Timber roof trusses — standard carpentry joints in a king-post truss Choose the correct combined statement about the typical joints used in a king-post roof truss between its principal members.

Introduction / Context:Traditional timber trusses rely on well-crafted carpentry joints to transfer axial forces and prevent rotation or slip. The king-post truss is the simplest roof truss with a central vertical king post tying the tie beam to the principal rafters. Knowing the conventional joints helps ensure load paths and durability.

Given Data / Assumptions:

• Members: tie beam, principal rafters, king post, and struts.
• Common historical joinery terminology: mortice-and-tenon, bridle joints, etc.
• Loads transmitted primarily as axial forces.

Concept / Approach:A bridle joint (open mortice) at the rafter–tie interface provides a large bearing area and resists rotation. Mortice-and-tenon joints are classic for connecting timber members such as rafters/struts to the king post; pegs or wedges may secure them to resist withdrawal. These joints align fibres and accommodate compression along the grain while controlling shear at the interfaces.

Step-by-Step Solution:

Verification / Alternative check:Historic manuals and conservation guides depict these exact joints in king-post trusses, often with draw-bored pegs.

Why Other Options Are Wrong:

• Any single statement alone is incomplete; all three are correct together.
• None of these: incorrect since all listed joints are standard.

Common Pitfalls:Substituting nails/bolts without considering long-term slip and creep; poor fibre orientation reducing bearing capacity.

Final Answer:All the above