The Practice of Construction Management

Analysis and Modelling of Fiber-Wrapped Columns and Concrete-Filled Tubes

Problem Statement
Fiber-wrapping offers a -high strength, low weight, and corrosion-resistant jacket which can be easily and quickly installed with negligible increase in the column's cross-section. Since the first application of fiber-wrapping technique to concrete chimneys in Japan (Katsumata and Yagi 1990), there has been an abundance of studies on the use of this technique. It has been put into practice in several states including California, Nevada, New York, and Vermont. Both carbon and glass fibers have been utilized, although carbon fibers are more expensive.
Since use of fiber composites for confinement of concrete is relatively new, theoretical work in this area is limited to the models that were originally developed for transverse steel reinforcement. However, it has been shown that concrete behaves very differently when confined by elasto-plastic materials such as steel as compared to linearly elastic materials such as fiber composites (Mirmiran and Shahawy 1997a). Applying the same models to fiber-wrapped concrete may result in overestimating the strength and unsafe design. In the absence of reliable models, construction industry may be forced to either avoid the use of advanced composites, or to incorporate high "factors of safety," making composite construction less economical. The PI has previously developed such a model for glass-wrapped concrete columns (Mirmiran 1997a&b). There is a need to extend the work to carbon-wrapped concrete columns.

Objectives
The objectives of this study were as follows:
1. Investigate the behavior of carbon-wrapped concrete specimens in uniaxial compression, based on the tests previously conducted by the Florida Department of Transportation.
2. Compare the experimental results with the confinement model of Samaan, Mirmiran and Shahawy (1998) which was developed for concrete-filled E-glass FRP tubes.
3. Compare the experimental results with a non-associative Drucker-Prager type plasticity model using the finite element analysis.

Materials and Methods for Corrosion Control of Reinforced and Prestressed Concrete Structures in New Construction

Salt-induced reinforcing steel corrosion in concrete bridges has undoubtedly be come a considerable economic burden to many State and local transportation agencies. Since the iron in the steel has a nat ural tendency to revert eventually to its most stable oxide state, this problem will, unfortunately, still be with us, but to a much lesser degree due to the use of various corrosion protection strategies currently used in new construction. The adoption of corr osion protection measures in new construction, such as the use of good design and construction practices, adequate concrete co ver depth, low-permeability concrete, corrosion inhibitors, and coated reinforcing steel is significantly reducing the occurren ce of reinforcing steel corrosion in new bridges. Because concrete has a tendency to crack, the use of good design and constructi on practices, adequate concrete cover depth, corrosion-inhibiting admixtures, and low- permeability concrete alone will not a bate the problem. Even corrosion-inhibiting admixtures for concrete would probably not be of use when the concrete is crack ed. This situation essentially leaves the reinforcing steel itself as the last line of defense against corrosion, and the use of a barrier system on the reinforcing steel, such as epoxy coating, another organic coating, or metallic coatings, is even more c ritical. It is likely that there may never be any organic coating that can withstand the extreme combination of constant wetting and high temperature and high humidity that reinforcing steel is exposed to in some mari ne environments. Either steel bars coated with a sufficiently stable metallic coating or some type of corrosion-resistant solid metal bars would have to be used. There are some very convincing reports of good corrosion-resistance performance shown by epoxy -coated steel bars in concrete bridge decks where the concrete does not remain constantly wet and other exposure conditions are not as severe. Recent improvements to the epoxy coating specifications and the tightening of requirements on the prop er storage and handling of epoxy-coated reinforcing steel at construction sites will ensure good corrosion protection. For construction of new prestressed concrete bridge members (where for structur al or other considerations epoxy-coated strands cannot be used), the use of a corrosion-inhibitor admixture in the conc rete or in the grout, in conjunction with good construction designs and practices, would provide adequate corrosion protection . However, the long-term effectiveness of all commercial inhibitor admixtures has not been fully verified

Budgeting, Costing and Estimating for the Injection Moulding Industry

Spreadsheet Calculator for RSA Pro 2012

Installed in Windows 7 32 bit and 64 bit.
Remember to use a 32 bit Excell (see my first post of RSA 2012).
When installed in 64bit with Office 2010 - Esop macro error.
Installed 32 bit Excell 2003 (for Wood need a update (office2003-KB907417-FullFile-ENU.exe) free from Microsoft.)
Now the excell works but something goes wrong with the licensing (adlm error 20) and the spreadsheet works only on demo mode.
In the 32 Windows 7 with RSA Pro 32 bit works without problems.
I installed in a fresh (from image) Windows 7 64 bit SP1 but maybe the licensing error reason is only in my system so please check.

Behavior of Pipe Piles in Sand