Question 3 of 3 · Trusses & Structural Analysis · Advanced · About 35 min

Two-bay Warren inspection bridge

A two-bay Warren inspection truss consists of nodes $A=(0,0)$ , $B=(2,2)$ , $C=(4,0)$ , $D=(6,2)$ , $E=(8,0)$ metres, connected by $AB,BC,CD,DE,AC,CE,BD$ . $A$ is pinned and $E$ is a vertical roller. Loads of $10\,\mathrm{kN}$ and $14\,\mathrm{kN}$ act downward at top joints $B$ and $D$ . Determine both vertical reactions and the axial forces in all members; pay particular attention to chord $BD$ .

A two-bay Warren truss with joints A (0, 0), B (2, 2), C (4, 0), D (6, 2) and E (8, 0) in metres. Exactly seven members: AB, BC, CD, DE, AC, CE and BD. A on a pin support, E on a roller support. Downward force arrows above top joints B and D. Dimension of 8.0 m under the whole span, and 2.0 m beside joint A showing the truss height. Labels: A; B; C; D; E; 10 kN at B; 14 kN at D; 8.0 m; 2.0 m — Schematic, not to scale unless dimensions are given.

Given

Span 8 m
Two apex loads 10 kN and 14 kN
Diagonals have $45^\circ$ slope

Find

$A_y,E_y$
Member forces and force in $BD$

Assumptions

All members and connections are idealised as specified in the question.
Use g = 9.81 m/s^2 where gravitational acceleration is required.

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Two-bay Warren inspection bridge

Given

Find

Assumptions

Worked solution