Connectors, Anchors and Fasteners
Helical Restoration for a Historic Skyscraper
DryFix System provides cornerstone solution to restoring Detroit’s Broderick Tower
The Broderick Tower was one of Detroit’s earliest “skyscrapers” when it pierced the downtown skyline at Grand Circus Park in 1928. Originally named Eaton Tower, the building’s neoclassical architecture was a combination of Chicago school and Beaux-Arts design by famed architect Louis Kamper. The building was considered “a beauty by day, a jewel by night.” During the years, it went from being Michigan’s second-tallest skyscraper to being the third-tallest abandoned building in the United States.
Standing basically vacant, but preserved since the mid-1980s, the 34-story historic building is now part of a $53 million restoration project funded by Motown Construction Partners L.P. The effort is led by Fred Beal and his Detroit-based JC Beal Construction Inc., which is acting as construction manager. Detroit’s Kraemer Design Group and Akins Construction Inc. are serving as the architectural firm and assembly contractor, respectively, to restore this key component of the city’s skyline to its original prominence and luster as a luxury residential and office building with panoramic views of downtown Detroit’s commercial and entertainment district.
With construction beginning in March 2011 and a Grand Opening slated for September 2012, significant budget concerns existed regarding the methods of repair to the exterior restoration, in order to properly preserve and enhance the building’s core. Notably, the deteriorating exterior limestone corners of the building would have to be completely replaced at great cost. To make the numbers work, Akins Construction enlisted industrial masonry repair reinforcement system manufacturer Helifix Inc., located in Streetsboro, Ohio. Helifix would implement its patented DryFix remedial pinning and tying system to reconnect, stabilize, and provide retrofit strengthening to the existing damaged limestone corners for all 34 floors.
In key masonry applications ranging from suspension of struts for electrical and air systems to hardware for overhead piping and sprinkler systems, Bosch Stop Bits are designed to bring precision, speed and professionalism to a task once marked by guess work and drill bits marked with tape. Applications are designed to incorporate drop-in anchors.
A steel collar on each bit marks the precise depth of the hole. Once the collar is flush with the concrete surface, the correct depth is reached. Bosch offers a complete line of five carbide-tipped steel bits that include 3/8-, 1/2- and 5/8-inch sizes. Depths range from 13/16- to 2-1/16 inches. The size and depth range of the Bosch offering accommodates more than 80 percent of all requirements for drop-in anchors.
Bosch Stop Bits take the place of the manual depth gauge on rotary hammers, a feature many users disable. Drill bit maximum speed is 1,100 rpm. For more information, visit www.boschtools.com.
Meeting the challenge
During the projects’ initial inspection, at least two large pieces of limestone corners had fallen from the 18th floor during a storm, due to rusted anchoring and freeze-thaw water damage. The historic style and age of the building’s expansion joints in the corner limestone columns, where major “sway” movement occurs, made the need to remove and replace the limestone corners on all 34 floors of the historic tower seem imminent.
Given the project’s economical budget restraints, other methods of repair were explored. But Akins Construction contacted Helifix, whom they had used during the years for creative applications, to provide an alternative solution to replacing the large volume of loose terracotta and limestone on the building’s deep corners.
Helifix recommended its DryFix Remedial Tying system that offered a solution quickly approved by JC Beal and Kramer Design.
An answer found
Developed by Helifix during many years, the DryFix Remedial Tying System is described as a versatile and reliable remedial pinning and tying system. Quick and easy to install, it provides an effective, economical, stress-free connection between all commonly used building materials in both cavity and solid masonry constructions without needing any special grouts, resins or mechanical expansion.
DryFix remedial ties, together with their associated installation techniques and high-performance Helifix grouts, produce secure connections with brickwork, CMU blocks, stonework, concrete, marble, limestone, travertine, terracotta and timber. The system is embedded within the existing masonry to be fully concealed once installed. Because it’s generally installed into the existing masonry, expensive and time-consuming tear down and rebuild are avoided. Visual aesthetics of the structure are retained, which made the system a good candidate for The Broderick Tower exterior restoration project.
The slim profile DryFix remedial ties are precision engineered from 10mm austenitic grade (304) stainless steel. The formed stainless-steel wires offer a typical 0.2 percent proof stress of 500N/mm². But after the cold-forming manufacturing process, which creates the helical hi-fin design, this more than doubles to around 1100N/mm². This means that, with its relatively small diameter, the system provides substantial tensile properties to the masonry.
