Bascule Bridge Research Articles

Hillsborough River Bascule Bridge Vibration and Rehabilitation

Hillsborough River Bascule Bridge, located in Tampa, Florida, vibrates significantly under traffic loading, and discomforting noises have been reported, especially in recent years. The cause of such a significant vibration was investigated. The bridge is briefly described. Analytical theory is then presented, including the vehicle model, bridge model, road surface model, and numerical methods. A vehicle is simulated as a three-dimensional nonlinear model. The bridge is treated as a space structure consisting of three-dimensional frame elements. The road profile is modeled as a stationary Gaussian random process that is described by a power spectral density function. The free and forced vibration characteristics of the bridge were investigated with trucks traveling over a rough deck. The stiffness effects of the main girders, bracings, and floor beams were studied. Analytical results indicate that insufficient stiffness of lateral bracings and floor beams is a main factor causing the severe vibration. Some rehabilitation schemes for mitigating the severe vibration were investigated. The actual behaviors of the rehabilitated bridge indicate that research results were correct and applicable to bascule bridge design and rehabilitation.

Development of a lightweight epoxy asphalt mixture for bridge decks

A lightweight epoxy asphalt mixture (LEAM) was developed by replacing part of the basalt aggregate in an epoxy asphalt mixture with lightweight aggregate. These mixtures were evaluated as alternative to basalt mixes for deck paving of the TianJin bascule bridge in China. Nine different types of LEAM with varying lightweight aggregate shapes and percentages were designed and tested. The results indicated significant variations in performance. This approach was deemed viable based on FEM analyses that indicated significant stress reductions using lightweight material. Based on the findings it is recommended that a LEAM with 70% rounded lightweight aggregate be used to reduce the deadweight of the deck paving and optimize performance in terms of rutting and cracking resistance.

Kinetic analysis and rehabilitation of old bascule bridge in Tianjin, China

Movable bridges involve a combination of structural, mechanical and electrical components with specific kinetic characteristics in operation. This paper presents the structural evaluation, kinetic analysis and innovative retrofit design in the rehabilitation of an 80 year old rolling lift bascule bridge in Tianjin, China. Structural inspection and evaluation were first performed; the decision was made to preserve the original style and re-enable the rolling function by replacing severely corroded members and the deck system, re-balancing the counterweights and restoring the mechanical and electrical systems. Then, based on a transformable three-dimensional finite-element model, the structure of the bascule bridge was analysed at different states of opening. Dynamic effects caused by abrupt stopping of the mechanism were analysed using a rigorous modal superposition method, and with an approximate equivalent static method. A low-depth steel orthotropic deck system was designed and finally new counterweights were optimised. The refurbished bridge is now fully operational.

Critical issues, condition assessment and monitoring of heavy movable structures: emphasis on movable bridges

In this paper, a relatively less studied class of structures is presented based on the research conducted on Florida's movable bridges over the last several years. Movable bridges consist of complex structural, mechanical and electrical systems that provide versatility to these bridges, but at the same time, create intermittent operational and maintenance challenges. Movable bridges have been designed and constructed for some time; however, there are fewer studies in the literature on movable bridges as compared to other bridge types. In addition, none of these studies provide a comprehensive documentation of issues related to the condition of movable bridge populations in conjunction with possible monitoring applications specific to these bridges. This paper characterises and documents these issues related to movable bridges considering both the mechanical and structural components. Considerations for designing a monitoring system for movable bridges are also presented based on inspection reports and expert opinions. The design and implementation of a monitoring system for a representative bascule bridge are presented along with long-term monitoring data. Various movable bridge characteristics such as opening/closing torque, bridge balance and friction are shown since these are critical for maintenance applications on mechanical components. Finally, the impact of environmental effects (such as wind and temperature) on bridge mechanical characteristics is demonstrated by analysing monitoring data for more than 1000 opening/closing events.

Classic projects: Tower Bridge

A MORE ABSURD structure than the Tower Bridge was never thrown across a strategic river, wrote artist Sir Frank Brangwyn, referring to the most famous bascule bridge in the world. In fact, Tower Bridge is a fusion of three bridges, two of the suspension category emerging from the north and south banks of London's River Thames, with a central span comprising two leaves, or 'bascules', that can be raised to allow high-masted ships to pass.

