Advanced Methods of Structural Analysis

74 3 Multispan Beams and Trusses

3.5.Where concentrated loadPshould be located (Fig. P3.5)

(a)For maximum positive (negative) reaction of supportA; (b) In order to reaction

RDD 0

ADB

C

Fig. P3.5

3.6.Analyze the design diagram of two-span Gerber beam is shown in Fig. P3.6.
(a)Find location of distributed load in order to reaction at supportCwill be equal
zero
(b)Find portion of the beam which is not deformable if concentrated loadPis
located at pointB
(c)Where are located extended fibers within the portionABif concentrated loadP
is located at pointD

A B D

C E

Fig. P3.6

3.7a–b.Provide kinematical analysis for trusses in Fig. P3.7.

a b

Fig. P3.7

3.8.Design diagram for a simple truss with a lower loaded chord is presented

in Fig.P3.8. Consruct the influence lines of the internal forces at the indicated

members.

Based on the constructed influence lines check the correct answer:

1.ForceV 1 is the maximum tension, if concentrated loadPis located at joint
1.E;2.C;3.K
2.ForceV 2 is always 1. positive; 2. negative; 3. zero