Main span closure for the New Samuel de Champlain Bridge (NSCB) - An innovative alternative closure using a temporary king-post to accelerate construction

2019 ◽  
Author(s):  
Gonzalo Osborne ◽  
Frederic Saleh
Keyword(s):  
Stay Cable ◽  
Project Completion ◽  
Long Span ◽  
Stay Cables ◽  
The Subject ◽  
Construction Schedule ◽  
Lifting Equipment ◽  
Main Bridge ◽  
Cable Stayed Bridges ◽  
Schedule Requirement

<p>Signature Saint Laurent (SSLC) is the consortium comprised of SNC Lavalin, Flatiron Constructors Canada, Dragados USA and EBC, that selected the design and construction for the New Samuel de Champlain Bridge (NSCB) in Montreal, Canada.</p><p>The NSCB’s construction schedule was the major challenge for a successful project completion. The geometry of the main bridge is complex, with an asymmetric stay cable arrangement and a unique transverse behavior with three independent corridors connected by crossbeams, involving the location of the stay cable anchorages. This geometry questioned the constructability and the stringent schedule requirement. The subject of this paper is relevant to this conference as it pertains to an innovative construction method for cable-stayed bridges.</p><p>The back span was fully erected on temporary towers in advance, followed by the main span which was to be built with heavy lifting equipment in cantilever sequentially from the main single pylon towards to the East approach. A set of three gantries erected the preassembled segments from the ground to the tip of the deck, where they were connected to the previous segment.</p><p>To expedite the construction, an innovative method was developed to erect some segments from the opposite end with cranes from the ground, with a stick-built conventional method. The closure location was therefore shifted by 50 meters (four segments) towards the pylon. These segments would be supported with temporary stay cables anchored to a 36-meter high king-post on top of the deck. The king-post would be sitting on top of the deck, supported temporarily by shoring towers to reduce the demands in the superstructure and adjacent pier.</p><p>This erection system can serve as an alternative method to expedite construction for long span single tower cable stayed bridges, by erecting segments with a temporary stay tower from the opposite end, therefore reducing schedule constraints.</p>

scholarly journals Serviceability Assessment Method of Stay Cables with Vibration Control Using First-Passage Probability

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Seunghoo Jeong ◽  
Young-Joo Lee ◽  
Sung-Han Sim
Keyword(s):  
Vibration Control ◽  
Control Method ◽  
Principal Component ◽  
Assessment Method ◽  
Stay Cable ◽  
First Passage ◽  
Long Span Bridges ◽  
Long Span ◽  
Stay Cables ◽  
Cable Stayed Bridges

As the construction of long-span bridges such as cable-stayed bridges increases worldwide, maintaining bridge serviceability and operability has become an important issue in civil engineering. The stay cable is a principal component of cable-stayed bridges and is generally lightly damped and intrinsically vulnerable to vibration. Excessive vibrations in stay cables can potentially cause long-term fatigue accumulation and serviceability issues. Previous studies have mainly focused on the mitigation of cable vibration within an acceptable operational level, while little attention has been paid to the quantitative assessment of serviceability enhancement provided by vibration control. This study accordingly proposed and evaluated a serviceability assessment method for stay cables equipped with vibration control. Cable serviceability failure was defined according to the range of acceptable cable responses provided in most bridge design codes. The cable serviceability failure probability was then determined by means of the first-passage problem using VanMarcke’s approximation. The proposed approach effectively allows the probability of serviceability failure to be calculated depending on the properties of any installed vibration control method. To demonstrate the proposed method, the stay cables of the Second Jindo Bridge in South Korea were evaluated and the analysis results accurately reflected cable behavior during a known wind event and show that the appropriate selection of vibration control method and properties can effectively reduce the probability of serviceability failure.

scholarly journals Automated Real-Time Assessment of Stay-Cable Serviceability Using Smart Sensors

2019 ◽  
Vol 9 (20) ◽  
pp. 4469 ◽  
Author(s):  
Seunghoo Jeong ◽  
Young-Joo Lee ◽  
Do Hyoung Shin ◽  
Sung-Han Sim
Keyword(s):  
Real Time ◽  
Damping Ratio ◽  
Assessment System ◽  
Smart Sensors ◽  
Stay Cable ◽  
Long Span Bridges ◽  
Long Span ◽  
Stay Cables ◽  
High Flexibility ◽  
Cable Stayed Bridges

