Modular Bridge Research Articles

프리캐스트 모듈러 피어캡의 구조성능 평가

Prefabrication technologies are making bridge construction safer and less disruptive to the environment and traveling public, making bridge designs more constructible and, improving the quality and durability by shifting site work to a more controllable environment. Modular bridge substructures with concrete-filled steel tube (CFT) piers and composite pier caps were suggested to realize accelerated bridge construction. The precast segmental pier cap consists of a composite pier table and precast prestressed segments on the table. The pier table has embedded steel section to mitigate stress concentration at the connection by small tubes. Each bridge pier has four or six CFT columns which connect to the pier cap. Shear strength of the pier cap was obtained by extending vertical reinforcing bars from the table to the precast segment. Transverse prestressing was introduced to control tensile stresses by service loadings. Structural performance of the proposed modular system was evaluated by static tests. Design requirements of the composite pier cap were satisfied by continuous reinforcing bars and prestressing tendons. Standardized modular substructures can be effectively utilized for the fast replacement or construction of bridges.

모듈러 슬래브교량의 횡방향 연결부 구조적 거동 및 사용성 평가

Jin-Woong Choi Sang-Seung Lee Sun-Kyu Park Sung-Nam HongAbstractRecently, in field of bridge construction, modular technology has been studied to reduce construction period, traffic impact andenvironmental impact. This study is a part of research related to the modular bridges. The aim of the study is to analyze the structural behavior and evaluate a serviceability for transverse connection of modular slab bridge. A total of four specimens werefabricated. including a control beam for finding the maximum load by static test. And one control beam and two segmental beamswere fabricated for cyclic loading test. As the test result, the beams that were introduced 100% of the design prestressing force showed a smaller maximum deflection, residual deflection and crack width than the control beam. The beam for serviceability evaluation was satisfied with structural serviceability limits of the deflection and crack. Keywords : Modular bridge, Slab, Transverse connection, Prestressing, Cyclic load, Serviceability

A Modular Balancing Bridge for Series Connected Voltage Sources

The operation of a nondissipative cascaded modular balancing bridge is described for automatically balancing series connected voltage sources, such as lithium-ion battery cells or capacitors. Automatic voltage balancing is achieved using coupled inductors; modularization and voltage balancing is achieved across N cells using cascaded transformers with coupled windings. The elementary modular bridge consists of four windings placed on a single core and is excited by an asymmetric half-bridge. Two of these windings are used to automatically balance voltages across two voltage sources, while the remaining two windings magnetically cascade one bridge with its neighboring bridges to balance N voltage sources. This configuration allows for the voltage balancing of N voltage sources using N/2 identical transformers, and N/2 asymmetric bridges. The voltage balancing action of the resultant magnetically coupled cascaded asymmetric bridges can be broken into two categories: intrabridge voltage balancing (within a single bridge) and interbridge voltage balancing (between neighboring bridges). Design parameters relating to automatic voltage balancing are highlighted, as the approach is more cost effective than methods using directed, or individualized, voltage balancing of each voltage source. The physical size considerations of the four winding coupled inductor are discussed and a lithium-ion battery-based experimental prototype is used to verify simulated results.

Analytical Study on the Shape of T-type Girder Modular Bridge Connection by Using Parameter

Analytical Study on the Shape of T-type Girder Modular Bridge Connection by Using Parameter

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.

Evaluation of the Serviceability of the Transverse Joint of a Modular Bridge under a Cyclic Load

Modular bridges have structurally weak joints that require a structural safety review. In this study, a static bending test was conducted on a specimen that was prestressed after grouting of its joints with shear keys. The results were compared with those of integral specimens to analyze the structural behavior characteristics of the specimen with grouted joints. Through cyclic loading tests (200,000 and 2,000,000 times), the long-term serviceability was examined in terms of deflections and cracks.

Structural performance of a hybrid FRP-aluminum modular triangular Truss system subjected to various loading conditions.

