Client: COMPANY SPECIALIZED IN DESIGN, CONSTRUCTION, MAINTENANCE AND MANAGEMENT OF URBAN AND INDUSTRIAL WASTE WATER TREATMENT PLANTS
Location: ITALY - ITALY
Application sector: WASTE WATER TREATMENT PLANT
Objectives
The goal was to build a chemical resistant structure to access a couple of tanks, in an aggressive environment subjected to corrosion, caused both by the specific use (in a waste water treatment plant) as well as by the site itself (brackish environment). The requirements were: • stand-alone installation (while excluding the possibility to fasten the structure to the existing metal tanks, as these weren’t designed to withstand additional forces); • wind resistance; • resistance to the design loads; • compliance with specific clearances related to the installation inside a storage basin (concrete tank for possible leakage containment). The Client also clarified the need of easily recognisable elements as safety devices. On top of the above-mentioned requirements, the compliance with UNI EN ISO 14122 has been requested.
Solution
The M.M. design team first examined the geometric constraints deducible from the Client’s assembly drawings, which had been prepared for the basic galvanized steel proposal. In addition, the combinations of both vertical loads (such as pedestrian live loads) and horizontal loads (such as wind-induced actions) were considered. The selection of sections and the sizing of the stainless-steel connections and base plates took into account the most demanding actions resulting from the different combinations. While M.M.’s standard sections were used for the staircases, more structurally significant H-type sections were selected for the landing towers, with the addition of various frames and bracings to limit deformations within the limits prescribed in Chapter 4 of the NTC 2018. The stair railings and visual barriers were manufactured in yellow to enhance visibility. The structure was delivered to the site in preassembled, easily transportable modules. On-site installation was limited to the simple joining of the structures using stainless-steel bolts with ground anchoring. The supply also included calculation reports and assembly drawings.
