Curved expansion joints follow the curve in the departures roadway at the Jet Blue terminal at New York’s JFK International Airport. The curve is both elegant, functional and ergonomically steers traffic to optimize flow. The roadway is structurally separated from the terminal building by an expansion joint. The joint is therefore curved. Curves also define Aero Saarinen’s iconic TWA Terminal attached to the Jet Blue terminal. Now the TWA Hotel, curved expansion joints abound in this magnificent repurposing of an architectural masterpiece.
Curved expansion joints can induce complex movements in the joint materials chosen to seal them. These movements can be managed, however, by a combination of the flexibility of high-quality materials and through the conservative sizing of the joint openings in relation to the expected movements. This being done, the capability of a manufacturer to fabricate and configure the joint system to follow the curve while ensuring continuity of seal becomes the next challenge, followed in turn by the installation of the systems by a qualified contractor.
Curved Expansion Joints Routine for Emseal
EMSEAL routinely handles curved expansion joints. Outside radii in joints in the vertical plane are handled through the flexibility of the material in the case of EMSEAL’s Seismic Colorseal family of unique hybrid silicone and pre-compressed foam sealants. In tight curves, notching of the back of these materials is used to relieve the bending stresses and facilitate the curve.
Inside radii in the horizontal plane are handled by EMSEAL’s deck expansion joint systems, like Thermaflex, through the flexibility of the thermoplastic-rubber extrusions. In tight radii conditions the thermoplastic rubber extrusions can be segmented and factory-welded to follow curves while ensuring continuity of seal. The curves of joints in ice-floor perimeters and other horizontal deck joints around curved or elliptical columns have routinely been handled by EMSEAL’s hybrid foam materials like the DSM System.
Plaza Expansion Joint - FP-System (For Plaza) Handles Curves and Ties Into Waterproofing
In the case of Jet Blue, the deck design required the use of the Migutan-FP system for split-slab construction. This is because the roadways at airports are also roofs. The roofs are over the arrivals area. There is nothing worse after a long flight and all its hassles than to have to wait for your cab beneath the icy drips of leaks from above.
Airport departure roadways are usually designed as split-slabs with a buried waterproofing membrane on the structural deck and a topping slab as the wear course. Expansion joints used to isolate the roadways from the terminal building must be watertight. In order to be watertight, the joint must tie into the deck waterproofing membrane.
Migutan and other FP Systems are specifically designed to achieve this membrane incorporation. The principle of static integration of the FP System side flashing sheets into the deck waterproofing membrane is in total contrast to buried flashing sheets, loops, and “band-aid” systems that suffer from tensile stresses during extension movement and flex-fatigue at the joint edge. The integration into a sandwich of the deck waterproofing membrane material of the FP System side flashing sheets ensures watertightness while joint movement is accommodated by the elastomeric insert at the wear course surface.
Following the curve in the deck is no problem either. Working with EMSEAL’s technical staff, the contractor provided field measurements and condition surveys from which EMSEAL produced detailed shop drawings showing the configuration of the materials to handle the radius. The materials were manufactured and marked according to the shop drawings making installation straightforward and efficient.
In tighter radii, it is easy to envision EMSEAL’s precompressed foam sealants following the curve. However, even when watertight integration into a split-slab or plaza deck is required, an FP System can also fit the bill. A case in point are the concourse joints in the new DC Nationals baseball park. These joints run tangent to elliptical columns.
Factory Fabricated Expansion Joint Transitions Ensure Continuity of Seal
Templates made by the contractor for each column became the basis of shop drawings by EMSEAL. From the shop drawings and using the templates as a quality control check, unique curved expansion joint transitions were produced for each of the columns.
The curves were fabricated in all the metal Migutan components including mounting flanges, retainer legs, stainless steel capping strips, and coverplates, but also in all of the rubber components that ensure watertightness and continuity of seal. The rubber components include the side flashing sheets that integrate into a watertight sandwich with the deck waterproofing membrane, and in the central sealing insert that bridges the expansion joint opening.
Curved Expansion Joint - Possible, Practical, Routine
The bottom line is that through careful joint-gap sizing, material selection, field measurement, fabrication and installation, watertight, curved expansion joints and expansion joint transitions are both possible and practical, and for EMSEAL, routine.
Precompressed Foam Expansion Joint Sealant Handles Extremes at CN TOWER, Toronto, ON
The glass-fiber reinforced jacket around the radio mast of 1800-ft tall CN Tower required new joint gaskets. Colorseal by EMSEAL was used to seal the joints against extreme weather conditions including wind-driven rain and snow.
The closer to the tip of the tower, the tighter the radius. EMSEAL manufactured full-scale mockups of the tightest radii in order to advise what degree of notching in the back of the Colorseal would be required in order to bend the material to the curve.
Curved Expansion Joints in Facades
Colorseal in simple facade expansion joint detail radius–Metal panel to brick.
Curved Curtainwall Expansion Joints
Seismic Colorseal in lateral curve in window wall system.
Curved Tunnel to Curtainwall Expansion Joints
The joints between the wonderfully elliptical pedestrian tunnels and the flanking curtainwall of the TWA Hotel at JFK are not only curved but tapered as well. The only option for handling the complex geometry while also handling movement, insulation, waterproofing, and air-pressure differential requirements is a precompressed hybrid foam sealant. Read more about how Seismic Colorseal fit the bill in the TWA Hotel case study.
Curved Fire Rated RWS Tunnel Expansion Joints
The ability to manufacture custom curved expansion joint transitions is not limited to waterproofing alone. Here our Emshield TFR-RWS system was used to ensure that expansion joints in the SFRM-protected tunnel lining were protected in the event of a RWS-type fire event. The edges of the tunnel are curved. Emseal manufactured curved transition pieces to handle the radius without needing to field-notch the backside of the foam. Notching would have compromised the fire-resistance capability of the foam. Read more about this in the Calgary Aiport Trail case study.