CIP piers. The ultimate flexural capacity is positively correlated with the base steel plate thickness and jacket height. The notched perfobond connector and the stiffeners set on the base steel plate can effectively improve the flexural capacity and optimize the shape of yielding line of base steel plate. The steel strength should be greater than 300 MPa in order to ensure that the steel connection yields later than the longitudinal reinforcement. Finally, the simplified model of base steel plate and the influence mechanism of the steel plate are discussed. This paper provides reference for the design of the proposed piers and other similar connections.

Experimental and numerical investigation of the seismic behaviour of corroded precast concrete piers with grouting sleeve connections

Due to several advantages, including controllable tolerance, accelerated construction and environmental friendliness, the grouting sleeve connections has been widely used in precast concrete pier structures. However, the seismic capacity of precast concrete piers would be significant impaired under the marine or deicing-salt environment. This article presents an experimental investigation on the seismic behaviour of corroded precast concrete piers with grouting sleeve connections. Five specimens with different corrosion levels were tested under cyclic loads. Seismic capacities of specimens with different corrosion levels, including hysteretic behaviour, stiffness degradation and energy-dissipation capacity, were analysed. The results showed that corrosion of reinforcements and grouting sleeve connections would significantly affect the seismic behaviour of the piers. The crack load, yield load and peak load decreased gradually with the increase of corrosion ratio, with the effect of corrosion on peak load being slightly greater than that on yield load. An approximate exponential decrease in yield displacement and peak displacement was observed as the corrosion ratio increased, and the decline rate in yield displacement and peak displacement gradually decreased. A numerical method for simulating the seismic behaviour of corroded precast concrete piers with grouting sleeve connections is proposed, and agreement between simulated and experimental results is observed.

Genetic Programming–Based Drift Ratio Limit Models for Segmental Posttensioned Precast Concrete Piers

Segmental posttensioned precast concrete (SPPC) is a promising approach to accelerated bridge construction (ABC). However, an impediment to the performance-based design of SPPC piers lies in the challenge of defining appropriate damage states and corresponding engineering demand parameter (EDP) limits. To address this, in this study, genetic programming (GP), a form of artificial intelligence, is used to develop drift ratio–based EDP limit models in order to identify the onset of four damage levels that are particularly introduced herein for SPPC piers. In this respect, a finite-element model using ABAQUS is developed and experimentally validated to simulate the response of SPPC piers under seismic loading. The model is then utilized to generate a data set of 316 cases, all within the feasible design space of SPPC piers. This data set is subsequently used to develop GP-based predictive equations that map the relationship between different SPPC pier design parameters (e.g., posttensioning strand ratio, concrete compressive strength, and gravity load level) and EDP (i.e., drift ratio) limits. The performance of the developed equations is evaluated through different measures, including fitness function and performance index. Ultimately, parametric and sensitivity analyses are conducted to demonstrate that the GP-based equations are robust enough to characterize the four damage states for SPPC piers.

Vehicular impacts on precast concrete bridge piers with grouted sleeve connections

The grouted sleeve connection has been demonstrated to be robust enough to maintain its integrity under earthquake loads. However, no research to date has examined the connection behaviour under direct shear, resulting in a high risk of failure of the pier subject to a vehicle collision. In this regard, this research first carried out static and impact loading tests on grouted sleeve specimens to characterize their direct shear damage mechanisms. Next, a simplified finite element (FE) modelling method was proposed to simulate connection behaviour, and its accuracy was verified using the test results. Based on the proposed connection modelling approach, truck-bridge collision analysis was performed on a prototype highway bridge that uses grouted sleeves in the pier. From the analysis results, increasing the number of column segments can lead to higher stiffness of the pier when resisting the vehicular impact. The friction property at the connection interface plays an essential role in avoiding unacceptably large rebar shear stress due to excessive sliding and developing the diagonal compression strut to resist the impact load. Finally, feasible retrofit techniques were explored for the precast concrete piers that showed inadequate impact resistance.

