1. FACULTY OF ENGINEERING
KYAMBOGO UNIVERSITY
FACULTY OF ENGINEERING
BACHELOR OF ENGINEERING IN CIVIL AND BUILDING ENGINEERING
COURSE: CONSTRUCTION TECHNOLOGY II
CODE: TCBE 2203
TASK: ASSIGNMENT 1: DISCUSSION ON WALLS AND PIERS
LECTURER: MADAM. AKIA CHRISTINE
GROUP 5 MEMBERS
NAME
REGISTRATION NUMBER
SSEKIGUDDE CHARLES
20/U/ECW/14198/WKD
WADRIBO RONALD
20/U/ECW/14166/WKD
TIBANGANYA RESTY
20/U/ECW/14185/WKD
OCHEN DANIEL
21/U/ECE/16790/PE
AKATURINDA LEEV
20/U/ECW/14179/WKD
OOLA PAUL MARY
20/U/ECW/14171/WKD
SSEGUJA GEOFREY
19/U/ECW/17615/WKD
MUBIRU SHARIF
20/U/ECW/14182/WKD
MUKERA YOFESI
20/U/ECW/14151/WKD

2. WALLS
A wall is a vertical structure, usually solid, that defines and sometimes protects an area. Most commonly, a wall defines a building and supports its superstructure, separates space in buildings into sections, or protects or defines a space in the open air
Importance of walls
They provide support to floors and roofs
They are used for privacy.
They are used for security.
They are used to provide available space of a building into compartments.

3. FUNCTIONAL REQUIREMENTS OF WALLS
1. Stability: Stability is how firmly fixed a wall is. The stability of a wall may be affected by foundation movement, eccentric loads, lateral forces (wind, rain and earth quake) and expansion due to temperature and moisture changes.
2. Strength: A wall should be designed to safely support its own weight; wind loads and the loads imposed by floors and roofs.
3. Weather and Groundwater Resistance of walls: Walls should have enough resistance against moistures like water vapour and liquid water that might penetrate through foundation walls by absorbing water from ground or falling of rain on walls.
Damp proof membrane with thickness of 150mm can be employed above the ground level for all foundations to prevent absorption of water from the ground.
4. Durability: A wall should be able to have a considerable lifespan with minimal maintenance after its construction.

4. 5. Fire resistance: The resistance of the elements of a structure to collapse, flame penetration and heat transmission during a fire is expressed in periods of from 1.5 to 6hours. Various periods of resistance are called for depending on the size, nature and occupancy of the building so that notional periods of resistance to fire of the elements of the buildings are assumed to be sufficient for the safe escape of the occupancy during fire.
6. Thermal properties: To maintain reasonable and economic conditions of thermal comfort in buildings, wall should provide adequate insulation against excessive loss or gain of heat, have good thermal storage capacity and the thermal face of walls should be at reasonable temperature.
For insulation against loss of heat, lightweight materials with low conductivity are more effective than dense materials with high conductivity whereas dense materials have better thermal storage capacity than lightweight materials.
7. Resistance to sound transmission and sound absorption: Sound is transmitted as airborne sound and impact sound. Airborne sound is generated as cyclical disturbances of air from the source of the sound with diminishing intensity.

5. Walls may be divided into two types:
Load-bearing walls; are walls which support loads from floors and roofs in addition to their own weight and which resist side pressure from wind and, in some cases, from stored material or objects within the building,
Non-load-bearing walls; are walls constructed for mainly partitioning of area and carry no floor or roof loads except their own weight

7. Examples of Load Bearing Wall
Precast Concrete Wall
Masonry Wall
Retaining Wall
Pre Panelized Load Bearing Metal Stud Walls
Engineering Brick Wall (115mm, 225mm)
Stone Walls
As the height of the building increases, the required thickness of wall and resulting stress on foundation will also increase and cause it to be uneconomical.

