Definition of a tie member in framed structures In structural frames and trusses, “ties” are members primarily designed to carry which type of loading under service conditions?

Introduction / Context:
Structural frames often distinguish between members that are mainly in tension (ties) and those mainly in compression (struts). Correct terminology matters for design detailing, end connections, and serviceability expectations in steel, timber, and reinforced concrete systems.

Given Data / Assumptions:

• Member is part of a two-dimensional frame or truss.
• Primary action is axial; flexure and torsion are secondary or negligible by design.
• Service load combinations keep the member in its intended force state.

Concept / Approach:

A tie is a member intended to resist axial tension. Examples include the bottom chord of a simply supported truss, rod ties in roof systems, or hold-down ties in shear walls. Conversely, a strut is a member intended to resist axial compression. Recognizing the force type dictates connection detailing (e.g., clevis, gusset plates), sizing, and buckling checks.

Step-by-Step Solution:

Verification / Alternative check:

Design guides consistently classify ties as tension members, requiring net-section checks, block shear, and connection slip considerations rather than buckling checks that are mandatory for struts.

Why Other Options Are Wrong:

• Transverse loads: Characteristic of beams, not ties.
• Axial compression: Defines struts.
• Torsional loads: Typical of shafts or closed-section members under torque.
• Biaxial bending: Pertains to columns or beam-columns, not pure ties.

Common Pitfalls:

• Treating a tie as a beam and overlooking the importance of axial stiffness and connection detailing.
• Allowing load reversals that could put a nominal tie into compression without verifying its buckling resistance.

Final Answer:

axial tension loads.