Week 1 Challenge

• ANSWERS:-

5.) CHANGE IN LENGTH=COEFFICIENT OF THERMAL EXPANSION X ORIGINAL LENGTH X CHANGE IN TEMPARATURE

= 12X10^-6`X 2000X20

=0.48M

4.) TRIBUTARY WIDTH OF EXTERIOR GIRDER =1/2(0+8)=4M

TRIBUTARY WIDTH OF INTERIOR GIRDER=1/2(8+8)=8M

TRIBUTARY WIDTH OF EXTERIOR BEAM=1/2(0+2)=1M

TRIBUTARY WIDTH OF INTERIOR BEAM=1/2(2+2)=2M

LOAD ON BEAM = TRIBUTARY WIDTHX FLOOR LOAD

LOAD ON EXTTERIOR GIRDER =4X10=40 KN/M

LOAD ON BEAM INTERIOR GIRDER =8X10=80KN/M.

LOAD ON BEAM EXTERIOR BEAM=1X10=10KN/M.

LOAD ONBEAM INTERIOR BEAM=2X10=20KN/M

1.) A IS THE PRATT TRUSS AND B IS THE HOWE TRUSS.

PRATT TRUSS IS ONE OF THE COMMON FORMS OF THE TRUSS AND IS MADE UP OF VERTICAL AND DIAGONAL MEMBERS THAT FORMS AN N SHAPE OR PATTERN. THE DIAGONAL MEMBERS ARE RESIST AXIAL TENSION ONLY. AVOIDING THE NEED FOR A COMPRESSION BUCKLING ANALYSIS. THE VERTICAL MEMBERS IN A PRATT TRUSS DEVELOPE 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 TOWARDS THE MIDDLE.

HOWE TRUSS IS ESSENTIALLY THE OPPOSITE OF PRATT TRUSSES IN TERMS OF GEOMETRY.IN FACT LOOKING AT A PRATT TRUSS UPSIDE -DOWN WILL VISIUALLIZE A HOWE TRUSS OF SORTS. THE ENTIRE STRUCTURE IS STILL RELATIVELY THE SAME,BUT THE DIAGONAL BRACES ARE NOW OCCUPYING THE UNOCUPIED JOINTS. THIS SWITCH IN THIS POSITION OF THE DIAGONAL MEMBERS HAS A VERY IMPORTANT EFFECT STRUCTURALLY.IT CONSIST OF ALTERNATE VERTICAL ADNINCLINED 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 APPLIVATION OF GRAVITY LOADS AT THE JOINTS OF THE TOP CHORD. FOR HOWE TRUSSES, THE REVERSE BECOME TRUE AS DIAGONAL MEMBERS ARE NOW IN COMPRESSION, WHILE THE VERTICAL LOADS ARE IN TENSION

HENCE THAT PRATT TRUSS(TRUSS A ) IS MORE EFFICENT IN CARRYING LOAD GRAVITY