Planning and processing
MIGUA expansion joint profile systems

In each statically indeterminate system, inner constraint forces occur which are caused, independent of the loads, by influences like temperature changes, different foundation settlements or concrete shrinkage. The influences cannot be avoided by construction alone, like different temperatures of the north- and south façade or different settlements between tower and flat building. The different rigidities of the individual parts of the bearing structure in this systems have the effect that the additional tensions from these constraint forces often must be taken up by those parts of the construction that are already exposed to the highest loads (rigid parts put on loads). When dimensioning the supporting structure, the planner must consider this additional stress. If the measures for limiting the crack formation become ineffective and uneconomical, movement joints must be implemented to reduce or prevent the constraint forces.

Not much about the layout and specification of joints can be found in standards.
DIN 18531-3 "Dachabdichtungen" (roof waterproofing) and DIN 18195-8 "Bauwerksabdichtungen" (structural waterproofing) deal with the execution of movement joints. DIN18560-2 "Estriche im Bauwesen" (Screeds in building construction) at least defines that a joint plan has to be made regarding the layout of the joints, which depicts the type and layout of the joints. "When laying out joints, the generally accepted technical rules and standards and the technical information of the Federal Associations have to be observed."

Corresponding information sheets are available at the "Bundesverband Estrich und Belag" (Federal Association for Screeds and Coverings)

• Construction joints usually to not take up any movement but separate individual construction parts.
• Controlled crack joints weaken the cross section of the screed or concrete. A controlled crack appears during the shrinkage.
• Contraction joints are only inserted in floor coverings and screed and take up the movements of the screed shrinkage.
• Building joints or movement joints separate the supporting structure and take up load-independent deformations to avoid additional forced tension.

• The main movement direction is the movement at right angles to the joint axis.
• The movement in the longitudinal direction of the joint is called shear.
• A settlement is the height offset between neighbouring building parts.
• Due to their construction, not all expansion joint profiles can take up these three movement, so this is an important criterion for choosing the right profile.

To be able to choose the correct profile for each application case, the load during the usage must be known. As with all floor coverings, it is not the evenly distributed load that is decisive here, but the specific surface pressure under the wheels. A small pallet track with hard wheels may, for instance, have a higher surface pressure than a large fork lift with pneumatic wheels.

If a vibration-free traversability is required, like for high-bay warehouses, special profiles with a wave cut are required.

If there are special demands regarding hygiene profiles with smooth inserts are available, which can be cleaned easily.

Should be profiles come into contact with aggressive substances, choose a stainless steel profile. For watertight profiles, the connection to the adjacent surface sealing must be considered. Apart from that, the consistency of the system is of particular importance here. That means that the must be edges must be watertight as well and the formed parts (terminations and intersections) must fit in free of play. For all these expansion joint systems, the supplementary service of the supplier is particularly important, as the complete system must be adapted to the joint run/pattern with all necessary formed parts and manufactured precisely in the factory.

Movement joins generally have a shorter lifespan than the lifetime of the building. That means the joints must be checkable and repairable. For this reason, our expansion joint profiles are sealed at the visible surface and the central seals are exchangeable.

First you need to make a pre-selection so you know you are searching in the right area:

• Low load, not watertight: MIGUTEC
• High load (not watertight, except STD): MIGUTRANS
• Low to high load, watertight: MIGUTAN
• Roof sealing, soil-covered areas, watertight: MIGUPREN
• Huge deformations, seismic profiles: MIGUMAX

For choosing the right profile. the corresponding tables in our MIGUA catalogues and on our website are available:

• The profile designation consists of the name of the profile and the heights of the brackets.
• The maximum joint width at the time of the installation, which must be bridged by the profile. Please consider that the actual joint width might be larger than the planned dimension due to construction tolerances.
• The total movement states how far the joint might open (+) or close (-). These values must be determined by the structural engineer.
• All profiles are available for various ground superstructures in several heights. Combinations are also possible. When determining the profile height it must be considered that a smooth ground (mortar bed) under the brackets of about 10 mm must be provided. Should the standard height not be sufficient, custom heights are available at request.
• The load capacity is separated into the classes for passenger cars/trucks, fork lifts according to DIN 1991-1 and industrial trucks with hard wheels.

After planning, choosing and delivery of the expansion joint profiles to the building site, these must be installed professionally. For this purpose we have created installation guides with information about the correct installation for each product group. Should you not wish to perform the installation yourself, we are glad to help you to find the suitable specialist for the installation. We can also offer you to perform the installation for you.

Before you install the profiles, it must be checked whether the technical data of the chosen profiles corresponds to those at the site. The joint width in the data sheet must not be exceeded in any case. The expected load capacity should also be checked again. The differentiation between vehicles with pneumatic wheels and those with other wheels is particularly important for that. If you don't perform the calculation of the "hard wheels" by yourself, our experts are at your disposal for that.

If you ordered profiles in standard lengths, these must be adapted to the situation and shortened accordingly. The profiles always have to be laid centered on the joint. Should there be any formed parts (terminations, intersections) be involved, these must be adapted, too. If you ordered custom lengths, the delivered profiles are numbered and equipped with custom-made precise formed parts so positioning and installing can be carried out quickly.

Due to the different tolerances of the underground and the delivered profile, it is absolutely necessary to smooth the surface/joints with mortar (normally 5-20 mm) (bedding). The profile is fully pressed into the wet mortar. The solid positioning (no voids) guarantees a safe and permanent load transfer. Therefore, only PCC-, PC- (Epoxy-) or PMMA mortar in corresponding grain size can be used. It is important that the minimum processing temperature required for the mortar is observed. The processing instructions of the mortar used must be observed in any case. The thickness of the bedding is calculated from the previously determined of the upper face of the finished floor.

Most of our profiles can be joined with connecting pins so that an installation at exactly the same height of multiple profile pieces is really easy. The spacers which make the installation easier must be removed immediately after the mortar has hardened.

When anchoring the profiles in the pre-defined distance afterwards, it is important that this must be done with non-spreading dowels due to the direct proximity to the edges of the joints. Usually chemical shear connectors or concrete screws are used which you can order from us.

For some profile types, sealing synthetic inserts must be put into the profiles. For this it is important that the inserts are first laid out completely and then pressed in at several points along the length of the profile. The insert shall not be draw in from one side. For filling the joint, a load-absorbing, low-shrink PC- or PCC-mortar is used depending on the expected usage.

For watertight profiles of the MIGUTAN product range require further steps for completing the installation and for sealing into the surface protection system of the building. These depend on the materials used.