CONSTRUCTION and types of bonding MODULE final.pptx

Bonding and tools

1. CONSTRUCTION MODULE Introduction

2. Construction is the process of building, assembling, installing, and maintaining various structures and infrastructures. It involves a wide range of activities, from planning and design to excavation, foundation work, and the installation of utilities and finishes. This presentation will provide an in-depth look at the key stages and components of the construction process.

3. Construction process Recognizing the need of the project Determining the technical and financial feasibility Preparing detail plans, specifications, and cost estimation Obtaining approval from regulatory agencies e.g. KCCA, NBRB Detail design, budgeting and contract document Tendering, project offer and construction works Building owner (client) Architect Clerk of works Quantity surveyor Consulting engineers Principal contractor Sub contractors Operatives Building team

4. Solid construction Framed or skeletal construction Forms of construction

5. Site layout The site layout plan should include the following aspects: Site space allocation: areas of the site for material delivery, material storage, temporary offices, and facilities Site access- to and from the site and to work areas within the site Material handling- including material movement on the site, both horizontally and vertically, lifting equipment, etc. Worker transportation-personnel movement on site Temporary facilities-offices, storage facilities, sanitary facilities, water, power, etc. Site security- temporary fencing, alarms, watchmen, etc. Signage and barricades Basic requirements of site layout Changes are required to match the construction works in progress No fixed rules or principles Try avoiding double handling of work

6. Layout 1

7. Layout 2

8. Typical construction process

9. cont. Construction of walls using solid structures of masonry or framed structures of timber continues until the window cill level is reached Installing windows and doors as brick/block work continues Scaffolding- to reach the top of window/doors and construction of lintels The bricklayer continues beyond the lintel level till the first-floor level when he must wait for the floor joists to be positioned by the carpenter or concrete slab to be cast. Otherwise, the bricklayer completes the work by bedding the timber plate in mortar, on top of the wall, ready to receive the roof.

10. Excavations and Foundations 1 Site Preparation The first step is to prepare the site, which involves clearing and leveling the land, and removing any existing structures or vegetation. 2 Excavation Excavation involves digging trenches and holes to create the necessary space for the foundation and other underground structures. 3 Foundation Work The foundation is the critical support system that distributes the weight of the structure evenly into the ground. It can be made of concrete, steel, or other materials.

11. SETTING OUT Setting out is the process of marking the exact location and dimensions of a building on the construction site, based on the architectural plans. Setting out is the process of transferring building designs onto the ground, ensuring accuracy and adherence to the plans It is a crucial step that lays the foundation for the entire construction project. Usually done when building a new house One must be able to read and interpret construction drawings. (Architectural, structural, mechanical, electrical, etc.) Construction drawings typically consist of: Plans; showing all walls, openings as seen from the top (bird’s eye view) Sections: showing levels, dimensions, and construction details in a vertical view Elevations: showing the outside (face) of the building The main function of setting out is to establish the position of the trench and walls of the house, as well as the positions of corners and rooms Techniques used in setting out Most commonly used approach is the 3:4:5 method. Other methods include Grid systems, triangulation, etc. Tools used in setting out Total stations, GPS Laser levels Profiles, boards, ropes, etc.

12. 3:4:5 Method of setting out First step is clearing the ground of any debris, vegetation, and other obstructions. The ground should be levelled. A triangle of sides 3m, 4m, and 5m will always have a right angle between the two shorter sides. A right angle can thus be constructed using a tape 3:4:5 procedure A peg with a nail is fixed exactly at 3m from the corner peg on the fixed line A measuring tape is hooked onto the nail on the corner peg and another tape is hoked to the nail of the peg on the front line Both the tapes are pulled towards the end wall with a distance of 4m showing on the first tape, and 5m showing on the other. Where they cross, a third peg is fixed. This will establish a line at 90o to the front line

13. Setting out a building perimeter

14. Assuming a standard plot: Establish a datum level. This point serves as a reference or base from which the whole building will be set out. This could be temporary or permanent like an existing building, road center line, kerb, etc. The datum should be clearly marked on-site so that it can be re-established at any time. After setting out the baseline, the main lines of the building can be set out, each corner of the building marked with a peg. Check for right angles and correct length (3:4:5) From the established outline, measure about 1.5-2m off the corner peg to the front and right side to establish the profile. The profile wood would help to mark out the building lines and will be discarded when the setting out is done. From the plan details, the width of excavation (trenches) to be done is also marked by threads with pegs at appropriate positions. The excavation width is then marked by lime/sand /any visible material using a spade.

