# FORCES ON CIVIL ENGINEERING PROJECT

## Presentation on theme: "FORCES ON CIVIL ENGINEERING PROJECT"— Presentation transcript:

FORCES ON CIVIL ENGINEERING PROJECT
TOPIC 1.2 FORCES ON CIVIL ENGINEERING PROJECT BY : NOR AZAH BINTI AZIZ KOLEJ MATRIKULASI TEKNIKAL KEDAH 1

CIVIL ENGINEERING PROJECT
FORCES ON CIVIL ENGINEERING PROJECT LEARNING OUTCOMES : a) Identify and describe the engineering forces due to; Physical forces Dead load, traffic loads, imposed loads, hydrostatic/ water pressure, lateral earth pressure Environmental forces Wind, earthquake, waves, explosion, flood, temperature and pollutants b) Identify and describe the engineering forces based on chosen case project.

INTRODUCTION In any building design, the strength and stability of an overall building and its individual components must be considered. This involves structural calculations to work out the effects of all the forces acting on any component in the building and on the building overall. To do this we need to resolve the forces in the system to see what the overall effects are likely to be.

INTRODUCTION An overview of the many different forces acting on a building.

INTRODUCTION A summary of all the forces acting on the building. The dotted arrow is the resultant force, a force representing the overall effect of the loads.

INTRODUCTION Structural Engineering
What does a Structural Engineer do? A Structural Engineer designs the structural systems and structural elements in buildings, bridges, stadiums, tunnels, and other civil engineering works Design: process of determining location, material, and size of structural elements to resist forces acting in a structure 6

Examples of Typical Structures
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TYPES OF PHYSICAL FORCES

which are transferred to structure throughout the life span. Dead load is primarily due to - self weight of structural members - permanent architectural component such as exterior cladding, partitions and ceilings - equipment and static machinery when permanent fixtures

A Simply Supported Beam

The total of all moving and variable loads that may be placed upon a building or home Load that acts on structural component. Loads produced by use and occupancy of the building structure including weights of movable partitions or furniture etc. These load are more difficult to determine accurately. Estimates done on standard codes of practice or past experience. 11

EXAMPLE Towers: Live and Dead Loads Towers serve many purposes. Radio, TV and wireless communication signals are transmitted from towers. Forest rangers keep a vigilant eye peeled for signs of forest fires from observation towers. Skyscrapers serve an important role in the world’s urban areas. Like other structures, towers are subjected to dead and live loads. In the case of a skyscraper, dead loads are comprised of steel columns and beams, concrete, and glass – the weight of the structure itself. Live loads include the people milling about on the floors and ascending the elevators; plus furniture, materials, and goods that move into the building. Another important live load acting on a skyscraper is the force of wind blowing against the exterior surfaces. Because the buildings have an enormous amount of surface area, the force of wind on a skyscraper can be extremely powerful.

ii) TRAFFIC LOAD Traffic load is the average number ofvehicles two-way passing a specific point in a 24-hour period, normally measured throughout a year The standard measurement for vehicle traffic load on a section of road, and the basis for most decisions regarding transport planning. Road authorities have norms based on traffic load with decisions to expand road capacity. 13

COMPOSITION OF TRAFFIC STREAM
Based on the various sizes of vehicles using intersection PCU (Passenger Car Unit) is used to calculate traffic stream Vehicle Type Equivalent Value (pcu) Motorcycle Passenger car Medium Lorry Light Van Bus & Heavy Lorry 0.33 1.00 1.75 2.00 2.25 EQUIVALENT FACTOR FOR VARIOUS VEHICLES RELATIVE TO PASSENGER CAR

Traffic Force Transfer Example - Bridge
8,000 lb 32,000 lb 22,000 lb* 18,000 lb** L = 60 ft 30 ft 15 ft 45 ft **Front axle: 8,000 lb x 15/60 = 2,000 lb Rear axle: 32,000 lb x 30/60 = 16,000 lb *Front axle: 8,000 lb x 45/60 = 6,000 lb Rear axle: 32,000 lb x 30/60 = 16,000 lb 15

ii) LATERAL EARTH PRESSURE
Lateral earth pressure is the pressure that soil exerts in the horizontal plane. The common applications of lateral earth pressure theory are for : such as retaining walls, basements, tunnels i) the design of ground engineering structures foundation ii) to determine the friction on the sides of deep 16

Lateral Support In geotechnical engineering, it is often
necessary to prevent lateral soil movements. Braced excavation Anchored sheet pile Tie rod Sheet pile Anchor Cantilever retaining wall

Lateral Support We have to estimate the lateral soil pressures acting on these structures, to be able to design them. Gravity Retaining wall Soil nailing Reinforced earth wall

Soil Nailing

Lateral Support Reinforced earth walls are increasingly
becoming popular. geosynthetics

Lateral Support filled with soil Crib Wall have been used in Queensland. Good drainage & allow plant growth. Interlocking stretchers and headers Looks good.

Lateral Support Reinforced earth walls are increasingly becoming popular. geosynthetics

Lateral Support Crib walls have been used in Queensland.
filled with soil Crib walls have been used in Queensland. Good drainage & allow plant growth. Looks good. Interlocking stretchers and headers

Retaining Walls - Applications

Retaining Walls - Applications
highway

Retaining Walls - Applications
High-rise building basement wall

Gravity Retaining Walls
cement mortar plain concrete or stone masonry cobbles They rely on their self weight to support the backfill

Cantilever Retaining Walls
Reinforced; smaller section than gravity walls They act like vertical cantilever, fixed to the ground

Soil exerts pressures on retaining structures
buckling

ii) HYDROSTATIC PRESSURE/
WATER PRESSURE In a fluid at rest, the weight of the liquidwill create a pressure on the surface of a body. This pressure is defined as the hydrostatic pressure. Its depend on density of the liquid and depth. dam structure. Normally consider for marine structure and 31

Dam Structure Arch Dam Cross Section

engineering structure due to
Environmental Forces Forces that acting to engineering structure due to environmental factor

positive or negative pressures exerted on a house when it obstructs the flow of moving air. generally act perpendicular to the surfaces of the building.

i) Wind Load What it affects
The significance of the load varies depending on the geographic location of the house, its height, and its roof pitch. have the most significant impact on roof framing, overhangs, and large openings, especially those near building corners. On a larger scale, shear-resisting elements, like the roof, floor framing, and sheathed wall segments (shear walls), are affected by wind loads. Typically, building are designed to resist a strong wind a very long return period, e.g 50 yrs or more. The design wind speed is determined from historical record to protect future extreme wind speeds.

ii) Earthquake Also known as quake or tremor. Is the result of sudden release of energy in the earth crust that causes seismic waves. Measured with a seismometer The seismic activity of an area refers to the frequency, type n size earthquake experienced over a period of time. At the earth’s surface, earthquake manifest themselves by shaking and sometimes displacing the ground.

ii) Earthquake When a large earthquake epicenter is located offshore, the seabed sometimes suffer sufficient displacement to cause a tsunami The shaking in earthquake can also trigger landslide and occasionally volcanic activity At the earth’s surface, earthquake manifest themselves by shaking and sometimes displacing the ground.

iii) Waves Load A waves is a disturbance that propagates. The impact of a pulsed or wavelike load to an engineering stucture. Commonly used in the analysis of offshore structure, piping and an engineering platform.

iv) Flood Flood is an overflow or accumulation of an expanse of water that submerges land.