Static structures (e.g. – buildings) – Laterally related – individually assembled courses – Utilizing discrete dissimilar material tie
Reexamination Certificate
2002-09-03
2003-12-30
Glessner, Brian E. (Department: 3635)
Static structures (e.g., buildings)
Laterally related, individually assembled courses
Utilizing discrete dissimilar material tie
C052S379000, C052S568000, C052S713000
Reexamination Certificate
active
06668505
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to improved anchors and reinforcements for masonry backup walls that serve cavity wall constructs with larger-than-normal cavities between the masonry backup wall and the facing brick veneer. More particularly, the invention relates to cavity walls requiring novel anchoring systems for spanning such cavities and, further to the use of resistance-welded, wire formatives to meet existing wind shear and seismic specifications.
2. Description of the Prior Act
Recently, there have been significant shifts in public sector building specifications which have resulted in architects and architectural engineers requiring larger and larger cavities in the exterior cavity walls of public buildings. These requirements are imposed without corresponding decreases in wind shear and seismic resistance levels or increases in mortar bed joint height. Thus, wall anchors are needed to occupy the same ⅜-inch-high space in the inner wythe and tie down a veneer facing material of an outer wythe at a span of two or more times that which had previously been experienced.
Exemplary of the public sector building specification is that of the Energy Code Requirement, Boston, Mass. (see Chapter 13 of 780 CMR, Seventh Edition). This Code sets forth insulation R-values well in excess of prior editions and evokes an engineering response opting for thicker insulation and correspondingly larger cavities. Here, the emphasis is upon creating a building envelope that is designed and constructed with a continuous air barrier to control air leakage into or out of conditioned space adjacent the inner wythe.
Another application for high-span anchoring systems is in the evolving technology of self-cooling buildings. Here, the cavity wall serves additionally as a plenum for delivering air from one area to another. While this technology has not seen wide application in the United States, the ability to size cavities to match air moving requirements for naturally ventilated buildings enables the architectural engineer to now consider cavity walls when designing structures in this environmentally favorable form.
In the past, the use of wire formatives have been limited by the mortar layer thicknesses which, in turn are dictated either by the new building specifications or by pre-existing conditions, e.g. matching during renovations or additions the existing mortar layer thickness. While arguments have been made for increasing the number of the fine-wire anchors per unit area of the facing layer, architects and architectural engineers have favored wire formative anchors of sturdier wire. On the other hand, contractors find that heavy wire anchors, with diameters approaching the mortar layer height specification, frequently result in misalignment. Thus, these contractors look towards substituting thinner gage wire formatives which result in easier alignment of courses of block.
In the past, there have been investigations relating to the effects of various forces, particularly lateral forces, upon brick veneer construction having wire formative anchors embedded in the mortar joint of anchored veneer walls. The seismic aspect of these investigations were referenced in the first-named inventor's prior patents, namely, U.S. Pat. Nos. 4,875,319 and 5,408,798. Besides earthquake protection, the failure of several high-rise buildings to withstand wind and other lateral forces has resulted in the incorporation of a requirement for continuous wire reinforcement in the Uniform Building Code provisions. The first-named inventor's related Seismiclip
R
and DW-10-X
R
products (manufactured by Hohmann & Barnard, Inc., Hauppauge, N.Y. 11788) have become widely accepted in the industry. The use of a wire formative anchors and reinforcement wire structures in masonry walls has been shown to protective against problems arising from thermal expansion and contraction. Also, such structures have improved the uniformity of the distribution of lateral forces. However, these past investigations do not address the mortar layer thickness vs. the wire diameter of the wire formative or the technical problems arising therefrom.
Over time and as the industry matured, besides the Uniform Building Code other standards came into existence, including the promulgation by the ASTM Committee A01 on Steel of the Standard Specifications for Masonry Joint Reinforcement, A951-00 (hereinafter A951). The Standard sets forth that masonry joint reinforcement is to be assembled by automatic machines to assure accurate spacing and alignment of all members of the finished product and that longitudinal and cross wires are to be securely connected at every intersection by an electric-resistance welding process that includes fusion welding together with applied pressure to join the materials. The Standard further sets forth details as to the exterior of the longitudinal wires and the mechanical requirements of the overall construct.
According to the ASTM Committee A01, joint reinforcement has been used in the masonry industry since 1940. In introducing A951, the Committee states:
For most of the period since then, its manufacture has been limited to a relatively small group of producers and users who simply referred to “manufacturers' recommendations” as the standard of quality and acceptance. With the adoption of a new consensus standard for the design of masonry, it became clear that a standard for the manufacture of joint reinforcement was needed. In developing this standard it was decided to use a format similar to that used for the ASTM Standard for Welded Wire Fabric, Plain, for Concrete Reinforcement, Specification A185, since many people had the notion that joint reinforcement was used in a manner similar to wire mesh. A significant difference between wire mesh and joint reinforcement arose when an attempt was made to fashion the requirements for weld shear strength after those in Specification A185.
The Committee found that almost all of the manufacturers of joint reinforcement use butt welds so that the total thickness of material at a weld is as small as possible. This is important since, in conventional mortar bed joints, there is not much room to install joint reinforcement. In addition, it found that in masonry joint reinforcement the majority of product produced is that with a “truss” configuration in which the angle of intersection varies for each different width of product produced since the pitch between welds is a constant 16 inches. These characteristics differentiated the testing for weld shear strength from those of Specification A185 and resulted in the development of a distinct test methodology.
In the course of preparing this disclosure several patents became known to the inventors hereof. The following patents are believed to be relevant and are discussed further as to the significance thereof:
Patent
Inventor
Issue Date
3,377,764
Storch
04/16/1968
4,021,990
Schwalberg
05/10/1977
4,373,314
Allan
02/15/1983
4,473,984
Lopez
10/02/1984
4,869,038
Catani
09/26/1989
4,875,319
Hohmann
10/24/1989
5,392,581
Hatzinikolas et al.
02/28/1995
5,408,798
Hohmann
04/25/1995
5,456,052
Anderson et al.
10/10/1995
5,816,008
Hohmann
10/15/1998
6,209,281
Rice
04/03/2001
6,279,283
Hohmann et al.
08/28/2001
It is noted that with some exceptions these devices are generally descriptive of wire-to-wire anchors and wall ties and have various cooperative functional relationships with straight wire runs embedded in the inner and/or outer wythe.
U.S. Pat. No. 3,377,764—D. Storch—Issued Apr. 16, 1968
Discloses a bent wire, tie-type anchor for embedment in a facing exterior wythe engaging with a loop attached to a straight wire run in a backup interior wythe.
U.S. Pat. No. 4,021,990—B. J. Schwalberg—Issued May 10, 1977
Discloses a dry wall construction system for anchoring a facing veneer to wallboard/metal stud construction with a pronged sheetmetal anchor. Like Storch '764, the wall tie is embedded in the exterior wythe and is not attached to a straight wire run.
U.S. Pat. No. 4,
Hohmann Ronald P.
Hohmann, Jr. Ronald P
Hohmann & Barnard, Inc.
Silber, Esq. Siegmar
LandOfFree
High-span anchors and reinforcements for masonry walls does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with High-span anchors and reinforcements for masonry walls, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High-span anchors and reinforcements for masonry walls will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3110063