15. SUBSTRUCTURE Soil investigations are either in-situ or laboratory tests. These include; visual inspections, plate load test, penetration tests (SPT, DCP) Laboratory test include; sieve analysis, shear strength test, etc. Factors affecting choice of foundation Structural factors (bearing capacity of the soil) Design resources Relative costs Working conditions The supporting part of a structure; the foundation. The purpose of the substructure of a building is to transfer loads of the superstructure to the soil that is underneath, and provide stability Foundations Generally, there are two types of foundations These are shallow foundations (for lighter structures) and deep foundations (for heavier buildings and challenging soil conditions) Shallow foundations include, strip, pad, and raft foundations Deep foundations typically include piles. Before building foundations, usually soil investigations are carried out. This is done so to: Determine the suitability of the site Determine an adequate and economic foundation design

16. SUBSTRUCTURE Pad foundation Suitable for most subsoils except loose sands, loose gravels and filled areas. a square hole is excavated thereafter placing a usually symmetric concrete pad. Raft foundation Usually used if the bearing capacity of the sub soil is so low, and resulting strips or pads meet. The foundation strips are allowed to meet as a continuous slab under the building and reinforced as a raft distributing the load on the soil over the whole area of the building Strip foundations The depth is determined by the nature of the subsoil. usually wide enough to allow working space for the brick layer. A trench is excavated, concrete placed in the bottom and the wall built upon it. The width is governed by the imposed load and the soil bearing capacity, and by the practical necessity of making it wide enough for a man to work in. 𝑚𝑖𝑛𝑖𝑚𝑢𝑚 𝑓𝑜𝑢𝑛𝑑𝑎𝑡𝑖𝑜𝑛 𝑤𝑖𝑑𝑡ℎ=𝑡𝑜𝑡𝑎𝑙 𝑙𝑜𝑎𝑑 𝑜𝑓 𝑏𝑢𝑖𝑙𝑑𝑖𝑛𝑔 𝑝𝑒𝑟 𝑚𝑒𝑡𝑟𝑒/𝑠𝑎𝑓𝑒 𝑏𝑒𝑎𝑟𝑖𝑛𝑔 𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑦 𝑜𝑓 𝑠𝑢𝑏𝑠𝑜𝑖𝑙

17. Materials used for foundation construction These include: Concrete Steel: for reinforcement Masonry: bricks, blocks, stones, etc.

18. Masonry, Bricks/Blockwork, and Bonding 1 Masonry Masonry construction involves the use of bricks, blocks, or stones laid in a specific pattern and held together with mortar. 2 Brick and Blockwork Bricks and concrete blocks are common masonry materials, each with their own unique properties and applications. 3 Bonding Patterns Proper bonding patterns, such as stretcher, header, and English bond, are crucial for the structural integrity and aesthetic appeal of masonry walls. 4 Quality Mortar Joints Well-executed mortar joints are essential for the strength and water-resistance of masonry structures.

19. Principle function of walls is to divide space such that rooms are used for their intended purpose Walls can be either internal or external. Walls can be made up of bricks, blocks, partitions, glass, among other materials. Clay bricks and concrete blocks are the commonest in Uganda. WALLS

20. A standard clay brick measures about 100mm x 150mm x 230mm A standard block measures about 150mm x 200mm x 400mm These sizes vary depending on the mold used Characteristics of good bricks Bricks should be uniform in color, size and shape They should be sound and compact They should be free from cracks and other flaws such as air bubbles, stone nodules, etc. Brick should not change in volume when wetted Bricks should neither overburnt nor under-brunt Salt attack hampers the durability of brick Tests done on bricks Absorption test- (must not exceed 20%) Compressive test- (min 3.5 MPa) Hardness test- (free from scratches) Soundness test- (clear bell ringing sound) Shape and size test- (standard size)

21. BRICK BONDING Types of bonds in brick masonry wall construction are classified based on laying style of bricks in walls The bonds in brick masonry is developed by the mortar filling between layers of bricks and in grooves when bricks are laid adjacent to each other and in layers in walls. Mostly used material for bonds in brick masonry is cement mortar. Lime mortar and mud mortar are also used The most commonly used types of bonds in brick masonry are: Stretcher bond Header bond English bond and Flemish bond There are other types of bonding used which include; Facing bond, English cross bond, Brick on edge bond, Raking bond, Zigzag bond, Garden wall bond, etc. Rules for good bonding Uniform arrangement of bricks through out the wall Minimized use of bats Vertical joints in every other course should be vertically over one another

22. Stretcher bond Longer narrow face of the brick is called as stretcher also called as running bond created when bricks are laid with only their stretchers showing, overlapping midway with the courses of bricks below and above. Stretcher bond in the brick is the simplest repeating pattern Walls constructed with stretcher bonds are not stable enough to stand alone in case of longer span and height Thus they then need supporting structure such as brick masonry columns at regular intervals Header bond Header is the shorter square face of the brick which measures 9cm x 9cm. also known as heading bond. In header bonds, all bricks in each course are placed as headers on the faces of the walls. In header bonds, the overlap is kept equal to half width of the brick. To achieve this, three quarter brick bats are used in alternate courses as quoins.

23. English bond English bond in brick masonry has one course of stretcher only and a course of header above it, i.e. it has two alternating courses of stretchers and headers. Headers are laid centered on the stretchers in course below and each alternate row is vertically aligned To break the continuity of vertical joints, quoin closer is used in the beginning and end of a wall after first header. A quoin close is a brick cut lengthwise into two halves and used at corners in brick walls. Flemish bond Flemish bond, also known as Dutch bond, is created by laying alternate headers and stretchers in a single course The next course of brick is laid such that header lies in the middle of the stretcher in the course below, i.e. the alternate headers of each course are centered on the stretcher of course below. Every alternate course of Flemish bond starts with header at the corner.

