Precast Concrete Girders Research Articles

Bridge Across the River Vah's Reservoir Hricov and Over the Road I/18, Motorway D3 in km 7.500

This bridge structure is designed as twin bridge of total length 1.40km, the structure has only two expansion joints in its length. Each bridge structure is designed as precast concrete girder with 29 and 30 spans.Three methods of casting were designed for this project, symmetrical cantilevers (part 3); stationary (part 1) and movable scaffolding system (part 2 and 4). The cross section of part 1,2 and 4 is double “T” beam, part 3 is box girder. Because of shortage of time all parts of structure had to be built together. Construction of the bridge has started in December 2014, the main prestressed concrete superstructure should be finished until December 2016 and all remaining works should be finalized in 2017.

Intermediate Diaphragm and Temporary Bracing Practice for Precast Concrete Girder Bridges

AbstractIntermediate diaphragms are used in precast concrete girder bridges for three primary reasons: (1) to prevent torsional girder rotations during girder erection and deck placement operations, (2) to increase vertical load distribution between girders, and (3) to transfer and spread horizontal impact loads from an overheight vehicle to adjacent girders. Significant variation currently exists in intermediate diaphragm specifications between states. The importance of bracing girders after erection and during construction is widely accepted as essential. Although it is clear that intermediate diaphragms have some effect on bridge performance, the benefit is considered by some to be negligible. Increasing numbers of states have adopted permanent steel or temporary intermediate diaphragm alternatives in place of traditional cast-in-place concrete. Wide variations are found between states regarding the configuration, spacing, and transverse alignment of diaphragms. This article presents a detailed survey ...

Simulating the response of CFRP strengthened shear-keys in composite concrete bridges

The reduction in the integral action between cast-in-situ slab and precast prestressed concrete girders in composite concrete bridges can be attributed to the increase in truck loads; increase in the allowable stress at service loads; exposure to aggressive environments; and the increase in traffic flow. It is a necessity to restore this integral action by strengthening against horizontal shear. In this paper, a finite element analysis (FEA) was performed considering 32 push off specimens using ANSYS software package to evaluate the behavior of shear-keys of composite concrete bridges. The studied parameters include: the concrete compressive strength, spacing of the shear stirrups, the carbon fiber reinforce polymer (CFRP) sheet spacing, and CFRP plate spacing, fiber angle, and anchorage length. The FEA results show that the reduced crack opening and slip in the strengthened shear-keys compared with the control specimen reflect the efficiency of the CFRP strengthening scheme. Moreover, the FEA results indicate that the CFRP composites anchorage length and angle had a notable impact on the longitudinal shear force and corresponding slip, failure mode, stiffness, and toughness. Finally, an empirical model was proposed for predicting the bond-slip behavior of shear-keys based on reliable experimental results available in literature.

Effect of curing condition on shrinkage reducing property of self-consolidating concrete with different expansive admixtures

In accelerated bridge construction, self-consolidating concrete (SCC) shows great potential of application to fill the gap between the deck soffit and precast concrete girders with heavy reinforcement especially in precast construction . An experimental program was undertaken to evaluate the performance of SCC incorporating different expansive admixtures for filling distance between precast bridge deck panels and girders. The study aimed to investigate shrinkage reducing properties as well as wokability of proposed SCC mixture under different curing conditions (water, air-dry and sealed cure). A combination of tests including slump flow, J-ring, V-funnel flow time, L-box and static bleeding were also conducted to measure the workability as well as mechanical properties of developed SCC.

Some Experience from the Analysis of Existing 40 Years Old Prestressed Bridges in the North of Slovakia

The paper deals with the analysis of the chosen short-span bridges from precast prestressed concrete girders. The analysis has been performed at the Department of Structures and Bridges recently. Part of the current technical condition assessment of these structures comprised the load carrying capacity and remaining life time determined by calculation [1, 2 and 3]. The load carrying capacity was calculated in compliance with the previous Slovak standards and new European standards.

