Concrete & Masonry Construction

Concrete & Masonry Construction

1. BIA1021 Concrete & Masonry Construction for Bachelor of Science of Architecture Session 2023/24, Semester 1

2. Introduction Most buildings have concrete and/or masonry components. The ability to use concrete and masonry materials is an essential skill for construction and, repair and maintenance of buildings . Concrete is “a mixture of stone aggregates, sand, Portland cement, and water that hardens as it dries .” Concrete does not dry, it goes through a chemical reaction called hydration. Concrete can be formulated with very specific performance characteristics in mind and include lightweight, heavyweight, porous, fiber-reinforced, mass, high-performance and cellular concretes.

3. Concrete Mixture Concrete : a mixture of aggregate and Portland cement paste. Aggregate : usually sand, gravel and/or crushed stone. Paste : Portland cement and water Process : the paste binds the aggregates into a rocklike mass as the paste hardens because of the chemical reaction (hydration) of the Portland cement and water . Basic concrete mix: • Air 6% • Portland cement 11% • Coarse aggregate 41% • Fine aggregate 26% • Water 16%

4. Advantages Advantages Fireproof Insect & rodent proof Decay resistant Storm resistant Wear resistant Waterproof (water resistant) Strong Attractive UV resistant Doesn’t require expensive equipment. Available locally Low original and maintenance costs Sanitary and easy to keep clean Recyclable

5. Disadvantages • Labor intensive • Requires moving a lot of weight • Requires forms • Dense material • Special skills required to place and finish

6. Sub-structure The substructure, or "underbuilding," is the part of the building that is built up from the foundations to the ground floor. Super-structure The superstructure of a building is the section of the structure that is created above the ground level and that is meant to serve the function of the structure's purpose . Building Structural Concept

7. Building Construction Typology-Process

8. Substructure Components Building Substructure has the following two components : a. Foundation b. Plinth Beam Function of Foundation a . It provides stability to the structure as a whole. b. It distributes the loads from the superstructure to the soil beneath. c. It anchors the superstructure safely into the earth .

9. Functions of Foundation To provide stability to the entire structure. To prevent the differential settlements. To transfer the loads from the superstructure to the soil beneath . There are two types of foundation: Shallow foundation D eep foundation

10. Shallow Foundation The features of a shallow foundation are as follows: Depth is less or sometimes equal to its width. It is placed immediately beneath the lowest part of the superstructures. It is spread more horizontally than vertically. It transfers the loads to subsoil at a shallow depth, close to the ground level.

11. Types of shallow foundation There are four types of shallow foundations: 1 . Spread footing 2. Strip footing 3. Mat foundation 4. Grillage foundation

12. Spread Footing This footing is also known as pad foundation. T he base is wider than the top to distribute the load from the superstructure over a large area. This type of foundation is suitable for walls and masonry columns.

13. Strip Footing Strip footing is the independent footing of two columns connected by a beam.

14. Mat footing / Raft footing Whenever the load on the column is extensive (multi-story column) or when the strength of the soil is low, the foundations overlap each other. In such a situation, it is beneficial to provide common footing to several columns. T his footing is called mat footing or raft footing. Load distribution is uniform in this footing .

15. Grillage Footing Most high-rise buildings are constructed with steel columns encased in concrete. Such columns carry a heavy load and require special foundations for spreading the entire load to a larger soil area. So grillage foundation is one such special foundation that is used where the load of the structure is excessive, the bearing capacity of the soil is poor, and a deep foundation is not possible.

16. Deep Foundation There are two types of deep foundations: 1. Pile Foundation 2. Pier Foundation

17. Pile Foundation A pile foundation is a long cylinder usually made of steel or concrete and sometimes timber. It driven deep into the ground to act as a base or support to the structure built on it. Pile foundations transfer the load through skin friction or end bearing mechanism . Pile foundations are mainly used for large structures when the upper soil layer is weak and does not have the sufficient bearing capacity to withstand the imposed load .

18. Pile Foundation When to use the pile foundation When load extent is high & non-uniform. When the groundwater table is high. When the soil has a very low load-bearing capacity.

19. Pier Foundation A collection of large diameter cylindrical columns to support the superstructure and transfer large super-imposed loads to the firm strata below . It is also known as “post foundation .” They are watertight structures made of steel, wood, or reinforced concrete and sunken into the ground .

