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Curtin University of Technology

Department of Civil Engineering

STRUCTURAL DESIGN 266 COVER SHEETSteel Design ASSIGNMENT TWO

Date due: Thursday, 22nd October 2009, 4:00 pm

Submission to: Assignments office building 204, level 2

Kerri Bland p1 of 8

This assignment is worth five (5)% of the assessment for Structural Design 266.This assignment can be done singly or in groups ofno more than four(only one assignment to be handed in

per group). If it is to be done in a group, I encourage all members to fully participate in calculation of all

parts of the assignment as any portion may be similar to questions in the end of semester exam.

Six different versions of Question 1 of this assignment have been set. Details for each version are indicated

in Table A. Each student (or group) is only required to do one versionn. Each group needs to advise me

(Kerri) by e-mail [[email protected]]) of the group members and I will then assign an assignment

version to your group.

Clearly indicate the Question 1 version that has been carried out here:

Show the names of all group members on this cover sheet.

Attach this cover sheet to the front of your assignment, but behind your assignmentoffice submission sheet.

Fill out the summary sheets and attach directly behind this cover sheet. All workingshould follow the summary sheet.

Summary sheets filled out in pencil will be penalised.

Marks will be deducted for failure to comply with all instructions given. Each group member will receive

the same mark. Late submission will attract a penalty of 10% per day.

Student Number / Name:

____________________________ _____________________________________________________________

____________________________ _____________________________________________________________

____________________________ _____________________________________________________________

____________________________ _____________________________________________________________

Marking Key:Question 1 (20)

Question 2 (10)

Question 3 (20)

Total Marks (50)

Reduction of mark for failure tocomply with instructions

Final Recorded Mark (50)

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STRUCTURAL DESIGN 266

Steel Design ASSIGNMENT TWO



SUMMARY SHEETS

Kerri Bland Summary Page p2 of 8

Summary Pages(to be located directly after cover sheet)

Insert question answers on these pages.

All working to support the answers given heremust also be attached.

Question 1

a) Draw diagrams (Figure S1):

PB PC PD

ab bc decdA

B C DE

SFD(kN)

BMD(kNm)

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SUMMARY SHEETS


b)Selected section: _______________________

For each beam segment considered, provide the following data:

Beam

Segment

Max M*

(kNm)

Le (m) m s

(critical

segment only)

Mb (kNm)

(critical

segment only)

c)Shear capacity (Vv) of selected section:

Show that shear capacity is sufficient:

Show shear/bending interaction checks:

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SUMMARY SHEETS


Question 2

Part I.

Vv of the existing unstiffened steel section = _______________ kN

Part II.

a. Bearing capacity (Rb) of selected section at critical location/s:

Location R* (kN) bbf(mm) bb (mm) Rby (kN) Rbb (kN) Rb (kN)

Are stiffeners required anywhere? __________

b. Including shear/bending interaction consideration, what shear capacity (Vv) is the

web required to provide at the maximum moment area? _______________ kN

What value ofvd is required to ensure shear capacity is achieved? __________

Stiffener spacing required? _______________ mm

c. Show extent of stiffeners on the beam below:

1200 kN

SFD(kN)300 kN

3600 kNm

BMD(kNm)

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SUMMARY SHEETS


Question 3

a) e,web = _____________, e,flange = _____________

Compactness of section (circle correct answer): C NC S

I =

Z =

S =

Ze =

Ms =

b) ry =

Is the beam Fully Laterally Restrained? (circle correct answer): Y N

Mb =

c) Maximum ultimate action (in kN/m) = _____________ kN

d) Maximum imposed action (in kPa) = _____________ kN

Can general office areas be adequately supported? (circle correct answer): Y N

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Kerri Bland p6 of 8

Question 1

A simply supported beam is required to support a series of three factored point loads

(gravity loads) applied to the top flange (as given in Table A). The arrangement of the

point loads is shown in Figure 1 and Table A. Lateral restraints to the top flange are only

provided at points B and D as shown. The beams are connected to adjacent support

structures by connections which can be considered to provide full torsional and lateral

restraint at each end of the member, but no restraint against rotation in plan.

a)Draw the BMD and SFD.

b)Determine the member size required to support bending moments induced by the pointloads (use a grade 300 UB or WB member only need to use a WB if no UB beam is

large enough to satisfy the member requirements). Indicate the critical segment.

c)Check that the member has sufficient shear capacity to resist the shear forces, andcheck for shear/bending interaction if necessary.