8. Precast-concrete wall
Precast concrete walls are constructed by casting concrete in reusable wall mold or form which is then cured in a controlled environment, transported to the construction site and lifted into place.
Figure 2:Precast concrete wall

9. Masonry Wall
A masonry wall is a wall made from materials which have traditionally been cemented together with the use of mortar .Masonry walls can be used as structural walls in buildings, and they can also be utilized to create barriers between property lines or different areas on a property. Brick, stone, tile, ceramic blocks, adobe, and glass blocks can all be used in the construction of a masonry wall
The material in the masonry units can be mud or adobe bricks, burnt clay bricks, soil blocks (stabilized or unstabilized), concrete blocks, stone blocks or rubble. Blocks can be solid or hollow.
Figure 3: Masonry walls

10. Retaining wall
A retaining wall is a structure designed and constructed to resist the lateral pressure of soil when there is a desired change in ground elevation that exceeds the angle of repose of the soil. They are used to bound soils between two different elevations often in areas of terrain possessing undesirable slopes or in areas where the landscape needs to be shaped severely and engineered for more specific purposes like hillside farming or roadway overpasses.
Types of retaining wall
Gravity retaining walls
Cantilevered retaining walls
Sheet piling retaining walls
Anchored retaining walls

11. Gravity retaining walls
These are walls that use the gravitational force of their own weight to resist from lateral earth pressure from the soil behind them which prevent toppling and sliding.
Cantilever Walls.
Cantilever walls are built of reinforced concrete and are typically composed of a horizontal footing and a vertical stem wall. The weight of the soil mass above the heel helps keep wall stable. Cantilever walls are economical for heights up to 10 m (32 feet).
Sheet Pile Walls.
Used to build continuous walls for waterfront structures and for temporary construction wall heights > 6 m if used with anchors.
Can be made of steel, plastics, wood, pre-cast concrete.

12. The advantages of using steel sheet-piling:
Provides higher resistance to driving stresses;
Is of an overall lighter weight;
Can be reused on several projects;
Provides a long service life above or below the water table;
Easy to adapt the pile length by either welding or bolting; and
Their joints are less apt to deform during driving.
Cantilever wall
Sheet pile wall

13. Anchored Retaining Wall
This type of retaining wall is employed when the space is limited or thin retaining wall is required.
Anchored retaining wall is suitable for loose soil over rocks.
Considerably high retaining wall can be constructed using this type of retaining wall structure system.

14. Pre Panelized Load Bearing Metal Stud Walls

15. Stone walls (Load bearing walls)
Precast concrete wall(load bearing wall)
Masonary wall(Load bearing wall)
Load bearing retaining wall

16. NON LOAD BEARING WALLS
Non-load bearing walls only carry their own weight and do not support any structural members such as beams and slabs. These walls are just used as partition walls or to separate rooms from outside. They are known as interior walls (do not carry  other load than its own load)
Examples of non load bearing wall
Hollow Concrete Block wall
Block Façade Bricks wall
Hollow Bricks wall
Brick Wall (115mm, 225mm)

17. Semi hollow brick (Non load bearing wall)
Brick wall (Non load bearing wall)
Facade brick wall (Non load bearing wall
Hollow concrete block wall (Non load bearing wall)

18. Cavity Walls
It is a wall constructed in 2 leaves / skins with a space / cavity between them. A type of building wall construction consisting of an outer wall fastened to inner wall separated by an air space. Cavity walls helps to prevent the penetration of rain to the   internal surface of the wall.

19. Shear Wall
Shear walls are a framed wall designed to resist lateral forces. It is a vertical elements of the horizontal force resisting system. It is used to resist wind and earthquake loading on a building. It is reinforced concrete or wood frame stud walls covered with a structural sheathing material like plywood.

20. Partition Wall
Partition wall is an interior non-load bearing wall to divide the larger space into smaller spaces. The heights of a partition wall depends on the use which may be one storey or part of one storey. These walls are made up of glass, fiber boards or brick masonry.

21. Panel Wall
Panel wall is generally made of wood and is an exterior non-load bearing wall in framed construction. It is used for aesthetics of the buildings both inside and outside. It remains totally supported at each storey but subjected to lateral loads.

22. Veneered Walls
Masonry veneer wall is a single non-structural external masonry wall made of brick, stone or manufactured stone. It has an air space behind and is called as anchored veneer.

23. Factors which will determine the type of wall to be used are:
The materials available at a reasonable cost.
Availability of craftsmen capable of using the materials in the best way.
Climate
The use of the building - functional requirements.
The height of walls should allow people to walk freely and work in a room without knocking their heads on the ceiling, beams etc. In dwelling houses with ceilings is 2.4m a suitable height. Low roofs or ceilings in a house create a depressing atmosphere and tend to make the rooms warmer in hot weather.

