Chapter 20, Problem 1RQ

To determine

Write about the common ways of attaching stone cladding attachment with simple sketches and describe each system.

Explanation of Solution

Stone cladding attachment:

Stone panels mounted on a steel sub frame:

Draw the free body diagram of steel sub frame with stone panels as in Figure (1).

• Initially, the vertical members are erected to transfer wind and gravity loads. Aluminum-support horizontal members are engaged in slots in lower and upper edges of the each stone.
• The joint between the stones are filled by the sealants and backer rods. Air barrier, insulation, interior finishes, and electrical wiring are provided by the construction of non-structural steel stud back-up wall and gypsum sheathing within the building frame.
• Sealant joints are the weak link for penetration of water.

Monolithic stone cladding panels:

Draw the free body diagram of monolithic stone cladding panels as in Figure (2).

• The fitting of panel is done to the building frame directly, and each panel weight is conveyed to two steel support plates using edge pockets that are cut into both sides of each panel at the stone mill.
• Steel angle strut pair is used to stabilize each panel that is bolted to the stone, using expansion anchors in drilled holes.
• Backer rod and sealant are used to close the joints and a nonstructural backup wall is needed.

Stone cladding on steel trusses:

Draw the free body diagram of truss-supported stone cladding as in Figure (3).

• In this system, stone sheets are joined into large prefabricated panels by escalating them on steel trusses.
• The design of each truss is done in such a way that it carries both wind loads and dead load of the stone to link brackets that convey these loads to the building frame.
• Sealant joints and non-structural backup wall complete the installation.

Posttensioned limestone spandrel panels:

Draw the free body diagram of spandrel panels as in Figure (4).

• Thick limestone blocks may be combined with adhesives into long spandrel panels, and high-strength steel tendons are used for posttensioned, so that the assembly is self-supporting between columns.
• This method is relatively very costly due to the usage of moderately large amounts of stone per unit cladding area.

Very thin stone facings:

Draw the free body diagram of thin stone facings as in Figure (5).

• Extremely thin stone sheets may be stiffened with a structural backing, such as a metal honeycomb, and escalated as spandrel panels in an aluminum mullion system.
• Very thin stone sheets may be applied as facings for precast concrete curtain wall panels.
• Thin stones are a result of the number of failures of cladding systems.