BTECH MOD 1 AND 2

Cast-in-place concrete

is

transported in an unhardened

state, primarily as ready-mix,

and placed in forms.

Ready mixed concrete

is proportioned and mixed off

the project site.

Pre-cast concrete

is made by pouring concrete into a mould in a

factory or plant, instead of directly pouring it at the

construction site. The cured concrete product is then

transported to the construction site and installed as a finished

material.

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.

In contrast, standard concrete is poured into

site- specific forms and cured on site.

Flat Slab

The principal

features of a flat slab floor

are a flat soffit, simple

formwork and easy

construction.

Flat Slab

is a reinforced concrete slab

supported directly by

concrete columns without the

use of beams.

Flat Slab

is a

one-way or two- way

system with thickenings in

the slab at the columns

and load bearing walls

called ‘drop panels’.

TWO WAY FLAT

SLABS

a flat plate Thickened at its

column supports to increase its shear

strength and moment-resisting capacity.

The slab is commonly reinforced with bars

running in two directions. This area of

increased thickness is called a drop panel

or drop. The columns are generally

square in cross section, but rectangular

or circular cross sections are also used.

flat plate system

is a type of

concrete slab construction similar to

the flat slab system, but with a key

difference: it does not include drop

panels or column capitals. The slab in a

flat plate system is directly supported

by columns without any additional

thickening around the columns or

beams.

Key Characteristics of a Flat Plate System

Uniform Thickness: Direct Support by Columns: Simplified Formwork:

Ribbed Floor Slab

Introducing voids to the soffit of

a slab reduces dead weight and

increases the efficiency of the

concrete section. A slightly

deeper section is required but

these stiffer floors facilitate

longer spans and provision of

holes.

Ribbed Floor Slab

are made up of

wide band beams running

between columns with equal

depth narrow ribs spanning

the orthogonal direction. A

thick top slab completes the

system.

Commercial Buildings: Where large, open spaces are needed, such as

shopping malls or exhibition halls.

Industrial Buildings: Where heavy loads and large spans are required.

Parking Garages: Where the ability to span large areas with minimal

columns is advantageous.

Theatres and Auditoriums: Where long spans and good acoustic

properties are needed.

Ribbed floor slabs are commonly used in:

waffle slab

is a type of reinforced

concrete slab system that resembles a

waffle pattern on its underside. It is a

two-way ribbed slab with ribs running in

both directions, creating a grid of squares

or rectangles. This grid of ribs provides

additional support and stiffness, allowing

the slab to span large distances without

the need for deep beams or thick slabs.

TWO WAY WAFFLE SLAB

is a two way

concrete slab reinforced

by ribs in two directions.

Waffle slabs can carry

heavier loads and span

longer distances than flat

slabs.

Waffle Slab

Moulds are very strong,

lightweight and capable

of supporting all the

normal loads encountered

in building works.

Lift slab construction

is a method of

building multi-story structures where

concrete slabs are cast on the ground,

one on top of the other, and then lifted

into their final position using hydraulic

jacks. This technique was developed to

streamline the construction process by

reducing the need for scaffolding and

formwork at elevated heights.

Slip Form Method

is used for forming

both horizontal and vertical

concrete structures.

It is often used for forming

highway pavements as

continuous operation is also been

used for forming vertical

concrete structures

Slip Form Method

Basically, this method

involves the continuous

placing of concrete in a

shallow mould having

the same plan as the

building to be

constructed.

Slip form

construction, or

continuously formed

construction , is a

construction method in

which concrete is poured

into a continuously moving

form.

1. Vertical Slip Form System

Cantilever Jump Form Method

the work of lifting devices in order to lift and expand the formwork is done by the electric motors The cantilever Jump Form Method minimizes the use of cranes as it is attached to the large area of formwork with respect to story height

Egg shape slip Form System

Being the diferent type of Slip Form System, however, its principle is based on jump form which ls adapted to any of the geometric shapes I The change in the circumference of the system results in the extension or removal of the cantilever plate . Adjustment of curvature can be done by simply adjusting the circumferential slope and axis E09 Shape SIp Form System is flexible to accommodate adjustment on each side of the wall as well as products of optimal working condition

Conical Form-work System

is having conical formwork which is made of cantilever plates as well as overlapping plates which are attached through steel yoke frames. Cantilevers as well as overlapping plates, have the mechanism of automatically adjusting the geometry. Structures of varying wall thickness including tapering walls can be constructed through this system. However, the structures whose formwork changes geometrically from angular to circular are also constructed through it, It provides integrated scaffolding systems which consist of horizontal work platforms provided at an optimal and safe working area for labor, engineers, and supervisors communities.