A novel hybrid FRP-aluminum truss system has been employed in a two-rut modular bridge superstructure composed of twin inverted triangular trusses. The actual flexural behavior of a one-rut truss has been previously investigated under the on-axis loading test; however, the structural performance of the one-rut truss subjected to an off-axis load is still not fully understood. In this paper, a geometrical linear finite element model is introduced and validated by the on-axis loading test; the structural performance of the one-rut truss subjected to off-axis load was numerically obtained; the dissimilarities of the structural performance between the two different loading cases are investigated in detail. The results indicated that (1) the structural behavior of the off-axis load differs from that of the on-axis load, and the off-axis load is the critical loading condition controlling the structural performance of the triangular truss; (2) under the off-axis load, the FRP trussed members and connectors bear certain out-of-plane bending moments and are subjected to a complicated stress state; and (3) the stress state of these members does not match that of the initial design, and optimization for the redesign of these members is needed, especially for the pretightened teeth connectors.

BIM 기반 3차원 모델 라이브러리를 통한 모듈러 교각의 정보모델링

Modular technology has become a major issue of the construction industries to enhance their productivity. Modular bridge construction generally requires the collaboration between the contractor, designer, fabricator and constructor. Therefore, a readily accessible information model based on BIM technology should be provided for their communication during a construction project life-cycle. In this study, BIM based 3D information modeling was carried out for the modular bridge pier. First, the product breakdown structure (PBS) and level of detail (LOD) of the pier were defined. Based on them, 3D models were created by using parametric modeling method. In addition, database was constructed for the exchange of geometry and property data of 3D models. Finally, application areas of 3D information model were suggested, including the quantity estimation and the 4D simulation.

거더형식 프리캐스트 모듈러교량 연속화 지점부에 적용되는 연결슬래브의 휨성능 및 피로성능 평가

모듈러 기술은 자동차, 플랜트, 조선산업 분야에서 이미 오래 전부터 적용해 오던 기술로, 최근 교량 분야에도 적용되고 있다. 모듈러교량은 부재별 세부설계 과정이 생략되고, 모듈별로 표준화 된다는 점에서 기존의 조립식교량과는 차별화 된다. 거더형식 프리캐스트 모듈러교량은 단순지지 교량 형식으로 개발되었으며, 다경간 교량에 적용할 경우 단순지지 교량 형식의 모듈러교량을 연속화하는 방법으로 적용할 수 있다. 거더형식 프리캐스트 모듈러교량의 연속화는 시공이 간편하고 급속시공에 적합한 연결슬래브를 적용하는 방법으로 이루어진다. 연결슬래브는 1950년부터 미국에서 RC 형식으로 사용되기 시작하였으며, 2000년대에는 ECC를 적용한 연결슬래브(ECC 연결슬래브)가 개발된 바 있다. 이 연구에서는 ECC에 비해 재연성이 좋고 경제적인 RC를 적용한 연결슬래브를 다경간 거더형식 프리캐스트 모듈러교량에 적용하였으며, 기존의 RC 형식 연결슬래브를 보완한 형태의 연결슬래브와 수정된 연결슬래브의 설계방법을 제안하였다. 제안된 연결슬래브 설계방법의 검증을 위하여 연결슬래브 바닥판 실험체를 제작하고 연결슬래브의 휨성능 및 균열 사용성 검증실험을 수행하였으며, 이후 실제 교량시스템을 모사한 실험체를 이용하여 200만회 피로성능 검증실험을 수행하였다.

AN EXPERIMENTAL STUDY ON THE CONNECTION OF CROSSBEAMS IN A MODULAR BRIDGE

A recently the application of modular bridge system, an assembly of the structural members, has been required to minimize traffic congestion, to reduce the period of construction, and to improve the quality and workability during the new construction and reconstruction of the bridge. For this reason, the modular bridge system is necessary to prepare for near future. In this study, alternative crossbeam system for modular prestressed concrete (PSC) T-girder bridge was developed. Static loading test was performed to inspect the structural characteristics of the alternative crossbeam system. Experimental results were analyzed and compared with each data. Therefore, the appropriate crossbeam system for modular PSC T-girder bridge was proposed.

