User:NKyoder/sandbox

Article Evaluation

Glass Brick

A. Most of the provided data seems to be up to date, though it was severely lacking in architectural history, details of manufacture, and any details on their structural effectiveness.

B. The article remained neutral in content and tone, (though the comments behind the scenes were surprisingly heated and terse.)

C. The article did not cite enough sources and Whole sections were missing citations, leading me to wonder if there was original research or personal opinion/observation involved.

D. As mentioned earlier, the conversations behind the scenes were adversarial, tending to focus on judgement of the people involved with writing the article, not the article itself. Frequent dismissal of article criticism was rampant.

E. The actual writing and flow of the article was good, despite the aforementioned omissions/deficiencies.

Question: Does anyone know more of the history of glass brick and would that be relevant to the article?

Cramp Anchor Citations

Stone Anchors glossary of stone terms wall ties Continental cast stone AISC Manual of Steel Construction: Allowable Stress Design (AISC 316-89) 9th edition, by Committee, AISC Manual published by American Institute of Steel Construction, 1989.

Facade Anchor/stone clip/stone anchor

a facade anchor is a metal fastener used to attach facade systems such as stone, terracotta or other paneling systems to the bearing wall of a building. A variety of facade anchors with various names have been used throughout history, such as straps, dovetails, rod cramp, rod anchor, and eyebolt and dowel. Traditionally, anchors were bolted into the bearing wall of a building, and held onto the facade material by rotating into continuous or localized slots called kerfs on the edges of said material.

historic stone and terracotta systems

modern facade systems?

materials and construction

see Stone_cladding

review possibilities in elliot.

Some Notes

Foulks, William G, Historic Building Facades: manual for maintenance and rehabilitation, (New York, Preservation press, 1997), P. 42-44.

Late 19th and early 20th centuriesload bearing walls regularly had stone facing that was non load bearing. With the development of tall buildings it became neccecary to try and decrease the thickness of walls to increase the hight for a proper ratio, façade materials began to be supported by a skeletal iron or steel structural frames. The frame supported the masonry load every story or so, and the cladding had to support it’s weight for that span, the load was then transferred into the frame. Stone walls today are almost always supported in this way. For walls with brick or concrete support in the back, cramp anchors are attached to every slab to attach stone to the backup. Dowels anchored stones to eachother. Portions of cornices or projections that did not fo too far could be supported by a counterweight from the stone above. Wiser projections could not be counterweighted or projected too far, it was attached to metal supports attached to the frame. Corrugated ties provided structural elements by wedging amale and female elements together with kerfs in te stone itself. The early development of high rise construction were addles with a lack of understanding that has created pathologies today. anchoring treatments,failure to let water pass out frodm the skin, and treatments of joints in the exterior wall Anchoring devices including cramps, dowels and ties were often made of unprotected iron or steel elements that rust and corrode resilting in cracking, spalling or façade failure. (today, they are made of protected or corrosion resistant materials.) Sometimes they misunderstood the the consequences of differing thermal qualities in the elements, thermal movement of large expanses of cladding itself, and joints of moratar which couldn’t absorb the movement and led to cracking. Today unmortared control joints are used to absorb the expansion in both vertical and horizontal directions, preventing restrained corners. Once a lack of proper flashing and weep holes allowing water in without an escape.

Lewis, Michael D., Modern Stone Cladding, Design and Installation of Exterior Dimension Stone Systems, (Philadelphia: ASTM, 1995), p. 8-18.

Theiron skeleton changed stone construction and allowed for cladding. Composite metal and masonry buildings allowed them to be built higher and with thinner walls allowing more floor space on the lower floors. A separate skin from the structural form developed. Each floor edge received peir and spandrel weights allowing masonry to not compound as it went down. Stones weight originally made it inideal in comparison to terracotta facades for it’s lightweight and fireproof nature, though eventually defects in terracotta façade systems became known and stone again rose to prominence as a cladding material for steel while windows expanded on buildings letting in more light. It became hung on the frame. Stanford Lovis patented a system of wrapping masonry, the first where a skeleton would support the weight of its own masonry. Eventuallt added masonry joints at the first floor as said above.