Stabilitas Pilar Beton Pracetak Segmental Pada Jembatan Standar Terhadap Beban Dinamik

The use of precast technology in the manufacture of segmental components for the bridge substructure is one application that can be used in the acceleration of bridge construction. Better concrete quality and precision are two advantages that can make precast technology a solution in accelerating bridge construction. Commonly, segmental precast concrete piers are not designed to resist earthquake loads; however, the use of segmental piers systems is still possible in seismic zones by limiting additional dead loads. This study discusses the load limitation using the dynamic response calculation methodology of segmental precast concrete pillar structures to the El Centro (1940) earthquake load by varying the slenderness of the piers/column between 22 to 100. Examination of the stress combination due to axial load (DL) and inertia load due to the earthquake is carried out to find out how much residual stress can be accommodated by the piers/columns. Additional dead load (WADD) is obtained by using Newton's second law by dividing the allowable additional inertial load based on the residual stress to the peak ground acceleration. The calculation results show a good correlation between piers’/columns’ slenderness and the proportion of additional dead load (WADD) to dead load (WDL), so that the applicability of using segmental precast concrete piers/columns in seismic zones can be predicted earlier through this correlation.

Load transfer mechanism of precast concrete piers with demountable connections

To investigate the replacement or rehabilitation of precast concrete piers, a novel demountable steel-concrete composite connection with notched perfobond connectors was proposed for the pier-pile cap joint. In the proposed connection, a bolted mechanical connection is used to connect the longitudinal reinforcing bars and steel plate, which is bolted to the pile cap through pre-stressed anchor bolts. Pseudo-static capacity tests of two half-scale specimens were conducted with different axial compression ratios, and the experimental results were verified by nonlinear finite element analysis. The lateral force-displacement curves, failure modes of connection joint, stress of steel plates and connector-concrete slip were compared and discussed. Furthermore, the internal load transfer mechanism and characteristics were revealed. The results indicate that the precast pier with the proposed connection realizes the rapid assembly and demountability. Specimens present flexural failure, and damage appears at the bottom of the pier columns but above the steel jacket. The connection steel plates and bolted connection remain intact as expected. The stiffness, capacity and failure process in numerical analysis agree well with the experimental results. The notched perfobond connectors set on the base plates effectively transfer the force from the concrete column to the base plate, and enhance the base plate-concrete connection and bending resistance of the base plate.

Seismically Resilient Hybrid Precast Concrete Piers with Ultrahigh-Performance Concrete

Abstract This paper investigated a novel hybrid precast pier system that utilized ultrahigh-performance concrete (UHPC). The pier combines features of emulative and nonemulative (of cast-in-place c...

A hysteretic model for self-centering precast concrete piers with varying shear-slip between segments

Self-centering, precast, post-tensioned concrete, bridge columns can provide low-damage under earthquake loading and accelerated bridge construction. These columns can also be designed so that shear-slip occurs between precast segments to provide energy dissipation. This paper, first, presents experimental results of large-scale testing of pier specimens that can self-center and undergo shear-slip under cyclic lateral loading. In these tests, segment interface properties, which control shear-slip, changed as the silicone layer placed between each segment degraded during testing. Specimens with fresh silicone had more energy dissipation, lower stiffness, and higher residual displacements compared with the ones with degraded silicone.A hysteretic model is created to predict the global load-displacement behavior of piers under lateral loading by superimposing self-centering and shear-slip responses. Shear-slip measurements under both quasi-static and rapid cyclic tests were used to characterize the interface frictional properties to be used in hysteretic modeling. Friction coefficients of segment interfaces were also investigated under varying accumulative displacement, normal force, and shear-slip velocity. The proposed hysteretic model is validated using the experimental results.A parametric study was performed using the established hysteretic model to investigate the influence of friction properties of interface materials and initial post-tension forces on the seismic response. The results show that interface materials with lower friction coefficient will lead to enhanced energy dissipation, lower stiffness, and smaller self-centering capability. Selecting lower initial post-tension force decreases the stiffness. Finally, incorporating the hysteretic model in the Capacity-Demand-Diagram method, seismic response of piers with varying properties was predicted. The increase in friction coefficient and initial post-tension force consistently increases the maximum base shear demand. Increasing initial post-tension force decreases the peak displacement in most cases. Increasing friction coefficient can either increase or decrease the peak displacement.

Ultrahigh-Performance Concrete for Posttensioned Precast Bridge Piers for Seismic Resilience

AbstractPrecast concrete bridge substructures accelerate construction. Precast concrete piers can also limit residual displacements after earthquakes when used with nonemulative connections. This p...

