CHAPTER 11 EXTERNAL WORKS

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EXTERNAL WORKS FENCING SURFACE DRAINS ROADS AND PAVEMENTS RETAINING WALLS CONSTRUCTION SITE WORK / SITE PREPARATION


DEFINITION A free standing structure designed to restrict or prevent movement across a boundary PURPOSE  Demark Property’s boundary  Keep out unwanted elements  Control visibility for privacy  Control sun, wind, snow, water  Control soil and erosion  Reduce or control noise  Means of landscaping MATERIALS  Timber  Concrete  Masonry  steel

FENCING


TIMBER FENCE POST AND RAIL FENCE

 easy to build  usually build with low grade materials  widely used around residences in the country, parks and farm

PICKET FENCES

 domestic / cottage image  decorative purpose & security  pattern variety


TIMBER FENCE BOARD FENCING

Disadvantages of timber fencing  high maintenance  skilled workers  quality timber – expensive


STEEL FENCE CHAIN LINK FENCING

• • • • •

commonly used maximum visibility lacks privacy low maintenance inexpensive

ORNAMENTAL STEEL FENCE

• lacks privacy • maximum visibility • ornaments add to visual interest


STEEL FENCE STEEL TUBULAR FENCING

 Used in parks and public places  Made of tubular or square section

steel  durable

LIVESTOCK STEEL FENCE

 used to protect or divide property  low maintenance  durable


MASONRY FENCE CLAY BRICKS

 expensive  both functional and decorative  mark boundaries/keep out intruders  controls privacy  Improve visual effect  Retain soil

CONCRETE BRICKS


MASONRY FENCE


CONCRETE FENCE DECORATIVE BLOCKS

 Low maintenance  Durable  Versatile

PRECAST CONCRETE PICKETS


DEFINITION Surface drains are natural or constructed channels to remove excess water from the surface of land through improved shaping of the land

SURFACE DRAIN SHOULD BE :  Constructed on a higher level and around the perimeter of the lateral field  Installed perpendicular to the slope of the ground to catch the surface water  Constructed to divert the surface water from the lateral field.  Surface drains slopes (recommended):  grass lawn and fields : 1.5% 10%  paved parking areas : 2% 3%

SURFACE DRAINS


SURFACE DRAINS

Surface water drainage problem:  Occurs when no drainage is provided  Surface drainage opening is blocked by rubbish (clogged drains)



SURFACE DRAINS  a highway gully is a drainage pit covered by an open metal grating  located on the road edge and it’s purpose is to drain rain water from the highway into the sewerage system  paved areas are laid to gradients or falls towards gullies or channels  gullies that collect surface water and discharge through drains to sewer or soakaways.



SURFACE DRAINS

A surface water sewer is a large underground drain connecting the highway drain to the sewerage treatment works. Its purpose is to carry surface water, and in some circumstances surface water and foul sewerage combined, to the sewerage treatment works.


KUALA LUMPUR SMART TUNNEL


DEFINITION 

Hard smooth surface especially of a public area or thoroughfare, that will bear travel. A sidewalk / pedestrian walkway

MATERIALS USED  Concrete  Bituminous Asphalt  Concrete pavers

PAVEMENTS


PAVEMENT WALKWAYS DESIGN ISSUES


DESIGN CONSIDERATIONS


RETAINING WALL DEFINITION  Wall constructed to hold in place a mass of earth or prevent the erosion of an embankment.

FUNCTION

 Prevent downslope movement or erosion and provide support for vertical or near-vertical grade changes.  Allows formation of steps or level areas on a sloped surface.


DESIGN PRINCIPLES  Retained material tend to

move forward and downslope due to gravity.

 This

creates lateral pressure behind the wall which depends on the internal friction and cohesive strength of the retained materials. (pressure develop by the backfill)

 Underground water behind the wall

causes horizontal pressure on the wall.

hydrostatic


TYPE OF RETAINING WALL    

Graviti wall Cantilever wall Piling wall Anchored wall


RETAINING WALL MATERIALS     

Masonry Stone Steel Metal Timber


DESIGN CONSIDERATION

Retained material tend to

move forward and downslope due to gravity.

This creates lateral pressure

behind the wall which depends on the internal friction and cohesive strength of the retained materials. (pressure develop by the backfill)

Underground water behind

the wall causes horizontal hydrostatic pressure on the wall.



GRAVITY WALL

 Depend on the weight of

their mass (stone, concrete) together with the friction on the underside of the base to overcome the tendency to slide or overturn.

 A slight `batter’ (vertical

face) to improve stability by leaning back to retained soil.

 Dry-stacked gravity wall are

flexible and do not require a rigid footing.

 Taller gravity walls built as

composite gravity wallsgeosynthetic, gabions, crib walls, etc


GRAVITY WALL

 They are generally

only economic up to a height of 1.8m.

 Mass walls can be

constructed of bricks bedded in a 1:3 cement mortar or of mass concrete.

