Faculty
of Science, Engineering and Computing
Postgraduate Modular
Scheme
April/May Examinations 2020/2021
Level 7
MODULE: CE7112
Design in concrete and steel
DURATION: 3
hours + 2 hours
General instructions
1.
This examination/assessment was designed to be
completed within the duration specified on the front cover (3 hours). However, Canvas will remain open for a
further two hours to allow additional time for submission and any technical
difficulties.
2.
If you experience technical difficulties, eg. access
and upload issues, or identify a potential error in a question please email the
module leader T.Donchev@kingston.ac.uk
who will be available throughout the exam.
3.
You must
not collaborate with anyone on this exam/assessment, it should be wholly your
own work. Your work will be checked for
evidence of plagiarism and/or collusion using Turnitin.
Submission Guidance
1.
You
should submit your answers as a single Word, pdf or Excel document via
Canvas. Add your ID to the top of each
page and indicate the questions you have answered on the first page of your
document.
2.
If
you include graphics in your answer, these should be embedded into the document
(eg. a photograph of a hand-drawn graphic).
The source of any copied and pasted figures should be cited.
3.
Please
make sure to save your work regularly and leave plenty of time to upload your
work not later than ½ hour before the deadline.
Late submissions will not be marked.
Instructions to Candidates
This
paper contains Four questions
Answer FOUR questions
All questions
carry equal marks
Candidates are reminded that the major steps
in all arithmetical calculations are to be set out clearly.
Design
Extracts will not be supplied as this is an open book examination.
Number
of Pages: 1 – 4
1 Design the
steel beam shown in Figure Q1 for Lateral Torsional Buckling (LTB) effects for
sagging between points B and C assuming LTB restrains at the supports. The loading generally consists of two types
of Uniformly Distributed Load (UDL), acting between points A and B and points B
and C correspondingly. The unfactored UDL for both parts is 25 kN/m permanent
load and 20 kN/m variable load. The partial safety factors for both parts of
the beam depend on the chosen loadcase. AB part of the beam is 4 m long and BC
part is 1.5 m.
Perform the following
design calculations based on EC3:
(a) Choose an appropriate loadcase for
maximum sagging moment to occur at the span AB and calculate the loads at Ultimate
Limit State (ULS) using appropriate load factors. Calculate the support reactions. Draw shear
force and bending moment diagrams for the above mentioned loadcase indicating
all significant values.
(6 marks)
(b) Choose an appropriate S275 steel Universal
Beam (UB) section which may be used to resist the LTB effects between points A
and B. Check the classification of the section.
(5 marks)
(d) Check the LTB effects between the
supports at ULS assuming laterally restrained compression flange at the
supports and at the end of the cantilever. The flanges are free to rotate in
plan between the supports.
Do the calculations only once and
indicate do you need bigger or smaller section at the end.
(8 marks)
(c) Check the deflections between A and B
according to SLS loading and assuming non-brittle finish for the ceilings.
(6
marks)
2
The simply supported frame ABC shown in Figure
Q2 is made from steel S275. It is subjected to the following nominal loads:
horizontal point load F at the
support at point C with magnitude 35 kN as permanent load and 30 kN as variable
load. In addition, uniformly distributed load w acting downwards is applied on the horizontal part BC of the
frame with magnitude 80 kN/m as permanent load and 65 kN/m as variable load.
Assume that
the column AB is supported by pinned supports top and bottom and loaded in
compression and uniaxial bending. The height of the column is 4m. Check the adequacy
of a UC 254x254x132 column for the load effects from simultaneous action of the
indicated loading as design values in ULS.
Perform the following
design calculations based on EC3:
(a) Calculate the design values for bending
and compression load effects at the top of the column AB assuming all loads
applied simultaneously. (4 marks)
(b) Check the resistance of the existing
cross section of the column at point B to bending and compression. (6 marks)
(c) Check the buckling resistance of the
column BC about the major and the minor axes. (5
marks)
(d) Check
lateral torsional buckling and combined buckling effects (10 marks)
3
A grade S275 steel beam 406x178x74 UB carries
permanent loads and variable loads from two secondary beams as shown in Figure
Q3. The beam is laterally restrained at the supports and the secondary beams.
Design mineral fibre box protection to give 90min fire performance if the thermal
properties of the proposed thermal insulation are as follows:
Figure
Q3 All distances are in mm
a) Determine
the design bending resistance of the beam at 20ºC temperature and compare with
the design load at room temperature.
(7 marks)
b) Determine
the critical temperature for the section. As a first iteration assume the
critical temperature to be 550ºC. During the heating the variable action is to
be considered as a quasi-permanent value 
where 
.
(12 marks)
c) Calculate
the required minimum thickness of the protection to satisfy the required 90min
of fire performance for the critical temperature.
(6 marks)
Continued…
4.
A
3-spans continuous beam with a fixed end is shown in Figure Q4a. The beam carries two uniformly distributed
loads and a point load. The cross
section of the beam is made up of a UB strengthened with a plate on the base of
the UB as shown in Figure Q4b. The yield
stress of steel is 275N/mm2.
(a)
Determine the full plastic moment of resistance
Mp of the section.
(5 marks)
(b)
Using Plastic Analysis method, investigate all
possible collapse mechanisms and determine the actual collapse load and the
corresponding collapse mechanism.
(10 marks)
(c)
For the collapse load in (b), draw the bending
moment diagram showing all significant values.
(10
marks)
END OF EXAMINATION PAPER
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