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.

Design Optimization of Modular Bridge Structure

Modular bridge structures are commonly used in areas where space and weight are major limitations. In this study, a modular bridge structure made of extruded aluminum alloy AA7005 was analyzed using numerical simulations. Parametric model of the bridge structure was produced and optimized for required loading conditions. The aim of the research work was to minimize the weight of the bridge structure without compromising its strength. Sensitivity analysis was performed by taking thickness of the structure member as optimization variable. Optimum thickness of the bridge member obtained from simulations was assigned for the analysis of the entire structure. Results obtained from Finite Element (FE) simulations predicted maximum stress at the center of the structure. Parametric modeling of the structure allowed to asses failure against different loading conditions.

Experimental Study of Specific Cross Beam Types Appropriate for Modular Bridges

Experimental Study of Specific Cross Beam Types Appropriate for Modular Bridges

Повышение безопасности длительно эксплуатирующихся мостовых сооружений на магистральных каналах обводнительно-оросительных систем

It is brought data on a technical condition of modular ferro-concrete bridges, extent to 18–24 m located on a network of meliorative channels of the North Caucasian region. Authors reflected problems of service and repair of bridge constructions of a network of the irrigation canals being on balance of managements of land improvement on an example of administrative units of the Southern federal district.

모듈러 강교량 상부모듈 구성파트의 3차원 조립설계를 위한 파라메트릭 모델링 방법

A parametric modeling method, one of the core technology of BIM (Building Information Modeling), is proposed for efficient 3D assembly design among components of a superstructure module of modular steel bridge. Assembly system is classified into 3 levels as LoD (Level of Details) for 3D assembly design of the parts. Components forming 3D shape of the parts are identified and defined as parameters, variables depending on parameters, or constants independent of the parameters. Then, spatial assembly rules among the parts are defined according to the assembly system. Positional relations among the identified shape components are defined for mating spatial position and geometrical relations are defined for constraining degree of freedom on X, Y, and Z axis. Finally, a standardized template is designed by applying the rules to 3D based assembly design for the parts of the superstructure module. In addition, applicability of the parametric modeling method is demonstrated by testing the shape variation of the superstructure module according to changing the defined parameters.

An Experimental Study on the Connection of Diaphragm in Prefabricated Bridge

A recently new construction and reconstruction of the bridge have been required to minimize traffic congestion, environmental disadvantage, to reduce the period of construction, and to improve the quality and workability during the construction. For this reason, the application of modular bridge system, which is assembly of the structural members, is necessary to prepare for near future. Fall of girders can occur at the moment to connect between precast girders during the construction, so appropriate cross beams should be installed to solve the mentioned problem. In this study, understanding the structural characteristics and status of cross beam, alternative cross beam system for modular bridge was developed. To inspect the structural characteristics of the alternative system, specimens were built and static loading test was performed. Afterward, the behavior of cross beam in terms of joints and load distribution was observed. Experimental results were analyzed and compared with each data. Therefore, the appropriate cross beam system for modular bridge will be chosen and proposed in this paper.

충전원형강관을 이용한 모듈러 교각의 휨 거동 평가

A new modular pier system using concrete filled circular steel tubes was suggested to realize modular bridge substructures for accelerated bridge construction. Structural details and connection details were proposed by connection multiple concrete filled tubes (CFT) for standardized products of fabrication, delivery and erection. Static tests were performed for the modular pier with suggested details under lateral load conditions for weak and strong axes. Due to the eccentricity by the bracing system, the modular pier showed 5.23 times higher flexural stiffness and 6 times greater flexural strength from the test. It is proper for the rational design to evaluate stress and deformation by frame modeling of the modular CFT pier. Structural capacity of the pier can be obtained by adjusting the spacing of the CFT columns. Design recommendations were derived from the test.