Evaluation of Cracks in a Large Single-Cell Precast Concrete Segmental Box Girder Bridge without Internal Struts

The Hathaway Bridge, an eastbound and westbound bridge pair, is located in Panama City, Florida. Each of the pair consists of a single-box precast concrete segmental girder with a deck width of 24.4 m (80 ft). The lengths of the eastbound and westbound bridges are 1,031.43 and 1,162.93 m (3,384 and 3,815 ft), respectively. To date, these are the largest single-cell precast segments without internal struts fabricated in the United States. During construction, many web cracks developed in the external anchorage areas. The purpose of this investigation is to identify the main causes of the cracks and provide some design recommendations for large precast concrete segmental box girders. First, a brief description of the bridge is given. Then, analytical models for the bridge, posttensioning forces, and construction forces are presented. The analytical results show that the external longitudinal posttensioning forces can cause significant high-tensile stresses in the interior face of the web around the anchorages. The information presented in this paper can assist bridge engineers in the design of concrete segmental box girder bridges.

Experimental study on the structural behavior of concrete dapped-end beams

A common structural system in precast pre-stressed concrete girders with dapped ends has been intensively used in elevated viaducts recently built in Mexico City. A critical aspect of this solution resides in the possibility of a premature cracking in the reentrant corner of the dapped-end beam. An experimental research program was carried out to evaluate the performance of the present solution of the dapped end, both under service loading and ultimate design loads, and also to explore other solutions that could improve the performance in terms of the cracking of the reentrant corner.Four dapped-end beams models at a 1:3.6 scale were built and tested under vertical loads. The first specimen reproduced the solution adopted in the prototype, which was designed and reinforced according to the recommendations of the PCI Design Handbook. To the second one a longitudinal post-tension was applied, in the third specimen diagonal bars replaced part of the hangers, and the fourth was provided with both diagonal bars and post-tensioning.Experimental results allowed to conclude that, the specimens with longitudinal post-tensioning at the dapped, performed within the code requirements both under the service and ultimate loads, showed the best behavior in terms of cracking control. The strut-and-tie model proposed by Mattock provides a good prediction of the load capacity attained in the experimental specimens.

Estimation of Strong Motion Experienced in the Vicinity of the Bolu Viaduct during the 1999 Duzce Earthquake: Development and Validation of a Hybrid Method

Abstract This paper revisits the 12 November 1999 earthquake in Duzce, Turkey, and attempts to derive realistic estimates of ground motions experienced near the edge of the fault‐rupture outcrop where the 2.5‐km long Bolu twin viaduct failed. The nearest accelerographic stations, in Bolu and Duzce, being neither sufficiently close to the fault nor in similar orientation with respect to the seismogenic fault, could hardly explain the observed damage when used as excitation at the exact location of the viaduct. The novelty of the research lies on the fact that the proposed ground motions are chosen on the basis of their ability to reproduce the observed rocking response of two sets of precast concrete girders temporarily stored along the highway axis at the time of the event—a case study that has hitherto received scarce attention in literature. Although lying in literally adjacent locations, all girders of the first set toppled, whereas most girders of the second set, with a different orientation than the first, remained standing. Scenarios of hybrid ground motions that account for likely near‐fault effects are devised and calibrated with nonlinear finite‐element analyses. The most likely motions identified that can simultaneously provoke toppling of the first‐site girders and not toppling of the neighboring site, are those combining a sufficiently strong forward‐rupture directivity pulse, with fault‐normal V max on the order of 100 cm/s, with a quite intense fault‐parallel direction fling‐step pulse that is compatible with a dislocation exceeding 60 cm.

Study on Precast Concrete Girders Curing System Based on Automatic Drip Irrigation

It is difficult to control quality for precast concrete girders in curing, so we set up the curing system of precast concrete girders with computer networks, automatic control of drip irrigation technology, database technology and two-dimensional code technology, With which we can control concrete girders curing continuously. Achieve well curing results, and storage the precast girders curing process temperature and humidity data, provide the data basis for quality assessment and acceptance of post-concrete structure.

