Onshore Structural Design

Solution Calculations for Civil/Structural Engineers

General Overview

There are a number of civil and structural engineers who have attempted to work in the energy, petrochemical and the oil industry without success. They usually find themselves not having the technical understanding that obtains in these sectors due to the specialist nature of the structural engineering approach. Some reasons young engineers do not have the requisite skills may be because:

  1. This aspect of structural engineering is not taught at undergraduate level.
  2. It is more complex than first degree subjects.
  3. It requires exposure and experience working in these facilities to understand parameters during the structural design process.
  4. Some of the literature in this sector borders around trade secrets.
  5. There is hardly literature on the subject. 

Onshore Structural Design

Onshore structural design is the field of structural engineer that covers design of power plants, petrochemical facilities and the oil industry. Onshore structures are those which are some distance from the sea or basically those which are on land. The reason this aspect of structural engineering is different, is that by the name, it implies more specialist structures on land, asides bridges, buildings and other kinds of general structures.

Onshore Structural Design Calculations Now available

In 2016, Dr. Mohamed El-Reedy unraveled the mystery behind onshore structural design in his book, “Onshore Structural Design Calculations” (https://www.amazon.com/Onshore-Structural-Design-Calculations-Processing/dp/0081019440). Dr. El-Reedy a consultant structural engineer and international lecturer has offered consulting services to major industry such as International Egyptian Oil Company, ARAMCO, PETRONAS etc. His book uses 430 pages to cover all required calculations for the facility features in plants and industry. The book may be complex for young structural engineers, so I have posted the link to another book called “Onshore Structural Design – Step by Step Calculations” (https://www.amazon.com/dp/B08Z3QPNP5). This book is a step by step compilation of complete calculations of all the different structures domiciled in plant and industry facilities.

What Features are designed for in onshore structural design

In a nutshell, onshore structural design involve considerations for structures and supports as it pertains to: industrial steel structures, equipment and storage facility, vibrating equipment support, soil investigation, pile design, assessment of structures in industrial plants, and resistance of buildings to explosion. In general, the following are the features of onshore facilities that require structural design:

  1. Pipe Rack
  2. Horizontal Vessels Support: Heat Exchangers, Separators etc.
  3. Vertical Vessels Support
  4. Pipe Bridges and Supports
  5. Storage Tanks
  6. Steel Structural Frames
  7. Piles and other types of Foundations
Photo 1 Showing Birds Eye View of a Plant Facility Showing the Basic Structural Features

What the design of these features entails

The structural design of onshore facilities is intricate due to the dependence of the structural engineer on experience, past projects, several internal/external stakeholders for parameters for the design and different codes of practice. For example, if an engineer is to design a vertical vessel, they will require the weight, wind load, bolt positions and size of the vessel from a mechanical structural engineering company prior to his commencement of the design of the pedestal and footing.

Features to be designed

  • Pipe Rack
    • What is a pipe rack and its uses? What is considered in the design?
      1. Pipe racks are the basic facility feature of industrial facilities as they support pipes, cable trays and other such utilities.
      2. Some parameters considered in the design are:
        • The sizes of the pipes to be carried
        • The total length of utilities to be supported
        • The maximum possible span of pipes and cable trays between supports
        • The maximum deflection and movement of the structure and parts
    • The following are the steps to take while designing the pipe rack
      1. Obtaining of the layout of the pipe rack from the project engineering managers
      2. Configuration of the structure
      3. Estimation of loading from pipes, cable trays and other equipment attachments on the beams and other supports
      4. Determination of other loads in accordance with relevant codes
        • Dead loads, live, wind, earthquake etc.
      5. Placement of loads on the structure and generation of load combinations
      6. Analyzing the structure and designing the members
    • STAAD Pro drawing of pipe rack analysis
  • Horizontal Vessel
    • What are horizontal vessels and their uses? What is considered in the design?
      1. Horizontal vessels are structures which contain and usually process fluids and span more in the horizontal direction
      2. Some parameters considered in the design of the footing of the supports are:
        • The sizes of the vessel to be carried
        • The likely purpose of the vessel, i.e. heat exchanger, oil separator etc.
        • Properties of the selected horizontal vessel
    • The following are the steps to take while designing the foundation of a horizontal vessel
      1. Obtaining of the template of the saddle and other dimensions of the horizontal vessel from the manufacturer
      2. Configuration of the footing positions
      3. Estimation of loading from the vessel(s), pipes, and other equipment attachments
      4. Determination of other loads in accordance with relevant codes
        • Dead loads, live, wind, earthquake, Thermal, Bundle Pull etc.
      5. Designing the steel slide plate, pier & sizing, footing sizing and design
      6. Designing of footing based on different load cases generated to obtain the most adverse footing condition and factor of safety.
  • Vertical Vessel
    • What are vertical vessels and their uses? What is considered in the design?
      1. Vertical vessels are structures which contain and usually process fluids and span more in the vertical direction. They could also accommodate human traffic
      2. Some parameters considered in the design of the footing of the supports are:
        • The sizes of the vessel to be carried
        • The likely purpose of the vessel
        • Properties of the selected vertical vessel
    • The following are the steps to take while designing the foundation of a vertical vessel
      1. Obtaining of the template dimensions of the bottom plate support of the vertical vessel from the manufacturer
      2. Selection of footing shape
      3. Estimation of loading from the vessel(s), pipes, and other equipment attachments
      4. Determination of other loads in accordance with relevant codes
        • Dead loads, live, wind, earthquake, Thermal, etc.
      5. Designing the pedestal, footing, or other type of foundation
      6. Designing of footing based on different load cases generated to obtain the most adverse footing condition and factor of safety.
  • Storage Tank
    • What are storage tanks and their uses? What is considered in the design?
      1. For the purpose of this literature and scope, Storage tanks are large usually cylindrical above ground tanks made of metal or concrete for the storage of fluids. They also accommodate human traffic.
      2. Some parameters considered in the design of the storage tank and foundation are:
        • The required capacity of storage
        • The purpose of the storage tank
        • Overfill and height characteristics of the tank
    • The following are the steps to take while designing the tank body and the foundation
      1. Obtaining of the capacity and overfill level of the tank
      2. Selection of the type of roof
      3. Determination of thickness of the shell (body) and the roof
      4. Estimation of loading from the stored fluid
      5. Determination of other loads in accordance with relevant codes
        • Dead loads, live, wind, earthquake, Thermal, etc.
      6. Designing of the bottom plate thickness
      7. Designing of soil bearing of the bottom of the tank. Designing of tank wall supporting beam and other types of foundation support.

Preview of Onshore Structural Design – Step by Step Calculations

Onshore Structural Design – Step by Step Calculations have covered the complete steps for the design in a summarized manner.

  1. This also book provides structural design calculations for each of the basic facility features
  2. It also contains line by line references to codes, and instruction notes
  3. The book also comprises of design calculations generated by hand and software. Thus, the steps by hand can be followed as well as that using a computer programme
  4. The software used are STAAD Pro and STAAD Foundation.
  5. Onshore Structural Design – Step by Step Calculations https://www.amazon.com/dp/B08Z3QPNP5

The design of onshore structural features follows standards which must be strictly adhered to. The book by Mohamed El-Reedy, Onshore Structural Design Calculations will provide a complete view of the intricacies in these kinds of designs. Here is the link to his book. https://www.amazon.com/Onshore-Structural-Design-Calculations-Processing/dp/0081019440