Saturday, March 23, 2013

Applications in Civil Engineering

TECHNICAL, SCIENTIFIC AND OTHER USES

This topic covers the topics in the GCSE National Criteria for Computer Studies under Assessment Objective D section (ii). This is on 'technical, mathematical and scientific uses (e.g. civil engineering calculations, data logging, computer-aided design, simulations).

gives a summary of some important applications in the field of civil engineering. some techniques used in many applications. These are data logging, computer-aided design and simulation. The examples given have not been restricted to the technical, mathematical and scientific fields as these techniques are widely used in other areas as well.

CHARACTERISTICS OF TECHNICAL AND SCIENTIFIC APPLICATIONS

The type of application dealt with in this unit generally requires one or both of the following:

1 Ability to respond to signals from external devices,

2 Complex calculations to be done quickly and accurately.

(Contrast this with the characteristics of commercial applications).

Note: Speed and accuracy produce a conflict. For calculations to be done accurately each number needs a large number of bits to store it. This makes the calculations slower

Applications in Civil Engineering

Civil engineering is the construction and maintenance of works such as bridges, roads and buildings.

Computers are used in civil engineering in an increasing number of ways.

MATERIALS EVALUATION

Materials evaluation involves:

1 Testing materials to find out how strong they are.

2 Testing materials to find out how long they last- their endurance.

3 Deciding which is the best material for a particular job.

Example of materials evaluation

A multistorey car park is to be built from concrete.

1 Different mixes of concrete are tested for strength.

The best mixes are tested with different types of reinforcing bars inside.

2 Reinforced concrete beams are tested in different conditions of damp and change of temperature. This is to see if there is any danger of the concrete cracking and the reinforcing bars going rusty.

3 Calculations are done of the stresses in the car park building with the different types of concrete. The most suitable type is chosen.

Computers are used:

1 To acquire data on materials being tested. Sensors can be fitted to a material. These sensors can then be directly connected to a computer. Often the sensors are analogue and are connected to the computer via analogue-to-digital converters. The sensors may provide data on:

(a) Loads or stresses or movement of a material.

(b) Temperature, pressure and humidity-this may affect a material being tested for endurance.

The computer records data from the sensors over a period of time. This is an example of data logging.

2 To analyse the data from tests. A computer can help by:

(a) Rapidly carrying out calculations.

(b) Showing the results in the form of tables and graphs.

Example

Testing wooden beams for strength.

The diagram in Fig.1 shows a rig for testing wooden beams. Each beam is moved into position and then a ram bends it slightly by a set distance. The force needed to do this is measured. This is done at a number of points along the beam. The beam is marked with paint to indicate how strong it is. The rig is controlled by a microcomputer which:

1 Receives signals from a light sensor indicating when the beam is in position to start testing.

2 Controls the rollers which move the beam.

3 Operates the hydraulic ram which bends the beam.

4 Monitors the force applied by the hydraulic ram.

5 Operates the paint sprayer which makes paint marks on the beam .

Applications in Civil Engineering

fig.1 A rig to test wooden beams for strength

STRUCTURAL DESIGN

Structural design is the design of mainly large structures such as dams and bridges.

The main role of computers in this field at present is in analysing designs. A structural engineer produces a design. The computer then does calculations to check that the design is safe. The engineers can then use the results to modify their designs if they so wish. For example, there are programs which help with bridge design by calculating the stress that would be found in various parts of the bridge.

GEOTECHNICAL DESIGN

Civil engineering does not just involve the materials used in construction. The soil and rocks on which a structure is built are also important. In the case of a road or a tunnel they may be very important. Geotechnical design refers to the design of the environment in which a structure is placed.

There are difficulties in applying computers in this area. Soil and rock are often more complex in structure than, say, concrete and steel. Applications include:

1 Working out whether a slope of a particular soil is stable or is likely to slip.

2 Finding the pressure produced by earth on a retaining wall-that is a wall built to stop the earth from slipping.

3 Analysing how water drains through different types of soil.

4 Using microprocessor-controlled instruments in the field.

Example of a geotechnical problem

When a new road is built large quantities of sail have to be moved. In some places the road cuts into hills and soil has to be removed. In other places the road is above ground level so that soil has to be added to build the road up. A computer can be used to work out the heights of the road so that soil does not have to be moved large distances.

Applications in Civil Engineering 2

Fig.2 A Toad showing soil movements. Soil from the cuttings at A and C is moved to make an embankment at B

The calculation is complicated by:

1 The need to make a road fit into the environment-, it cannot be built up above the countryside just to get rid of some soil.

2 The fact that soil dug out may not be suitable for building up the road.

3 The need to keep the slope of the road to a fairly gentle gradient.

COMPUTERS IN THE WATER INDUSTRY

1 The introduction of the microcomputer has meant that it is now possible for individual depots to make local measurements of the quantity and quality of water.

Example

Burst mains are more easily detected so that less water is lost through leakage.

2 The revolution in communication technology has meant that data collected from remote locations can be monitored centrally. It has also meant that what happens at such locations can be directly controlled from a central point.

Example

Many of the large old pumping stations have been replaced by small automatic stations.

OTHER USES

Other uses of computers in civil engineering include:

1 Computer-aided design .

2 Information retrieval from databases .

Information available to civil engineers includes data provided by the British Standards Institute.