TSS and RVK Telescopic Stair Connectors

Invisible Connections’ range of telescopic stair connectors is designed to solve the problems associated with unsightly support systems for precast stair landings, particularly those associated with traditional bracketry.

Offsite construction methods are increasingly recognised for improving construction efficiency and providing cost certainty. With adequate planning, they can present an easier, more flexible and economical building process than conventional construction. No onsite welding and minimal onsite casting is necessary.

Often, by reducing on site task complexity, greater accuracy, less wastage and more rapid installation is achieved. Fewer resources contribute not only to improved efficiencies but also to environmental sustainability.

Meeting stakeholders’ demands

By using TSS and RVK telescopic connectors:

  • The Architect achieves a smooth obstacle-free soffit, with no supports on show
  • The Engineer gains a simple, efficient connection, which satisfies requirements for robustness
  • The in situ Contractor does not need to drill fixings into the wall, which require tight tolerance and can lead to variable performance
  • The Precaster keeps control of the connection within the factory with no need for specialist operations on site
  • The Main Contractor benefits from reduced crane hook-time and rapid provision of access stairs

If you would like to see our products in action, please have a look at our videos in the resources area.

Stair and landing connectors

Standard version suits wherever connectors can be fitted to three sides of stair landing. Pinned version allows robustness requirements to be met when connectors can only be fitted into two walls. Acoustic version reduces vibration from stairwell.

TSS Telescopic Connectors

The TSS range is hot dip galvanized as standard to ensure smooth operation of unique ejection method by wire cord. The connectors can be supplied in standard or pinned versions and are used in conjunction with REDiBOX permanent recess formers.

Cord operated, sliding inner. No visible markings on landing top surface – especially appealing for landings without screed toppings.

RVK Telescopic Connectors

Supplied ‘black’ as standard (optionally galvanised). Operated by a bolt mechanism from above landing. Cost-effective, rugged solution ideal for screeded landings.

REDiBOX PRF-STD (standard version)

REDiBOX Permanent Recess Former

Purpose-designed ‘left-in’ component for simply creating recesses in precast or in situ concrete walls.

Standard or pinned versions used in conjunction with TSS and RVK connectors.

Choose connector by job requirements

TSS and RVK telescopic connectors can be used in different layouts according to stair landing configuration. Various layout options are shown below to help you select the most appropriate connector and download the relevant Technical Enquiry Form.

Alternatively, our Product Selection Guide offers an ‘at a glance’ overview of all Invisible Connections’ products, indicating where and how they might be used.

Landing with connectors on three sides

Landing with connectors at both ends

Integral flight and landing with connectors on side and end

Integral flight and landing with connectors on end

Integral flight and two landings with connectors on sides and ends

Integral flight and two landings with connectors at both ends

Selecting the right product

Find below which Invisible Connections’ products are best suited for your project requirements, or download our at a glance Product Selection Guide to view the entire product range, features and benefits.

TSS Telescopic Connectors
TSS 41 (standard version)Small, compact unit. Connector capacity up to 40 kN. Appropriate for light stair landings of thickness >150mm.

Ideal for fair-faced concrete (without screed).
Used with REDiBOX PRF-STD (standard version).

TSS 101 (standard version)Connector capacity up to 80 kN in a minimum 200mm thick landing increasing to 100 kN for 265mm thick landing.

Popular product for most stair landing applications.
Used with REDiBOX PRF-STD (standard version).

TSS 81-30 (pinned version)Suitable where wall locations are only on two sides of landing and connector has to be pinned to meet robustness requirements. Axial capacity 30 kN.

Robustness requirements achieved when only two walls available to connect to.
Used with REDiBOX PRF-PIN (pinned version).

TSS 102 (acoustic version)Incorporates sound reducing rubber composite.

Reduces sound vibration from stairwell into adjacent accommodation.
Used with REDiBOX PRF-STD (standard version).

RVK Telescopic Connectors
RVK 101 (standard version)Standard connector capacity up to 80 kN in a minimum 200mm thick landing, increasing to 100 kN for 265mm thick landing.

Popular product for most stair landing applications.
Used with REDiBOX PRF-STD (standard version).

RVK 101-30 (pinned version)Where wall locations are only on two sides of landing and connector has to be pinned to meet robustness requirements. Axial capacity 30 kN.

Robustness requirements achieved where only two walls available.
Used with REDiBOX PRF-PIN (pinned version).

RVK 101-30-E20 (extended version)Longer extending inner-tube to span airgaps up to 50mm.

Robustness requirements achieved when only two walls available to connect to.
Used with REDiBOX PRF-PIN (pinned version).

REDiBOX Permanent Recess Former
New REDiBOXREDiBOX PRF-STD (standard version)Purpose-designed 'left-in' component for simply creating recesses in precast or in situ concrete walls.

Provide tolerance for positioning and assembly of stair landings. No drilling, dust or noise.
Used in conjunction with TSS 41, TSS 101, TSS 102 and RVK 101.