Structural Characteristics of FRP-Concrete Bridge Deck System

This paper describes the structural forms for hybrid FRP-concrete highway bridge deck. This bridge deck is applid in a project, which involved the implement of FRP-concrete deck over prestress concrete girders. In this project three forms of FRP reinforcing were combined to reinforce the concrete deck. This paper introduced another stiffened FRP deck panels connecte with the FRP composite girders in the steel-free FRP-composite modular bridge system. It is shown that the combination of FRP meterial and concrete for bridge deck is recommended in the design of highway bridge.

조립식 교량의 가로보 연결에 관한 실험적연구

최근 교량의 신설 및 교체 공사 중 요구되고 있는 교통 혼잡의 최소화, 환경 영향의 최소화, 공사기간의 단축, 품질과 시공성 향상 등을 위해 조립식 교량 시스템의 적용이 시대적 요구로 대두되고 있다. 조립식 교량 시공 중 거더 간의 연결 시 발생할 수 있는 전도 및 추락 사고는 교량 시스템에 적합한 가로보의 사용으로 해결이 가능할 것으로 보여 진다. 본 연구에서는 가로보의 구조적 특성을 조사하고 국내 외 적용현황을 분석하여 조립식 PSC T형 거더 교량에 접합한 가로보 대안을 설정하여 가로보 연결부의 특성을 규명하고자 실험체를 제작하여 정적 하중 재하실험을 실시하였다. 정적 하중 실험을 통하여 실험체의 접합부의 거동과 하중분배에 대해 살피고 실험결과를 비교, 분석하였고 실험을 통한 구조 성능의 결과 치, 시공성을 고려하여 조립식 PSC T형 거더 교량에 접합한 가로보 대안을 제안 하였다. Recently new construction and reconstruction of the bridge have been required to minimize traffic congestion, environmental disadvantage, to reduce the period of construction, and to improve the quality and workability during the construction. For this reason, the application of modular bridge system, which is assembly of the structural members, is necessary to prepare for near future. Fall of girders can occur at the moment to connect between precast girders during the construction, so appropriate cross beams should be installed to solve the mentioned problem. In this study, understanding the structural characteristics and domestic and international case of cross beam, alternative cross beam system for modular bridge was developed. To inspect the structural characteristics of the alternative system, specimens were built and static loading test was performed. Afterward, the behavior of cross beam interms of joints and load distribution was observed. Experimental results were analyzed and compared with each data. Therefore, the appropriate cross beam system for modular bridge will be chosen and proposed in this paper.

조립식교량의 콘크리트 방호울타리 연결시스템 개발을 위한 실험적 연구

최근 교량의 건설에서는 공사기간의 단축 등을 위해 조립식 형태의 교량 시공이 연구되고 있다. 하지만 이는 대부분이 주 구조물인 교각, 거더와 바닥판 등에 국한되어 있고, 조립식 교량에 적합한 방호울타리와 같은 부대시설에 대한 연구는 미흡한 실정이다. 이에 본 연구에서는 조립식 교량 적용을 위한 콘크리트 방호울타리 연결 시스템을 제안하고, 제안된 시스템의 구조적 성능을 검증하기 위하여 정적 실험을 수행 하였다. 변수는 볼트의 수직 수평 접합방식으로 기준실험체와의 비교를 통해 조립식 교량에 적합한 콘크리트 방호 울타리 연결시스템을 제안하고자 하였다. 그 결과, 볼트의 수직접합이 구조적 성능 및 건전성이 일체형의 기준실험체와 거의 동일하다는 것을 알 수 있었고, 조립식교량 적용을 위한 연결시스템으로 적당하다고 판단된다. Recently, in field of bridge construction, modular technology has been studied to reduce construction period. However, main stream of the study is limited to the pier, girder and deck of bridge, which are huge or main members. Studies on incidental facilities like concrete barrier is out of sight. Thus, in this study, connection system of concrete barrier was developed to apply to modular bridges and static experiment was performed in order to verify structural capability of proposed system. Variables of experiment are composed of bolt direction such as vertical and horizontal. The experimentation due to the designed variables was conducted by comparison with a standard concrete barrier, which is a traditional barrier. As a result, vertical joint way of the bolt showed nearly identical structural performance and healthy to standard specimen's. it can be applied to modular bridges.