BUILDING CONSTRUCTION 1 LECTURE 4 PRESENTED BY ARCH. S.M ESSENDI

FLOORS CONCRETE FLOOR SLABS definition A concrete slab is a flat, rectangular and reinforced concrete structure, which can be sized in its length and width but is of a lesser depth, and used in the construction of floors, roofs, bridge decks, etc.

design A slab that is not supported by the ground ( grade level slab) is referred to as a suspended slab. These include slabs on floors higher than ground floor, and/ or slabs on ground level that are raised from the ground. There are many designs, for suspended slabs. This is so, in order to develop the ratio of its strength and weight. In all the cases only the bottom side is changed/ profiled where as the top surface is flat the types include: precast ( prefabricated/ off-site) slabs and cast-in-situ ( on site) slabs

construction The slabs could be: Prefabricated/precast, or cast in-situ. Prefab slabs are made off-site in factories and then transported to the site for placement while in-situ slabs are cast on site through use of formwork. Once brought to site, prefabs are laid in place between already built beams which could either be steel or concrete

CONCRETE FLOOR SLABS PREFABRICATED SLABS Corrugated : concrete is discharged in a ridged tray made of steel. It increases the strength of the slab and stops the bending of the slab under its weight. Ribbed slab: significant additional strength is given in one direction. Waffle slab: extra strength is given in both of the directions. One-way slab, here the structural strength is given in the shortest direction. Two-way slab, here the structural strength is given in two directions. Hollow core slabs

Prefabricated slabs Waffle slab

Prefabricated slabs corrugated slab

Prefabricated slabs Ribbed slab

Prefabricated slabs One way slab

Prefabricated slabs Two way slab

Advantages of Prefabricated construction Freedom to choose elements sizes without restrictions Multiple use of individual formwork elements Easy handling and laying without lifting equipment

Cast in- situ slabs

WALLS

DEFINITION A wall is a continuous, usually vertical structure, thin in proportion to its length and height built to provide shelter as an external wall or to subdivide/ partition houses into rooms as internal walls. The core function of an external wall is to provide shelter from rain, wind , sun and other elements of weather. Load bearing walls act as structural supports in addition to screening while non-load bearing walls are mainly partitions and only carry their own weight

WALL TYPES ( based on construction technique) Walls can be classified into two: Solid (masonry e.g brick, concrete block, and stone and monolithic). Masonry walls are held together using a binding material called mortar. If the concrete block is one continuous mass, it is called a monolithic wall. Framed. A framed wall is build from many small sections of timber, concrete or metal joint together to achieve strength and rigidity.

WALL TYPES-masonry

WALL TYPES-framed

WALL TYPES ( based on functionality) Interior walls: can either be masonry or framed External walls: both framed and masonry Party walls: both framed and masonry Retaining walls : mainly masonry Boundary walls: both framed and masonry

FUNCTIONAL REQUIREMENTS The general requirements for walls may vary with functionality and place of use. Generally, walls should meet the following conditions: Strength and stability Resistance to weather and ground moisture Durability and freedom from maintenance Fire safety Thermal control Sound control ( acoustic viability) security

WALL MATERIALS- BRICK Brick is obtained by burning scaled blocks of clay. They can be hand made or machine made & wire cut Walls made from bricks are good insulators, resistant to fire, durable and cheap.

BONDING BRICK bed

BONDING BRICK The objective of bonding is to get the wall to work as a single unit ( stiffen), through effective transfer of the loading forces. If one brick fails, the rest still act together in unity. It also makes it possible to create openings in the wall when bonding is properly executed. The loads above the openings are transferred to the sides via lintels.

BONDING BRICK Stretcher bond

BONDING BRICK Flemish bond: counters the monotony in stretcher bonds However, it leads to loss of brick and additional cost hence is expensive

BONDING BRICK Header bond- mostly considered unattractive

BONDING BRICK Flemish bond- header faces lie directly below and above stretcher faces

BONDING BRICK English bond- header face lies directly at the center of a stretcher face.

JOINTING & POINTING Bricks are held together using mortar, which is mixture of sand, cement and water. Jointing is the word used to describe the mortar joint finish in fairface brickwork. Although used interchangeably with pointing, the latter refers to the actual finish given to the joint as an appearance enhancer or weather guard.

JOINTING & POINTING Any of the joints below can be used both for pointing and jointing.

ASSIGNMENT On a scale of 1:50, draw a well annotated section through a two story house clearly showing the foundation and roof structure. The section must show at least one of the windows in the wall.