What is an isotropic deck?
An isotropic bridge deck is composed of an arrangement of reinforcement in which the bars are the same size and spaced equally in both the transverse and longitudinal directions.
Which type of wearing surface is least used on timber decks?
Partial wearing sur faces
Partial wearing sur faces offer the least protection and frequently result in deck wear from vehicle off-tracking (Figure 11-2). In addition to protection from vehicle damage, the wearing surface should protect the deck from moisture and weathering effects.
What’s the meaning of orthotropic?
Definition of orthotropic 1 : having the longer axis more or less vertical — compare plagiotropic. 2 : being, having, or relating to properties (such as strength, stiffness, and elasticity) that are symmetric about two or three mutually perpendicular planes a piece of straight-grained wood is an orthotropic material.
What is a concrete wearing surface?
This work consists of placing a concrete wearing surface, to the specified thickness, on precast concrete members such as deck beams and deck panels. Included in this work is cleaning and preparing the precast concrete surface prior to placement of the concrete wearing surface.
What are bridge planks made of?
Glulam, which is the most widely used modem timber bridge material, is manufactured by bonding sawn lumber lamina tions together with waterproof structural adhesives. Thus, glulam members are virtually unlimited in depth, width, and length and can be manufac tured in a wide range of shapes.
What is the difference between anisotropic and orthotropic?
The key difference between orthotropic and anisotropic materials is that orthotropic materials show similar results when similar stimuli are applied in only three mutually perpendicular directions whereas anisotropic materials show different results when similar stimuli are applied in all possible directions.
What is the difference between an orthotropic and transversely isotropic material?
Orthotropic materials show values for properties at a particular point in an object rather than the whole object. But if the object is homogenous, the values measured can be the same. Transversely isotropic materials are orthotropic materials that have only one axis of symmetry.
What is the advantage of using steel deck?
Using steel and roof deck/Resindek® can lower a project’s overall cost and use fewer materials, and many times other materials are more durable than concrete and more flexible with their application. There are also construction and installation concerns with a concrete deck system.
What type of deck consists of a flat thin steel plate stiffened by a series of closely spaced longitudinal ribs?
Originally developed in Germany, the OSD system generally consists of a flat, thin steel plate that is stiffened by a series of closely spaced longitudinal ribs and transverse floor beams.
What are the different types of wearing surfaces?
There are four basic types of wear: adhesive, abrasive, corrosive, and surface-fatigue.
What is non wearing surface?
Non-wearing surface means any non-road surface that has an incline greater than twenty (20) percent, including, but not limited to, the use of riprap, road cuts, or soil stabilization.
What is glulam construction?
Glulam is a stress-rated engineered wood beam composed of wood laminations, or “lams”, that are bonded together with durable, moisture-resistant adhesives. The grain of the laminations runs parallel with the length of the member. Glulam is versatile, ranging from simple, straight beams to complex, curved members.
What size are bridge timbers?
Bridge/Railroad Lumber
| WCDF: | 3″ x 12″ | 8′ through 34′ #2 and better |
|---|---|---|
| 8″ x 16″ | Through 30′ #1 and better, select structural | |
| 12″ x 12″ | Through 40′ #1 and better, select structural | |
| 14″ x 14″ | Through 40′ #1 and better, select structural | |
| Piling: | 20′ through 50′ | Southern Yellow Pine |
What is orthotropic steel decking?
The San Mateo Hayward orthotropic steel deck uses 3/4″ deck plate or 5/8″ deck plate with open or flat plate ribs. The original wearing surface installed in October 1967 is still in use – that’s 48 years of service life! Steel orthotropic decks can either be integral with the main girders or be a decking system supporting the steel superstructure.
What is an orthotropic bridge?
An orthotropic bridge or orthotropic deck is typically one whose fabricated deck consists of a structural steel deck plate stiffened either longitudinally with ribs or transversely, or in both directions. This allows the fabricated deck both to directly bear vehicular loads and to contribute to the bridge structure’s overall load-bearing behaviour.
What are the limitations of orthotropic decking?
Resistance to use of an orthotropic deck relates mainly to its cost of fabrication, due to the amount of welding involved. In addition, it must be prefabricated rather than assembled on site, which offers less flexibility than in-situ concrete decks.
How many orthotropic steel deck bridges are in the US?
More than 1,000 orthotropic steel deck railroad bridges exist in Europe, with most utilizing flat-plate orthotropic ribs. In the United States, four BART (Bay Area Rapid Transit) weathering steel superstructures with weathering steel deck systems have been in service since 1972 in the San Francisco, California area.