Steel - Storage and Handling

Hello..

Generally, greater care is required in storing and handling stainless steel than carbon steel to avoid damaging the surface finish (especially for bright annealed or polished finishes) and to avoid contamination by carbon steel and iron.

Storage and handling procedures should be agreed between the relevant parties to the contract in advance of any fabrication and in sufficient detail to accommodate any special requirements. The procedures should cover, for instance, the following items:

• The steel should be inspected immediately after delivery for any surface damage.
• The steel may have a protective plastic or other coating. This should be left on as long as possible, removing it just before final fabrication. The protective covering should be called for in the procurement document if it is required (e.g. for bright annealed finishes).
• Storage in salt-laden humid atmospheres should be avoided. Storage racks should not have carbon steel rubbing surfaces and should, therefore, be protected by wooden, rubber or plastic battens or sheaths. Sheets and plates should preferably be stacked vertically; horizontally stacked sheets may get walked on with a risk of iron contamination and surface damage.
• Carbon steel lifting tackle, e.g. chains, hooks, and cleats should be avoided. Again, the use of isolating materials, or the use of suction cups, will prevent iron pick-up. The forks of fork lift trucks should also be protected.
• Contact with chemicals including undue amounts of oils and greases (which may stain some finishes) should be avoided.
• Ideally, segregated fabrication areas for carbon steel and stainless steel should be used. Only tools dedicated to stainless steel should be employed (this particularly applies to grinding wheels and wire brushes). Note that wire brushes and wire wool should be of stainless steel and generally in a grade that is equivalent in terms of corrosion resistance (e.g. do not use ferritic stainless steel brushes on austenitic stainless steel).
• As a precaution during fabrication and erection, it is advisable to ensure that any sharp burrs formed during shearing operations are removed.
• Consideration should be given to any requirements needed in protecting the finished fabrication during transportation.

Thats all for today..see u next articles.

How To Calculate Shear Forces On Bolts Connection Joints

How to determine shear forces on bolts?

Here's below shows one of the simple shear forces calculation of bolts connection joints when received Mxx = 46.223 kN/M of maximum bending moment.

Mxx =     M dead  +  M live   
        =   16.147  +  30.076
        =     46.223 kN/M

Flexible Pavement Design

Flexible Pavement Design

Design Procedure of IRC

Design Approach and Criteria - The following three types of pavement distress resulting from repeated application of traffic are considered:

(i) Horizontal tensile strain at the bottom of the bituminous layer
(ii) Vertical compressive strain at the top of the subgrade
(iii) Pavement deformation with in the bituminous layer

The deformation with in the bituminous layer is assumed to be controlled by meeting the mix design requirements

Failure Criteria

1. Fatigue Cracking

• Is due to the build up of tensile strain at the bottom of Asphaltic Concrete Layer
• Pavement is considered failed if 20% of the surface has cracked

2. Rutting Failure

• Is due to the build up of excessive compressive strain at the top of subgrade layer
• Pavement is considered failed if it exhibits a rut depth of 20 mm.

IRC Design Approach and Criteria

The pavement has been modeled as a three layer structure and stresses and strains at

critical locations have been computed using the linear elastic structural model FPAVE.