Seismic provisions in current model building codes and standards include rules for
design of structures using nonlinear response-history analysis, which are based, in
large part, on recommendations for analysis of seismically isolated structures from
more than 20 years ago. Unfortunately, there is currently no consensus in the
earthquake engineering community on how to appropriately select and scale
earthquake ground motions for code-based design and seismic performance
assessment of buildings using nonlinear response-history analysis.
This report provides guidance to design professionals on selection and scaling of
ground motions for the purpose of nonlinear response-history analysis. Gaps in the
current knowledge related to selecting and scaling ground motions for seismic design
and performance assessment are identified, and relevant provisions in current and
recent ASCE/SEI Standards are explained and clarified.
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
-Supports a rich expression format, which is in most cases identical to what you would type in your programming language.
-Support for adding unlimited numbers of variables.
-Built-in debugger that lets you see the expression simplified step by step.
-Debugger Back-step lets you backup as many steps as you like so that you can replay critical operations.
-C/C operator precedence
-Mouse optional, all calculator commands and functions can be done using the keyboard alone.
-Mini-Calc Mode lets your calculator take up very little screen real estate, and yet remain entirely usable.
-Numerous built-in unit conversions (memory sizes, lengths, areas, volumes, temperatures etc.)
-Built-in great circle route and straight line distance calculators.
Input/Output Formats:
-Binary, Octal, Decimal, Hexadecimal, Booleans, Characters, UTF-8 (out only), and UTF-16 (out only)
-Convert automatically between these types in your expression with the keyboard, a button, or a contextual menu.
Operators and Functions:
-Standard: Addition, Subtraction, Multiplication, Division, Modulus, Power, Square Root
-Grouping: Parenthesis
-Variables: Previous Answer
-Bitwise: complement, and, or, xor, shift left, shift right
-Comparators: equals, less than, greater than, less than or equal, greater than or equal
-Logical: and, or, and not
-Logarithms: Natural logarithm, log base 10, log base e, e raised to x
-Trigonometric: Sine, Cosine, Tangent, Hyperbolic-Sine, Hyperbolic-Cosine, Hyperbolic-Tangent, Arc-Sine, Arc-Cosine, Arc Tangent (2 Variants), Degrees To Radians, Radians to Degrees
-Other: Min, Max, Round, Ceiling, Floor, Absolute Value, Sign, Random
What users are saying:
• I use iota-calc pretty much on a daily basis to plan out calculations for programming tasks I have. I also use it when helping my son with his homework. -- Steve Mayer
• Very, very useful little app, well worth the money the author is asking for! -- ScottM review of Mac OS X version on MacUpdate com
• This is a very nice and unique calc, and they are steadily improving it. I'm giving it a five for current usability, improvements, and a GREAT price. Get it now, before demand drives up the cost. -- MikeyK review of Mac OS 8/9 version on VersionTracker com
Private Note:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
This document was produced by CDM Smith Inc. (CDM Smith) under a Cooperative Research and Development Agreement (CRADA) with the U.S. Environmental Protection Agency (EPA). It has been subjected to EPA’s peer and administrative review and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
The statutes and regulations described in this document may contain legally binding requirements. Neither the summaries of those laws provided here nor the approaches suggested in this document substitute for those statutes or regulations, nor are these guidelines themselves any kind of regulation. This document is intended to be solely informational and does not impose legally binding requirements on EPA; U.S. Agency for International Development (USAID); other U.S. federal agencies, states, local, or tribal governments; or members of the public.
Any EPA decisions regarding a particular water reuse project will be made based on the applicable statutes and regulations. EPA will continue to review and update these guidelines as necessary and appropriate.
