UNIVERSITY OF NEWCASTLE UPON TYNE

DEPARTMENT OF CIVIL ENGINEERING

BACHELOR OF ENGINEERING & MASTER OF ENGINEERING

IN

CIVIL & STRUCTURAL ENGINEERING,

Stage 1

CIV 133 - STRUCTURAL MODELLING & TESTING

 

Note: To comply with the Department's Quality Assurance procedures, you will need to complete 3 copies of the Coursework Quality Assurance Form. You can obtain the form from Lilian Swan in the coursework office from 2pm most days. To see how to complete the form, click here. The electronic form has been partially completed, so use it to help you complete the paper form in triplicate. Please transfer all items which are on the electronic form onto your paper form, especially the things in the table near the foot of the form.

 

Purpose and nature of Module

Most subjects in an engineering degree course are concerned with developing numerical techniques and understanding. The aims and objectives of your degree recognise that civil and structural engineers need to acquire other skills, some of which are developed in this series of 8 tasks. This Module is designed to give the student an appreciation of how structures actually behave. It deals with forces in frameworks, bending of beams, stability, deflexion and loading. Each student will complete 8 tasks and submit one report describing all 8 tasks. Some of the tasks involve making structures, some are desk studies, some involve sketching, and some involve laboratory tests. Some will be undertaken individually and some in groups. Assessment will be on the basis of how well your report shows how your understanding of fundamental structural behaviour has developed. Your report is to be submitted on Friday 7th December by 2pm. The recommended texts are "Basic Structural Behaviour" by Barry Hilson, published by Thomas Telford, London (1993), "Understanding Structures" by Derek Seward, published by MacMillan, London (1994), and "Design of Structural Elements" by Chanakya Arya, published by E. & F.N. Spon, London, (1994).

 

Task No.

Group Size

Description

1

1

Design and construct

paper tower

2

Usual laboratory group

Forces in a two-

dimensional framework

3

1

Deflexion, slope, curvature,

moment, shear and load

4

Usual laboratory group

Deflexion of balsa wood

square grid

5

Usual laboratory group

Composite action

6

1

Freehand sketches

7

Usual laboratory group

Equilibrium of forces

8

1

Using the Internet

 

 

An essential part of the civil & structural engineerís daily routine is to account for his time. You are expected to spend 100 hours in total on this module, including reading, constructing, testing, travelling and report writing. Keep a diary of time spent on each task and in your report, summarise how you spent the time. Assign a cost to your time for each task on the following basis.

 

Background study £70/hr

Practical work £40/hr

Preparing report £50/hr

Team discussion £45/hr

 

TASK 1 : Design and construct a paper tower

Design and build a structure which will support one of the three recommended textbooks at a clear height of 600mm above a square flat horizontal surface of side length 150mm. Use only A4 sheets of paper to build the structure. No glue or other material may be used. Use the minimum number of sheets of paper. The book must be supported for at least 1 minute. All of the structures will be tested at 2pm on Friday 23rd November. Scissors may be used. Write 500 words explaining how you dealt with buckling.

 

TASK 2 : Forces in a two-dimensional framework

Use the frame construction set to build a frame as shown in the diagram. Measure the force in each member and show the forces on an A4 sketch. By resolution of forces, calculate the forces in the members

 

Repack the parts in their boxes after undertaking the experiment.

 

 

TASK 3 : Deflexion, slope, curvature, moment, shear and load

The above terms are related to each other by :

 

y = deflexion

 

dy = slope

dx

 

d2y = curvature=moment/EI

dx2

 

d3y = shear force/EI

dx3

 

d4y = load/EI

dx4

 

 

Where

x = distance along beam from one end

E = elastic modulus of beam

I = second moment of area of beam

 

A beam is of length 4m and has EI of 4. Its deflexion is given by the equation:

  

Find the equation for the bending moment, the shear force and the load. Draw the bending moment diagram and the shear force diagram. What do these diagrams tell you about the beam. Calculate the beamís reactions. Repeat the above for the beam when its deflexion is given by:

  

TASK 4 : Deflexion of balsa wood square grid

You will be provided with sufficient 3mm square balsa wood to make 6 No. 200mm long beams. Arrange the 6 beams to form a square grid as shown in the diagram on the next page. Glue the beams together at each of the 9 intersection points or nodes. Using the 150mm square frame supplied by the technician, suspend a load hanger from the centre of the grid and add loads in 100g increments up to 1kg. At each increment, measure the deflexion of the central node, a side node and a corner node. For each position, plot a graph of load against displacement. Draw the deflected shape of one of the two centre beams and one of the four off-centre beams.

