Tuesday, January 17, 2012

Staad Analysis

Staad Examples

This Staad book covers the following topics

Introduction
ProjectWise Integration
Features Affecting the Pre-Processor (Modeling Mode)
ASME NF Steel Design Codes
Floor Response Spectrum
Russian Wind Loading
Additional Standard Profile Databases
Features Affecting the Analysis and Design Engine
Time History Animation
Enhanced Plate Stress Results

ProjectWise Integration
Purpose
ProjectWise is an engineering project team collaboration system which is used to help
teams improve quality, reduce rework, and meet project deadlines. One of the major
pieces of functionality provided by ProjectWise is an Integration Server which allows
data to be managed and shared across a distributed enterprise.
STAAD.Pro has been enhanced so that the model STD data file can be managed on a
ProjectWise server.

Description
Four integration functionalities have been added. These are

• Open a STAAD model from a ProjectWise repository.
• Save a local STAAD model into a ProjectWise repository.
• Update an existing model from ProjectWise.
• Review model properties (meta-data) which has been opened from a
ProjectWise repository.

Note that access to all of these functionalities is available from ProjectWise sub-menu
under the general File menu described below.

ProjectWise repository
Installation and management of a ProjectWise server is beyond the scope of this
document and should be obtained from the ProjectWise installation.

ProjectWise client
A local ProjectWise client should be installed which allows access to ProjectWise
repositories.


STAAD.Pro ...... to see more download the following book

Download Staad Analysis
http://www.docstoc.com/docs/111051358/Staad-Pro-User-book

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Staad Example

Staad Pro Tutorials
Solved Example Using Staad Pro.
Here is what you can get step by step solved example of analysis and design using staad.

Download Staad Pro solved example
http://www.docstoc.com/docs/32106588/Using-Staad-Pro--httpmosttutorialsblogspotcom

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Sunday, January 15, 2012

What is Post Tensioning

Post Tensioning
Post-tensioning is a method of reinforcing (strengthening) concrete or other materials with high-strength steel strands or bars, typically referred to as tendons. Post-tensioning applications include office and apartment buildings, parking structures, slabs-on-ground, bridges, sports stadiums, rock and soil anchors, and water-tanks. In many cases, post-
tensioning allows construction that would otherwise be impossible due to either site constraints or architectural requirements.
Although post-tensioning systems require specialized knowledge and expertise to fabricate, assemble and install, the concept is easy to explain. Imagine a series of wooden blocks with holes drilled through them, into which a rubber band is threaded. If one holds the ends of the rubber band, the blocks will sag. Post-tensioning can be demonstrated by placing wing nuts on either end of the rubber band and winding the rubber band so that the blocks are pushed
tightly together. If one holds the wing nuts after winding, the blocks will remain straight. The tightened rubber band is comparable to a post-tensioning tendon that has been stretched by hydraulic jacks and is held in place by wedge-type anchoring devices.

BENEFITS
To fully appreciate the benefits of post-tensioning, it is helpful to know a little bit about concrete. Concrete is very strong in compression but weak in tension, i.e. it will crack when forces act to pull it apart. In conventional concrete construction, if a load such as the cars in a
parking garage is applied to a slab or beam, the beam will tend to deflect or sag. This deflection will cause the bottom of the beam to elongate slightly. Even a slight elongation is usually enough to cause cracking. Steel reinforcing bars (“rebar”) are typically embedded in the
concrete as tensile reinforcement to limit the crack widths. Rebar is what is called “passive” reinforcement however; it does not carry any force until the concrete has already deflected enough to crack. Post-tensioning tendons, on the other hand, are considered “active” reinforcing. Because it is pre stressed, the steel is effective as reinforcement even
though the concrete may not be cracked. Post-tensioned structures can be designed to have minimal deflection and cracking, even under full load

DVANTAGES/APPLICATIONS
There are post-tensioning applications in almost all facets of construction. In building construction, post-tensioning allows longer clear spans, thinner slabs, fewer beams and
more slender, dramatic elements. Thinner slabs mean less concrete is required. In addition, it means a lower overall building height for the same floor-to-floor height. Post-
tensioning can thus allow a significant reduction in building weight versus a conventional concrete building with the same number of floors. This reduces the foundation load and can
be a major advantage in seismic areas. A lower building height can also translate to considerable savings in mechanical systems and fa├žade costs. Another advantage of
post-tensioning is that beams and slabs can be continuous, i.e. a single beam can run continuously from one end of the building to the other. Structurally, this is much more efficient
than having a beam that just goes from one column to the next. Post-tensioning is the system of choice for parking structures since it allows a high degree of flexibility in the column lay-
out, span lengths and ramp configurations. Post-tensioned parking garages can be either stand-alone structures or one or more floors in an office or residential building. In areas
where there are expansive clays or soils with low bearing capacity, post-tensioned slabs-on-ground and mat foundations reduce problems with cracking and differential settlement. Post-tensioning allows bridges to be built to very demanding geometry requirements, including complex curves, variable superelevation and significant grade changes. Post-tensioning also allows extremely long span bridges to be constructed without the use of temporary intermediate supports. This minimizes the impact on the environment and avoids disruption to water or road traffic below. In stadiums, post-tensioning allows long clear spans and very creative architecture. Post-tensioned rock and soil anchors are used in tunneling and slope stabilization and as tie-backs for excavations. Post-tensioning can also be used to produce virtually crack-free concrete for water-tanks.