Analysis of heating and cooling methods for assembly of steel fulcra in bascule bridges

Assembly procedures for assembling steel fulcra of simple-trunnion bascule bridges by heating the girder with heating coils instead of dipping an already stressed trunnion-hub assembly in liquid nitrogen are studied for decreasing the likelihood of failure by cracking and yielding. In the assembly procedure called AP3-A, only the girder is heated to shrink-fit the trunnion-hub assembly in the girder. This assembly procedure AP3-A is found to be infeasible because the girder fails by yielding if heating is expected to be completed in a reasonable amount of time. An alternative assembly procedure called AP3-B is suggested for shrink-fitting where the heating of the girder is combined with cooling the trunnion-hub assembly in dry-ice/alcohol mixture. This assembly procedure AP3-B is found to be feasible. A complete design of experiments study is conducted on AP3-B to find the influence of parameters like hub radial thickness, and radial interference at trunnion-hub interface on the design parameter of critical crack length-a measure of likelihood of fracture. Critical crack lengths during the assembly procedure AP3-B are quantitatively compared with currently used assembly procedures. The results of this work suggest that increasing the hub radial thickness decreases the likelihood of fracture significantly. For hubs with large radial thickness, heating the girder combined with cooling the trunnion-hub in dry-ice/alcohol mixture (AP3-B) is recommended but for hubs with high radial thickness, multistage cooling of the trunnion-hub assembly in dry-ice/alcohol mixture followed by dipping in liquid nitrogen (AP1- multistage cooling) is recommended.

Te Wero Bridge, Auckland, New Zealand

Auckland City Council set up an international design competition for an opening bridge and, after two hotly contested stages, selected the striking design prepared by Hyder Consulting with architect Denton Corker Marshall and mechanical and electrical consultant Kenneth Grubb Associates. The project’s aspiration was to create an iconic object, a breathtaking symbol for Auckland embodied in a unique and distinctive structure. Iconic status demands differentiation and, in the case of opening bridges, this can be provided by the built form, operation and scale. The Te Wero design responded to this challenge with a solution targeted specifically at the Viaduct Basin’s unique history and environment. This paper considers the function and visual aspects of the bridge, its form and image, together with consideration of materials, design and construction issues that led to the final bridge design. The design is for a twin bascule bridge, with a tall mast structure that houses counterweights and a control room. When it opens, the effect will be dramatic, with the twin decks rising to either side. Thanks to lightweight aluminium decks and an ingenious counterweight system, however, it will be a low-energy, low-maintenance and sustainable solution.

Teglvaerks Bridge—Copenhagen

The missing link has finally been completed between two newly developed residential areas located in the small islands of Teglholmen and Sluseholmen in Copenhagen Harbour. For the past 10 years several relatively large residential areas have been developed on the connected islands of Teglholmen and Sluseholmen and it has been a fundamental request from the residents and the Copenhagen Municipality to provide the areas with a connection in the form of a bridge in order to divert the traffic from the residential areas directly to the main traffic roads of Copenhagen. A bridge was therefore built between Teglholmen and Sluseholmen with a new outstanding concept of hydraulically operated bascule bridge. The new bridge is an important contribution towards improving the infrastructure of the area. The structure is 100 m long and was designed with five spans in total of which the centre span is a bascule bridge and the two adjacent spans on each side are post-tensioned concrete. The purpose for designing the bascule span was that when the inner harbour is blocked with ship traffic a navigational opening 15 m wide can be established.

Performance evaluation of a lightweight epoxy asphalt mixture for bascule bridge pavements

This paper proposes a lightweight epoxy asphalt mixture (LEAM) for pavement on bascule bridges. The material properties of LEAM are evaluated with the Marshall test, indirect tensile test, wheel tracking test, and bending beam test. Moreover, the structural performance of LEAM is evaluated by a finite element numerical analysis for a bascule bridge with LEAM pavement. Test results show that the LEAM has a good resistance to moisture damage, permanent deformation, and low-temperature cracking. The LEAM with a 70% lightweight aggregate replacement percentage has been found to have the best effect on deadweight reduction as well as the other performance measures. Moreover, the analytical result shows that LEAM can reduce pavement stress significantly when compared to an epoxy asphalt mixture, which indicates that the LEAM has a good structural performance.

