What is podium slab?
Podium slabs are unique type of floor system that transfers loads from a steel or wood frame structure above the slab to concrete walls and columns below. Podium Slab consists of a 1- to 2-story reinforced or post tension concrete podium that allows several stories of light-frame wood framing above it.
Podium construction works best for 5-7 stories in a hotel or multi-family occupancy type as it is faster and more cost effective than block and plank construction.
4 over 1- Consist of 4 stories of wood frame over 1 story podium
5 over 2- Consist of 5 stories of wood frame over 2-story podium
Podium slab construction techniques
The following construction systems have been used for podium slabs:
1. Post-tensions cast in place construction technique
2. Precast hollow core; this construction system is preferred it provides immediate safe working platform and excellent construction speed.
IBC Code Allowance
Construction Type Material used Height Range Stories Allowed
I & II Concrete, Steel, metal studs Unlimited Unlimited
III Exterior: FRT Wood 75'-85' 5
V Standard wood 60'-70' 4
Wood-framed construction is limited to 4 stories and Type III construction FRT wood is limited to 5 stories. If you are building a hotel utilizing either construction types, you will be limited to this.
The main of podium construction is that the IBC allows you for additional floor than the limits noted above utilizing the horizontal building separation allowance (IBC 510.2). This allowance consents the building to be considered as two separate and distinct buildings for the purpose of determining the maximum number of stories, assuming certain criteria are met.
you can place a Type V or Type III building on top of a Type I building.
7 Advantages of Podium slab for hotels and mid-rise apartments
1. Provide solid separation between parking areas and living spaces and consequently offers sound and fire protection. This separation allows for mixed-use as per IBC. ( Hotel/Retail, Multi-family/retail)
2. The application of post-tensioned two-way podium slab permits the decrease of overall thickness of the frame. This will cause the reduction of excavation because the parking is below grade.
3. Flat soffit does not need extra fire protection provided that adequate cover for rebars and post tensioning are provided. Additionally, the flat soffit permits efficient lighting, electrical, heating, ventilation, and air conditioning.
4. It provides large open spaces at or below grade for example parking and retail. In single family and multi-family residential structures, podium slab provides high fire rating, decline sound transmission and floor vibration.
5. Forms can be stripped two to three days after the post tensioning application.
6. It provides large open spaces at or below grade for example parking and retail.
7. A podium model can be very cost and time efficient for hotels and mid rise multi-family as the ground floor of a hotel is where the large, open, common space typically is located. To achieve necessary span lengths, these areas require heavier non-wood framing, such as steel or concrete, and makes the design one step closer to a podium anyway.