24. Concrete blocks used are either solid or hollow in nature. These can be classified as load bearing or non-load bearing units. The load bearing category must satisfy a higher minimum compressive strength. Other terms associated with bricks/block work Mortar A mixture of cementitious material, aggregate and water. Can be classified as cement-lime mortar, cement mortar, or masonry cement mortar. Functions of mortar include; bonding masonry units together, serving as a seating material for the units, levelling of the units, and providing aesthetic quality of the structure. Plaster A fluid mixture of Portland cement, lime, sand and water which is used for finishing masonry works. Mortar joints Bed joints are the horizontal mortar joints, or the bed of mortar that the next brick sits on. The vertical joints between masonry units are called head joints. Levelled horizontally (spirit level) and vertically (plumbline)

25. CONCRETE WORKS Concrete is the most common building material used in today's construction industry. It can be cast in any desired shape and fashion and is therefore applicable for most building purposes. Its long life and relatively low maintenance requirements add to its popularity. Concrete does not rot, rust or decay and is resistant to wind, water, rodents and insects. It is a non-combustible material, making it fire resistant and able to withstand high temperatures CONSTITUENTS Concrete is a mixture of cement, water and aggregate. The aggregate consists of a mixture of various sizes of gravel and sand. When water is added to cement, a chemical reaction takes place causing the mix to harden MATERIALS AND STORAGE Cement: Usually supplied in bags weighing 50kg. Loading and unloading the bags should be done carefully since entry of moisture triggers the chemical action causing the cement to harden.

26. Cement should be stored in a dry place such that bags don’t get damp or wet. The floor should have a good clearance from the ground or walls to avoid moisture penetration. Cement deteriorates with time and thus it should be purchased just before it is to be used. AGGREGATE Main contributor of strength of concrete. Consists of fine aggregate (sand:0.3-5mm) and coarse aggregate containing particles up to a size of 40mm Aggregates are obtained from various sources, like rivers, quarries, etc. Aggregates for concrete should be of sufficient strength, not prone to deterioration, not porous, not brittle, or soft. Sometimes its necessary to wash the aggregate if it contains impurities, especially those that negatively affect strength like clay impurities.

27. Aggregates of different sizes should be stored separately. WATER Good quality water is required for the mixing of concrete. Salt water should not be used for mixing concrete. Water is used for both the mixing process as well as during curing. Proportioning of materials It is important to make sure that the proportions of the aggregates used in the mixture are correct and that the right quantities of cement and water are added. This process is called a mix design. Mix designs can be by mass or by volume batching Water to cement ratio: When water and cement is mixed, it forms a paste that coats and binds the aggregate particles together. Through a chemical process called hydration, the paste hardens and gains strength. The strength of the paste is determined by the applied ratio of water to cement. The strength of concrete increases when less water is used during the preparation of the mix. Water for workability should also be accounted for. A low water to cement ratio leads to high strength but low workability while a high water to cement ratio produces a low strength concrete but good workability. Water/cement ratios in the range between 0.4 and 0.6 provide a good workability without compromising the quality of the concrete.

28. MIXING CONCRETE Thorough mixing is essential in order to obtain a homogeneous mixture of all the ingredients and achieving a suitable workability. Workability is used to describe the ease at which the concrete can be placed and consolidated without segregation or separation. Generally hand mixing and mechanical mixing are used. Steps in hand mixing Limit the size of the batch to approximately a third of a cubic meter. P lace a layer of sand on the mixing platform on which the cement is spread. Mix thoroughly by turning the heap over several times Mix until the cement is evenly distributed in the sand, i.e. until the mix has a uniform color. Add coarse aggregate and turn the mix until the batch is once again properly mixed. Sprinkle the predetermined quantity of water gradually on top of the mix while turning it over another three times, or until the water is evenly distributed. Use the wet concrete immediately after it has been mixed. Make sure it is placed and compacted straight away, avoiding that it starts setting before it is used.

29. Mechanical mixing Steps in mechanical mixing P lace a part of the water into the mixer to clean the drum walls of any concrete left from the previous mix; C harge half the volume of coarse gravel. The gravel will also assist in cleaning the inner surfaces of the drum; A dd the prescribed amount of sand and finer gravel; Add the cement; Add the remainder of the coarse gravel; Mix dry for one minute; When the aggregate and the cement have been thoroughly mixed, add the remaining quantity of water and mix wet for another two minutes.

30. OTHER CONCRETE CONSIDERATIONS Formwork Should be of good quality, durable, able to carry the strength of the concrete, free from defects, etc. The formwork should be clean and free from debris. Removal of formwork should take place when the concrete has hardened sufficiently to hold its own weight. Care should be taken not to damage the edges and corners Transporting and pouring concrete Proper compaction Quick transportation When placing, take care not to damage the formwork Vibrate the concrete upon placement to avoid honeycombing and other defects. Finally when the concrete has set, curing should be done to enable the concrete gain its strength. Tests on concrete Slump test Compressive test Rebound hammer