REDiBOX PRF-PIN (pinned version)Purpose-designed 'left-in' component for simply creating recesses with pinning location for tying landings to walls.

Robustness requirements met when connectors can only be located on two walls.
Used in conjunction with TSS 81-30, RVK 101-30 and RVK 101-30-E20.

Retrofit Accessories
Pin Linkage Unit (for pinned applications)Retrofitted into a concrete wall if the recess doesn't incorporate a pocket to receive the axial tie rebar pin.

TSS 81-30 / RVK 101-30 can be pinned to wall where recess incorrectly or not installed.

Extension Piece (for pinned applications)Retrofitted into connector to allow pin to fit into recess former.

TSS 81-30 / RVK 101-30 can be pinned to wall where recess former has moved during construction.

To make an enquiry, email [email protected] or [email protected] or talk to us by calling 01844 266000

Application

Primarily intended for connecting precast stairs and landings, TSS and RVK connectors have also been used for a diverse range of applications, such as:

See more construction projects where TSS and RVK connectors have been used, or read our Case Studies.

Robustness

UK regulations require that all precast floor and stair elements are anchored to the main structure to provide robustness in the event of an incident. Traditionally this involved dowels or other mechanical connections into the walls, resulting in more work and additional cost on site.

TSS and RVK telescopic connectors provide this anchorage. Where layout allows, simple positioning of the connectors satisfies robustness requirements, also being a ‘zero cost’ solution. In this layout position, the connectors are designed to work laterally, in addition to carrying the vertical loads. Alternatively, where the layout dictates otherwise, factory-modified versions of RVK connectors also provide axial anchorage, by pinning the connector into the wall.

Capacity

To ensure lean and cost-efficient design, there are two standard capacities; 40kN & 100kN. Connectors may be used in pairs for even higher load requirements.

All telescopic connectors, from the smallest TSS to the largest BSF, incorporate integral half-round bearing blocks, for correct seating of the local reinforcement, to avoid local crushing/cracking.

Standards

Design is in accordance with the following standards:

  • Eurocode 2: Design of concrete structures Part 1-1 General rules and rules for buildings.
  • Eurocode 3: Design of steel structures Part 1-1 General rules and rules for buildings.
  • Eurocode 3: Design of steel structures Part 1-8 Design of joints.

Steel is grade S355 (minimum) which has a high stress capacity.

All TSS and RVK products are covered by appropriate European Technical Approvals, based on testing at SINTEF, the largest independent research organisation in Scandinavia.

Benefits

It is increasingly common to combine precast concrete stairs and landings with core walls which are poured in situ. When connection methods are left as an afterthought, using rolled steel angles is often the only practical, yet inefficient, fixing solution.

With a little upfront planning, there’s much to gain by incorporating telescopic connectors, which come with a host of advantages; such as improved health and safety, robustness compliance, and significantly improved cost effectiveness.

REDiBOX Permanent Recess Former

All TSS and RVK telescopic connectors work in conjunction with the relevant REDiBOX permanent recess former. A purpose-designed ‘left-in’ component to simply create recesses in either precast or in situ concrete walls, REDiBOX is suitably sized to accommodate the telescopic connector’s sliding inner section before receiving cementitious grout fill.

Manufactured from high density polyethylene (HDPE), the REDiBOX permanent recess former has a ribbed monocoque structure on all sides to provide strength and a substantial key for the outer concrete.

The REDiBOX faceplate can be nailed to timber moulds or shutters. Alternatively, fixing lugs on all sides provide ample points to tie-wire the unit to the wall reinforcement, which is ideal for slip forms. A central ‘soft eye’ in the faceplate is designed so that a hammer claw can be inserted to withdraw the faceplate easily to reveal the open recess.

REDiBOX (STD)

The standard version is designed to work in conjunction with TSS41, TSS101, TSS102 and RVK101.

The recess measures 180mm wide x 120mm high x 104mm deep. Setting out in the wall should be from the top edge of the faceplate, which for an RVK101 connector is 27mm below the top of the landing. If a TSS connector is specified, setting out will be project-specific owing to the variable depth of the connector within the slab.

REDiBOX (PIN)

The pinned version is designed to work in conjunction with TSS81-30 and RVK101-30.

The recess measures 180mm wide x 230mm high x 120mm deep. Setting out in the wall should be from the top edge of the faceplate, which for an RVK101 connector is 90mm above the top of the precast landing (without finishes). If a TSS connector is specified, setting out will be project specific owing to the variable depth of the connector within the slab.

Can't find what you're looking for? Our resources area provides much more information. Or get in touch.

Related projects

If you would like to discuss your specific project requirements, please contact us for technical advice without obligation.

Telescopic connectors provide us numerous advantages for precast stair installation. Apart from improved time and efficiency, the health and safety gains over traditional support methods are a key driver to satisfy our own needs, as well as those of our clients.

Shane Dunleavy, Project Manager, Morrisroe