Without undertaking any calculations, draw the approximate shear force diagram for the grid, using a 3-dimensional sketch.

TASK 5 : Composite action

Using thin card and 3mm square balsa, make a 300mm long beam of cross-section as shown in file composit.doc. Initially, do not glue the components together. Place the beam over supports with a clear span of 260mm.

 

Place incremental loads of 100g to 1kg on the centre of the beam and measure the deflexion beneath the beam. Plot a graph of central vertical deflexion against load. Repeat the test but with the components glued together continuously. Calculate the second moment of area, firstly when each part of the beam is acting independently, then when the gluing causes the parts to act compositely.

  

TASK 6 : free hand sketches

Prepare an A4 freehand labelled sketch of each of the following indicating approximate dimensions. Use either pencil or drawing pen. Use plain paper. Include as much detail as possible.

 

(1) Side elevation of Cassie Building.

(2) Section through Newcastle Central Station roof, showing supporting columns.

  

TASK 7 : Equilibrium of Forces

The objectives of this experiment are to:

1 Show that a number of forces acting on a particle may be represented by a vector diagram and when those forces are in equilibrium, the force vector forms a closed polygon.

2 To show that two forces acting on a member in equilibrium must be equal in magnitude, opposite in direction and colinear.

3 To show that three forces acting on a member in equilibrium must be concurrent.

4 To show that four forces acting on a member in equilibrium need not be concurrent.

 

Students need to bring drawing paper, sellotape and a protractor to the laboratory. A circular table top is used with five pulleys which may be clamped to the edge of the table. A theoretical particle is represented by a 45mm diameter ring. The member is represented by a 200mm diameter disk. Hangers, weights and cords are provided. Each hanger weighs 100g. Prepare a perspective or isometric drawing of the assembled apparatus.

 

Test 1

Using the 45mm diameter ring and a set of three cords, hangers and weights, obtain an equilibrium position. Ensure that the ring is not touching the central pin in the table top, and that there are different weights on each hanger. Use a piece of drawing paper to record the angles of the cords. Measure the angles and record the force (including the weight of the hanger) in each cord. Repeat this test with four forces, then with five forces.

 

Test 2

Using the 200mm diameter disk and two of the cords, hangers and weights, obtain an equilibrium position as for Test 1. Ensure that the loads lift the disk clear of the table and avoid attaching the two cords to diametrically opposite holes. Record the angles of the cords on a piece of drawing paper, all as before, and note the force in each.

 

Test 3

Repeat Test 2 but this time using 3 cords, ensuring each hanger has a different weight. Show that the only equilibrium position gives concurrent forces. Record angles and forces as before.

 

Test 4

Repeat Test 2 using four cords, ensuring different forces are applied through each cord and obtain an equilibrium position in which the four forces are not concurrent. Record angles and forces as before.

 

In your report, record all of the results and draw a polygon of forces to scale for each test. Note and record any closure error. Analyse each result using X and Y axes, and the components of each force. Present these results in graphical form.

 

Find S Fx and S Fy for all tests and S M for Test 4. Show that these are near zero. Note and record any closure error. Comment on all of these results and discuss how the objectives were achieved.

 

TASK 8 : The Internet

Using one of the University Computer Clusters, gain entry to the World Wide Web and access Prof. Knaptonís home web site

 

www.staff.ncl.ac.uk/john.knapton/

 

By navigating around this site, you will be able to complete the following:

 

  1. What is meant by the term Two Pinned Arch? Sketch the Tyne Millennium Bridge.
  2.  

  3. Prepare a table showing the cost of building the Prebends Bridge, Durham in 1772, The Ribblehead Viaduct in 1876 and the Wearmouth Bridge in 1929.
  4.  

  5. Explain why the reinforced concrete bridge collapsed on the Accra to Cape Coast road in Ghana.
  6.  

  7. Make a three-dimensional sketch of the Cragside Iron Bridge.