24. Materials used in construction of walls.
Bricks
Blocks
Stone
Timber
Mud

25. Bricks
Brick masonry is built with bricks bonded together with mortar. For temporary sheds mud mortar may be used but for all permanent buildings lime or cement mortars are used.
The various types of bonds generally used in brick masonry are
Stretcher bond
Header bond
English bond and
Flemish bond

26. 1. Stretcher Bond
A stretcher is the longer face of the brick as seen in the elevation. In the brick of size 190 mm × 90 mm × 90 mm, 190 mm × 90 mm face is the stretcher. In stretcher bond masonry all the bricks are arranged in stretcher courses as shown in Fig-1. However, care should be taken to break vertical joints. This type of construction is useful for the construction half brick thick partition wall.

27. 2. Header Bond
A header is the shorter face of the brick as seen in the elevation. In a standard brick it is 90 mm × 90 mm face. In header bond brick masonry, all the bricks are arranged in the header courses as shown in Fig-2. This type of bond is useful for the construction of one brick thick walls.

28. 3. English Bond
In this alternate course consist of headers and stretchers. This is considered to be the strongest bond. Hence it is commonly used bond for the walls of all thicknesses. To break continuity of vertical joints a brick is cut lengthwise into two halves and used in the beginning and end of a wall after first header. This is called queen closer. (Refer Fig-3). Fig-3 shows typical one brick and one and half brick thick wall with English bond.

29. 4. Flemish Bond
In this type of bond each course comprises of alternate header and stretcher [Fig-4]. Alternate courses start with stretcher and header. To break the vertical joints queen closers are required, if a course starts with header. Every header is centrally supported on the stretcher below it.
Flemish bonds may be further classified as
Double Flemish Bond
Single Flemish Bond.
In case of double Flemish bond, both faces of the wall have Flemish look, i.e. each course consists of alternate header and stretcher, whereas single Flemish bond outer faces of walls have Flemish look whereas inner faces have look of English bond [Fig-4 (a), (b)].

30. Concrete blocks
Much of the procedure for the construction of concrete block walls has been discussed under the heading 'Foundations'. However, there are a few additional factors to be considered.
It is best to work with dry, well-cured blocks to reduce shrinking and cracking in the wall to a minimum. Except at quoins (corners), load-bearing concrete block walls should not be bonded at junctions as in brick and stone masonry. At junctions one wall should butt against the face of the other to form a vertical joint which allows for movement in the walls and thus controls cracking. Where lateral support must be provided by an intersecting wall, the two can be tied together by 5mm x 30mm metal ties with split ends, spaced vertically at intervals of about mm. Expansion joints should be allowed at intervals not exceeding 2 1/2 times the wall height. The two sections of wall must be keyed together or stabilized by overlapping jamb blocks as shown in Figure 25. The joints are sealed with flexible mastic to keep water from penetrating the wall.

31. Stones
Quarried stone blocks, either rough or dressed to a smooth surface are laid in the same way as concrete or stabilized soil blocks. Random rubble walls are built using stones of random size and shape as they are found or come from the quarry. Walls using laminated varieties of stone which split easily to reasonably straight faces of random size are called squared rubble walling.
In these walls, as in all masonry, longitudinal bond is achieved by overlapping stones in adjacent courses, but the amount of overlap varies because the stones vary in size. Since rubble walls are essentially built as two skins with the irregular space between solidly filled with rubble material (small stones), transverse bond or tie is ensured by the use of long header stones known as bonders. These extend not more than three- quarters through the wall thickness to avoid the passage of moisture to the inner face of the wall and at least one is required for each m² of wall face. Large stones, reasonably square in shape or roughly squared, are used for corners and the jambs of door and window openings to obtain increased strength and stability at these points.

32.   Mud and Pole Walls
The construction of mud and pole walls is dealt with at the end of Section Earth as Building Material along with some other types of mud wall constructions. A pole frame wall can be built with either thick earth construction (25cm or more) or thin earth cladding (10cm or less). While soil block walls and rammed earth walls usually are superior to mud and pole wall, this should only be used when a supply of durable poles is available and the soil is not suitable for block making. Regardless of the type of wall, the basis of all improvement is to keep the wall dry after construction.
Install a dampproof course on top of the foundation wall, about 50cm above ground level. Pre-fabricate ladders out of green bamboo or wooden poles that are about 5cm diameter. The outside wooden or split bamboo battens are nailed or tied to the ladders as the soil is filled in successive layers. The corners must be braced diagonally. Earthquake resistance is improved by securing the base frame to the foundation with a layer of lime or cement soil mortar.

