Dynamic experimental study on anti-progressive collapse of polyline-shaped large-span double-layer grid space...

Area of Science:

• Structural Engineering
• Civil Engineering
• Mechanics of Materials

Background:

• Large-span double-layer grid structures are prevalent in modern architecture.
• Understanding their behavior under progressive collapse is crucial for safety and design.
• Previous research often focuses on uniform load conditions, necessitating studies on localized failures.

Purpose of the Study:

• To investigate the dynamic response and failure mechanisms of polyline-shaped large-span double-layer grid structures subjected to progressive collapse.
• To analyze the influence of failure location and load magnitude on structural behavior.
• To identify critical components for collapse resistance design.

Main Methods:

• Fabrication of a grid model representing a typical large-span double-layer grid structure.
• Conducting dynamic collapse tests under four different failure conditions (varying load and location).
• Monitoring and analyzing strain, displacement, and failure patterns.

Main Results:

• Upper chord rods were identified as key components in collapse resistance.
• Failure of upper chord rods resulted in significant displacements and buckling of surrounding members.
• Failures in web members and lower chord rods had minimal impact, causing internal force redistribution.
• Test conditions D3 and D4 showed the most significant strain and displacement changes, particularly near failure points.

Conclusions:

• The upper chord rods play a vital role in the progressive collapse resistance of double-layer grid structures.
• The location and nature of component failure significantly influence the overall structural response.
• The findings provide critical insights for enhancing the collapse resistance design of large-span grid structures.