In addition, both precast segmental construction technology and cast-in-place segmental technology as discussed in this Handbook are applicable to construction of concrete cable-stayed bridges. The typical span length is feet, and 28 cantilevers will be constructed using precast segments. Typical segments are 25 feet long, 82 feet wide, and the maximum segment weight is tons. Segments are delivered on barges since the entire structure is over water.
Resolving obstacles in transportation involving any water body, requires the concern of bridge engineering. In current scenario, many structural configuration options are available for bridge structure. Bridge decks supported with cables are aesthetically pleasant and in some cases proved cost efficient too.
As a result of advancement in the construction technology, construction field is spectating merger of structural configuration to achieve desirable results. Extradosed bridges are perfect example for combination in structural configuration of, stay cable bridges for aesthetics and girder bridges for their durability, strength and ease of construction.
Merger of both bridge configuration leads to economical bridge construction in terms of design and construction costs savings. The 3rd Narmada bridgeis taken as a case-study in this paper to describe components and functioning of an extradosed structure.
This paper addresses the design characteristics and construction methodology for bridge decking in extradosed bridge structure.
Narmada bridge design and construction comprises of bored cast in situ pile foundation, pier-cap, Y-shaped pylons, and extradosed cable deck which consist of m varying length segments having three-cell precast segmental box girder cast with short-line method and erection with balance-cantilever under-slug method by Bridge Builder.
Stay-cables and post tensioning systems are provided to have structurally sound deking system. Route considered as one of the busiest national highway across the country. Inheavy traffic conjunction issues are being encountered on this NH-8 due to distress of existing Sardar Bridge on Narmada River at Bharuch.
Some of the salient features of the project are as under: Name of the Project: Six Laning of Km On Narmada River, Nr. Zadeshwar crossroads, Bharuch, Gujarat, India. Engineering Procurement and Construction Type of Structural: Extradosed type Bridge structure Specific Technology: Stay cable extradosed system-Dyna-Link Anchor box stay cable system, Post-tension bar stressing.
Bridge structural configuration Fig. Structural component details This bridge has segmental precast girders erected in balance cantilever manner on both side of pylons supported eventually on pile foundation. Concept is more or less module based design, where nine numbers of pylons having balance cantilever extradosed design along with two abutments makes the bridge.
Module geometry is illustrated in Figure 1. Alignment and Geometry of Bridge The extra-dosed bridge has straight alignment between abutments A1 and A2. The length of main bridge is m with two end spans of The superstructure consists of Superstructure also has a single 3.
Stay cables are anchored at the edges of box girders to support them which are later deviated in short pylons. The precast segments are erected by balanced cantilever construction method using a beam and winch erection system. Transverses slope of 2.
Expansion joints are located at mid-span of every other span. For vertical displacement between two adjacent cantilevers, a shear key is provided at the expansion joint. The bridge substructure is Y-shaped cast-in-situ concrete pylons supported on pile foundations.
Piling in Water Front Bored cast-in-situ piles of 1. Top of pile cap is at low water level. Vertical pile capacity is duly modified for scour condition by considering overburden pressure from scour level. Pylon The typical pylon for the main bridge substructure is chosen to have a Y-shaped with rounded corners to improve aesthetics and to reduce wind and water current loads.
To cast this kind of shape, special steel formwork with adequate scaffolding and false-work system was designed and provided to have control over geometry of structure.
Pylon consist of four major components Lower pylon cast-in-situ in 3 lifts specially design steel-forms of approximately 5m height Pier Table cast-in-situ consist of segment shape to have uniform connection between segments and pylon Upper pylon cast-in-situ in three lifts specially design steel-forms of approximately 5m height Anchor-box with support system embedded in second and third lift of upper-pylon, during construction system is supported by frame For stay cable, DYNA Link system is provided by Dywidag System International.
Superstructure In the super-structure of the main bridge, three-cell of precast segmental box girder with depth of 4.
Soffit corners are rounded due to presence of transverse tendons in outer sloping webs and also to reduce drag coefficients under wind loadings. The length of typical segment is limited to 3.
Segments are to be match-cast. Integral connection at the pylon location of substructure and the superstructure is provided by pier tables.Jun 08, · The point is that in the 1/3 span you usually got enough reinforcement to carry shear of that location, as it is always far lower than the maximum shear of the beam, but in the location of zero shear you will have maximum moment that you will design reinforcement exactly for that, then a joint would be danerous.
SANSKRITI TIWARY | BEM | SCHOOL OF PLANNING AND ARCHITECTURE Parameters Single Segmental Box Girder I girder and slab Inferences C D Length of viaduct studied 28 m m Length of D is almost a times that of C as only a single span of C was required Cost per meter ₹ 4,00, ₹ 2,61, Cost per unit length of C .
1. Introduction. Recently precast segmental bridge construction has attracted the interest of many researchers. This type of bridge has the advantages of the short period of construction without the necessity of cutting off the main roads which accompanies higher quality construction.
Segmental Bridges External PT - Free download as PDF File .pdf), Text File .txt) or read online for free. procedures for long-span prestressed concrete bridges of segmental construc â tion box girder construction in achieving long spans in bridge structures. Construction Of The Precast Segmental Approach Structures.
Shear behavior of joints in precast concrete segmental bridges. However, in engineering practice, the stitch is usually located at the mid-span of segmental bridges, where both bending moment and shear force are present.
to evaluate the mechanical behaviour of in-situ stitches in precast concrete segmental bridges. The following.