Full bridge testing at scale constructed with novel FRP stay-in-place structural forms for concrete deck

A system of FRP stay-in-place (SIP) formwork for concrete bridge deck is tested within a full bridge setting, including multiple girders, diaphragms and monolithic connections between components. The 4350×3250mm footprint of the test bridge represents a 1:2.75 scale of a 12.5m span full scale bridge. It includes four simulated precast concrete girders, supported at both ends on neoprene bearing pads with integral concrete end diaphragms. The deck is cast compositely on the girders using a novel configuration of FRP SIP forms, except for a control portion constructed using traditional steel reinforcement. Fifteen tests were carried out to investigate the effects of girder spacing, interior versus exterior spans, end- versus middle-sections, loading on versus loading off splices of FRP panels, FRP surface treatment, and splice method. Results show the FRP SIP form system exceeded code requirements, exhibiting safety factors between 2.8 and 4.3 over factored loads. Location of test pads (interior versus exterior span) had a substantial impact on performance, leading to a difference of up to 32% in capacity, with exterior and edge pads exhibiting the lowest loads. Using adhesive bond at concrete–FRP interface mitigated this reduction. Lack of panel-to-panel splice detailing reduced strength by 21% if loading was between splices, but no reduction occurred when loading was directly above splice.

Design implications of increased live loads on continuous precast, prestressed concrete girder bridges

Continuous precast, prestressed concrete bridges for live loads reduce maintenance costs by eliminating problematic deck joints, especially in bridges subjected to heavy truck loading. Continuity introduces negative moments over the supports in the composite section under live load and superimposed dead load. This paper investigates the implications of increased live loads on the design of continuous precast, prestressed concrete girders based on service load stress limits. Overstress can occur if design live loads are increased. Conversely, overstress can be reduced by debonding prestressing strands in the girder end-zone regions, but this is often not done because of restrictions on the numbers of strands that can be debonded. This paper proposes an alternative solution to compensate for the decrease in shear capacity due to debonding by providing solid ends in the precast concrete girder in regions where continuity is achieved. The authors conclude that precast, prestressed concrete girders made continuous at the supports offer an economical solution to multispan bridge structures by reducing positive moments at midspan and eliminating joints.They suggest that increasing the web thickness and the number of debonded strands in the end zones can substantially reduce overstress without affecting the shear capacity of the girder.

Whiteman Creek Bridge: A synthesis of accelerated bridge construction, ultrahigh- performance concrete, and fiber-reinforced polymer

The replacement of the Whiteman Creek Bridge, located in Ontario Canada, is described in this paper. Synthesizing accelerated bridge construction, ultra-high-performance concrete, and fiber-reinforced polymer reinforcement, a three-span, concrete T-beam bridge was replaced with a single-span bridge during a seven-week highway closure. Age, condition, and shear cracks in the T-beams made the replacement necessary, and prefabricated components such as precast concrete abutments, wing walls, deck elements, and steel girders were used. To enhance durability, glass-fiber-reinforced polymer (GFRP) bars were used in the top reinforcing mat of the precast concrete deck elements and in the cast-in-place concrete barrier walls; conventional black reinforcement steel was used for the bottom reinforcing mat. Ultra-high performance concrete reduced the dimensions of joints between precast concrete elements and eliminated formwork on the deck. Deck slab erection, grouting, and construction of the bridge are described, and the project timing and costs are discussed.

Dingman Drive Bridge: Reinstatement of severed strands on prestressed concrete girders damaged by vehicle impact

In 2010, the four-span Dingman Drive Bridge near London, Ontario was damaged when an overheight vehicle carrying a hydraulic excavator struck it. The vehicle hit three of the five AASHTO Type III precast concrete girders, severing three strands in two girders and causing significant concrete damage. This paper describes a unique alternative to replacing the girders which involved using a mechanical strand coupler system to reconnect the strands. The methods used to reconnect and restress the broken strands are described in detail, including the testing conducted, the use of carbon-fiber-reinforced polymer strips to reinforce the girders, and the use of a mobile barrier system for worker protection. This repair solution was completed for 50% less money than replacement of the girders would have cost. It also improved the speed of the repair.

Implication of increased live loads on the design of precast concrete bridge girders

American Association of State Highway and Trans- portation Officials (AASHTO) design live loads are sometimes increased as directed by relevant authorities to reflect actual traffic conditions. A 50% increase is adopted in some regions of the Middle East based on comparisons of AASHTO LRFD specifications HL93 live loads with the British Standards HA + HB live loads. Even in some U.S. jurisdictions, the AASHTO live loads may not represent modern truck configura- tions. This paper examines the effects of increasing AASHTO LRFD specifications HL93 live loads on the design of precast, prestressed concrete girders. A parametric study was first conducted for this purpose. Design aids in the form of charts that relate the precast concrete girder size and spacing to the span length as a function of the 28-day concrete compressive strength and environmental classifications were developed for HL93 and 1.5 × HL93 live loads. It was shown that the increase in live loads can be economically accom- modated by increasing the 28-day concrete strength. The charts not only set up the basis of comparisons but also provided a practical solution that can be simply used by precast concrete designers for optimizing the precast concrete girder size and spacing.

