Building Expansion Joint for Concrete Parking Structures: Deck and Wall Joints

Concrete parking structures require expansion joints in both the deck and the walls to accommodate thermal movement and prevent cracking. The deck joints must withstand vehicle loading and provide reliable waterproofing, while the wall joints must accommodate the movement of the deck relative to the walls. Deck expansion joints in parking structures are subject to vehicle loading from cars and light trucks. The joint must be designed to resist the wheel load without damage to the joint or the adjacent concrete. Armored joint systems with steel edge angles are the standard choice for parking structure deck joints. Waterproofing of parking structure deck joints is critical because water infiltration causes corrosion of the reinforcement and deterioration of the structure below. The joint must provide Class 3 waterproofing per EN 14187, with no leakage under a 50 mm water head. Traffic-bearing waterproofing membranes that bridge the joint gap are used for parking structure deck joints. Wall expansion joints in parking structures must accommodate the differential movement between the deck and the walls. The deck expands and contracts with temperature changes, while the walls are partially restrained by the foundation. The joint must allow this differential movement without damage to the wall or the deck. Sealant selection for parking structure wall joints must consider the movement range, chemical exposure, and UV resistance. Polyurethane sealants are the standard choice for interior wall joints. For exterior wall joints exposed to UV radiation, silicone or hybrid sealants are preferred. Drainage at parking structure deck joints must prevent water accumulation at the joint. The deck must slope toward the drains, and the joint must be designed to drain water away from the joint gap. Blocked drainage causes water ponding at the joint, increasing the hydrostatic pressure on the waterproofing and accelerating deterioration.