Table of Contents
What is precast drawing?
Shop drawings are graphic diagrams of precast concrete units and their connecting hardware, developed from information in the contract documents. They show information needed for both field assembly (erection) and manufacture (production) of the precast concrete.
How is precast made?
Precast concrete is made up of coarse and fine aggregates, cement, water, and admixtures. It is mixed in the factory’s batch plant according to the concrete mix design specified by the engineer. The approved batch of concrete is transported in a dispensing machine to the molds using an overhead crane.
How are precast concrete members connected to the structure?
The connections are usually made by placing a loose plate between two structural steel plates that are embedded both in the cast-in-place or the precast concrete panel and welded together. Some connections are designed to bend and yield in one direction while remaining rigid in all other directions.
How is precast concrete prepared?
Precast concrete is a construction product produced by casting concrete in a reusable mold or “form” which is then cured in a controlled environment, transported to the construction site and lifted into place (“tilt up”). In contrast, cast-in-place concrete is poured into site-specific forms and cured on site.
How are precast concrete made?
Precast concrete is a form of concrete that is prepared, cast and cured off-site, usually in a controlled factory environment, using reusable moulds. Precast concrete elements can be joined to other elements to form a complete structure.
What are the disadvantages of precast concrete?
Disadvantages of Precast Concrete If not properly handled, the precast units may be damaged during transport. It becomes difficult to produce satisfactory connections between the precast members. It is necessary to arrange for special equipment for lifting and moving of the precast units.
What are four 4 ways to connect precast units?
Grout Coupler Precast column to column connection. Precast beam to column connection. Precast wall to foundation connection. Precast wall to wall connection.
How strong is precast concrete?
Precast manufacturers commonly use concrete with compressive strengths in the range of 4,000 psi to 5,000 psi. When the industry was in its infancy, 3,000 psi was the common 28-day compressive strength specified.
Is precast concrete cheaper?
A recent research project directly compared the costs of precast concrete to on-site pouring and found precast concrete slabs save 23 percent over cast-in-place concrete. Columns yielded a similar result, with savings at 21 percent less cost than on-site pouring.
Is precast house safe?
Safe Construction Platform: No raw materials have to be stocked in site for Precast Concrete construction. It reduces the requirement of traditional formworks and props, wastage, workers, etc. and thus provides a safe working platform.
What are precast elements?
Precast Construction Technology consists of various precast elements such as walls, beams, slabs, columns, staircase, landing and some customized elements that are standardized and designed for stability, durability and structural integrity of the building.
How thick are precast concrete panels?
Precast is a minimum 4″ thick concrete panel system that looks like many natural stones and granites by exposing the beautiful aggregates within the mix designs. Architectural precast consists of a solid concrete panel that typically has a 4″ minimum thickness.
What are precast walls?
Precast Concrete Wall Panels Precast concrete simply means concrete cast into a reusable mold or “form,” which is then cured in a controlled environment, transported to the install-site and lifted into place. Our precast wall panels make a beautiful addition to any plan.
Where is precast concrete made?
Precast concrete products are manufactured in specially-equipped factories, which are established in permanent locations.
What is precast column?
Precast concrete columns may be single or double storey height. Columns are provided with necessary supports for the ends of the precast beams(corbels or cast-in steel sections). There will also be some form of connection to provide beam-column moment connection and continuity.
What is precast beam?
Precast concrete beams and slabs (or planks and joists) is a construction system comprised of precast concrete elements that span in modules between walls and are tied together with rebar that locks into a thin cast-in-place slab. A thin reinforced concrete layer is then poured on top.
Is precast wall good?
Precast walls are resistant to mold, fire, and moisture and have no effects on them. In case of any failure during construction, only a few columns might be affected so we can replace those panels only. By doing minor repairs panels can be reused. The precast panels provide high security.
What are the main basic type of connections for precast panels?
(1) beam-to-slab connections (2) beam-to-column connections (3) wall-to-frame connections (4)column splices, including to foundations. Importance of Basics of Precast Connections Design Concepts acting as fundamentals of development of Advances in Precast Connections.
Are precast wall load bearing?
Architectural precast concrete wall panels that act as loadbearing elements in a building are both a structurally efficient and economical means o f transferring floor and roof loads through the structure and into the foundation. In many cases, this integration can also simplify construction and reduce costs.
What are the advantages and challenges in precast structures?
The precast construction technology offers advantages such as 1) cost-saving, 2) Time savings, 3) Quality enhancement 4) Less labor required, 5) Enhanced safety 6) Reduced wastage.
Why is precast concrete better?
Because precast concrete is more easily controlled, the quality and durability is typically much better than cast-in-place concrete. A precast manufacturer is also more likely to receive greater discounts on materials due to the volume of purchases that can be made for multiple projects at a time.
How long does precast concrete last?
Precast concrete structures can be designed for 100-year service life with minimal upkeep.