Camposinhos, Rui De Sousa, Stone Cladding Engineering, (New York, Springer, 2014),

Larger limestone slabs at least 10 cm thick began to be used in the 1920s The empire state building is a paradigm of this use, having two spandrels in steel at each floor, one inside for structural purposes, and one outside to accommodate the load of the stone veneer. The façade is a seriws of vertical bands of brick as a backing to a limestone veneer. The buildings veneer acts like a skin and takes the stress of wathering from human activity, pollution or weather. Direct or adhered fixing systems rely on a cement bonding of the entire back of the stone. The full connection does not allow for expansion and contraction to varying degrees between the substrate and the stone, causing cracking, spalling and failure. Leaving an air space between the cladding and the support wall allows any water or weathering that penetrates the façade to drain out and not get trapped in the buildings internal systems. Rain screen Common cuts made in stone for adhesion include small holes for dowel insertion, kerf cuts for angles or double t anchorages, slot cuts for disks with shanks Most common is the hole and dowell system suitable for vertical cladding systems for facades. Pins at the bottom take weight and pins at the top keep it from tipping at the top. Kerf system is a groove vut into the edge of a stone panel a kerf bar is a bar or plate that is fashioned to fit into the slot and connect t o the structure behindnormally extruded steel or aluminum profiles. Undercut anchoring system uses an expansion bolt or cone that is inserted into an undercut slot and the pressure of the bolt being wound in the hole causes metal to expand and fill the hole, thereby locking the stone to the bolt.

In the Late 19th and early 20th centuries non-load Bearing stone veneers were regularly affixed to load bearing walls behind. As buildings began to grow taller with the advent of steel skeletal framing It became necessary diminish the thickness and weight of masonry walls in order to withstand the dead weight of a load bearing masonry wall. Without steel supports, load bearing walls could grow several meters thick on their lowest stories. A solution employed in the construction of early skyscrapers was the use of a steel structural frame that supported exterior stone walls at every floor, thereby distributing the load into the skeletal frame. This avoided the gradual buildup of weight that resulted in inconveniently thick lower walls.

Systems
There are a variety of systems for attaching stone veneers to facades including direct fixing, hole and dowel, kerf, and undercut anchoring systems. The direct or adhered fixing system relies on a mortar or cement bonding between the substrate wall and the backside of the stone veneer. This application is generally used indoors as exterior weathering and temperature extremes cause the veneer to crack and spall. The complete connection between the veneer and substrate does not account for differing rates of expansion and contraction between materials, causing them to bind under pressure. Most exterior veneer systems hang stone from a support wall by pins and anchors allowing air space between, essentially using stone as a rain screen. These systems are superior for exterior use because they permit any water that permeates the veneer to escape, and the air space allows the materials of the supporting substrate wall to expand and contract at different rates to those of the veneer. The hole and dowel system is one such method of hanging veneer. The system relies on holes drilled into the sides of stone panels in which metal dowels are inserted. The dowels are connected to a shank that is in turn connected to the load bearing wall or steel frame behind. Kerf systems operate in much the same way with different metal hardware. The kerf system uses grooves cut into the edges of stone veneer panels in which kerf plates are inserted, those plates are mounted to the wall behind and act much like a shelf on which the stone panel rests. Bo the hole and dowel and Kerf systems can be attached to the top, bottom and sides of each panel ensuring a secure hold and binding the panels together to make a complete veneer. A fourth and somewhat less common anchoring system is the Undercut anchoring system which uses an expansion bolt or cone inserted into an undercut hole. Pressure from turning the bolt causes metal to expand in the hole, thereby locking the bolt to the stone, which is in turn attached to the supporting wall behind.