Walling (Load Bearing) Connections
Technical Information - Basic design principles for loadbearing wall units are shown in FIGURE 1. Loadbearing units may have a window or other opening incorporated into them.
The location of vertical and horizontal joints is important. The doughnut configuration with the window enclosed in the panel is best. If another configuration must be used then weatherproofing of the facade needs to be carefully thought out, see FIGURE 2.
Vertical load bearing connections should be made panel-to-panel as illustrated in FIGURE 3. Connections are detailed to provide for ease of erection and grouting. Issues not resolved on the consultants drawings will be addressed with by Austral during the shop drawing process.
As with all precast concrete the design should produce the most commercially attractive result consistent with the architectural and other customer requirements.
Panel sizes should be maximised within the limits of transport, crane capacity and temporary support arrangements.
Window openings can often be glazed, or at least have the frames installed, before the panels leave the factory. Careful detailing and selection of surface finishes will minimise the effects of weathering.
FIGURE 1 - Design Principles for Load Bearing Facades
FIGURE 2 - Typical Connection Details for Load Bearing Facades
FIGURE 3 - Location of Joints
Walling (Cladding) Connections
Cladding refers to non-loadbearing precast panels connected to a supporting structure. The ten basic design principles for cladding panels are shown in FIGURE 4.
The following principles should be recognised in the design of connections for precast cladding units:
Connections must be detailed to ensure that each unit supports only its own weight and no weight is transferred from the units above.
Connections should be chosen so that the loads are transferred through the connections as simply as possible with minimal eccentricities. The design of the fixings must recognise all forces and allow for them in the detailed design, FIGURE 5.
Units should be provided with at least four fixings as shown in FIGURE 6. The arrows show the freedom of movement that must be provided at each of the fixings in the plane of the panel. The fixings must provide resistance to wind forces perpendicular to the plane of the panel. Panels must not bear on one another.
The connection details should be standardised as much as possible. This results in economy, speed and simplicity during production and erection, and also reduces the chance of error.
FIGURE 4 - Design Principles for Load Bearing Facades
FIGURE 5 - Eccentric Forces on Load Bearing Facades
FIGURE 6 - Typical Panel Fixing Details
Typical Panel-Fixing Details
Adequate tolerances and clearances are required. Connections should allow economical fabrication of the precast elements. The hardware should not interfere with concrete placement, cause finishing problems nor make it difficult to provide the specified cover to reinforcement. Connections should be detailed so that hoisting equipment can be quickly released.
It may be necessary to provide temporary connections that are released after final adjustments are made. Typical cladding general arrangements & panel connection details are shown in FIGURE 7 & 8.
Design for repetition; aim for the least number of variations between panels and increased repetition of mould usage for maximum economy.
Design for the largest possible panel size within the limits of transport, crane capacity and temporary support arrangements. This will reduce costs and close up the building more quickly.
FIGURE 7 - General Arragement for Wall Cladding Panels
FIGURE 8 - Typical Connection Details for Wall Cladding Panels