Modular Bridge Expansion Joints Research Articles

Fatigue performance of an innovative shallow-buried modular bridge expansion joint

Bridge expansion joint can accommodate the deformation under the effects of vehicle load and temperature. Fatigue damage readily occurs because it is directly subjected to repeated load. In this paper, fatigue and static loading tests were conducted on modular bridge expansion joint (MBEJ). This is an innovative type of shallow-buried modular bridge expansion joint, and the anchoring depth is reduced by 40%-50% compared with traditional ones. The reduced overall height can well adapt to the slide shutter rapid construction method in practical engineering. A loading device was designed to simulate vertical and horizontal load. The load-deflection relationship after fatigue loading were discussed. The fatigue crack types, crack initiation locations, failure criteria, and fatigue failure modes of MBEJs were also studied. Following that, a finite element model was established to calculate the internal force of welded connections. Structural analysis on MBEJs was used to calculate the stress range within center beam and support bars under the test conditions. A theoretical fatigue performance assessment method on MBEJs was introduced, which is based on the nominal stress method and a linear Miner damage accumulation rule. The theoretical prediction agreed well with the experimental observations.

Monitoring Fatigue Damage of Modular Bridge Expansion Joints Using Piezoceramic Transducers.

Modular bridge expansion joints (MBEJs) are commonly used in bridges and are often subjected to fatigue damages, which necessitate fatigue monitoring of MBEJs to ensure the reliable operation of the bridges. In this paper, a stress wave based active sensing approach using piezoceramic transducers is developed to monitor the fatigue damage of MBEJ. A MBEJ involves mainly center beam, edge beam, support bar, support box, sliding bearing, sliding spring, elastomeric strip seal, full-penetration weld and reinforcing plate. In practice, for a MBEJ, the part that is most prone to fatigue damage is the full-penetration weld between the center beam and the support bar. In this paper, a specimen, which is the full-scale center-beam/support-bar (CB/SB) assembly, was designed and fabricated to facilitate the experimental study. The assembly mainly includes center beam, support bar, reinforcing plate, and full-penetration weld. The lead zirconate titanate (PZT) transducer bonded on the support bar was used as the actuator and the PZT transducer mounted on the center beam was as the sensor. Dial indicators were utilized to measure the vertical displacement of the center beam. Two series of tests, including static test, and fatigue test, were performed on the specimen in an alternating fashion. Based on the number of cyclic loading, the experiment was divided into six different stages: 0th cycle (the healthy state), 0.8 million cycles, 1.6 million cycles, 2.4 million cycles, 3.2 million cycles, and 4 million cycles. The signals received by the PZT sensor were analyzed with the help of wavelet packet analysis. In addition, the structure stiffness also was considered as a comparative approach in this paper. Experimental results show that during the fatigue test, the structure stiffness decreases with the number of cycle loading. However, the method can only obtain the fatigue damage impact on the entire structure, and cannot determine the fatigue damage degree of a certain weld. On the other hand, the proposed method can accurately monitor the fatigue damage degree of full-penetration welds. The research results show that the developed piezoceramic enabled active sensing approach can monitor and estimate the fatigue damage in MBEJ in real-time.

Fatigue life of the bolted yoke connection in single support beam (SSB) modular bridge expansion joints

The objective of this article is to demonstrate a comprehensive procedure for the estimation of the fatigue life of the component centre-beam-to-support-beam (CB/SB) bolted yoke connection. In this procedure, all the aspects are included such as fatigue vehicle loading, cycles per truck passage, lifetime average daily truck volume, fatigue classification of the detail and determination of fatigue infinite life. A typical single support beam (SSB) steel modular beam expansion joint (MBEJ) was modelled as 3D space frame. Moreover, three F.E. sub-models were created for the simulation of the (CB/SB) bolted yoke connection with preloaded bolts M16, M20 and M22 respectively. The Fatigue Load Model 2 (FLM2), recommended in EN 1991-2:4.6.4 for infinite fatigue life was chosen for the fatigue verification of the bolted yoke connection detail, assumed to be travelling at 90 km/h over the expansion joint. The 3D space frame was analysed by using Time-history dynamic analysis and thereafter, the calculated outputs were introduced in the F.E. sub-models. From the analysis of the sub-models the stress ranges were obtained and the fatigue evaluation of the yoke joint was performed. The investigation shown that poor detailing at the connection between the centre-beam-to-support-beam (CB/SB) bolted yoke connection is susceptible with reference to fatigue. Finally, important conclusions were extracted for both the behaviour of the entire modular joint and the fatigue life of the bolted yoke detail.

