Amir Hassan, M.Sc., P.Eng., P.E. Building Science Manager with EXP has more than 25 years of experience in Building Envelope and Forensic Restoration in the Middle East, Europe and North America. He has worked on very complex projects for both existing buildings (including historical and heritage buildings) and new construction. Hassan shared his expertise on parking deck systems in the Consultant's Corner section of Chamberlin's latest newsletter.
It is hard to imagine any urban setting without parking garages. Giving the limited availability of usable areas in busy cities, parking structures efficiently provide stalls for vehicles in airports, train stations, bus stations, commercial buildings, hospitals and malls. Those structures are commonly built using cast-in-place, precast concrete, post-tensioned concrete, structural steel, even engineered lumber, or a combination of these systems. Structural parking decks consist typically of reinforced concrete slabs over precast supporting units. Slabs' initial slopes and their structural deflections are important to direct the water toward the drains as per the water management plan.
Hassan goes on to discuss the importance of a durable deck and water management. Designing, installing and then testing waterproofing systems are the keys to divert water away from the structural elements. Water is the major cause of concrete deterioration and steel rusting. The waterproofing layer can be placed on the top of the deck system where it’s easy to inspect and repair; however, the layer is not protected from pedestrian and vehicular traffics. Therefore, the preferable approach in parking garages is to use protected waterproofing membrane. As the name implies, the membrane will be protected from the traffic, and that will extend the service life of the deck. Nonetheless, the limited accessibility will make the assembly hard and expensive to maintain. Loose-laid membrane can be applied; however, the most common application of the deck membrane is full adhesion.
Flood test
Inflatable drain plugs
High-voltage ELD testing
Parking decks are harmfully affected by wear, abrasion, aggressive chemical agents, damaging environmental agents, extreme temperature variations, rough use, salt and water intrusions; therefore, they require comprehensive maintenance programs. Ignoring a small water leakage into the assembly may lead to serious and costly structural deficiencies and to catastrophic failures in extreme cases. Preventive measures increase the service life of parking structures and reduce disruptive and expensive repair. Parking Facility Maintenance Manual, a publication by National Parking Association is a great guide to extend the lifespan of parking garages through site-specific maintenance and repairs.