TERMINOLOGY
A post-tensioning "tendon" is defined as a complete assembly consisting of the anchorages, the prestressing strand or bar, the sheathing or duct and any grout or corrosion-inhibiting coating (grease) surrounding the prestressing steel. There are two main types of post-
tensioning: unbonded and bonded (grouted). An unbonded tendon is one in which the prestressing steel is not actually bonded to the concrete that surrounds it except at the anchorages. The most common unbonded systems are monostrand (single strand) tendons, which are used in slabs and beams for buildings, parking structures and slabs-on-ground. A monostrand tendon consists of a seven-wire strand that is coated with a corrosion-inhibiting
grease and encased in an extruded plastic protective sheathing. The anchorage consists of an iron casting and a conical, two-piece wedge which grips the strand.In bonded systems, two or more strands are inserted into a metal or plastic duct that is embedded in the concrete. The
strands are stressed with a large, multi-strand jack and anchored in a common anchorage device. The duct is then filled with a cementitious grout that provides corrosion protection to the strand and bonds the tendon to the concrete surrounding the duct. Bonded systems are more commonly used in bridges, both in the superstructure (the roadway) and in cable-stayed bridges, the cable-stays. In buildings, they are typically only used in heavily loaded beams such as transfer girders and landscaped plaza decks where the large number of strands required makes them more economical. Rock and soil anchors are also bonded systems but the
construction sequence is somewhat different. Typically, a cased hole is drilled into the side of the excavation, the hillside or the tunnel wall. A tendon is inserted into the casing and then the casing is grouted. Once the grout has reached sufficient strength, the tendon is stressed. In slope and tunnel wall stabilization, the anchors hold loose soil and rock together; in excavations they hold the wood lagging and steel piles in place.

CRITICAL ELEMENTS
There are several critical elements in a post-tensioning system. In unbonded construction, the plastic sheathing acts as a bond breaker between the concrete and the prestressing
strands. It also provides protection against damage by mechanical handling and serves as a barrier that prevents moisture and chemicals from reaching the strand. The strand coating material reduces friction between the strand and the sheathing and provides additional corrosion protection. Anchorages are another critical element, particularly in unbonded systems. After the concrete has cured andobtained the necessary strength, the wedges are inserted nside the anchor casting and the strand is stressed. When the jack releases the strand, the strand retracts slightly and pulls the wedges into the anchor. This creates a tight lock on the strand. The wedges thus maintain the applied force in the tendon and transfer it to the surrounding concrete. In corrosive environments, the anchorages and exposed strand tails are usually covered with a housing and cap for added protection.

CONSTRUCTION
In building and slab-on-ground construction, unbonded tendons are typically prefabricated at a plant and delivered to the construction site, ready to install. The tendons are laid out in the forms in accordance with installation drawings that indicate how they are to be spaced, what their profile (height above the form) should be, and where they are to be stressed. After the concrete is placed and has reached its required strength, usually between 3000 and 3500 psi (“pounds per square inch”), the tendons are stressed and anchored. The tendons, like rubber bands, want to return to their original length but are prevented from doing so by the anchorages. The fact the tendons are kept in a permanently stressed (elongated) state causes a compressive force to act on the concrete. The compression that results from the post- tensioning counteracts the tensile forces created by subsequent applied loading (cars, people, the weight of the beam itself when the shoring is removed). This significantly increases the load-carrying capacity of the concrete. Since post-tensioned concrete is cast in place at the job site, there is almost no limit to the shapes that can be formed. Curved facades, arches and complicated slab edge layouts are often a trademark of post-tensioned concrete structures. Post-tensioning has been used to advantage in a number of very aesthetically designed bridges.