PANEL WALL

are

exterior non-load

bearing walls

whose outer surface may or

may not form the exterior

facing of the building and

whose interior surface may

or may not form the

interior finish. It may rest

on the building structure or

may be hung from the

structure

FLAT TYPE

Wall panel is a

single piece of

material, usually

flat and cut into a

rectangular shape

serves as the visible

and exposed

covering for a wall.

FLAT TYPE

Can reduce

construction costs

Application of paints

or other finishing

materials are not

required

Companies introduced

environment friendly

ribbed type wall panel

is light construction, modular, aesthetic, economcal, functional wall panel

section type wall panel

has a traditional rib and micro rib, v rib, and h wave

Window type

panel.

Transparent

glass and frame

incorporated in

panel curtain

wall.

TILT-UP WALL PANEL SYSTEM

involves site-casting the

concrete walls of a

building on its floor slab

or

on separate casting

bed then tilting and

lifting them into position

by crane.

Tilt-up construction

It is a special form

of

precast wall construction in

which wall panels are cast

horizontally at the job site

and then erected.

Tilt-up construction

The wall panels are usually

cast on the previously

placed building floor slab

using only edge forms to

provide the panel shape

Tilt-up construction

The floor slab thus serve as

the bottom form for the

panel

Panels may also be cast

one on top of another

where slab space is limited

A bond breaker compound

is applied to the slab to

prevent the tilt-up panel

REINFORCED CONCRETE

• Concrete is strong in compression weak in

tension

• Steel is strong in tension

• Reinforced Concrete uses concrete to resist

compression and to hold bars in position and

used steel to resist tension

• Tensile strength of concrete is neglected (i.e.

zero)

• R.C. Beams allows crack under service load

Pre-Stressed Concrete

Internal stresses are induced to

counteract external stresses.

• In 1904, Freyssinet attempted to

introduce permanent acting forces in

concrete to resist elastic forces under

loads and was named “Pre-Stressing”

Reinforced Concrete

concrete in which steel is

embedded in such a manner that the two

materials act together in resisting forces. The

reinforcing steel—rods, bars, or mesh—absorbs

the tensile, shear, and sometimes the

compressive stresses in a concrete

structure.external stresses.

Pre-Stressed Concrete

is a system devised to

provide sufficient recompression in the concrete

beam by tensioned steel wires, cables, or rods that

under working conditions the concrete has no

tensile stresses or the tensile stresses are so low

that no visible cracking occurs.

Pre - Tensioning – most often used in factory situations

• Post – Tensioning – site use

Pre-Stressed Concrete Methods

Pre-Tensioning

The tendons are tensioned against

some abutments before the concrete is

place. After the concrete hardened, the

tension force is released. The tendon

tries to shrink back to the initial length

but the concrete resists it through the

bond between them, thus, compression

force is induced in concrete. Pre –

Tension is usually don with precast.

Post-Tensioning

The tendons are tensioned after the

concrete has hardened. Commonly,

metal or plastic ducts are placed inside

the concrete before casting. After the

concrete hardened and had enough

strength, the tendon was placed inside

the duct , stressed, and anchored

against concrete grout may be injected

into the duct later. This can be done

either as precast or cast-in-place

Panel walls

are exterior non-load bearing walls whose outer surface

may or may not form the exterior facing of the building and whose

interior surface may or may not form the interior finish. It may rest on

the building structure or may be hung from the structure.

Masonry panel walls

are exterior non-load bearing walls whose outer

surface may form the exterior building face or it may be used as a back-

up wall of a panel curtain wall.

a) Stone Masonry Panels

b) Pre-cast Masonry Panels

Masonry panel walls types

Panel curtain walls

are exterior non-load bearing walls made up of

panels attached directly to the building structure with an adjustable

attachment or mounted on supports (subframe), which in turn, are

attached to the building structure by adjustable attachments. Exterior

face of panels form the face of the building; interior face may or may not

form the interior finish.