Dynamic numerical analysis of single-support modular bridge expansion joints

Severe fatigue and noise problems of modular bridge expansion joints (MBEJs) are often induced by vehicle loads. However, the dynamic characteristics of single-support MBEJs have yet to be further investigated. To better understand the vibration mechanism of single-support MBEJs under vehicle loads, a 3D finite element model of single-support MBEJ with five center beams is built. Successive vehicle loads are given out and the vertical dynamic responses of each center beams are analyzed under the successive loads. Dynamic amplification factors (DAFs) are also calculated along with increasing vehicle velocities from 20 km/h to 120 km/h with an interval 20 km/h. The research reveals the vibration mechanism of the single-support MBEJs considering coupled center beam resonance, which shows that dynamic responses of a given center beam will be influenced by the neighboring center beams due to their rebound after the vehicle wheels depart. Maximal DAF 1.5 appears at 120 km/h on the second center beam. The research results can be utilized for reference in the design, operation and maintenance of singlesupport MBEJs.

Effect of dynamic impact at modular bridge expansion joints on bridge design

To analyze the dynamic impact induced by a heavy vehicle crossing a modular type expansion joint and its effect on the bridge response, a numerical method based on a distributed spring-damper element is presented, in which the contact patch between the tire and the road is considered. The dynamic response of the vehicle and bridge can be obtained by dynamic finite element analysis of the vehicle-bridge system taking into account the bumpy ride of vehicle at the expansion joint. The reduced support to the parts of tire structure over the cavities of the modular expansion joint is considered, and the vertical tire load can be obtained by an iteration procedure. To assess the dynamic impact at the expansion joint on bridge design, the impact factors associated with the vehicle tire loads, and the bearing reactions, shear forces and bending moments of the bridge are evaluated. The multi-gap modular expansion joints leads to lower impact factors than single-gap expansion joints. The effects of dynamic impact at expansion joint on the bearing reactions and shear forces are greater than that on the bending moments of the bridge. Numerical results also show that the impact effects of vehicle axle load and internal forces of the bridge may be higher than those recommended by bridge codes, and they may affect the durability of components in the vicinity.

Fatigue Testing and Performance of Welded Single-Support Bar Modular Bridge Joints

Single-support bar modular joints are widely used in large-span bridges because of their competitiveness and their ability to accommodate larger movements than conventional multiple-support bar joints can accommodate. Despite their general acceptance and use, detailed fatigue testing and design guidelines well suited for these joints are still not well documented. This has been the main impetus for carrying out this experimental and analytical investigation on the fatigue performance of a single-support bar modular bridge expansion joint with welded stirrups. Three identical subassemblies were tested in fatigue to establish the experimental fatigue S-N curve for the main critical details. In addition, a few variants of stirrup specimens were separately tested under static and fatigue loadings to investigate failure modes and the effects of important geometric parameters such as bottom-plate thickness on the stress range and fatigue resistance of the stirrups. The tested joint subassemblies and stirrup specimens developed characteristic fatigue cracks in and around the stirrups and their welded connections. These cracks are classified into three distinct categories, and expressions for computing their associated stress ranges and fatigue resistance are presented. This study reveals that secondary bending moments within the stirrup make a major contribution to the stress range at critical sections of the stirrup. This contribution should be included for adequate prediction of the fatigue life of single-support bar modular joints and can be reasonably determined with basic models using one-dimensional (1D) beam elements for the center beam and for the stirrup. The importance of secondary bending moments within the stirrup is strongly related to the relative stirrup bottom plate-to-vertical leg bending stiffness and to the relative stirrup vertical leg-to-center beam bending stiffness.