The number of cable-stayed bridges being built worldwide has been increasing owing to the increasing demand for long-span bridges. As the stay-cable is one of critical load-carrying members of cable-stayed bridges, its maintenance has become a significant issue. The stay-cable has an inherently low damping ratio with high flexibility, which makes it vulnerable to vibrations owing to wind, rain, and traffic. Excessive vibration of the stay-cable can cause long-term fatigue problems in the stay-cable as well as the cable-stayed bridge. Therefore, civil engineers are required to carry out maintenance measures on stay-cables as a high priority. For the maintenance of the stay-cables, an automated real-time serviceability assessment system using wireless smart sensors was developed in this study. When the displacement of the cable in the mid-span exceeds either the upper or the lower bound provided in most bridge design codes, it is considered as a serviceability failure. The system developed in this study features embedded on-board processing, including the measurement of acceleration, estimation of displacement from measured acceleration, serviceability assessment, and monitoring through wireless communication. A series of laboratory tests were carried out to verify the performance of the developed system.

The Analysis of Stayed Cable Wind-Induced Vibration Morphology and Damping Measures

2014 ◽  
Vol 501-504 ◽  
pp. 1174-1177
Author(s):  
Xiao Ming Du ◽  
Nan Li
Keyword(s):  
Time Effect ◽  
Stay Cable ◽  
Main Bearing ◽  
Cable Vibration ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Stay Cables ◽  
Long Span Bridge ◽  
Long Time ◽  
Wind Induced Vibration

The stayed cable is the key part of the cable-stayed bridge and the main bearing section. Stay cables are prone to vibration under the loads of the rains winds, earthquakes and transportation for the long-span bridge is very flexible and the damping is small. A long time effect of cable vibration on the structure durability has become a serious problem of cable-stayed bridge in the development and operation. Wind induced vibration of stay cable shape is analyzed, and some common damping measures are expounded in the article and it provides the basis for further study in the future.

Deviation saddles for cables bridges: development and qualification ofstay cable technology

2019 ◽  
Author(s):  
Julien-Erdem Erdogan ◽  
Ivica Zivanovic ◽  
Matthieu Guesdon
Keyword(s):  
Corrosion Protection ◽  
High Performance ◽  
Cost Effective ◽  
Stay Cable ◽  
Stay Cables ◽  
Accurate Definition ◽  
High Performance Fiber ◽  
Definition Of ◽  
Bridge Aesthetics ◽  
Cable Stayed Bridges

<p>Deviation saddles for cables are regularly used in projects such as cable stayed bridges, suspended bridges or extradossed bridges. The choice of a deviation saddle may be imposed to improve the bridge aesthetics with a slender pylon and to simplify the construction with a solid pylon section. Saddles are a proper anchorage and must be designed such as to ensure a safe transfer of vertical forces and of differential forces of stay cables into the pylon structure.</p><p>For parallel strand cables, since grouted stay cable tends to disappear from commonly accepted design and technologies, due to corrosion protection and fatigue issues, the most widely used concept of saddle is made of a battery of individual tubes, placed inside a guide pipe poured of concrete.</p><p>The most recent saddle system developed consists in allowing the passage of the strands through the saddle without individual tubes. Strands go directly through concrete recesses within the Ultra High Performance Fiber Concrete (UHPFC) matrix. Recesses are made thanks to reusable rubber bars removed after poured concrete is hardened. Thanks to an optimized cross section of the recesses, individual holes maximize the friction between the concrete and specially sheathed strands with local application of a cohesive sheathing (Cohestrand®), which allow strands to transfer important asymmetrical loads to the saddle without sliding. Meanwhile, a continuous corrosion protection is ensured by the strand sheathing from one deck anchorage to the other.</p><p>This make the use of saddle a cost-effective and durable mean to deviate and anchor parallel strand cables, that suits Owners needing simple but robust design for stay cable or extradossed bridges. Such saddle bridge design is nowadays clearly described in the 7<span>th</span> edition of the PTI recommendations, that specifies the qualification process of saddle technologies, especially in regards to the accurate definition of a minimum friction coefficient.</p>

scholarly journals The use of Classical Rolling Pendulum Bearings (CRPB) for vibration control of stay-cables

