Week 1 Challenge

1. Truss type reasoning

Out of the two through type truss systems shown below, which is the most efficient in carrying gravity load? Reason it out.

2. Deflection shape & Bending Moment Drawing (Qualitative approach)

For the beam & Frame below draw deflected shape and bending moment drawing. (Qualitative approach). E & I are constants.

ANS

FIG A

FIG B

FIG C

DEFLECTION OF BEAM

3. Determine MOI, Weight, C/S area of sections below

MOI OF CHANNEL SECTION

Izz= 2*80*10^3/12 +8*180^3/12+2*80*10 *(200/2 +95)

= 1.834 *10^7 MM3

CS = 2*80*10 +180*8 =3040 MM2

WEIGHT=

DENSITY OF STEEL=7850 KG/M3

WEIGHT= 3040MM2 *7850 = 26.69 KG/M

MOI = 2*300*30^3/12 +8* 1000^3/12 + (500+30/2)30*300

= 5.44*10^9MM4

CS = 2*30*300 +8*1000 =26000 MM2

WEIGHT = 7850* 26000 MM2

MOENT OF INERTIA OF ISMB 300 ABOUT XX AXIS = 8603.6 CM4

= 8603.6*10^4 MM4

MOMENT OF INERTIA ABOUT XX AXIS

= A= 12*160 =1920 mm2

h=300/3+12/2 =156m

by parallel axis theorem

I= ixx+ Ah^2

= 8603.6 *10^4 +1920*156

=183.35 *10^6 MM4

CS = 5860 MM2 + 2*12*160 = 9700 MM2

WEIGHT = 7850*9700=76 KG/M

4. Load calculation problem

For the floor framing below, Calculate the load on interior beam, Exterior beam, Interior Girder and exterior girder having Floor Load of 10kN/m²

LOAD ON INTERIOR BEAM = 10*1+10*1=20 KN/M

LOAD ON EXTERIOR BEAM= 10*1 =10KN/M

LOAD ON GIRDER =

INTERIR GIRDER = 20KN/M *4 =80KN

FROM TWO SIDES = 80*2 =160 KN @ 2M APART

LOAD ON EXTERIOR GIRDER

20KN/M*4M= 80 KN

5. Expansion joint size determination for temperature stated problem

Assuming a bridge, made of steel, with an initial total length of 2000 m at -20 ºC, calculate the length difference at 40 ºC and its total length.

`triangle l`= l`alpha`t

= 2000 *12*10^-6 *60

=1.444 m