Stone Masonry Panels.

Natural or artificial stone slabs which are

anchored to the building structure by masonry anchors

Pre-cast Masonry Panel.

Ordinary reinforced or pre-stressed

concrete wall units which may be one or several stories high

1. Stick System.

2. Unit and Mullion System.

3. Unit System (Grid Type System).

4. Panel System (Sheathed Type).

5. Spandrel System.

TYPES OF PANEL CURTAIN WALLS

Stick System.

refers to the method of installation where the

mullions and horizontal rails (gutter section and window sill section) are installed

first before installation of the window and wall panels. In terms of appearance it

is called the Unit and Mullion System.

Unit and Mullion System.

refers to

the wall’s appearance where the supports (or the mullions) are

clearly expressed. Vertical lines are therefore dominant.

Unit System (Grid Type System).

also refers to the

method of installation where the frames, both mullions and rails are installed first

and are equally dominantly expressed. In the Unit System wall panels come as

preassembled framed units where the supports (vertical and horizontal

members) are clearly expressed. Vertical and horizontal lines equally dominant

4. Panel System (Sheathed Type).

Supports not expressed. Non-lineal pattern.

Joints vertical and horizontal usually without trim.

Spandrel System.

The supports are not a primary element of expression in

this type of wall. Horizontal lines are dominant and the length of spandrel is

unlimited.

PRESSURE EQUALIZED DESIGN FOR CURTAIN WALLS

Pressure differential between the outside atmosphere and an interior

environment can cause rainwater to migrate through even the smallest

openings in wall joints. Pressure-equalized design can significantly

reduce this cause of water leakage in wall construction by employing

the rainscreen principle.

1. Skin type panel.

2. Sandwich type panel.

TYPES OF METAL PANELS

1. Skin type panel.

Panel made up of one material

2. Sandwich type panel.

Panel made up of assembly of several

materials

Open Sandwich type.

Sandwich panel with top and bottom

edges closed

b. Closed Sandwich type.

Sandwich panel in which all edges of

panel are closed except for weep holes and vents

retaining wall

is a wall whose purpose is to resist the thrust of a bank

of earth or other material. It is differentiated from breast walls which is

similar to the retaining wall, in that in the retaining the earth or other

filling is deposited behind it after it is built, while the breast wall (or face

wall) is built to prevent the fall of earth which is in its undisturbed,

natural position, but from which part has been excavated, leaving a

vertical or inclined face.

Gravity wall.

Cantilever wall.

Counterfort wall.

Retaining walls are of three

types:

Gravity wall.

This is a type of

wall which is constructed of such

proportions that its weight alone

resists the thrust of the earth.

Low walls are invariably gravity

walls constructed of brick, stone

masonry or concrete.

Cantilever wall.

is constructed of reinforced

concrete and makes use of the

weight of the earth in resisting

the tendency to overturn at the

outer edge. The vertical wall,

supported on a horizontal base,

serves as a cantilever beam in

resisting the earth pressure.

Walls of intermediate height are

generally of the cantilever type.

Counterfort wall.

It is similar to the cantilever wall with the exception

that the vertical wall is tied to the base at regular intervals with

triangular-shaped walls called counterforts ( a counterfort is similar to a

buttress, but where a buttress is placed on the side of the wall opposite

the pressure acting on it, a counterfort is placed on the same side of the

wall ). It is usually more economical to use the counterfort wall for

heights of 20 ft. or over.

Pre-stressed concrete

is used where spans and loads cannot be

adequately designed in reinforced-concrete, and for deckings, beams,

girders and other prefabricated units where greater spans and loads

with thinner, stronger, and in some cases, lighter members are required.

1. Solid Flat Slabs

2. Hollow Core Slabs

3. Single Tees

4. Double Tees

5. Rectangular, L-Shaped and Inverted Tee Beams

6. AASHTO Girders

TYPES OF PRE-CAST CONCRETE FLOOR UNITS