Which of the following statements about the placement of vertical and horizontal stiffeners in plate girders is correct?

Introduction / Context:
Stiffeners in plate girders (vertical and horizontal) control web buckling and distribute concentrated loads. Practical detailing allows several equivalent placement patterns that satisfy stability, fabrication, and inspection needs.

Given Data / Assumptions:

• Web stiffening required by design.
• Access for welding/riveting/bolting is available on both sides.

Concept / Approach:
Both vertical and horizontal stiffeners may be arranged in pairs (both sides) for symmetry and stiffness, or they can be alternated on opposite faces to simplify welding while maintaining overall panel stability through an alternate pattern.

Step-by-Step Solution:
Consider vertical stiffeners: pairs or alternating single placement are acceptable.Consider horizontal stiffeners: likewise, pairs or alternate placement are acceptable.Therefore, all stated configurations are permissible in principle, subject to spacing and welding requirements.

Verification / Alternative check:
Code commentary and fabrication practice notes show either symmetric or alternating arrangements being used depending on access and economy.

Why Other Options Are Wrong:

• Each of A–D is individually correct; only E captures the full set.

Common Pitfalls:
Ignoring minimum spacing and termination details; not checking panel aspect ratio and interaction with bearing stiffeners.

Final Answer:
All of the above