Comparing two procedures for assembling steel fulcra in simple-trunnion bascule bridges

Involving shrink fitting, two procedures for assembling steel fulcra of simple-trunnion bascule bridges are quantitatively compared for the likelihood of fracture during assembly. In assembly procedure called AP1, the trunnion is shrink fitted into a hub, followed by shrink fitting the trunnion-hub assembly into the girder of the bridge. In assembly procedure called AP2, the hub is conducted to find the influence of geometrical parameters such as the radial thickness of the hub radial interference, and various shrink-fitting methods on the design parameter of critical crack length - a measure of likelihood of fracture. For single-staged shrink-fitting methods, for high and low hub radial thickness to hub inner diameter ratio, and where staged shrink-fitting methods are used, for AP2, cooling the trunnion in dry-ice/alcohol and heating the girder, and for AP1, cooling the trunnion-hub assembly into dry-ice/alcohol following by immersion in liquid nitrogen is recommended. For fulcra with high hub radial thickness to hub inner diameter ratio and where staged shrink-fitting methods are used, cooling the components in dry-ice/alcohol and heating the girder is recommended for both AP1 and AP2.

Numerical Study of Dynamic Response of Steel Deck Pavement on the Bascule Bridge

The bascule bridge is one of the most suitable bridge types for ports and rivers in cities. In order to discuss the mechanical behavior of the pavements in the opening process, the finite element model of the pavement system on the Haihe Bridge being built in Tianjin China was built, and the mechanical response in the opening process was calculated. The research results show that the asphalt paving with the thickness of 30mm~40mm is fit for the bascule bridge. The max shear stresses of pavement between pavement and steel plate in the opening process rise with the increase of Young’s modulus, and the high temperature during the construction and conservation after construction should be provided.

A Coordinated Effort

Engineers designing a bascule bridge rehabilitation that was intended to extend the life of the structure by 10 years quickly discovered that the bridge’s deficiencies warranted additional work. The client agreed to a more extensive overhaul that would extend the bridge’s life by 25 years, but weaving the more complex work around restrictions on navigation channel and bascule operations, lane closures, and environmental disturbances, among many other considerations, required skillful coordination.

American Bridges of the NSW North Coast Railway

The North Coast Railway of New South Wales from Maitland to South Grafton, 1911–1923, was the first trunk line of the NSW railway network built to uniform standards for track and structures, particularly the underbridges. Unlike the earlier trunk lines, north, west and south of Sydney, which were progressively upgraded to main line standards, the North Coast Railway was designed and built to main line standards to ensure reliable long-term, cost-effective performance compatible with the projected extension of the standard gauge railway to Brisbane. Importantly, all the steel trusses, steel girders and transom-topped timber spans were based on American bridge technology, including the American Railway Engineering Association Design Code. The original steel bridges continue in service (the timber bridges having been replaced by welded steel girders) and now constitute a family of historical bridges of high heritage signifi cance. This paper summarises the background to the change from British bridges to the new designs by eminent bridge engineer J. W. Roberts, culminating in closing the gap across the Clarence River in 1932 with an American double-deck bascule bridge.

Problem-Centered Approach in a Numerical Methods Course

This paper is an illustration of using a problem-centered approach in an undergraduate course in numerical methods. The problem used in the course was first encountered in a research project that related to the assembly procedure of the fulcrum of bascule bridges. It involved the study of the fulcrum assembly procedure where a trunnion cooled in a dry-ice/alcohol mixture for shrink fitting became stuck halfway in the hub before full insertion could take place. The solution of the problem and its implementation involved numerical solutions of mathematical procedures taught in a typical numerical methods course. The effect of the problem-centered approach in the classroom was quantitatively and qualitatively surveyed over a two-semester period. The results indicate very high student satisfaction in helping them: acquire basic knowledge and skills; reinforce information presented in class, reading assignments, and problem sets; learn to clearly formulate a specific problem and then work it through to complet...