Structural GFRP Permanent Forms with T-Shape Ribs for Bridge Decks Supported by Precast Concrete Girders

A new concrete bridge deck cast onto glass fiber–reinforced polymer (GFRP) stay-in-place (SIP) structural forms is studied. The forms, which replace the bottom layer of conventional rebar, are essentially flat plates with T-up ribs. They span between support girders spaced at 1,772 mm and are lap-spliced using adhesive and mechanical fasteners. Special attention was given to the detailing of monolithic connections between the deck and girders to simulate continuity. The flange of the supporting concrete girders had a rough surface finish and protruded steel stirrups and mimicked AASHTO Type III girders. Five full-scale decks were tested to (1) compare the novel system with a conventional RC deck, (2) examine the effect of eliminating a top layer of orthogonal GFRP rebar, (3) assess a practice commonly used in bridge deck tests of using simple spans resting on neoprene pads, neglecting connection to girders, and (4) examine a commercially available all-GFRP deck, using the same GFRP panels but with a top GFRP plate fastened to the T-up ribs. Four auxiliary flexural specimens were tested to examine the lap-splice. The concrete deck with GFRP SIP form showed 33% higher strength than the conventional RC deck. It also achieved a peak load 7.8 times higher than the service load plus impact. Deflection under the service load was less than span/1,600. Remarkable deformability and pseudoductility was achieved at ultimate load, beyond punching shear, because of the progressive failure of the lap-splice. The simply supported deck failed at a slightly lower strength than the monolithically cast one but had a much lower stiffness.

Behavior of precast prestressed concrete bridge girders involving thermal effects and initial imperfections during construction

The instability of precast prestressed concrete bridge girders during construction have been of particular concern to bridge engineers. After they are installed on bearing supports, prestressed concrete girders are immediately subjected to environmental thermal loads that may be exacerbated by fabrication and construction errors. Thus, in this research, the environmental thermal loads, which cause extremes in thermal deformations in precast prestressed concrete girders, were determined. Then a three-dimensional nonlinear finite element sequential analysis procedure was developed to evaluate the behavior of a precast prestressed concrete girder subjected to both thermal loads and geometry and support imperfections during each construction stage. This analysis indicated instability in a 30-m long prestressed concrete BT-1600 girder when total lateral deformation in the middle height of the girder at mid-span exceeded about 25cm.

Creep of UHPC in tension and compression: Effect of thermal treatment

Abstract Steel fiber-reinforced ultra-high performance concrete (UHPC) is of increasing interest for use in precast prestressed concrete highway bridge girders due to its superior durability and the potential for reducing or eliminating shear reinforcement, due to the presence of steel fibers. However, the contributions of creep, and especially tensile creep, to long-term performance must be better understood to develop appropriate design specifications. Due to practical considerations, it is also of interest to investigate the influence of varying thermal treatment, including temperatures lower than those recommended by the manufacturer (i.e. 90 °C), on the creep of UHPC. In this 1-year study, the effects of three different thermal treatment regimes on tensile and compressive creep performance of UHPC are examined, with complementary characterization by nanoindentation and scanning electron microscopy. Results show that UHPC creeps phenomenologically differently in tension and compression. Both thermal treatments examined resulted in similar tensile creep behavior, suggesting that a lower temperature applied over a longer period could effectively cure UHPC. For the non-thermally cured UHPC, a 10 μm wide region observed at the fiber/matrix interface was characterized by reductions in elastic modulus as well as greater porosity and microcracking than the bulk paste. It is suggested that the quality of the fiber/matrix interface is a major contributor to the measured increased creep of non-thermally treated UHPC as compared to UHPC treated at 60 °C or 90 °C.