ENSURING QUALITY CONSTRUCTION
The amount of post-tensioning strand sold has almost doubled in the last ten years and the post-tensioning industryis continuing to grow rapidly. To ensure quality construction,
the Post-Tensioning Institute (PTI) has implemented both a Plant Certification Program and a Field Personnel Certification Training Course. By specifying that the plant and the installers be PTI certified, engineers can ensure the level of quality that the owner will expect. PTI also publishes technical documents and reference manuals covering various aspects of post-tensioned design and construction.

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Monday, January 9, 2012

Using Staad Pro

Analysis and Design Using Staad Pro

Step by Step example for analysing and designing a beam and structure using staad pro

Analysis and Design of Structure using Staad
http://www.docstoc.com/docs/32106588/Using-Staad-Pro--httpmosttutorialsblogspotcom

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Tekla Structure Integration into Analysis Softwares

Tekla Structure Integration with Different Structure Analysis Softwares

Integration between Tekla Structures and STAAD improve the workflow in the design phase at engineering
offices. The modeling of the physical structure starts in Tekla Structures, whereas the engineer will achieve an
understanding about how the structure is put together. With loads, support conditions and other analysis
properties set up in Tekla Structures, the model can then be analyzed in STAAD. After analysis in STAAD, the data results, for example section property changes are automatically integrated back into Tekla Structures model.As project changes occur, the updated Tekla Structures model can be re-analyzed and incorporated into STAAD at any time, while changes from STAAD can re-update the Tekla model and engineering drawings.The integration between Tekla Structures and STAAD is done through standard Open Application Programming Interfaces (API) that enables roundtrip functionality and good maintainability of the integrated workflow.

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http://www.4shared.com/office/E0NyNAkA/Tekla_Structure_analysis__desi.html

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Sunday, January 8, 2012

Facial Expression Using Morpher in 3D Studio max

Facial Expression Using Morpher in 3D Studio max

Introduction

Various setups and rigs are there for lip sync and facial expression .The easiest way to create a set of predefined facial expressions based on morpher modifier can be applied to animate moods and lip synchronization is explained in this tutorial.
Head Setup for Facial Expression

Most models are modeled half to create a perfect symmetry .The symmetry modifier is efficient in this way .However the edge of the model should be aligned to grid to be efficient as well as to prevent mistake when welded with its true center .Lastly it is to allow the rigger to paint weights correctly .The symmetry modifier should not be collapse unless both sides of the face intended to be different .In most cases due to complex facial setups,mirror modifiers and symmetry will collapse.We will retain modifier for this small setups



Next Clone the head to several other models.These other models are used to create
different features for expressions or lip sync.The several heads will be modeled to desired features.Keep the original head unchanged.Few examples that are interesting to work on are eyelids,a smiling faze and angry face.

When you tweak the clone models,keep in mind how facial muscles move.An example would be a smiling face.When the mouth twiched into a smile,the muscles will affect the cheeks and slowly ,easing off to the temples.One good practice is to observe muscle reactions by acting in front of a mirror.That way you will get most of the features right.Once you are satisfied with your facial features,we will move on to add these expressions to your original head.

In The modifier list dropdown window,select Orpher,In Morpher,there are sub categories or channel color legend,Global Parameters,Channel List,Channel Parametere and Advance Parameters.

Creating A series of FAcial Feature/Expressions
The empty slots are used to assign the tweaked models.

  • Select the first empty slot.
  • Click Pick Object from Scene
  • Select the model with the expression
If you model has a complex expression (example might be having a series of different laughs),then you need to pick the entire series and tweak the expressions and assign it to the selected slot.It will show the different models in the Target List.
  • To check the toplogy of the morph targets(s) that are assigned to the Original head ,increase the number in the parameter feld of the selected slot.
  • Repeat for other facial expressions

If the model did not morph into the expression that was assigned after keying the parameters ,check the Target List Under Progressive Morph.If there is nothing in the list,it means no tweaked model has been assigned to the selected slot.
You may also want to change the Spinner Increments to 0.1 If you want the animation to be smoother or more subtle.
A good work habit for recommendation is to save the heads to a separate MAX file after you are done as you can delete the heads in the scene without compromising the effects.However,It will be quite hazardous if you did not keep a copy of the clones hould you have a need to change or tweak them.

After you deleted the clone models,the slot activation color will be changed from green to blue.The heas is now ready for animation,An important thing to note is that if you adjust the othere parameter of the morph slot without first zeroing offthe previous parameter,the deformation will stack.It simply meant that if you animate your character to smile and decide to hange it to an angry expression ,you should key your smile slot backt to zero before keying the angry slt to hundred.It is because your angry model deformation will add to the smile deformation model,causing it to deform frther if you did not zero out the parameters correctly.


Lastly ,in order to attact the head back to the body ,edit poly modifer has to be added to attact and weld the body vertices back to its original state




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