2018 ◽  
Vol 148 ◽  
pp. 02002
Author(s):  
Georgia Papastergiou ◽  
Ioannis Raftoyiannis
Keyword(s):  
Suspension Bridges ◽  
Geometrical Parameters ◽  
Structural Elements ◽  
Stay Cable ◽  
Stay Cables ◽  
Taut String ◽  
Integral Differential Equations ◽  
Cable Vibrations ◽  
Cable Stayed Bridges

Cables are efficient structural elements that are used in cable-stayed bridges, suspension bridges and other cable structures. A significant problem which arose from the praxis is the cables’ rain-wind induced vibrations as these cables are subjected to environmental excitations. Rain-wind induced stay-cable vibrations may occur at different cable eigenfrequencies. Large amplitude Rain-Wind-Induced-Vibrations (RWIV) of stay cables are a challenging problem in the design of cable-stayed bridges. Several methods, including aerodynamic or structural means, have been investigated in order to control the vibrations of bridge’s stay-cables. The present research focuses on the effectiveness of a movable anchorage system with a Classical Rolling Pendulum Bearing (CRPB) device. An analytical model of cable-damper system is developed based on the taut string representation of the cable. The gathered integral-differential equations are solved through the use of the Lagrange transformation. . Finally, a case study with realistic geometrical parameters is also presented to establish the validity of the proposed system.

Reliability Assessment for the Balanced Cantilever Construction Phases of Super Long-Span Cable-Stayed Bridges with Steel Box Girder

2014 ◽  
Vol 578-579 ◽  
pp. 1542-1550 ◽  
Author(s):  
Bing Bai ◽  
Qing Hua Zhang ◽  
Qiao Li
Keyword(s):  
Reliability Evaluation ◽  
Long Span ◽  
Stay Cables ◽  
Sample Structure ◽  
Sutong Bridge ◽  
The Stability ◽  
High Level ◽  
Cantilever Construction ◽  
Random Nature ◽  
Cable Stayed Bridges

Balanced cantilever construction phases are of great importance for the total life cycle processes of super long-span cable-stayed bridges. For assessment purpose, a systematic study on the reliability evaluation of these phases is carried out. Taking Sutong bridge as the sample structure studied, a series of load and resistance models are then established on the basis of field measurement. Using all these achievements, a typical phase of girder segment 6# lifting is chosen for reliability evaluation. Results of the analysis show that the established models are quite representative and reflect actual random nature perfectly. Furthermore, compared with pylon and stay cables the stiffening girder seems more likely to fail in accordance with reliability index. The major failure mode of it in terms of present analysis is the stability failure due to the action of bending and axial load. Nonetheless, the components on the whole are still in a high level of reliability, which can guarantee the proceeding of construction with efficiency.

Structural optimization of two-girder composite cable-stayed bridges under dead and live loads

2020 ◽  
Vol 47 (8) ◽  
pp. 939-953
Author(s):  
C.A.N. Santos ◽  
A.A. El Damatty ◽  
M.S. Pfeil ◽  
R.C. Battista
Keyword(s):  
Structural Optimization ◽  
Concrete Slab ◽  
Slab Thickness ◽  
Optimization Approach ◽  
Stay Cable ◽  
Algorithm Optimization ◽  
Stay Cables ◽  
Design Variables ◽  
Live Loads ◽  
Cable Stayed Bridges

A large number of variables are involved in the optimization of cable-stayed bridges, which makes the optimization impractical when many load cases are considered. To reduce the number of variables to be optimized, a discrete phases approach for structural optimization is developed in this study. The approach couples the finite element method with the genetic algorithm optimization approach. The design variables are divided into two categories: (i) main variables: number of stay cables, I-girder inertia, concrete slab thickness, and tower dimensions; and (ii) secondary variables: I-girder dimensions, stay-cable areas, and pre-tensioning forces. Two design objectives are tested: (i) lightest deck mass; and (ii) lowest material cost. Three load cases are considered: (i) dead and truck plus lane live loads; (ii) dead and lane live loads; and (iii) dead load. The results show the importance of considering the truck loads in structural optimization and the efficacy of the phases approach for different objectives.

