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Comparison of design procedures for PEB

An industrial structure (Ware House) is analyzed and designed according to the Indian codes and also by referring to international standards. The economy of the structure is discussed in terms of its weight comparison, between Indian codes (IS800-1984, IS800-2007), American code (MBMA-96) and between Indian codes (IS800-1984, IS800-2007).

Steel is the material of choice for design because it is inherently ductile and flexible. In structural engineering, Pre Engineered Building (PEB) is designed by a manufacturer, to be fabricated using a pre-determined inventory of raw materials and manufacturing methods that can efficiently satisfy a wide range of structural and aesthetic design requirements.

In recent years, the introduction of PEB concept in the design of structures has helped in optimizing design. The complete designing is done at the factory and the building components are brought to the site in knock down condition. These components are then fixed/ jointed at the site and raised with the help of cranes. It can be fitted with different structural accessories including mezzanine floors, canopies, fasciae, interior partitions, etc. The adoptability of PEB in the place of Conventional Steel Building (CSB) has resulted in many advantages, including economy and easier fabrication

The Study

The concept of PEB is the frame geometry which matches the shape of the internal stress (bending moment) diagram thus, optimizing material usage and reducing the total weight of the structure. In this study, a structure with length 187m, width 40m, clear height 8m and Roof-Slope 1:10 is considered to carry out analysis and design for 2D frames (End frame, frame without crane and frame with three module cranes).

Selected structure is located in Rajasthan, seismic zone IV with wind speed 47m/sec and considered life span of structure as 5 years. Other details include

  • Crane Capacity: 10 t (for all three cranes)
  • Soil type: Medium
  • Importance factor: 1
  • Response reduction factor: 5
  • Purlin spacing: 1800 mm
  • Girt spacing: 2200 mm

Dead load calculation includes the weight calculation of sheeting, sag angles, purlins and insulation material as follows:

  • Sheeting unit weight: 4.78kg/m2 (5mm thick galvanized sheet)
  • Purlin wt.: 4.71kg/m (spacing of purlin = 1.8m)
  • 4.71/1.8:
  • 2.61 kg/m2
  • Sag rods wt.: 1.2kg/m:
  • 1.2/1.8 :0.667kg/m2
  • Insulation material wt.: 2kg/m2

Dead load: 4.78 + 2.61 + 0.667 + 2 = 10kg/m2: 0.1KN/m2

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