New steel‐concrete connection for prefabricated composite bridges

AbstractAn investigation of a new type of connection between precast concrete decks and steel girders, for composite steel‐concrete bridges, is being performed by the Steel Structures Laboratory, ICOM, of Ecole Polytechinque Fédéral de Lausanne, EPFL. The connection resists the loads by shear resistance between base materials. Hence, a fundamental part of the research focuses on the behaviour of the different confined interfaces of the connection, subjected to shear, static and fatigue loading. The confinement is a combined outcome of the kinematic law of the interfaces and the section geometry. Experimental investigation through a series of direct shear tests on confined interfaces has resulted in the development of failure criteria and constitutive and kinematic models describing the behaviour of the different interfaces. Those laws are used as an input for a model that simulates the connection behaviour. The model of the connection is validated by push‐out tests on large‐scale specimens. Finally, a composite beam has been tested under constant amplitude for five million cycles. A static test, following the fatigue sequence, has shown that the composite beam reaches its plastic moment capacity due to the sufficient ductility of the connection.Neue Stahl‐Beton‐Verbindung für vorgefertigte StahlverbundbrüKen. Im Labor für Stahlkonstruktionen (ICOM) der Eidgenössischen Polytechnischen Hochschule Lausanne werden Untersuchungen für eine neue Verbindungsart zwischen Betonfertigteil‐Fahrbahn und Stahlträgern bei Stahlverbundbrücken durchgeführt. Die Verbindung nimmt die Beanspruchungen über den Schubwiderstand zwischen den Grundmaterialien auf. Daher konzentriert sich ein wesentlicher Teil der Forschung auf das Verhalten der verschiedenen, eingeschlossenen Verbundfugen, die Schubkräften und statischen und ermüdungswirksamen Beanspruchungen ausgesetzt sind. Die Zwängungsbeanspruchung ist ein kombiniertes Ergebnis der Kinematik der Verbundfugen und der Profilgeometrie. Experimentelle Forschung anhand einer Reihe von direkten Abscherversuchen an eingeschlossenen Verbundfugen führte zur Entwicklung von Versagenskriterien, Materialgesetzen und kinematischen Modellen zur Beschreibung des Verhaltens der verschiedenen Verbundfugen. Diese Gesetze werden als Eingangsgrößen für ein Modell verwendet, welches das Verhalten der unterschiedlichen Verbundfugen simuliert. Das Modell der Verbindung wird durch Push‐ Out‐Versuche an großen Prüfkörpern validiert. Abschließend ist ein Verbundträger unter konstanter Amplitude mit 5 Millionen Lastwechseln geprüft worden. Eine statische Prüfung der Resttragfähigkeit hat gezeigt, dass der Verbundträger die vollplastische Momententragfähigkeit aufgrund einer ausreichenden Duktilität der Verbindung erreicht.

A method for evaluation of longitudinal joint connections of decked precast concrete girder bridges

As bridge conditions in the United States continue to deteriorate, rapid bridge replacement procedures are needed. Decked precast prestressed concrete (DPPC) girders are used for rapid bridge construction because the bridge deck is precast with the girders eliminating the need for a cast-in-place slab. One of the concerns with using DPPC girders as a bridge construction option is the durability of the longitudinal joints between girders. The objectives of this paper were to propose a method to use a spring element modeling procedure for representing welded steel connector assemblies between adjacent girders in DPPC girder bridges, perform a preliminary study of bridge performance under multiple loading scenarios and bridge configurations, and discuss model flexibility for accommodating future field data for model verification. The spring elements have potential to represent the contribution of joint grout materials by altering the spring stiffness.

Full-Scale Testing for Composite Slab/Beam Systems Made with Extended Stud Spacing

Investigation of the background of the 610 mm (24 in.) spacing of stud shear connectors showed that this limit was set on the basis of a small amount of testing of beams with spacing greater than this limit. The literature search showed that some attempts have been recently made to extend this limit. One of the objectives of the NCHRP 12-65 research project was to investigate the possibility of extending this limit to 1,220 mm (48 in.) for cluster of studs used for precast concrete panels made composite with steel I-beams. The experimental investigation included testing of push-off specimens and full-scale composite beams. Results of the push-off specimens have shown that the fatigue loading has no detrimental effect on the load-slip relationship when the number of studs is doubled per cluster. This paper covers the second part of the experimental investigation, which is fatigue and ultimate testing of full-scale composite beams. The full-scale testing has proven that full-composite action between precast concrete panels and steel girders can be achieved when the spacing between the stud clusters is extended up to 1,220 mm (48 in.).