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>

Experimental evaluation on engineering properties and microstructure of the high-performance fiber-reinforced mortar with low polypropylene fiber content

2021 ◽  
Vol 72 (7) ◽  
pp. 824-840
Author(s):  
Hung Vu Viet ◽  
Cuong Nguyen Tuan ◽  
Duy Nguyen Huu ◽  
Tho Ngo Nguyen Ngoc ◽  
Phuoc Huynh Trong
Keyword(s):  
High Performance ◽  
Polypropylene Fiber ◽  
Cost Effective ◽  
Fiber Content ◽  
Engineering Properties ◽  
Fiber Reinforced ◽  
Cement Mortars ◽  
High Performance Fiber ◽  
New Construction ◽  
Local Materials

Recently, high-performance fiber-reinforced mortar/concrete (HPFRM) has been researched and developed in many fields such as repair, maintenance, and new construction of infrastructure works due to its high strain capacity and tight crack width characteristics. Optimizing the design of mixture proportions and structures using HPFRM is still a complex mechanical and physical process, depending on the design principles, specific site conditions, and their local materials. This study aims to develop an HPFRM with low polypropylene fiber content by using locally available ingredients in Southern Vietnam to address the deficiencies commonly observed in traditional cement grout mortars. Three mixture proportions were prepared with different water-to-binder (w/b) ratios of 0.2, 0.25, and 0.3. Then, the performance of HPFRM was evaluated in both fresh and hardened stages. Additionally, the microstructural characteristics of each mix design were also assessed through scanning electron microscope observation. The experimental results showed that the optimum w/b of 0.25 and a fixed dosage of 0.6% polypropylene fiber produced positive impacts on the rheological, mechanical properties, and also ductility of the high-performance mortar. It was concluded that HPFRMs are promising for cost-effective and sustainable cement mortars.

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 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.

scholarly journals INVESTIGATIONS ON THE GEOMETRIC QUALITY OF CAMERAS FOR UAV APPLICATIONS USING THE HIGH PRECISION UAV TEST FIELD ZOLLERN COLLIERY

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 531-538 ◽  
Author(s):  
H.-J. Przybilla ◽  
M. Gerke ◽  
I. Dikhoff ◽  
Y. Ghassoun
Keyword(s):  
High Performance ◽  
Cost Effective ◽  
Test Field ◽  
Camera System ◽  
Software Products ◽  
Significant Difference ◽  
Effective System ◽  
Geometric Quality ◽  
Definition Of

<p><strong>Abstract.</strong> The geodetic-photogrammetric test field at the industrial monument Zollern colliery in Dortmund offers a scenario for carrying out geometric and radiometric tests of UAV systems. The foundation for this builds a geodetic precision network (position and height accuracy approx. 2&amp;thinsp;mm) with a total of 45 ground control points, distributed over an area of approx. 7 hectares. Within the scope of a campaign carried out in autumn 2017, various UAV sensor systems were tested under comparable conditions. Within this paper geometric investigations of two current DJI cameras, Zenmuse X4S (20 Mpix) and X5S (20.8 Mpix), as well as a Phase One IXU 1000 (100 Mpix) are presented. While the Zenmuse cameras reflect the current state of development of the manufacturer DJI, the medium format camera system from Phase One is primarily settled in the classic aerial segment. However, the desire for increased measurement accuracy (e. g. for engineering applications) also makes such a high-performance sensor interesting for UAV applications.<br />In addition to the configuration of the test field, the system comparison requires identical parameters for flight planning, in particular image overlapping, a complete cross flight configuration at different flight altitudes and the definition of a uniform ground resolution (GSD&amp;thinsp;=&amp;thinsp;14&amp;thinsp;mm).</p><p>The investigations show clear differences in the achievable quality of the cameras. Though the high-priced Phase One system shows the best results, the most cost-effective system, the Zenmuse X4S, delivers only slightly worse results. In contrast, the Zenmuse X5S performs significantly worse than the other systems, mainly resulting from the mechanically unstable camera concept with interchangeable lenses. Finally, the comparison of the software products Pix4D Pix4Dmapper, Inpho UASMaster by Trimble and Agisoft PhotoScan partly shows significant differences in the results of image orientation. In particular in settings with sparse GCP usage the results vary considerably, indicating different strategies on how the residuals are distributed and the datum is defined, mostly Pix4Dmapper outperforms the others. In better GCP configurations there is no significant difference between Pix4mapper and Agisoft PhotoScan, while UASMaster does never deliver the best results.</p>

scholarly journals Seismic Retrofitting of a Bridge Pier with Ultra High Performance Fibre Reinforced Concrete

2018 ◽  
Vol 199 ◽  
pp. 09015
Author(s):  
Reggia Adriano ◽  
Alessandro Morbi ◽  
Giovanni A. Plizzari
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Cost Effective ◽  
Bridge Pier ◽  
Seismic Retrofitting ◽  
Fibre Reinforced Concrete ◽  
Seismic Behaviour ◽  
Environmental Actions ◽  
Definition Of ◽  
High Performance Fibre

The increasing number of road infrastructures needing repair and retrofit is raising the problem of how to improve seismic behaviour for all those structures for which substitution is unlikely. This work deals with the application of a retrofitting technique for Reinforced Concrete (RC) elements based on the use of Ultra High Performance Fibre Reinforced Concrete (UHPFRC). A thin layer of UHPFRC, cast around an existing RC element, can both improve its structural performance and enhance its durability against environmental actions. This kind of rehabilitation intervention may represent, in many practical cases, a cost effective solution compared with the replacement of the entire structure. The aim of this paper is the definition of a reinforcement strategy and the presentation of a 1:4 scale laboratory test of a highway bridge pier reinforced with a 30 mm layer of UHPFRC.

Design and Construction of the Komono Secon Viaduct in Mie, Japan

2019 ◽  
Author(s):  
Tohru Makita ◽  
Yuichiro Nakamura ◽  
Shigeaki Kouroki ◽  
Tetsuya Yamazaki
Keyword(s):  
Service Life ◽  
Corrosion Protection ◽  
Prestressed Concrete ◽  
Composite Structure ◽  
Stay Cable ◽  
Box Girder ◽  
Stay Cables ◽  
Inspection And Maintenance ◽  
Key Aspects ◽  
Design And Construction

<p>The present paper describes key aspects of the design and construction of the Komono Second Viaduct. The viaduct is a three‐span prestressed concrete extradosed bridge with a three‐cell box girder across the Mitaki River, carrying the Shin‐Meishin Expressway at Komono, Mie Prefecture in Japan. The extradosed bridge has an overall length of 341m and a main span of 161m with a 23.35m wide deck carrying dual carriageway with two lanes for each direction. Dual central cable planes are adopted allowing for future deck widening. The stay cable consists of either 37 or 48 seven‐wire prestressing strands of 15.2mm diameter and has four‐layer corrosion protection system for 100‐year service life. The top half of the pylon is built with steel‐concrete composite structure and the stay cables are anchored inside the pylon box sections to facilitate inspection and maintenance works of the stay cable anchorages.</p>

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.

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>

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.

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