We adapted an existing forecourt for chemical transport unloading

Project: To construct a new off-loading bay for road haulage tankers at a chemical plant.

HA Consulting Engineers was tasked with building a tanker off-loading bay that fulfilled all the required health and safety standards for transporting and offloading hazardous chemicals.

The current forecourt was unsuitable for purpose and extensive construction work had to be implemented, creating a new structure and facilities to ready the bay for the unloading of this chemical cargo.

Initial Challenges

The basic requirements for the project were as follows

  • The existing forecourt, adjacent to the building, which needed to be converted into the new bay was at a level 2 meters below the parallel road; requiring us to create a level platform for the haulage tankers.
  • A containment bund had to be constructed to cope with any kind of chemical spills during the loading process.
  • To prevent the transported chemicals coming into contact with water, an enclosed building and gantry had to be erected on top of the bay, completely covering the area whilst managing all run-off.
  • Historic issues with large voids under the building required the solution to minimise soil stresses.

We were required to construct a new off-loading bay and gantry for the transportation of hazardous chemicals.

Further Considerations

Our first solutions for the project encountered problems

  • The original solution was to install a suspended pre-stressed concrete slab over the drop between the road and the building, but this proved too uneconomical and created issues with the confined space under the slab.
  • We considered filling in the space between the road and the building with mass concrete, but this option was disregarded as it would have been too heavy and difficult to deliver this amount of concrete to the site.

A large height differential between the road and the proposed site of the bay presented a problem to construction.

Proposed Solution

Together with the client we decided on an innovative solution

  • We decided to create an area level with the road, making up the difference in height with a lightweight void former and adding a concrete deck on top.
  • A wraparound bund was designed under the new offloading slab, offering the containment required to manage a complete spill of all the chemical products within a single haulage tanker.

We utilised the height differential to create a containment bund and chose to fill and cover the remaining area for use as the offloading bay.

Practical Implementation

We completed the construction using these systems

  • We sourced an incredibly robust, lightweight, high strength and compact polystyrene fill material which was quick, easy and safe to install.
  • A traditional ground-bearing reinforced concrete slab was then constructed on top of the polystyrene forming the base for the unloading bay.
  • Finally the lightweight steel-frame offloading building and the gantry were designed to be supported partly by the existing structure and forecourt, negating the need for any new foundations, which could have disturbed the fragile ground below.

The new construction was completed without the need for further foundations, which could have impacted the site’s integrity.


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