WELCOME TO MY
PRESENTATION
YANGON TECHNOLOGICAL UNIVERSITY
DEPARTMENT OF CIVIL ENGINEERING
STUDY ON VARIATION OF JOINT FORCES IN STIFFENING TRUSS OF CABLE-STAYED BRIDGE
SUPERVISOR STUDENTDR.NYAN MYINT KYAW MA YEE MON KHAINGPROFESSOR AND HEAD ROLL NO. C-28DEPARTMENT OF CIVIL ENGINEERING M.E. THESIS
Outlines of the First Seminar
Objectives of the study
Scopes of the study
Flow chart of the study
Component parts of the cable-stayed bridge
Design procedure
Implementation program
Expected outcomes
Objectives of the study
To get knowledge on design and analysis of a superstructure of cable-stayed highway bridge
To know the components of cable-stayed bridge
To have some knowledge of the design specifications for highway bridge published by American Association of State Highway and Transportation Officials (AASHTO) specifications
To get better knowledge on practices and standards in bridge design
To get detail information on the variation of joint forces in stiffening truss of cable-stayed bridge
To be skillful for the way how to use STAAD-Pro software
Scope of the study
Only superstructure of cable-stayed bridge will be designed
AASHTO design specifications and HS 20-44 loading will be used
The preliminary design and joint design will be done by STAAD-Pro software
The effect of thermal change, wind force and earthquake effect will be considered
The variation of joint forces in stiffening truss which mainly supports the floor of cable-stayed bridge are determined
Anchorage, substructure and construction methods are not involved in this study
Literature Study
Design Configuration
Modeling for Analysis
Construction Methods and Procedures
Analysis and Design
Final Design and Result
Joint Detail Design of Stiffening Truss
Variation of Joints forces in Stiffening truss
Fig. Flow chart of the study
Component Parts of Cable-Stayed Bridge
1. Cables
2. Cable System
3. Pylon
4. Stiffening girder or Truss
5. Cable anchorage and Connection
Types of cables
Cables Cables are the most important elements of a cable-stayed bridge.
They carry the load of the girder and transfer it to the tower and the
back-stay cable anchorage.
Cables are tension members.
New Parallel Wire Strand
Locked coil Strand Helical Strand Bar Bundle
Seven Wire Strand
Cable SystemThree basic arrangements have been developed for the longitudinal
layout of the stay cables. They are
Radial System
Harp System
Fan System
Number of Cable PlanesThe three basic transverse cable of configurations are following;
(a) Single Plane
(b) Double Plane
(c) Triple Plane
Pylon or Tower
The design of the pylon must adapt to the various stay cable layouts.
The primary function of the pylon is to transmit the force arising from
anchoring the stays and these forces will dominate the design of cables.
Tower configurations for single-plane cable
Tower configurations for single-plane cable
Tower configurations in the case of the high installation position for girder
Stiffening Girder
The role of the stiffening girder is to transfer the applied loads, self
weight as well as traffic load, into the cable system.
The traffic load is acting on the deck of the girder, and both the dead
load and wind area in most cases are larger for the girder than for the
cable system.
Stiffening girders may be I girders, trusses and box girders.
The stiffening truss will be made as a space truss comprising four
chords connected by four diagonal bracings, two vertical and two
horizontal.
Bracing System
The bracing system used in stiffening trusses are generally the same as found in the other trusses with constant depth.
Three types of bracing system for the vertical main trusses . They are1. Warren truss2. Pure warren truss 3. Pratt truss
(a) (b)Warren truss
Pratt trussPure warren truss
Figure; Relevant Bracing Systems for the Main Trusses
Bridge Type - Cable-Stayed Bridge
Total Length of Bridge - 240 m
Span Arrangement - 3 spans arrangement
Main Span - 130 m
Side Span - 55 m (each)
Clear width - 22 m (six lanes)
Side Walk Width - 1.5 m (each)
Pylon (or) Tower - H Type
Truss Type - Warren Truss Type
Cable type - 7̋=ΦParallel Wire Strands
Cable System - Fan type
Traffic (live loading) - HS-20-44 (AASHTO)
Height of Truss - 3 m
Stringer Spacing - 5.87̋5 m c/c
Design Procedure
Implementation Program
Literature study on proposed bridge
Configuration of proposed bridge
Preparation for analysis of bridge
Modeling analysis of bridge using STAAD-Pro software
Design of main structural components
Detail for joints of stiffening truss of bridge
Expected outcomes
Achieve knowledge and skill in design of a cable-stayed bridge
Provide complete joint design data for construction of a cable-stayed bridge
THANK YOUFOR YOUR
ATTENTION
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