PROGRESSIVE COLLAPSE

Concrete building structures whether, insitu or precast, are required to perform in the event of accidental damage or explosion by meeting the design criteria set out in BS8110 for progressive collapse.

Within the building structure, ties are incorporated to resist calculated forces determined by a variety of factors, including:

• number of stories
• centres of walls / size of spans
• total loads carried

These are achieved by the use of the following ties incorporated into the precast cross-wall design:

• vertical ties
• horizontal ties
• peripheral ties
• internal ties

Joints between panels are tied together using pre-shuttered insitu-fill to create a robust joint with minimal finishing required. The joints use wire ties designed to meet the specific tie-force criteria, but also to allow flexibility in assembly tolerances during erection.

Peripheral and internal ties use high strength steel strand within the nominal insitu joints at cross-wall locations and around the perimeter of the building to create a continuous tie arrangement.

Building design is analysed for structural stability by Precast Structute's consultants who have extensive knowledge in the design stability of cross-wall building structures.