Development of an Experimentally Validated Analytical Model for Modular Bridge Expansion Joint Behavior

Modular bridge expansion joints (MBEJ) are large-capacity systems placed between two superstructure segments designed to provide safe joint crossing based on anticipated bridge movements. Locations of discontinuity in bridges are often recognized as weak links and therefore characterizing the behavior of expansion systems installed at deck joints under various excitations is critical to support the forecasting of bridge functionality. This paper presents the development of an analytical model representative of a common modular bridge expansion joint including its critical components, such as friction elements, equidistant devices, support bars, and center beams. The model is then validated through full-scale experimental testing of the joint. The results of this study offer a predictive model for the longitudinal motion of bridge joints excited through anticipated service or extreme events, which can be used to help determine local and global failure within the joint and make inferences as to how a bridge system could be affected. Such models provide a key step toward aiding design efforts, enabling more accurate specification of MBEJs, and supporting functionality-based risk assessment for bridges.

Mitigation of noise emissions from vehicles passing bridge expansion joints

In the German project �silent road traffic 2� a special sub-project for bridge expansion joint noise mitigation was launched. Travelling over a standard modular bridge expansion joint (lamella joint) with a vehicle creates a short noise impulse. The noise is the result of the vehicle�s tyres striking the rectangular face of the expansion joint units and traversing the discontinuous surface profile. This noise can be annoying for those residing near the bridge. A reduction of the noise emission can be achieved by mounting noise reduction elements on top of the transition segments, by creating an even surface for the tyre to traverse, and still allowing the joint to contract or elongate as required due to the influence of seasonal temperature variation. Different surface elements for covering the transition segments with varying shapes and surface textures were tested in the tyre-road-interaction test-facility (PFF) of BASt. The surface elements had different shapes and surface characteristics; five were of a rhomboidal shape with three profile angles, one was �mushroom� shaped, and two were of a sinusoidal shape. The surface elements were provided by two German manufacturers. The noises emission caused by traversing of a standard passenger car tyre was investigated for different velocities. All tests were carried out with two different spacings representing summer and winter position. It was found that a noise reduction of up to 9 dB could be achieved, when compared to conventional surface elements

Numerical investigation of noise generation and radiation from an existing modular expansion joint between prestressed concrete bridges

Noise generated from modular bridge expansion joints during vehicle pass-bys has caused localized environmental problems in Japan and elsewhere. The objective of this study was to understand the mechanism of noise generation and radiation from a modular expansion joint installed in an expressway bridge. A numerical investigation was conducted in order to understand the dynamic characteristics of the joint and the acoustic characteristics of the sound field around the joint that measurements cannot reveal due to their limitations, such as the number of measurement locations that are required. Vibro-acoustic analysis was conducted by using the finite element method–boundary element method (FEM–BEM) approach: dynamic analysis of the joint was carried out by FEM and the sound fields inside the cavity located beneath the joint and outside of the cavity were analyzed by BEM. It was concluded that dominant frequency components in the sound pressure inside the cavity were due to excitation of the structural modes of the joint and/or acoustic modes of the cavity. For the expansion joint investigated, the sound field farther than about 35 m from the joint–cavity center could be considered as far field in the range of 50–400 Hz.

Vibro-acoustic analysis of noise generation from a full scale model of modular bridge expansion joint

Noises generated from modular bridge expansion joints during vehicle pass-byshavebeencausinglocalenvironmentalproblemsrecently.Previousexperimentalstudies showed that possible causes of dominant noise components generatedfromthebottomsideofthejointmightbedifferentfromthosefromthetopside.The objective of this study was to obtain theoretical insights into the mechanismof noise generation from the bottom side of the joint for which a main noisesource might be structural vibration of the joint. Vibro-acoustic analysis wasconducted based on the information from a full-scale model of modularexpansion joint obtained in previous experimental studies. The dynamicbehavior of the joint model was investigated by using the finite element method(FEM) and the sound field inside the cavity located beneath the joint model wasanalyzed by using the boundary element method (BEM). Indirect BEM wasused to calculate the sound pressure inside the cavity with the velocity responseobtained by the FE analysis as a boundary condition. The frequency rangeconsidered in the analysis was 20–400 Hz where dominant frequencycomponents were observed in the noise measured in the cavity beneath the jointin the previous experiment. It was intended to interpret numerical resultsobtained by a model developed with available mechanical properties of the jointcomponents to seek a general understanding of the noise generation mechanismof the modular expansion joint. It was observed that the peaks in the spectrumofnoiseinsidethecavitywereduetoresonancesofstructuralvibrationmodesofthe joint and/or resonances of acoustic modes of the cavity.There was evidencethat showed possible interaction between structural modes of the joint and theacoustic modes of the cavity.