Conceptual design of light bascule bridge

This paper proposed a conceptual design of bascule bridge, which is a new kind of movable bridge with an aim of reducing the weight of superstructure. Compared with the traditional bascule bridge, the light bascule bridge chooses cable-stayed bridge with inclined pylon as its superstructure; therefore, the functions of balance-weight and structure will fuse into one. Otherwise, it adopts moving counterweight to adjust its center of gravity (CG) to open or close the bridge. In order to lighten the superstructure, it uses contact springs to auxiliary retract, and intelligent prestressing system (IPS) to control the main girder's deformation. Simultaneously the vibration control scheme of structure is discussed. Starting from establishing the mechanical model of bridge, this article tries to analyze the conditions that the design parameters of structure and attachments should satisfy to. After the design procedure was presented, an example was also adopted to explain the primary design process of this kind bridge.

Lord Delaware Bridge Replacement: Precast Concrete Replaces Steel in West Point, Va.

This 3545-ft-long (1080 m) precast, prestressed concrete river crossing with main spans up to 240 ft (73 m) replac- es an obsolete, two-lane, movable bascule bridge. The new bridge features spliced bulb-T girders for the main spans using lightweight, high-performance precast concrete.

Cover Picture: Chemical Clockwise Tridifferentiation of α- and β-Cyclodextrins: Bascule-Bridge or Deoxy-Sugars Strategies (Chem. Eur. J. 35/2007)

A bascule-bridge strategy…︁has been delineated for the highly selective clockwise deprotection of a reversibly capped cyclodextrin. This concept is illustrated on the cover, created by Adrien and Karine Leroy, displaying the 1 Moct (Palace Bridge), a famous bascule bridge in Saint Petersburg, operating only a short distance away from the historical University where Mendeleev proposed his periodic table. This is one of two tools, proposed by M. Sollogoub et al. in their Full Paper on page 9757 ff., to efficiently and selectively functionalize cyclodextrins.

Sensitivity analysis of cooling methods and geometric parameters in the assembly procedure of bascule bridge fulcra

To assemble the fulcrum of a bascule bridge, a trunnion is shrink fitted into a hub, followed by shrink fitting of the trunnion-hub (TH) assembly into the girder of the bridge. To shrink the TH assembly, it is cooled in a medium such as liquid nitrogen; however, during this process in some cases, the hub cracks. To reduce the possibility of such failures, a formal design-of-experiments study is conducted to find the influence of geometrical parameters such as the hub outer diameter and the radial interference (at the TH interface), and different cooling methods on design parameters such as the critical crack lengths and stress ratios. Cooling methods include immersion in, first, liquid nitrogen; second, a dry-ice-alcohol bath followed by liquid nitrogen; third, a refrigerated air chamber followed by liquid nitrogen; and, fourth, a refrigerated air chamber followed by a dry-ice-alcohol bath and then liquid nitrogen. The cooling method contributes the most to increasing the critical crack length (between 58 and 79 per cent) and increasing the stress ratio (between 48 and 84 per cent) when considering the TH assembly procedures in representative fulcrum geometries. Moreover, the second cooling method, which is immersion of the TH assembly in a dry-ice-alcohol bath followed by immersion in liquid nitrogen, gives larger critical crack lengths (between 262 and 406 per cent) and larger stress ratios (between 17 and 87 per cent) compared with the current cooling method that uses only liquid nitrogen.

Synthesis in optimization of bionics bascule bridges

AbstractThe optimization of modern bionics bascule bridges mapping the configurations from the nature and adopted in advanced structural engineering is dealt with in the present paper. Theoretical and numerical approaches suggested are based on the evolution algorithms also appearing in the nature. Generalized synthesis in optimization of ultimate behaviour of bionics bascule bridges is analysed. Actual structural application based on such principles is submitted. Copyright © 2007 John Wiley & Sons, Ltd.

Kinematics of Movable Bridges

The majority of all built movable bridges can be grouped into one of the following three structural systems: Bascule bridges, swing bridges, and lift bridges. Many examples for each of these three types of bridges exist and have been documented in the existing literature. The kinematics of these three traditional bridge systems are simple at first sight but nevertheless are important for conceptual design and calculation. Moreover, some recently built or proposed movable pedestrian bridges in Europe differ distinctly from the three aforementioned traditional types of movable bridges. A range of these new ideas is presented here in the context of their kinematic behavior. The writers believe that the understanding of kinematic principles, which are applied regularly in other engineering disciplines, will assist with the development of further new ideas for movable bridges. This paper endeavours to present some such principles and illustrate the application to the given topic.