The design of connections is one of the most important considerations in the structural design of precast concrete structures. The purpose of a connection is to transfer load and to provide stability. A single connection may be required to transfer several loads simultaneously. The Engineer must consider each one of those loads in the design. A good connection combines practicality and economy with sound design and therefore requires an understanding of several factors: strength, serviceability, production, erection and economics.

Precast concrete connections must meet a variety of design and performance criteria, and not all connections are required to meet the same criteria. These criteria include:

  • Strength: - A connection must have the strength to transfer the forces to which it will be subjected during its lifetime, including those caused by volume restraint and those required to maintain stability.
  • Ductility: - This is the ability to undergo relatively large inelastic deformations without failure. In connection, ductility is achieved by designing and detailing such that steel devices yield prior to weld failure. Concrete typically fails in a brittle manner unless it is confined.
  • Volume change accommodation: - Restraint of creep, shrinkage and temperature change strains can cause large stresses in precast concrete members and their supports. These stresses must be considered in the design. It is usually far better if the connection allows some movement to take place, thus relieving the stresses.
  • Durability: - When a connection is exposed to weather, or used in a corrosive environment, steel elements should be adequately covered by concrete or be painted, epoxy coated or galvanized.
  • Fire resistance: - Connections that could jeopardize the structure’s stability if weakened by fire should be protected to the same degree, as that required for the members that they connected.
  • Constructability: - includes using standardize products or connection, using repetitious details, use standard hardware items and as few sizes as possible, using connections that are not susceptible to damage in handling, avoiding reinforcement and hardware congestion, avoiding penetration of forms where possible, provide for field adjustment, provide accessibility, reduce post-stripping work etc.

The Software ‘PCPack Connection’ provides the design of various connections and has been divided into 12 modules viz. Angle, Corbel, Haunch, Base Plate, Wall to Foundation, DT Slab to Shear Wall, DT Flange to DT Flange, DT Flange to DT Flange (at ends), IT Beam to DT Slab, Dapped End Connection, Beam End Bearing and Spandrel Ledger Beam. The software is intended for use by those with an understanding of engineering mechanics and structural design, and in no case should it replace good engineering judgment. The designs are based on the provisions of ‘Building Code Requirements for Structural Concrete (ACI 318-08) and PCI Design Handbook 7th Edition.

Simple user friendly input screens along with graphical and text outputs make this software, an excellent tool to increase the productivity of the Engineers, builders and contractors in residential/commercial building industry.

pcpack - Connection