Cast-In-Place Concrete Slabs in Construction PDF

ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE CAST IN SITU CONSTRUCTION  A.k.a poured-in-place,  a concreting technique which is undertaken in situ or in the concrete component’s finished position.  preferred choice for concrete slabs and foundations, beam...

ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE CAST IN SITU CONSTRUCTION  A.k.a poured-in-place,  a concreting technique which is undertaken in situ or in the concrete component’s finished position.  preferred choice for concrete slabs and foundations, beams, columns, walls, roofs, and so on.  flexibility both from batching to mixing to placing, curing and drying.  ability to effect necessary changes based on present situations on site. ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE  A floor slab (also called plate slab or filigree slab) is a reinforced concrete slab with a minimum thickness of 5–6 cm  made into a solid and monolithic  Standard concrete floor slab thickness in residential construction is 4 inches.  5 to 6 inches is recommended if the concrete will receive occasional heavy loads. ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION FLAT PLATES  erected as one-way or two-way slabs  support is provided directly through columns or walls.  easy and simple formworks are required  length of 6 to 8m, and live loads among 3 and 5KN/m2  pre-stressed flat plates remains among 8-12m ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION FLAT PLATES  can also be erected as post-tensioned slabs  low-cost formwork, uncovered flat ceilings, and rapid construction  low shear strength and considerably low stiffness, which may lead to significant deflection. ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS A simple flat slab is often made of concrete and does not include any beam support but is sustained by caps and columns. The simple flat slab may be constructed with little effort and needs only a small quantity of formwork. As a result, the building’s loads are transmitted into the columns so that the structure can maintain an efficient balance. These simple flat slabs are appropriate for spans extending from 6 to 9 metres in length. In this context, the term “span” is the distance that exists between the structure’s two discrete supports. Likewise, the flat slabs are the optimal choice for dynamic loading weighing around 7 kN/m2 and up. SIMPLE FLAT SLABS ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS SIMPLE FLAT SLABS ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS SIMPLE FLAT SLABS ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS  ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS Slabs that use drop panels and column capitals are called “flat slabs with drop panels.” The slab’s increased thickness at its uppermost column is known as the drop panel. The shear resistance of the flat slab can be improved greatly with the help of these drop panels. The flat slab with drop panels added to it also boosts the structure’s potential for absorbing negative moments. The bending moment that is created when the compressive stress from the bottom end of the beam acts in conjunction with the tensile stress from the top side is known as the negative moment capacity. These flat slabs significantly decrease deflection while enhancing the slab’s overall stiffness. FLAT SLABS WITH DROP PANELS FLAT SLABS WITH DROP PANELS FLAT SLABS WITH DROP PANELS FLAT SLABS WITH DROP PANELS FLAT SLABS WITH DROP PANELS  ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS A column head is an expansion made of reinforced concrete that is placed on the top of a column and functions as an essential component of the system. For architectural applications, the angle of such column heads could be designed to be anything the architect desires. On the other hand, the concrete should be placed at an angle of 45 degrees on both faces of the column if designs are to be stamped into the concrete. FLAT SLABS WITH COLUMN HEAD FLAT SLABS WITH COLUMN HEAD FLAT SLABS WITH COLUMN HEAD FLAT SLABS WITH COLUMN HEAD ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION CONVENTIONAL SLAB  The slab that supported on beams and columns  thickness is small, depth of the beam is large, load is transferred onto the beam and then the column  requires extra formwork  no column cap, thickness is 10 cm  5 to 6 inches is recommended if it will receive heavy loads occasionally ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION TYPES OF CONVENTIONAL SLABS ONE WAY SLAB  principle reinforcement is within the short run  distribution reinforcement is supplied in the long run  principle bars are cranked to withstand the formation of pressure ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION TYPES OF CONVENTIONAL SLABS One Way Slab  supported by a beam on two opposite sides to move the load in one direction  ratio of longer span (l) to short duration (b) is equal or greater than 2  horizontal are called main reinforcement bars, vertical are called distribution bars. ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION TYPES OF CONVENTIONAL SLABS ONE WAY SLAB  Although a minimum reinforcement referred to as distribution steel, primary reinforcement resistance is provided to uniformly distribute the load over long intervals above temperature and shrinkage stresses. ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION TYPES OF CONVENTIONAL SLABS ONE WAY SLAB Example:  All cantilever slabs are usually one- way slabs  square in shape and 4 meters in size ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION TYPES OF CONVENTIONAL SLABS TWO-WAY SLAB  supported by beams from all sides load is  carried along both directions  ratio of long duration (l) to short duration (b) is less than 2  distribution reinforcement is provided in both directions  length and width of the slab is more than 4m  distribution strips are provided at two ends to resist stress formation  used multilevel building floors. ALTERNATIVE BUILDING CONSTRUCTION SYSTEMSQUES CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION TYPES OF CONVENTIONAL SLABS TWO-WAY SLAB  short direction is the main direction  main reinforcement is arranged along the short direction  longer the direction is the secondary direction  secondary reinforcement is arranged in the longer direction ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION JOIST SLAB (RIBBED)  made up of wide band beams running between columns with narrow ribs spanning the orthogonal direction  ribs and the beams are the same depth  thin topping slab completes the system ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION JOIST SLAB (RIBBED)  one-way joist floor slab  consists of a series of small, reinforced concrete T beams  connected with girders that in turn carried by the building column  T beams are known as joists  concrete is cast between those spacing to make those ribs ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION JOIST SLAB (RIBBED)  the soffit can reduce the quantity of concrete and reinforcement and the weight of the floor  deeper, stiffer floor permits longer spans  formwork complexity can be minimized by the use of standard modular, re-usable formwork  when flying form panels are used, the ribs should be positioned away from the column lines ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION JOIST SLAB (RIBBED)  very adaptable for accommodating a range of service openings.  economic in the range 8 to 12 m.  saving of materials tends to be offset by some complication in formwork  ribs should be at least 125 mm wide to suit reinforcement detailing  spacing between the ribs is 20-30 inch RIBBED SLAB ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION WAFFLE SLABS  made of reinforced concrete with holes underneath  preferred for large spans greater than 12 meters  used to avoid many columns interfering with space  flat on top while it appeared like a grid-like surface on the bottom  grid is created by the removal of molds after the concrete sets ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION WAFFLE SLABS  more solid when used on longer spans and with heavier loads  recommended for buildings that require minimal vibration  buildings that require big open spaces  composed by intricate formwork, and may be more expensive than other types of slabs ALTERNATIVE BUILDING CONSTRUCTION SYSTEMS CAST-IN-PLACE DIFFERENT TYPES OF CONCRETE SLABS IN CONSTRUCTION WAFFLE SLABS  ribs are constructed perpendicular to each other  laid in equal depth having a uniform rib appearance  provide good aesthetic features  reinforcement laid in boththe directions  depth of slab varies from 85 to 100 mm  width of inside beams range from 110 to 200 mm