Construction of Space and Vector Diagram

Construction of Space Diagram:

It means the construction of a diagram of the given frame to a suitable linear scale, along with the loads it carries. The magnitude of support reactions is also found out and shown in the space diagram. Now, same the various members and forces according to Bow’s notations as shown in fig:

In the space diagram of the truss ABC shown in fig. The members AB, BC and CA are represented by SR, SQ and PS respectively. Similarly, load at C and reactions at A and B are represented by PQ, RP and QR respectively.

Construction of Vector Diagram:

After driving the space diagram and naming the various members of frame according to Bow’s notations. The next step is the construction of vector diagram. It is done in the following steps:

1. Select a suitable point p and draw pq parallel to PQ and equal to the load W at C to some suitable scale.

2. Now cut off qr parallel to QR to the reaction RB to the scale.

3. Similarly, cut off rp parallel to RP equal to the reaction RA to the scale. Thus, we see that in the space diagram, we started from P and returned to P after going for P-Q-R-P.

4. Now, through p draw a line ps parallel to PS and through r draws rs parallel to RS, meeting the first line at S as shown in fig. Thus psrp is vector diagram for the joint (A).

5. Similarly, draws the vector diagram qrsq for the joint (B) and pqsp is the vector diagram for the joint (C).