Why are precast concrete structural elements usually cured with steam? Steam curing of precast elements develops the full strength of the concrete many times faster than curing at ambient temperature, which allows the precasting plant to reuse its casting beds on a 24-hour pouring cycle.

Connecting precast concrete elements In order to do this, steel connectors are embedded in the concrete at the time of casting. This must be done with great precision. They can be grouted or concreted together. In this method, loops of steel reinforcement are left protruding out of the precast concrete members.

Welded connections are the most common and typical connection used in the erection of precast concrete. 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.

False, Wall panels can be ribbed, to increase their vertical span capacity while minimizing weight, or formed into other special shapes. Wall panels can be ribbed, to increase their vertical span capacity but maximizing weight, or formed into other special shapes.

Increased efficiency; higher quality control. Assembly on site is faster and less affected by adverse weather conditions. Used for floor and floor decks. Deeper elements span further than those that are shallower.

Which of the following is an advantage of using precast concrete? There is a higher degree of quality control possible than with cast-in-place concrete.

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.

Following are the 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.

Production. Concrete waffle slabs may be purchased and shipped to the construction site as prefabricated (the most expensive type) or precast sections, or poured onsite.

Ribbed slabs are made up of wide band beams running between columns with narrow ribs spanning the orthogonal direction. Normally the ribs and the beams are the same depth. Waffle slabs have a thin topping slab and narrow ribs spanning in both directions between column heads or band beams.

1) is a kind of ribbed slab, it is also called waffle reinforced concrete floor. Coffered slab is a ribbed structure with reinforced ribs in the lower zone which have mutually perpendicular arrangement. The resulting thickness of the slab is much less flat.

They work perfectly well on non-reactive sites, slightly reactive clay sites and some moderately reactive clay sites. Waffle slabs are not recommended for use on highly reactive clay sites (Class H1 and H2) because the requirements for good drainage will be nearly impossible to achieve.

Advantages:

• Larger span of slab and floor with less number of columns.
• load carrying capacity is greater than the other types of slab.
• Savings on weight and materials.
• Good vibration control capacity.
• Attractive soffit appearance when exposed.
• Lightweight.
• Vertical penetrations between ribs are easy.

Waffle pod slabs are also very lightweight and much easier to handle than traditional slabs, reducing the overall amount of labour involved. These factors generally mean that a waffle pod slab will be significantly cheaper than a regular concrete raft slab.

Key benefits of waffle pod slabs also include simplicity of construction using interconnecting components; increased energy efficiency of the building from the ground up; stronger building slab than traditional concrete foundations; and cost efficiencies in terms of trades needed and time to construct.

about seven days

WHAT ARE WAFFLE PODS? This is where the concrete is sitting on (and around) a series of boxes (or Pods) set out in a grid pattern. Think of a waffle pod as a raft lying flat above your soil.

The construction process involves a building system of concrete slabs that are shored up by columns. The monolithic poured concrete will form a flat top surface while the rectangular grids form deep concrete beams on the underside, with the beams resembling waffle pockets spread out at right angles.

130 mm

This slab is usually 100mm thick with thickened edges varying between 300mm and up to 700mm deep. Throughout the slab there are also stiffening beams which are 300mm wide and vary in depth up to 700mm. These beams are spaced at a maximum of 6000mm to a minimum of 4000mm.

ANSWER: Every concrete slab has cracks. Even when you don’t see them, slabs are laced with networks of micro-cracks resulting from common shrinkage. When new concrete hardens, shrinkage always occurs. And because concrete is not an elastic material, cracks are inevitable and rarely a cause for concern.

insulating

Precast concrete structures provide superior resistance to fires, natural disasters, insects and mold. Like no other building material, its resistance to rain, wind damage, earthquakes, termites and decay provides lower maintenance and insurance costs.