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
This report documents a research investigation on connection details and bracing layouts for stability bracing of steel bridges with skewed supports. Cross-frames and diaphragms play an important role in stabilizing steel girders, particularly during construction. The commonly used bent plate connection between skewed braces and steel girders can introduce flexibility that can have detrimental effects on the bracing behavior. An alternative detail investigated in this study is a split pipe stiffener used to connect cross-frames to girders at a skew. The split pipe stiffener allows perpendicular connections to the cross-frame connection tab, regardless of the skew angle. The split pipe provides a stiffer connection between the cross-frame and the girder. More importantly, the split pipe stiffener increases the torsional stiffness of the girder by introducing substantial warping restraint. This increases the lateral torsional buckling capacity of the girder and allows the first line of intermediate cross-frames to be moved farther from the support. Overall, the increase in girder torsional stiffness and buckling capacity that results from the use of the split pipe stiffener will enhance the safety of the girder at all stages of construction: during transportation, lifting, erection, and placement of the concrete deck. This study also examined layout patterns for intermediate cross-frames in skewed bridges. Results showed that staggering the intermediate cross-frames reduces live load induced forces in the cross-frame members and mitigates the potential for associated fatigue cracking. This report also provides design recommendations for the split pipe stiffener and provides a procedure for computing the buckling capacity of girders with split pipe stiffeners.
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
Behavior of Field-Cast Ultra-High Performance Concrete Bridge Deck Connections Under Cyclic and Static Structural Loading
Author: Graybeal, Benjamin A | Size: 4.56 MB | Format:PDF | Quality:Original preprint | Publisher: Federal Highway Administration | Year: 2010 | pages: 116
The use of modular bridge deck components has the potential to produce higher quality, more durable bridge decks; however, the required connections have often proved lacking, resulting in less than desirable overall system performance. Advanced cementitious composite materials whose mechanical and durability properties far exceed those of conventional concretes present an opportunity to significantly enhance the performance of field-cast connections thus facilitating the wider use of modular bridge deck systems. Ultra-high performance concrete (UHPC) represents a class of such advanced cementitious composite materials. Of particular interest here, UHPCs can exhibit both exceptional bond when cast against previously cast concrete and can significantly shorten the development length of embedded discrete steel reinforcement. These properties allow for a redesign of the modular component connection, facilitating simplified construction and enhanced long-term system performance. This study investigated the structural performance of field-cast UHPC connections for modular bridge deck components. The transverse and longitudinal connection specimens simulated the connections between precast deck panels and the connections between the top flanges of deck-bulb-tee girders, respectively. Testing included both cyclic and static loadings. The results demonstrated that the field-cast UHPC connection facilitates the construction of an emulative bridge deck system whose behaviors should meet or exceed those of a conventional cast-in-place bridge deck. This report corresponds to the TechBrief titled “Field-Cast UHPC Connections for Modular Bridge Deck Elements” (FHWA-HRT-11-022).
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
Large numbers of reinforced concrete deck girder bridges that were constructed during the interstate system expansion of the 1950s have developed diagonal cracking in the stems. Though compliant with design codes when constructed, many of these bridges have flexural steel bars that were cut off short of the full length of the girders. When load-rating these structures, the current design specification check of tension reinforcement anchorage often controls the capacity of these bridges. The tensile force demand is controlled by the load-induced moment and shear, the number of stirrups, and the diagonal crack angle; however, little information is available regarding bond stresses developed with larger-diameter bars for full-size specimens in the presence of diagonal cracks. This research used large-size specimens to investigate the influence of diagonal cracks near flexural cutoff locations on the behavior and strength of vintage reinforced concrete girders. Testing indicated that a diagonal crack crossing the development length of cutoff longitudinal bars may not necessarily control specimen failure. Analysis showed that the required tensile demand at a diagonal crack location as predicted by AASHTO LRFD was reasonable. Two analytical methods and a non-linear finite element method were investigated for predicting the failure mode and capacity of the laboratory beams. A procedure was developed to rate existing bridges for flexural anchorage requirements around cutoff locations. Cracking characteristics indicative of flexural reinforcement slippage were defined for bridge inspection.
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
Author: Groenier, James Scott | Size: 39.25 MB | Format:PDF | Quality:Original preprint | Publisher: Department of Agriculture | Year: 2011 | pages: 108
Trail bridges not only provide convenient access to the national forests for hikers or packstock, but also can protect fragile riparian ecosystems. But. trail bridges can be difficult—in some cases, dangerous—to build. This report includes the results of controlled tests and case studies of field installations of fiber-reinforced polymer bridges. Fiber-reinforced polymer trail bridges are lighter and easier to assemble than traditional bridges built from wood or steel. At some remote sites, the advantages of light weight and ease of assembly may make fiber-reinforced polymer trail bridges a better alternative than wood or steel bridges. Wood for bridges made from native materials may be in short supply at some remote sites. Care must be taken in transporting fiber-reinforced polymer materials, though. Fiber-reinforced polymer materials are easy to damage when they are being transported to the bridge site and when they are being assembled.