20. Plinth Beam A plinth beam is generally constructed in areas more prone to earthquakes. It reduces the length of columns by reducing their slenderness. A plinth beam is a horizontal structural element that interconnects columns, preventing buckling of columns .

21. Plinth Beam Functions of Plinth Beam   Prevents the differential settlements in foundation. Transfers the load coming from the superstructure to the foundation. Check and prevents the ingress of moisture. Acts as ties to interconnect columns.

22. Plinth Beam Advantages of Plinth Beam   To sustain the masonry load at ground floor level. Plinth beams aim to withstand the dead weight of the masonry wall Disadvantages of Plinth Beam   Increases Cost. Need more reinforcement and concrete.

23. Concrete Floor Structures Concrete slabs are plate structures that are reinforced to span either one or both directions of a structural bay. 6 common types of concrete s lab: One-Way Slab One-Way Joist Slab Two-Way Slab and Beam Two-Way Waffle Slab Two-Way Flat Plate Two-Way Flat Slab

24. Concrete Floor - One-Way Slab A one-way slab is uniformly thick, reinforced in one direction, and cast integrally with parallel supporting beams. • Suitable for light to moderate loads over relatively short spans of 6' to 18' ( 1830mm to 5490mm) • Slab is supported on two sides by beams or loadbearing walls; beams, in turn, may be supported by girders or columns.

25. Concrete Floor - One-Way Joist Slab A joist or ribbed slab is cast integrally with a series of closely spaced joists, which in turn are supported by a parallel set of beams. Designed as a series of T-beams, joist slabs are more suitable for longer spans and heavier loads than one-way slabs.

26. Concrete Floor - Two-Way Slab and Beam Two-way slab and beam construction is effective for medium spans and heavy loads, or when a high resistance to lateral forces is required . For economy, however, two-way slabs are usually constructed as flat slabs and plates without beams. A two-way slab of uniform thickness may be reinforced in two directions and cast integrally with supporting beams and columns on all four sides of square or nearly square bays.

27. Concrete Floor - Two-Way Waffle Slab A waffle slab is a two-way concrete slab reinforced by ribs in two directions. Waffle slabs are able to carry heavier loads and span longer distances than flat slabs.

28. Concrete Floor - Two-Way Flat Plate A flat plate is a concrete slab of uniform thickness reinforced in two or more directions and supported directly by columns without beams or girders. Simplicity of forming, lower floor-to-floor heights, and some flexibility in column placement make flat plates practical for apartment and hotel construction.

29. Concrete Floor - Two-Way Flat Slab A flat slab is a flat plate thickened at its column supports to increase its shear strength and moment-resisting capacity.

30. MASONRY WALLS Masonry walls consist of modular building blocks bonded together with mortar to form walls that are durable, fire resistant, and structurally efficient in compression. The most common types of masonry units are bricks, which are heat hardened clay units , and concrete blocks, which are chemically hardened units . Masonry walls may be constructed as solid walls, cavity walls, or veneered walls . Masonry walls may be unreinforced or reinforced .

31. UNREINFORCED MASONRY WALLS

32. UNREINFORCED MASONRY WALLS

33. UNREINFORCED MASONRY WALLS

34. REINFORCED MASONRY WALLS

35. REINFORCED MASONRY WALLS

36. MASONRY LINTELS

37. MASONRY LINTELS

38. MASONRY BONDING

39. MASONRY BONDING

40. ROOF SYSTEMS The roof system functions as the primary sheltering element for the interior spaces of a building. The form and slope of a roof must be compatible with the type of roofing —shingles, tiles, or a continuous membrane—used to shed rainwater and melting snow to a system of drains, gutters, and downspouts. The construction of a roof should also control the passage of moisture vapor, the infiltration of air, and the flow of heat and solar radiation as well as resist to fire.

41. ROOF SYSTEMS Like floor systems, a roof must be structured to span across space and carry its own weight as well as the weight of any attached equipment and accumulated rain and snow. Flat roofs used as decks are also subject to live occupancy loads . The form of a roof structure —whether flat or pitched, gabled or hipped, broad and sheltering, or rhythmically articulated—has a major impact on the image of a building .

42. FLAT ROOFS

43. REINFORCED CONCRETE ROOF SLABS

44. REINFORCED CONCRETE ROOF SLABS

45. PRECAST CONCRETE ROOF SYSTEMS

46. PRECAST CONCRETE ROOF SYSTEMS

47. Thank You!