Dynamic Anomalies in a Modular Bridge Expansion Joint

Environmental noise complaints from homeowners near bridges with modular bridge expansion joints (MBEJs) led to an engineering investigation into the noise production mechanism. The investigation identified modal vibration frequencies in the MBEJ coupling with acoustic resonances in the chamber cast into the bridge abutment below the MBEJ. This initial acoustic investigation was soon overtaken by observations of fatigue induced cracking in structural beams transverse to the direction of traffic. These beams are, in the English-speaking world, universally referred to as center beams. However, in Europe the term lamellae is equally common. A literature search revealed little to describe the structural dynamics behavior of MBEJs but showed that there was an accepted belief dating from around 1973 that the loading was dynamic. In spite of this knowledge many bridge design codes used throughout the world specify a static or quasi-static load case with no mention of the dynamic behavior. This paper identifies the natural modes and operational response modes of vibration of the MBEJ installed into Sydney’s Anzac Bridge. In addition, the paper will introduce the dynamic range factor (DRF) and report a DRF of 4.6 obtained after extensive static and dynamic strain gage measurements. The studies indicated that the Anzac Bridge MBEJ was very lightly damped (<2% of critical) and a reduction in the measured DRF through the introduction of additional damping was an option.

Fatigue performance of modular expansion joints for bridges

This paper presents results of an experimental investigation on the fatigue performance of the welded multiple support bar modular bridge expansion joint (MBEJ) used for the recent Jacques Cartier Bridge rehabilitation in Montreal. Three identical subassemblies of the modular joint system were tested in fatigue. Both vertical and horizontal load ranges were applied to the test specimen simultaneously in the following proportions: (i) vertical load range = ΔPv and (ii) horizontal load range = 0.2ΔPv. Different loading ranges were applied to each specimen giving a sufficient number of points to define the experimental fatigue stress range versus the number of cycles (S–N) curve. The number of cycles varied between 567 900 and 3 600 000, while the calculated stress range within the welded connection details varied between 81.4 and 166.7 MPa. Static calibration tests were performed prior to the fatigue testing of each specimen. These calibration tests confirmed the validity of the structural three-dimensional analytical models and also established the repeatability of the experimental data, in conformity with the requirements of the NCHRP-402 report. Fatigue cracks of the same type as those reported by the NCHRP-402 report were observed within the welded connection detail. No fatigue cracks were observed elsewhere. The experimental fatigue curve of the welded connection showed that the fatigue resistance of the welded MBEJ is compatible with category C and C' details, as defined by the AASHTO LRFD 1998 bridge design code. This paper is very useful, as it demonstrates the applicability of the complex requirements of the NCHRP-402 report. These requirements are increasingly gaining wide acceptance among bridge engineers and bridge owners.Key words: modular expansion joint, bridge, deck, test, fatigue, stress range, cycles.

Fatigue Performance of Modular Bridge Expansion Joints

Several premature fatigue failures of modular bridge expansion joints have occurred in Europe and the United States. The principal causes of such failures have been poor detailing (for instance, choice of fillet welds instead of full-penetration welds) and the tendency to reduce production costs by adopting larger beam spans. A critical analysis of data from field measurements is discussed. This analysis is focused on (1) the magnitude of the forces acting on the considered component of the joint (center beam), (2) the dynamic amplification factor due to the impulsive axle loading, and (3) the dynamic properties of the joint such as damping, natural frequencies, etc. Comparisons with results obtained by other researchers are presented. A simplified method for the dynamic analysis of the joint is proposed and compared with results obtained from field measurements. Finally, results from laboratory fatigue testing are reported, together with a proposal for a “reasonable” fatigue design load, based on traffic...