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
I am looking for Composite Steel Deck Design Handbook - No. CDD2 of SDI
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
Author: El-Zghayar, Elie A | Size: 6.28 MB | Format:PDF | Quality:Original preprint | Publisher: University of Central Florida, Orlando | Year: 2011 | pages: 147
Post-tensioning tendons in segmental bridge construction are often only anchored within the deviator and pier segments. The effectiveness of the post-tensioning (PT) system is therefore dependent on proper functioning of the anchorages. On August 28, 2000, a routine inspection of the Mid-Bay Bridge (Okaloosa County, Florida) revealed corrosion in numerous PT tendons. Moreover, one of the 19-strand tendons was completely slacked, with later inspection revealing a corrosion-induced failure at the pier anchor location. Anchorage failure caused all PT force to transfer to the steel duct located within the pier segment that in turn slipped and caused the tendon to go completely slack. After the application of PT force, the anchorage assembly and steel pipes that house the tendon are filled with grout. These short grouted regions could, in the event of anchorage failure, provide a secondary anchorage mechanism preventing the scenario mentioned above from occurring. This paper presents the results of a full-scale experimental investigation on anchorage tendon pullout. The study focuses on the length required to develop the in-service PT force within the pier segment grouted steel tube assembly. Seven, twelve, and nineteen 0.6 inch diameter strand tendons with various development lengths were considered. Recommendations for pier section pipe detailing and design will be discussed.
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
Author: Pokharel, Sanat Kumar | Size: 3.54 MB | Format:PDF | Quality:Original preprint | Publisher: University of Kansas, Lawrence | Year: 2011 | pages: 70
Soil nail walls are a widely used technology for retaining vertical and nearly vertical cuts in soil. A significant portion of the cost of soil nail wall construction is related to the construction of a reinforced concrete face. The potential for use of a flexible facing design for soil nail walls to replace reinforced concrete facing was evaluated using three-dimensional finite difference modeling and physical testing of a 1.5 meter by 1.5 meter unit cell of a soil nail wall in clay. A steel mesh form of flexible facing was used as a substitute for concrete. The finite difference model predicted large vertical and horizontal deformations for surcharges of approximately 5 psi. In the physical testing, the flexible facing products performed well with regard to strength, but the facing experienced large vertical and horizontal deformations that were consistent with the numerical modeling. Based on these results, it is recommended that use of flexible facing as a substitute for reinforced concrete be limited to non-critical structures where large vertical and horizontal deformations are acceptable.
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
![[Image: 80009037865104649708.jpg]](https://pic.civilea.com/images/80009037865104649708.jpg)
![[Image: info.png]](http://postgen.civilea.com/icon/info.png){kind=icon}
![[Image: download.png]](http://postgen.civilea.com/icon/download.png){kind=icon}
![[Image: screen.png]](http://postgen.civilea.com/icon/screen.png){kind=icon}
![[Image: 94188381986144927275.png]](https://pic.civilea.com/images/94188381986144927275.png)
![[Image: 23671275678961100041.png]](https://pic.civilea.com/images/23671275678961100041.png)
![[Image: tips.png]](http://postgen.civilea.com/icon/tips.png){kind=icon}
![[Image: homepage.png]](http://postgen.civilea.com/icon/homepage.png){kind=icon}
![[Image: crack.png]](http://postgen.civilea.com/icon/crack.png){kind=icon}
![[Image: password.png]](http://postgen.civilea.com/icon/password.png){kind=icon}
![[Image: 53782495739207813192.jpg]](https://pic.civilea.com/images/53782495739207813192.jpg)
![[Image: 30742427041137187009.jpg]](https://pic.civilea.com/images/30742427041137187009.jpg)
![[Image: 28797047165174428783.png]](https://pic.civilea.com/images/28797047165174428783.png)
![[Image: 08491180624061978066.png]](https://pic.civilea.com/images/08491180624061978066.png)
![[Image: 81006100461696912532.png]](https://pic.civilea.com/images/81006100461696912532.png)
![[Image: 77057222866425379272.png]](https://pic.civilea.com/images/77057222866425379272.png)
![[Image: 45909985579550735642.png]](https://pic.civilea.com/images/45909985579550735642.png)