Forces in an above-ground pressure conduit on trestles A pressure conduit carried on trestles (i.e., above ground) predominantly develops which structural action due to self-weight and spans?

Introduction / Context:
When a pipeline is supported above ground on trestles or piers, it behaves structurally like a beam between supports while also containing internal fluid pressure. Understanding the dominant structural effect is important for support spacing and wall checks.

Given Data / Assumptions:

• Conduit spans between trestles.
• Self-weight of pipe and water acts vertically; internal pressure acts circumferentially and longitudinally.

Concept / Approach:
Between supports, gravity loads cause bending moments and shear forces. The pipe wall must resist hoop and longitudinal stresses from internal pressure, but the span action from supports introduces flexure. Thus, the principal structural response due to being carried on trestles is bending.

Step-by-Step Solution:

Verification / Alternative check:
Design guides require section modulus checks and support spans based on allowable bending stress and deflection limits.

Why Other Options Are Wrong:

• Tension (a) or compression (b) alone do not represent the beam action.
• Temperature stress (c) may exist but is not the defining action from trestle support.
• Torsion (e) is not primary unless geometry induces twists.

Common Pitfalls:
Ignoring the combination of internal pressure and bending, leading to underestimation of maximum wall stress.

Final Answer:
Flexural (bending) stress