Post-tensioned concrete structures offer many benefits in
multi-story buildings such as long spans, thin floor depths and of course fire
resistance. Although this type of structure can be labor intensive and require specialized
labor, it remains an excellent design choice. However, when this workforce is unavailable in a certain area or if a project is over budget, the Peikko Frame is the best alternative to post-tensioned concrete.
 |
| Peikko Frame / Source: Peikko |
The
Traditional Alternatives:
Reinforced concrete or Cast-in-place
Structures
A cast-in-place concrete structure is in some regards
similar to a post-tensioned structure, yet in order to achieve the same spans,
the reinforced concrete slabs need to be thicker and therefore heavier. Not only
does this additional thickness add to the cost of the concrete but it also
increases the weight of the entire structure which will lead to bigger and more
expensive foundations.
Just like a post-tensioned structure, cast-in-place
is inherently non-combustible.
 |
Cast-in-place structure / Source: Peikko
|
Steel
Structures
Since it is to a large extent prefabricated, a steel
structures has the ability to be erected quickly with a comparatively small
crew of installers. Nevertheless, the thickness of the traditional assembly of
the beams supporting the joists and deck will inevitably increase the
floor-to-floor height when compared to a post-tensioned structure. With steel structures, to maintain the same number of floors the building height will have to be increased. If the overall height cannot be increased than there is a possible lost of one or more floor levels.
 |
| Conventional steel decking / Source:weldersuniverse.com |
Additionally this increased floor-to-floor height will have
a direct impact on the cost especially on the more expensive vertical
components such as exterior cladding.
Since unprotected steel members do not resist fire, the
fireproofing of steel structures adds another trade that will lead to
additional costs.
 |
| Fireproofing a steel structure / Source: Wikipedia |
Precast Structures
Precast structures composed of hollowcore slabs, precast
columns and precast beams are not very common in the United States. Even though
hollowcore slabs are a very competitive product, making precast columns and
beams at low cost remains a challenge in most regions.
The prestressed hollowcore slabs offer an unmatched span to depth ratio, but the bottom flange of the precast beams protruding under the hollowcore slabs will inevitably increase the floor to floor height.
 |
Precast beam supporting hollowcore slabs / Source:Peikko
|
 |
| Precast beam supporting hollowcore slabs / Source:Peikko |
Just like post-tensioned and cast-in-place, precast
structures are non-combustible
The Peikko Frame:
The Peikko Frame was developed to encompass all the major benefits
of the traditional types of structures in one simple system.
Speed of
construction with minimal workforce
By utilizing long span prefabricated components such as 36
feet hollowcore slabs combined to 25 feet Deltabeam®, Peikko frames allow for exceptionally
fast construction without an extended workforce.
 |
| Peikko Frame Time LapseVideo / Source: Peikko |
 |
| Shoring of a conventional concrete slab / Source:Peikko |
 |
| Shoring of Deltabeam® / Source:Peikko |
The Peikko Frames are typically shored only for torsion when
loading the precast slabs on one side of the beam. The few shoring posts
are typically removed only a few days after the hollowcore slabs have been
installed.
Superior
span to depth ratio without protruding beams
It is well known that hollowcore slabs offer an excellent
span to depth ratio since they are prestressed and light weight due to their longitudinal
voids. However, when combined with traditional beams, the overall floor
assembly can sometimes be increased by the full height of the beam profile.
 |
| Hollowcore slabs on wide flange steel beams / Source:Peikko |
 |
| Additional floor depth when using wide flange beam vs. Deltabeam® / Source:Peikko |
Deltabeam® is designed to only have its bottom flange
protruding under the hollowcore slabs. Typically the flange will be less than
1” thick and will not interfere with HVAC or other systems.
Deltabeam® bottom flange supporting hollowcore slabs / Source:Peikko
Non-combustible
structures
Peikko frames will result in exposed steel columns and
Deltabeam (bottom flange) that do not require any fireproofing material applied
on site.
Deltabeam® has been tested by Underwriters laboratories (UL)
and is now listed for 1, 2, 3 & 4 hours without requiring any kind of
fireproofing material. The reinforcement inside the concreted beam will assure
the beam capacity remains sufficient in case of fire.
 |
| Interior of Deltabeam® / Source:Peikko |
Click to play the video:
Deltabeam® Fire test at UL / Source:Peikko
The composite columns act in a similar fashion by relying on
its reinforced concrete core to ensure the load bearing capacity in under fire.
Cost
effective solution
Direct Costs
By using big prefabricated components major savings can be
made. Less components means less time to erect a floor and large floor-plates can be installed with a handful of installers.
 |
| Hollowcore slab installed on a Deltabeam® / Source:Peikko |
One of the major components of the Peikko Frame is the
hollowcore slab. Hollowcore slabs have been used in millions of square feet of
buildings in America and have a proven record of being economical and highly
capable.
Indirect Costs
In addition to having a competitive direct cost, the Peikko
Frame leads to other significant savings.
When compared to post-tensioned structures, Peikko Frames
allow for immediate access to the lower floors to other sub-trades (partition
walls, plumbing, HVAC, etc.) since it requires minimal shoring.
The reduced weight of the hollowcore slabs also leads to
savings for the foundations.
Having very minimal formwork reduces the cost of waste collection.
Compared to steel structures, the Peikko Frame will greatly reduce the floor-to-floor height. Also, hollowcore slabs are usually faster to
install than traditional metal deck and requires less steps to be completed.
Extra Costs
Perhaps the most important cost reduction factor with the
Peikko Frame is the most intangible: Predictability. Since the entire
frame is prefabricated and modeled in 3D and it leaves limited probabilities for
errors and omissions. Also, large prefabricated component are less impacted by
weather during construction and erection can proceed even with relatively high
winds, rain or snowfall.
Peikko Frames are also very easily enclosed during
construction which leads to saving on heating when the construction site runs
during winter time.
The Alternative to Post-Tensioned Structures
When a multi-story building requires long spans, a non-combustible structure and low floor-to-floor height, the Peikko Frame should be a system to consider. With it's prefabricated components, the Peikko frame will likely reduce the construction time and budget when compared to a conventional post-tensioned building.
For more information:
www.peikkousa.com
1-888-PEIKKO-1
1-888-734-5567
The Alternative to Post-Tensioned Structures
When a multi-story building requires long spans, a non-combustible structure and low floor-to-floor height, the Peikko Frame should be a system to consider. With it's prefabricated components, the Peikko frame will likely reduce the construction time and budget when compared to a conventional post-tensioned building.
For more information:
www.peikkousa.com
1-888-PEIKKO-1
1-888-734-5567