 Natural

stone is suitable for walls up to 1m high.


CANTILEVER WALL  A reinforced concrete walls

often in the shape of an inverted `T’.

 These walls cantilever loads

(beam) to a large, structural footing- converting horizontal pressures from behind wall to the vertical pressures on the ground below. (eg. Basement wall)

 T-shape of L-shape. The

footing is to resists tipping (sliding forces) from the soil behind the wall.


 Two basic forms- a base with

CANTILEVER WALL

large heel or cantilever wall with a large toe.

 Sometimes

walls are buttressed on the front or counterfort (triangular beams) on the back.

 Reinforced cantilever walls

have an economic height of 1.2-6.0m.

 Any durable facing material

may be applied to the surface to improve appearance of the wall for


CANTILEVER WALL


SHEET PILING WALL

 Constructed by driving

prefabricated vertical pile sections into the ground to form a straight wall.

 Common

materialsmetal, steel, wood plank, etc.

 Often used in soft soils

and tight spaces and in deep excavation.


SHEET PILING WALL



Usually driven 1/3 above the ground, 2/3 below the ground.

 Taller piles require a tie-

back anchor usually by cable or rod, placed behind the potential failure plane in the soil.


SHEET PILING WALL


ANCHORED WALL

A

non-gravity wall which relies on ground anchors (tiebacks) for lateral support.



An anchor- is a structural system designed to transmit tensile loads to the retained soil behind a potential slip surface.

 Anchors are installed

using drilling and grouting procedures.


ANCHORED WALL


DRAINAGE OF RETAINING WALL

Backfill

of rainwater and/or groundwater need to be drained to protect the stability of a retaining wall.

Hydrostatic pressure can cause or

induce retaining wall failure.

Drainage

systems usually weepholes and drainage lines.

utilize

Weepholes penetrate the retaining

wall and drain the area behind the wall immediately.

For

large walls, 4” (100mm) weepholes are common. Adequate spacing between weepholes allows uniform drainage.


DRAINAGE OF RETAINING WALL

Weepholes

should always have some kind of filter material between the wall and the backfill to prevent fines migration, clogging, and loss of backfill and caving.

Drainage

lines are often perforated and wrapped in geotextile or buried in a granular filter bed, and serve to carry water to the weepholes from areas deeper within the backfill.


END OF LECTURE


SITE PREPARATION/ORGANIZATION 

Every construction project begins with site preparation.

 A good start is an essential element of successful projects.  Basic components of site preparation are clearing and grubbing,

erosion control, grading, utility system installations and paving.

Each site is uniquely different and presents its own set of challenges. 

 Site preparation project demands versatility and innovation in

order to develop groundbreaking solutions that allow projects to stay on time and on budget.


SITE PREPARATION COMPONENTS CONSTRUCTION PLANNING  Is

a fundamental and challenging activity in execution of contract management  Planning the project from initial to implementation stage  Involves the choice of technology, definition of work tasks, estimation of required resources and duration of individual tasks  Basis of developing budget and schedule of work


SITE SURVEY

 Involves

site measurement and assessment to obtain technical data necessary to complete the design project

 Site

inventory, determine platform levels recording of as built elements

 Documentation of all

aspects of construction site

the


SITE CLEARING AND GRADING  Involves the removal

and demolition of unused structures, materials, hedges, ditches and other vegetation and services from the site  Also cover disposing

and recyling of materials and highlighting and protecting any ecological and environmental issues pertaining the construction site  Formation of land

levelling thru Cut and Fill


TEMPORARY SITE UTILITIES

 The

provision and installation of safe and suitable equipment and facilities and maintenance of construction site utilities including power, lighting, water and roads are vital to the overall success of a construction project.


MOBILISATION AND ERECTION OF WORKERS QUARTERS, CANTEEN, SITE OFFICE, SIGNBOARD AND HOARDING.  Prior to construction

works starting, contractor is to install storage for materials, erect hoardings, signage board, temporary workers cabin, canteen and site office for staffs and workers welfare and accommodation


On the construction site‌ There was this Spanish guy, this Korean guy and this Russian guy all working for the same construction company. At the beginning of the day the boss comes out and says to the Spanish guy, "You're in charge of the cement." Then he said to the Russian guy, "You're in charge of the dirt." Then he said to the Korean guy, "You're in charge of the supplies.“ Then he said, "I'm gonna be back at the end of the day to check on your work. It better be good or you're fired." So, off they go to get their work done. At the end of the day, the boss comes back to check on their work. He looks at the big pile of cement and goes, "Good work," to the Spanish guy. Then he looks at the big pile of dirt and says, "Good work," to the Russian guy. Then he couldn't find the Korean guy so he asks, "Where the heck is the Korean guy?" All of a sudden, the Korean guy jumps out from behind the big pile of dirt and yells, " SUPPLIES!!!!!"


END OF LECTURE


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