Additionally, DryFix ties may be used in hollow materials and close to edges. They are sufficiently flexible to permit normal masonry movement, are designed to shed water in cavity construction as well as provide strong, reliable axial restraint in both tension and compression.
|Starborn Industries Expands DECKFAST Epoxy Coated Line of Screws|
Starborn Industries Inc., a manufacturer and distributor of fasteners and related products for the building industry, has expanded the Deckfast line of screws for decks and exterior use. Deckfast epoxy coated screws now are available with a star recess in gray, green, red and tan, in addition to the green and gray square drive versions, which have been popular for years.
“Our company prides itself on listening to our customers’ needs and being on the cutting edge of fastener technology,” says Larry Crossley, VP of sales at Starborn Industries. “Over the past several years, star drive fasteners have grown in popularity and new colors of pressure treated lumber have been introduced. This is our way of addressing these changes to the decking market.”
Deckfast fasteners incorporate an epoxy-based polymer resin coating over zinc plate to provide excellent corrosion resistance in many types of decking, including ACQ treated lumber. They also feature reinforced flat heads with nibs to ensure greater strength and better countersinking, as well as an auger point for faster, easier entry.
The cornerstone application
In the case of The Broderick Tower, Helifix delivered the DryFix materials within 24 hours of approval and remained onsite to assist Akins Construction during the installation process. A variety of lengths and sizes (10 to 15 inches) of DryFix remedial ties were utilized to secure the loose terracotta and limestone on all four corners of the building’s 34 floors. This was done in addition to various re-anchoring throughout the remainder of the building.
Installation involved the simple power-driving of about four to six DryFix anchor ties per corner stone into position via a small pilot hole, using a special installation tool that leaves the end of the tie recessed below the outer face to allow an “invisible” finish. Since there was no sound back-up anchor stone available, the ties were anchored into adjacent limestone corners on each side for an optimal structural repair. High-performance Helifix polymer grout also was used in key areas to help increase the bond.
Helifix’s concealed, non-disruptive DryFix remedial tying system is on track for completion of The Broderick Tower’s Grand Opening in September 2012. Notably, none of the limestone corner columns needed removal, and ensuing pull-tests conducted on completed installations indicate optimal flexibility and movement during sway as the stones stay securely anchored.
“Other methods were explored to remove the limestone completely with new anchors to the back-up walls,” says Rich Akins, owner of Akins Construction. “Ultimately, Helifix’s DryFix solution provided the ability to restore, rather than replace, the limestone corners and saved Motown Construction Partners upward of approximately $1 million to the project’s exterior restoration budget.”
|Wedge Anchors for Cracked, Uncracked Concrete Expand Manasquan Product Line|
Manasquan Premium Fasteners, a provider of stainless steel fasteners to the residential, commercial and marine construction industries, has expanded its product line with the addition of Strong-Bolt 2 type 316 stainless steel wedge anchors by Simpson Strong-Tie.
The Strong-Bolt 2 represents the next generation solution for cracked and uncracked concrete. Rigorous testing according to ICC-ES acceptance criteria earned classification as a Category 1 anchor, the highest category for performance in cracked concrete under static and seismic loading. The anchor is code listed by ICC-ES under 2009 IBC requirements for post-installed anchors in cracked and uncracked concrete.
The Strong-Bolt 2 is available in several lengths in 3/8, 1/2-, 5/8- and 3/4-inch diameters. For more information, visit www.ManasquanFasteners.com.
Chris Watson works with Helifix Inc. and can be contacted at 630-219-8256 or firstname.lastname@example.org. View an animated DryFix demo video here: www.helifix.com/usa/products/dryfix_remedial_tying_system/dryfix_installation.aspx
CINTEC International’s Archtec bridge reinforcement system is a diagnostic design and installation service, utilizing sophisticated technology and drilling methods designed to strengthen masonry arch bridges, while maintaining historical integrity.
CINTEC says the Archtec process involves numerical modeling and simulation of the loading regime in order to specify a retrofitted reinforcing system. A computer model then determines the load carrying capacity. At the site, the CINTEC Anchor System is inserted into holes bored from either the road surface or beneath the bridge. Then a developed grout is injected, fusing with the mesh, expanding and shaping to fit the wall’s spaces. Archtec preserves the bridge’s historical features without impacting the natural environment. The Archtec reinforcement method can be completed with little traffic delays.