Masonry and Wall. Walls

Transcription

1 Masonry and Wall By Mohamad Syazli Fathi Walls Definition : The structures constructed to enclose an area, to support floors and roof or devide the floor area of a building into a required number of rooms. The walls may be constructed of any suitable material such as bricks, stones, concrete, timber, steels, etc. 1

2 Function of walls. 1. To enclose an area of the building. 2. To support the floors and roofs of a building. 3. To devide the floor area of a building into a number of rooms as required. 4. To provide privacy to the inmates. 5. As a protection of sound, fire, noise and heat. 6. Aesthetic purpose and to place doors and windows so that the building looks attractive. Walls classification Load bearing walls The wall itself carries the load of the structure( floors or roofs) such as the dead load and live load. These walls take and transfer the load coming over them to their foundations laying underneath. These walls are usually constructed as main walls of a building. Non-load bearing walls These walls do not take any super-imposed load but should be strong to take their own load. Only constructed as partitioning so as to devide the floor area of a building into a number of rooms required. 2

3 Types of Load Bearing Walls 1. Masonry or Rubble Wall The walls are constructed as main walls, probably used for single or doublestorey building. Rubble walls are usually constructed as front walls of a building for providing architectural appearance. 2. Retaining Wall The walls can be constructed t as retaining i walls of basement for resisting the lateral pressure of earth and the load(water pressure from the ground), if any coming over them. Two types of retaining wall: 1. In-Situ concrete 2. Precast concrete. In Situ concrete. These walls can be conveniently constructed and form one of the strongest walls. Formworks are required before reinforcements are fixed and later concrete are poured and vibrated to form hardened concrete. Time is required for the concrete to harden. Precast concrete. These walls consist of precast posts and planks as in the figure. Sometimes referred as crib wall. It is constructed of reinforced precast concrete. The crib portion is precast in the factory and transported to the construction site. It can be constructed quickly. 3. Brick wall 225 mm Walls are constructed using engineering bricks used as partitions of a building. Types of Non-load Bearing Wall Brick wall 113 mm Normally used as partition. Easy and cheap to construct as the bricks are of low quality and breakable. Hollow concrete wall The walls are constructed of precast hollow concrete blocks.the blocks are moulded in machines to the required shape and size. Can be used as the main and partition walls. Fair-face brick wall Are advantageously used for face work to provide better appearance. Pointing is required using mortar mixed with black colored matter. Perforated Brick. Brick walls of this type are vertically stack so that steel rods can be placed in the holes to strengthen them. 3

4 Masonry Concrete Masonry Unit (CMU) Brick Mortar Accessories horizontal masonry reinforcement wall ties lintels - coping - sills Reinforcing Bars Cleaning Equipment Concrete Masonry Unit Separate masonry according to: size of the units shape of the units colors of the units type of bond (pattern) shape of the mortar joints color of the mortar joints fire rating 4

5 Bond The arrangement of bricks in each layer so as to avoid continuity of vertical joints in any two adjacent courses both on the face and inside of a structure is called bond. This is done by overlapping bricks or stones in the successive courses longitudinally as well as transversely. Necessity of providing bond to achieve the following objects: The primary object is to break the continuity of the vertical joints in the successive courses both in length and thickness of a masonry structure. To ensure longitudinal and lateral strength of the structure. To enable the structure to act as a bounded mass and to distribute the load uniformly to its foundation. To provide pleasing appearance by laying bricks symmetrically. 5

6 6

7 Concrete Masonry Unit The standard modular face dimensions of the CM units are 7 5/8" high and 15 5/8" long. Thicknesses available are 3, 4, 6, 8, 10, and 12 inches (nominal, actual dimensions are 3/8"less). A 3/8" mortar joint provides 8"x16" face dimension (112.5 units per 100 sf of wall). Heavy weight versus lightweight units Concrete Masonry Unit Thicker face shells are required for a specific fire rating. Unit: No of units required (SF of wall x 1.125) Corners should only be taken once. Deduct all openings in excess of 10 sf. Allowance for waste and breakage: 5 to 10% Cutting of the units is expensive and should be anticipated. 7

8 Bricks Brick is a solid masonry (when its core unit is less than 25% of the cross sectional area) made of clay. Bricks are classified by: kind (common or face) size texture or finish on the face 8

9 Bricks No. of brick per square foot of wall depends on: size of brick (standard size: 2 1/4"x 3 5/8"x75/8") width of the mortar joint style of bond For running bond with 3/8" thick mortar joint, number of standard brick per 100 sf is 675 (2 2/3 x4 x8 ) Make deduction for all openings Waste: 5 to 10% 9

10 Mortar Masonry mortar usually consists of Portland cement, mortar sand, and hydrated lime. Type M - 1:1/4:3 mix by volume - 1 part cement, ¼ part lime 3 parts sand) for heavy loads and below grade Type N - 1:1:6 for use above grade 3/8" is a common mortar joint thickness, but 1/4" and 1/2" joints are also used. Colored mortars (red, brown, white, and black) may be used. 10

11 Horizontal Masonry Reinforcement Steel reinforcing is placed continuously in the mortar joints to minimize shrinkage, temperature, and settlement cracks in masonry and to provide resistance to shear. Unit: LF (note the size, type, plain or corrosion resistant, and spacing). Add 5% for waste and 5% for lap. For large quantities (over 1500 sf) multiply the square footage by the factor: Reinforcement every course, 1.5 Reinforcement every other course,

12 12

13 Reinforcing Bars Vertical reinforcing (to provide lateral support) Horizontal reinforcing i in bond dbeams Unit: ton 13

14 14

15 Wall Ties to tie the outer wythe with the inner wythe type of ties spacing (horizontally and vertically) unit: each 15

16 Coping Covers the top course of a wall to protect it from the weather. coping block (no of units) stone (lf, note type, width, and thickness) precast concrete (lf, note width, thickness, and finish) 16

17 Sills members at the bottom of window or door openings bik( brick (no. of units) stone (lf, note type, thickness, and width) precast concrete (lf, size) Lintels steel (lb, misc. metal Div. 5) precast concrete (lf of each size) lintel block with rebar and filled with concrete (no. of units, size) 17

18 Cleaning the type of materials required to clean with the area of the surfaces to be cleaned Example: acid wash, smooth brick $0.40/sf Acid wash, rough brick $0.55/sf Equipment scaffolding (length of time required, height, rent or own) hoisting equipment mortar mixer 18

19 Timber partitions or paneling/boarding. Wall weather boarding and internal partition of wood. Advantages: 1. light in weight. 2. can be easily constructed 3. can be contracted in any position and provide facility for transmitting and concentrating the load in any part or parts of the wall. Disadvantages: 1. Costly 2. deficient in fire-resistant qualities. 3. not soundproof 4. subjected to termites or fungus attack 5. shrink, swell or warp in the presence of dampness. 6. cannot support sanitary fittings and heavy fixtures. Steel Frame Walls. Aluminum and gypsum. Partition walls are of aluminum frame and gypsum panels provide good appearance. Easy in construction, no need painting, easy to manage and does not rust. The gypsum panels provide good insulation against heat. Wall paper can be used to improve the appearance of the gypsum panels. 19