pre-cast vs. post-tensioned parking garages
pre-cast vs. post-tensioned parking garages
(OP)
I have to generate a letter to a state university system comparing the advantages and disadvantages of post-tensioned cast-in-place parking garages vs. pre-cast parking garages. The purpose of the letter is to facilitate the university in choosing one of the two systems for a new 630 space parking garage. I need to generate the letter this weekend. I have the following:
Precast - lesser construction cost, long term maintenance costs higher, less freedom in layout (use local precasters typical bay sizes), need for shear walls or K-walls for lateral force resisting system
Post-tensioned - more open feel, less surfaces for migratory birds to nest on, costs for crack repairs due to restraints against elastic shortening, concrete frames resist lateral forces so no walls to hide crime.
Does anyone know of a web site that makes a comparison between precast and post-tensioned parking garages?
Precast - lesser construction cost, long term maintenance costs higher, less freedom in layout (use local precasters typical bay sizes), need for shear walls or K-walls for lateral force resisting system
Post-tensioned - more open feel, less surfaces for migratory birds to nest on, costs for crack repairs due to restraints against elastic shortening, concrete frames resist lateral forces so no walls to hide crime.
Does anyone know of a web site that makes a comparison between precast and post-tensioned parking garages?






RE: pre-cast vs. post-tensioned parking garages
In my own opinion, the long-term durability of pre-cast concrete makes it a difficult system to beat. However, they are plagued with leakage problems because of the number of joints. Annual maintenance is strongly recommended to flood test the parkade to flush the chlorides and identify the joints in need of repair.
Regarding cast-in-place, post-tensioned parking garages, based on the number of post-tensioned structures we have repaired, I'm very reluctant to recommend any such system for parkades, even for the newer extruded sheathed tendons.
As you are aware, there are many arguments for each case, it depends on your priorities. If cost is number one, you will likely be using a precast parkade; if long-term protection against leakage is a priority and the Owner is vigilant, a cast-in-place, post-tensioned parkade, protected with a membrane may be the most appropriate.
If you want to discuss it further, feel free to contact my at john.w@ckpeng.com.
Regards,
John
RE: pre-cast vs. post-tensioned parking garages
RE: pre-cast vs. post-tensioned parking garages
Economical Carparks - A Design Guide
http://www.onesteel.com/systems.asp?systemID=63
Economical Carparks - A Guide to Fire Safety
http://www.onesteel.com/productspecs.asp?specID=54
RE: pre-cast vs. post-tensioned parking garages
The leakage problems identified by Pinehurst was something I had not considered.
This project is a design-build project and the contractor has already determined that the precast option costs $500,000.00 less than the post-tensioned option. Thanks Dik.
The information on composite steel design is handy. I'll have to review the information from a vibration, fire resistance, and life span point of view before I present this information to the University. Thanks dbuzz.
RE: pre-cast vs. post-tensioned parking garages
If design build, you have the advantage of having a contractor in your pocket to help with cost estimating... remember, it's usually the system chosen that determines the economy... not a tight design...
RE: pre-cast vs. post-tensioned parking garages
Let us know what you find out.
RE: pre-cast vs. post-tensioned parking garages