Design, Specification, Installation, and Maintenance of Modular Bridge Expansion Joint Systems

Data regarding service performance and durability of modular bridge expansion joint systems were gathered through a comprehensive literature review, survey of transportation agencies, and field observations. Typical service life and desired service life targets are discussed. Maximum movement and rotation demands are given with respect to three axes. Performance and durability problems include problems that can be traced to poor design and/or installation, wear and tear of elastomeric parts, and fastener loosening and fatigue cracking of the metal parts. Fatigue cracking has been addressed in previous research. Guidance on design, detailing, specifications, installation, and maintenance is discussed, which should reduce the problems in the first group. Problems with the elastomeric parts and fasteners are best addressed through performance tests on the modular bridge joint systems as a system. Two system performance tests, an opening movement/vibration test, and a seal push-out test are suggested for the prequalification of specific modular bridge expansion joint systems.

Fatigue Design of Modular Bridge Expansion Joints

Experimental and analytical research was recently performed to develop performance-based specifications and commentary for the fatigue design of modular bridge expansion joints (MBEJ). The resulting proposed fatigue-design and test specifications resulting from this research are discussed. These specifications are intended for integration into the present AASHTO Load and Resistance Factor Design (LRFD) Bridge Design Specifications. For consistency with the bridge design specifications, the proposed MBEJ fatigue-design specifications used the same fatigue-design truck as was used by the present AASHTO bridge specifications. However, one important modification of the AASHTO truck loading for MBEJ is the explicit recognition that the rear axles of the HS series trucks actually represent tandem axles. A simplified method to estimate the distribution factor (i.e., the fraction of the range of the design-wheel load assigned to a single “centerbeam”) is recommended. Dynamic impact on both the vertical and horizontal direction is discussed. Also, guidance on structural analysis of MBEJ, good detailing practice, and fatigue resistance and testing are presented. MBEJ designed under the proposed specifications should be resistant to fatigue cracking. The additional material and the improved details, which will be required to comply with the proposed specifications, are not expected to increase the initial first cost of MBEJ substantially.

Jointless Bridges and Bridge Deck Joints in Washington State

Highlights of a 1997 Quality Improvement Review (QIR) of jointless bridges and bridge deck joints in Washington State are summarized. The purpose of the QIR is to determine, assess, and disseminate the current state of the practice and to share this information with the other FHWA Region 10 states and other FHWA regions. The inspection team included personnel from FHWA, the Oregon Department of Transportation, and the Washington State Department of Transportation (WSDOT). Interviews were conducted with design, construction, inspection, and maintenance personnel. During the QIR, 18 WSDOT bridges were inspected in the field to gauge the performance of jointless bridges and bridge deck joints. Background information on jointless bridges is given, and current practices involving bridge deck joints are presented. The use of jointless bridges eliminates the need for expansion joints and joint maintenance. The QIR found that WSDOT’s semi-integral jointless bridges, with overall lengths of 122 m and skews less than 30 degrees, performed well. Approach slabs are recommended for jointless bridges to minimize the effects of approach settlement. Quality improvement recommendations are presented in the review. WSDOT has developed a new saw-cutting procedure for compression seals, as well as a specification for a second-generation, fatigue-based, modular bridge-expansion joint to improve long-term durability.

Modular Bridge Expansion Joints for Lacey V. Murrow Floating Bridge

The Lacey V. Murrow Bridge (LVM Bridge) is a 2013-m-long floating bridge on Interstate 90 across Lake Washington in Seattle, Washington. Single-support-bar, swivel-joist modular bridge expansion joint systems are located at each end of the bridge between the shore approach spans and the floating pontoons. These joints were designed for 960 mm of longitudinal movement as well as horizontal and vertical rotations caused by wind, wave, temperature, and changes in lake level elevation. A similar joint in an adjacent floating bridge had experienced premature fatigue cracking at welded attachment details because of low fatigue strength. For the LVM Bridge the joint components were fatigue tested and designed by using fatigue limit-states loads, resulting in welded attachment details with improved fatigue strength. In addition, a stiffer center beam and reduced center-beam span lengths produced lower fatigue stress ranges. Joint movements and rotations, fatigue design methodology, results of dynamic analyses, field measurements of the dynamic response, and construction details are described. The total cost of the LVM joints was 1 percent of the final bridge cost. The Washington State Department of Transportation required a 5-year guarantee for the LVM joints. These are the largest modular bridge expansion joints in the United States to be tested and designed for fatigue.