Week 1 Challenge

 Ans 1) -

We can see that Truss A is a Pratt Truss and Truss B is a howe truss.

Pratt Truss -
It is one of the common forms of the truss and is made up of vertical and diagonal members that form an N shape or pattern. The diagonal
members are arranged so that they only develop tensile forces. As such, they can be designed to resist axial tension only. avoiding the
need for a compression buckling analysis. The vertical members in a Pratt Truss develop compression forces. This means they will
typically be more robust and capable of resisting buckling.
It is composed of alternate vertical and inclined members.
It has diagonal members that slant down toward the middle.

Howe Truss -
It is essentially the opposite of pratt trusses in terms of geometry. Looking at a pratt truss upside-down will visualize a howe truss
of sorts. The entire structure is still relatively the same, but the diagonal braces are now occupying the unoccupied joints. This switch in this
position of the diagonal members has a very important effect structurally.
It consists of alternate vertical inclined members.
It has diagonal members that slant down away from the middle.

Pratt trusses have their vertical members in compression and diagonal members in tension upon the application of gravity loads at the joints
of the top chord. For howe trusses, the reverse becomes true as diagonal members are now in compression, while the vertical loads are in tension.

Hence that Pratt Truss ( Truss A ) is more efficient in carrying load gravity.

Ans 2) -

Ans 3 )-

 

Ans 4)-

^{Floor Load - 10kN/m2} 

^{Tributary width of exterior girder - 0.5(0+8)= 4m}

^{Tributary width of interior girder - 0.5(8+8)= 8m}

^{Tributary width of exterior beam - 0.5(0+2)= 1m}

^{Tributary width of interior beam - 0.5(2+2)= 2m}

Load on beam = Tributary width x floor load

Load on exterior girder = 4 x 10 = 40 kn/m

Load on beam interior girder = 8 x 10 = 80 kn/m.

Load on beam exterior beam = 1 x 10 = 10 kn/m.

Load on beam interior beam = 2 x 10 = 20 kn/m.

Ans 5 ) -

Change in length = coifficient of thermal expansion x original length x change in temparature

                         =  12x10^-6/°C x 2000 x 20

                         =  0.48 m