What is match cast?
452-3.2 Match Cast: A precast concrete fabrication process whereby a segment is cast against the preceding segment producing a matching interface which permits the re-establishment of the cast geometry at erection time. Match casting is accomplished by either the short line or long line casting method.
Which are the methods of pre casting segments in segmental construction?
Precast segments are usually erected using the span-by-span method, balanced cantilever method, or progressive placement method.
- Span. In the span-by-span method, an entire span is assembled, post-tensioned, and erected so that it is self-supporting before the next span is erected.
- Cantilever.
- Placement.
- Cantilever.
What is segmental construction?
A segmental bridge is a bridge built in short sections (called segments), i.e., one piece at a time, as opposed to traditional methods that build a bridge in very large sections. These bridges are very economical for long spans (over 100 meters), especially when access to the construction site is restricted.
What is precast segments?
Precast structures are completely constructed before positioning them. A precast structure is constructed from pre-stressed concrete and the final form of the structure is then positioned where it has to be used.
What is a casting yard?
A casting yard is a confined place where all the concrete structures like segments, I-griders/ beams etc are casted. Producing bridge segments in casting yard away from the bridge construction site is a major advantage of segmental concrete bridges.
What is balanced cantilever bridge?
The Balanced Cantilever Method refers to a construction method that does not install scaffolding systems under the bridge and completes the superstructure of the bridge by sequentially joining the segments to form a span by post-tensioning and balancing them left and right from each pier using special erection …
What are the construction techniques used for segmental bridges?
Precast segmental erection techniques for concrete bridges include the erection on falsework, erection by gantry, erection by crane, erection by lifting frame, and full span erection techniques etc.
What is balanced cantilever method?
What is the simplest and the least expensive kind of bridge to build?
Beam Bridge A beam or “girder” bridge is the simplest and most inexpensive kind of bridge. According to Craig Finley of Finley/McNary Engineering, “they’re basically the vanillas of the bridge world.” In its most basic form, a beam bridge consists of a horizontal beam that is supported at each end by piers.
What is segment in civil engineering?
Segmental Construction Method Balanced Cantilever. A Segmental Bridge is a bridge built in short sections (called segments), that is one piece at a time. And then segments are erected to make the bridge. The bridge is either cast-in-place or precast.
What is a concrete casting yard?
Introduction A casting yard is a confined place where all the concrete structures like segments, parapets, I- girders/beams, boundary wall panels, cable troughs etc.
What are the advantages of a cantilever bridge?
The Pros of Cantilever Bridges
- They are less invasive. Because they only require impacting one other tooth, less natural tooth surface is disturbed.
- They look natural.
- A cheaper alternative.
- Their longevity makes them attractive.
- The healthier alternative.
- They are easy to place.
Why is short line match casting used for precast bridges?
Short-Line Match Casting of Precast Segmental Bridges Segmental precasting of prestressed-concrete bridges is a well-established construction method that offers many benefits on suitable projects. The advantages include economies from industrialized, repetitive construction procedures that reduce costs and construction time.
Which is better in place casting or segmental precasting?
Compared with segmental precasting, in-place casting with MSS offers simpler geometry control and a much smaller number of structural joints, requires less post-tensioning as many design standards allow edge tensile stresses in service conditions, and avoids precasting facility and segment shipping and handling.
What are the different types of precast segmental bridges?
Precast segmental bridges may be erected with four construction methods: span-by-span erection with self-launching gantry; balanced cantilever erection with ground cranes, lifting frames or self-launching gantry; progressive placement with a cable-stayed system or temporary piers; and incremental launching.
What is the principle of match cast concrete?
The principle of the match-cast joint is that the connecting surfaces fit to each other very accurately, so that only a thin layer of filling material is needed in the joint. Each segment is cast against its neighbor. Use of a bond breaking agent allows the seg- ments to be taken apart.