Figure 1:

Table A

Assignment Version A B C D E F

Point load PB (kN) 70 20 20 10 25 40

Point load PC (kN) 30 70 10 60 40 40

Point load PD (kN) 40 80 120 20 75 40

Dimension ab (m) 2.0 2.5 4.0 6.8 3.5 5.5

Dimension bc (m) 1.0 0.7 0.5 1.2 0.6 1.5

Dimension cd (m) 3.0 0.7 1.5 3.6 1.8 1.5

Dimension de (m) 6.0 4.5 1.0 0.5 4.0 5.5

PB PC PD

ab bc decd

Lateral restraint (denoted by X)available at points B and D only.

AB C D

E

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Kerri Bland p7 of 8

550

8

32

1000

Question 2

A steel girder has been designed to span 12 metres. The

dimensions of the cross section are shown in Figure 2A. The steel

used to fabricate the girder is Grade 300 plate (AS/NZS 3678).

The girder can be assumed to be fully laterally restrained. The

design capacities of the girder are as follows:

Ms = Mb = 3930 kNm

Vw = 1339 kN

Part I.

Find the shear capacity (Vv) of the proposed unstiffened girder

(disregarding any shear/bending interaction effects for now).

Part II. (Disregard the self weight of the girders for all of the Part II questions.)

The girder is subjected to a design point load of 1200kN, applied at 3.0metres from one

support. The BMD and SFD for the beam is shown below:

a) Check the bearing capacity of the web at the supports and the load application point(assume the stiff bearing width at the supports is 100mm (from the cut end of the

beam) and the stiff bearing width at the applied load is 50mm). State whether

stiffeners are required for bearing. It is not necessary to design the stiffeners.

Figure 2ANot to scale

SFD(kN)

BMD(kNm)

900 kN

300 kN

3600 kNm

1200 kN

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Kerri Bland p8 of 8

It should be apparent that the proposed unstiffened girder is currently unsuitable to

support the design actions due to insufficient shear capacity.

b) Determine the stiffener spacing required to increase the shear capacity of the proposedgirder so that it will be able to support the design actions. This should incorporate

shear/bending interaction consideration.

c) Determine the required extent of stiffeners (ie: should the stiffeners be equally spacedalong the whole length of the beam, or can they be discontinued or spaced further

apart at any point?). It is not necessary to design the stiffeners.

Question 3

Some proposed welded plate girders (assume heavily welded), as shown in Figure 3, are

to support a reinforced concrete suspended slab.

The girders are to be fabricated from Grade 300 steel plate(AS/NZS 3678) (determine fy from of code).

Assume there are no web stiffeners.

The girders will be placed at 7 metre centres

(ie: each girder will be located parallel to and 7m awayfrom its adjacent girder).

The girders are to be simply supported and are to span 15m.

The end connections will be able to provide full torsionaland lateral restraint at each end of the girder, but no restraint

against rotation in plan.

The series of parallel girders will be supporting a concretedeck. The girders will have shear studs welded to the top

flange at 900mm centres, providing lateral restraint to the

top flange of the girders at the shear stud locations.

Figure 3Not to scale

a. Find the section moment capacity (Ms) of the girders.

b. Determine whether the shear stud spacing is sufficient to provide full lateral restraint

to the girder. From this, calculate the member moment capacity (Mb).

c. What is the maximum ultimate action (in kN/m) that the girder can support?

d. If the slab being supported is 200mm thick, determine the maximum imposed action

(in kPa) that can be supported, based only upon the member moment capacity of thegirders. Dont forget to consider the weight of beam in your calculations. Will it be

suitable to support an office area (general use)?

350

10

25

800

sd266 assn2 2009_1

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