Concrete Cast-in-place Post-Tensioned Parking Garage
Durability of Parking Garage Structures Note 2 March 1994
The purpose of this best practice series on the Design, Construction,
Maintenance and Repair of Parking Garages is to inform Property
Managers, Project Managers and Project Leaders on the essential
requirements in obtaining a durable parking garage structure.
The objective of this note is to summarize the main points which
relate to Concrete Post-Tensioned parking structures.
General
Cast-in-place post-tensioned structures provide the designer with
the capacity to use long column free spaces and improved parking
layouts. Spans of 20m are common as opposed to 7.6m to 9.0m in
conventionally reinforced structures. Due to the post-tensioning
that introduces compressive forces into the tension zones of the
beams and slabs cracking is reduced and in
well designed structures virtually eliminated. However salt laden
water can still penetrate the slab through the pores in the concrete.
To achieve a durable structure, prevention of the entry of chlorides
into the concrete or coming into contact with the prestressing
tendons and reinforcing is required. To achieve a durable structure
redundancy of the durability systems is needed. If one factor
fails there should be another to take over.