Performance assessment of precast concrete pier cap system

The purpose of this study was to investigate the performance of precast concrete pier cap system. The proposed precast pier cap provides an alternative to current cast-in-place systems, particularly for projects in which a reduced construction time is desired. Five large-scale pier cap specimens were constructed and tested under quasistatic monotonic loading. The computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology) was used for the analysis of reinforced concrete structures. A bonded tendon element is used based on the finite element method, and can represent the interaction between the tendon and concrete of a prestressed concrete member. A joint element is used in order to predict the inelastic behaviors of segmental joints with a shear key. This study documents the testing of the precast concrete pier cap system under monotonic loading and presents conclusions and design recommendations based on the experimental and analytical findings. Additional full-scale experimental research is needed to refine and confirm design details, especially for actual detailing employed in the field.

New Technologies Proven in Precast Concrete Modular Floating Pier for U.S. Navy

Representing a breakthrough in naval vessel berthing infrastructure, a test bed structure for a large-scale modular hybrid floating pier was designed with state-of-the-art precast/prestressed concrete technology and a number of material and design innovations. In 2004, the $5 million 15.2 x 30.5 x 8.8 m (50 x 100 x 29 ft) test structure was fabricated, erected, and open-ocean towed to its final destination in San Diego, California, as proof of concept for a future $45 million, 400 m (1300 ft) long double-deck floating pier for the U.S. Navy. The Modular Hybrid Pier was conceived as a replacement for obsolete and deteriorating naval berthing facilities. Designed for 100 years of repair-free service, the pier will provide a high level of support services to a variety of vessel classes and facilitate a rapid upgrade of vessel utilities with the advance of fleet support system technologies. More than 25 government, university, and private entities collaborated to develop this groundbreaking concept in precast concrete pier infrastructure.

Physical Modeling of Foundations for Northumberland Strait Crossing

The 13-km-long Northumberland Strait Crossing will become the longest continuous marine span bridge in Canada. The marine and navigational spans of the bridge will be supported by 44 precast concrete piers founded on bedrock using ring-shaped footings in a maximum water depth of 35 to 40 m. Bedrock stratigraphy ranges from massive strong sandstone to a variable sequence of thinly bedded weak mudstones and siltstones. Foundation conditions vary significantly from pier to pier and in several cases can vary through the vertical and lateral extent of a particular foundation. In addition to the complex foundation conditions, the large horizontal environmental loadings on each pier must be considered in the geotechnical analyses. Reduced-scale physical model tests of selected marine piers on a centrifuge investigated potential mechanisms of failure and examined how these mechanisms varied with loading and foundation conditions. The results of the experimental program were used in conjunction with analytical results to enhance the fundamental understanding of the geotechnical aspects of foundation design and have led to an improved design methodology.

SECOND SEVERN CROSSING - VIADUCT SUPERSTRUCTURE AND PIERS.

This paper describes the design and construction of the 4.2 km long viaduct for the second Severn motorway bridge between England and Wales. The design of the precast segmental deck was heavily influenced by the Government's requirement of external post-tensioning tendons with free lengths limited to 40% of span. Over 2200 deck units up to 200 t in weight were match-cast on site and erected in balanced cantilever using a 234 m long launching gantry. The paper also describes the precast concrete piers, elastomeric bearings, movement joints, deck finishes and furniture, mechanical and electrical works (including a monorail deck access train and three service gantries) and the toll plaza. (A) For the covering abstract see IRRD 896358.

Design and construction of foundations for bridges on the Kuantan to Segamat Highway, Malaysia : Kemp, G J; Chew, S H Proc International Conference on Structural Foundations on Rock, Sydney, 7–9 May 1980, P271–281. Publ Rotterdam: A A Balkema, 1980

This paper details the sub-surface investigations, design considerations and construction techniques associated with two bridges, namely the bridges over the keratong and rompin rivers. The 250 m long prestressed concrete bridge over the keratong river was designed to be overtopped during floods of large return period. Under such conditions and under some live load conditions tension could be induced into the precast concrete pier piles. In some locations, these piles were founded on fresh granite some 9 m below the pile cap and after allowing for some scour had insufficient penetration to provide adequate resistance against uplift. For this reason, the driven square precast reinforced concrete tension piles for the piers were cast with a central circular duct and after driving to bedrock and capped were post- tensioned to the bed- rock and grouted, using prestressed rock anchors. The 330 m long rompin river bridge was designed to be submersible and carried similar loads to those of the keratong river and as well was required to straddle a highly faulted rock zone which generally followed the course of the river in the vicinity of the bridge sito. The highly fragmented and crushed rock along the fault line had low bearing and tensile capacities and the piers supporting the main channel span of the bridge had to be founded on this crushed igneous and sedimentary rock.