Structural Design of Experimental Study on Rain-Wind-Induced Vibration of Strayed Cables

2012 ◽  
Vol 532-533 ◽  
pp. 412-416
Author(s):  
Wei Li ◽  
Wei Guo ◽  
Hua Bai
Keyword(s):  
Aerodynamic Characteristics ◽  
Wind Pressure ◽  
3 Dimensional ◽  
Pressure Coefficients ◽  
Long Span ◽  
Stay Cables ◽  
Safe Production ◽  
Wind Induced Vibration ◽  
Fluctuating Wind ◽  
Cable Stayed Bridges

To study the aerodynamic characteristics of strayed cable under wind and rain, with the object of the Zhijiang bridge, pressure experiments on the 2- and 3-dimensional models of stay cables in wind tunnel are made. Mean and fluctuating wind-pressure coefficients with 2 kinds of surface morphology under different wind direction angle are obtained. The results show that the rivulet position will greatly influence the distribution of pressure coefficients on the cable surface, and the separation point of the flow nearby the rivulet will be changed obviously. Aerodynamic coefficients will be changed when the rivulet be in a certain position, then the rain-wind-induced vibration will occur .The experimental results will be the guidance for the wind-resistant design and the safe production of the long-span cable-stayed bridges.

Measuring Methods of Cable Tension in Cable-Stayed Bridges

2011 ◽  
Vol 295-297 ◽  
pp. 1230-1235
Author(s):  
Jiang Bo Sun ◽  
Zuo Zhou Zhao ◽  
Hong Hua Zhao
Keyword(s):  
Natural Vibration ◽  
String Model ◽  
Beam Model ◽  
Stay Cable ◽  
Fem Model ◽  
Cable Tension ◽  
Cable Stayed Bridge ◽  
Stay Cables ◽  
Beam Bending ◽  
Cable Stayed Bridges

This paper presents several methods usually used for measuring cable tension in cable-stayed bridges, especially frequency vibration method. Taken two different length stay-cables under given tension forces in a real cable-stayed bridge as an example, different modeling methods in finite element methods (FEM) were used to solve their natural vibration frequencies. The results by FEM were compared with those from other available theoretical predicting method. It was found that FEM based on tightening string model is more suitable for a long stay-cable. For a short stay-cable under given tension force, beam bending stiffness can be ignored in predicting its first five natural frequencies using a hinged beam model in FEM. While the predicted lower frequency using clamped beam FEM model is more accurate and reasonable.

scholarly journals Optimization of Cable Force Adjustment in Cable-Stayed Bridge considering the Number of Stay Cable Adjustment

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Han-Hao Zhang ◽  
Nan-Nan Sun ◽  
Pei-Zhi Wang ◽  
Man-Hui Liu ◽  
Yuan Li
Keyword(s):  
Sensitivity Analysis ◽  
Calculation Method ◽  
Maintenance Phase ◽  
Optimization Method ◽  
Stay Cable ◽  
Stay Cables ◽  
Design Variables ◽  
Optimization Calculation ◽  
Cable Force ◽  
Cable Stayed Bridges

Modern cable-stayed bridges are spatial, multicable systems. The cable force needs to be adjusted during the construction phase and maintenance phase. The existing calculation methods of cable force adjustment mainly considered the rationality of structural force, but only few research studies have been conducted on how to reduce the number of stay cables which need to be adjusted. This study aims to propose an optimization calculation method including the optimization module with the sensitivity analysis and updating design variable module (UDVM), which are used for cable force adjustment in cable-stayed bridges. Based on the finite difference method, the sensitivity analysis is adopted in the optimization module, which can capture the response of structures as design variables vary; the particle swarm optimization method is adopted for structural optimization. The proposed method can dramatically reduce the number of stay cables which need to be adjusted and ensure the main girder stresses remain in a reasonable state during stay cable adjustment progress by UDVM. Moreover, the proposed method can continuously update the objective function, constraint conditions, and design variables. Finally, this proposed optimization calculation method is applied to two different cable-stayed bridges to validate the reliability and feasibility of the method.

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