33. CLASIFICATION OF PIERS
A pier is a vertical support structure of bridges. They are intermediate support whose function is to transmit the forces they receive from the load bearing elements to the foundation
A pier is also defined as a raised structure that rises above a body of water and usually juts out from its shore, typically supported by piles or pillars, and provides above-water access to offshore areas. Frequent pier uses include fishing, boat docking and access for both passengers and cargo, and oceanside recreation. Bridges, buildings, and walkways may all be supported by architectural piers. Their open structure allows tides and currents to flow relatively unhindered. Piers can range in size and complexity from a simple lightweight wooden structure to major structures extended over 1,600 m (5,200 ft).
Piers have been built for several purposes, and because these different purposes have distinct regional variances.
CLASIFICATION OF PIERS
BASED ON THE STRUCTURE OF PIERS
Piers are categorized into two major types based on its structure which include;
Solid piers.
Open piers.

34. SOLID PIERS
Solid piers possess solid and impermeable structure, and usually constructed from bricks, stone Masonry, mass concrete or reinforced concrete. Solid piers are categorized into solid masonry piers and solid reinforced concrete piers

35. Solid Masonry Piers
It is constructed from brick masonry, stone masonry, and concrete. For economic reasons, the outer part of solid masonry pier is built from stone masonry and the inner part is filled with the help of mass concrete.

36. Solid Reinforced Concrete Piers
Solid reinforced concrete piers are mostly constructed from reinforced concrete and commonly rectangular in cross-section. It is used in the case where the height of the piers is more and the solid masonry piers would not be strong enough to bear the load and can be uneconomical.

37. OPEN PIERS
Open piers permit the passage of water through the structure and classified into the following types:
Cylindrical Piers
Cylindrical pier is constructed from cast iron or mild steel cylinders which are filled with concrete. This type of pier is suitable for bridges with moderate height. In certain cases, horizontal and diagonal steel bracing may be used to improve stability.

38. Column Piers or Column Bent
This type of pers is suitable for bridge with significant height. It consists of a cap beam and supporting columns forming a frame. Column bent piers can either be used to support a steel girder superstructure or be used as an integral pier where the cast-in-place construction technique is used.
The columns can be either circular or rectangular in cross section. They are by far the most popular forms of piers in the modern highway system.

39. Multicolumn or Pile Bent
Multicolumn or pile bent or frame bent piers are composed of two or more column that supports a cap. Isolating footing is used for this type of piers if the spacing between columns are large otherwise combined footing would be more suitable. There is a problem of debris collection when the water is allowed to flow between the columns.

40. Pile Pier or Pile Bents
Pile pier is the modification of multicolumn bent and used for the type of bent on low height and short span structure. So, pile pier or pile bents are specified when the ground is unstable and the low piers are required.
Trestle Pier or Trestle Bent
Trestle pier is composed of column with bent cap at the top. It is suitable for bridges in locations where river bed is firm and water current is slow. It is also employed for flyovers and elevated roads.

41. Reinforced and Prestressed Concrete Piers
Reinforced concrete or prestressed concrete piers have small cross- sectional area compare with masonry and mass concrete piers. That is why such pier require much less foundation area in addition to offering less obstruction to waterway.
Reinforced concrete or prestressed concrete cellular piers arc suitable for major bridges where both the span and the depths are considerable and the self-weight of the piers should be as minimum and the section modulus as maximum as possible.

42. BASED ON LOAD TRANSFER MECHANISM
Fixed Piers
Fixed piers support a fixed bearing and subjected both to transverse and longitudinal forces
Free Piers
Free piers support free bearings and transfer only axial forces from the bearing to the foundations.
OTHER TYPES OF PIERS
Hammerhead or Cantilevered Piers
Hammer head pier, which is also termed as solid shaft pier, has a single solid concrete cross section upon which a cap is placed. This type of pier is used to support steel girder or precast prestressed concrete superstructures. It is mostly constructed in urban areas where space limitation is a concern. Not only does it aesthetically pleasing but also occupy small spaces, thereby providing more room for the traffic underneath.
Generally, spread footing are recommended as a foundation for hammerhead piers. The major axis of solid shaft pier shall be in the direction of the stream flow otherwise circular or small rectangular cross section need to be selected. Standards for the use of hammerhead piers are often maintained by individual transportation departments.

43. Hammerhead Pier
Special Shaped Bent
V Shaped Concrete Pier
V Shaped Steel pier

44. THE END
GROUP 5