Expansion joints in precast terracing
Typically, terracing units are precast concrete units which are lifted into and fixed in position. Invariably the need to accommodate movement (as well as pre-casting tolerances) means that gaps are left between units and these gaps must be covered with an expansion joint which not only accommodates movement but must be waterproof and (in most instances) fireproof.
The expansion joint employed must follow the tread and riser form and dimensions of the terracing and must not interfere with passage of people traversing terraces.
Vexcolt manufactures a specialised range of expansion joints for use in terracing where the joint seamlessly transitions from tread to riser unit forming a near seamless system running from the top to bottom of terraces.
Expansion joints in front of house areas
High level of pedestrian traffic combined with maintenance vehicles such as scissor lifts or cherry pickers mean that expansion joints must be particularly robust.
- It is vitally important that the joints selected provide smooth transit for pedestrians and most particularly those with disabilities. They should all meet current disability legislation requirements through the entire movement cycle of the jointing system.
Vexcolt’s jointing systems have been designed meet current European and USA Disability Legislation (ADA).
- The use of cleaning and maintenance equipment means that expansion joints need to be able to support high frequency vehicular loading and meet the requirements of Eurocode 1 – EN-1991-1-1 ‘Actions on structures’. Clause 126.96.36.199 of this Norm ‘Actions induced by forklifts’ (which pinpoints vehicle types, gross vehicle load, individual wheel load and wheel contact area) should be used as the basis of design in ensuring that any jointing system specified can accommodate loading from scissor lifts, cherry pickers, maintenance and cleaning equipment.
It is recommended that FL2 loading capacity (as detailed within EN-1991-1-1) be considered as the minimum acceptable. FL2 equates to a forklift truck of 46kN (4.6 tonnes) fully laden weight and closely matches loading from larger cherry pickers with spreaders.
This data must be used to calculate (normally by Finite Element Analysis FEA) whether (or not) a selected jointing system can resist repeated loads from the type of vehicle classified.
Control joints in front of house areas
Control joints in internal floors in stadiums should be laid to form bays to accommodate local moisture movement, such as the drying shrinkage of substrates. They are also used to compensate for small deflections arising from thermal expansion and contraction.
Typically, internal control joints are formed in maximum 6 metre x 6 metre bays in finishes laid on both ground-supported and suspended slabs. With suspended slabs control joints should also be laid directly over beams and at the mid-point of spans where anticipated creep deflection exceeds 20mm.
In high traffic environments such as stadiums it is strongly recommended that control joints with metal side plates are installed in floors. The reason is that these metal plates help protect and support the finishes from the worst rigours of impact and abrasion which can often result in cracking and spalling of the edges of paving.
Expansion joints in back of house areas
This category includes service areas as well as changing rooms, pool areas and access points. Often these areas have special requirements in terms of loading and waterproofing in excess of that required for general zones or, for example expansion joint seals around plunge pools rather than mechanical joints.