Tube and Clamp scaffolding is a common type of scaffolding system that consists of steel or aluminium tubes and clamps (also known as couplers or fittings) to connect the tubes together. Tube and coupler scaffolding is common in the construction industry where cheap and reliable temporary structures are required to facilitate efficient construction.

In scaffolding a coupler refers to a fitting used to connect two scaffolding members. Οι ζεύκτες διατίθενται σε διαφορετικούς τύπους και επιλογές.

Right-angle clamps are used to connect horizontal and vertical scaffolding tubes and swivel clamps are used to connect bracing to the structure. End-to-end clamps such as sleeve couplers or joint pin couplers can be used to extend a straight run of scaffolding. A screw jack (also know as adjustable leg) can be used as a starting base for scaffolding with an adjustable height to ensure that level scaffolding can be achieved even on uneven surfaces.

Standard scaffolding tube has a 48.3 χιλ (1.900 ίντσα) outer diameter (OD) and most clamps are designed for this standard sizing.

In the scaffolding weight capacity calculator the connections included depend upon the design standard referenced and what is included in the provisions of that design standard.

Το BS ΕΝ 12811-1:2003 Annex C gives characteristic values of the resistances for the following couplers:

• Right-Angle Coupler
• Friction Type Sleeve Coupler
• Swivel Coupler
• Parallel Coupler

These couplers are divided into class A and class B couplers with the characteristic strength given for each with respect to the types of load it can carry. A partial safety factor of 1.5 is then used to account for load action variability and a partial safety factor of 1.1 is used for resistance variability. Για παράδειγμα, a Class A right-angle coupler has a characteristic slipping resistance of 10.0 ΚΝ. We can then determine a working load limit of 10 / (1.1 * 1.5) = 6.1 kN for Class A right-angle couplers resisting a slipping force.

The AS/NZS 1576.2 (Couplers and accessories) gives guidance on the minimum testing criteria for the following couplers:

• Right-Angle Coupler
• Swivel Coupler
• End-to-End couplers (δηλ. Friction Type Sleeve couplers)
• Parallel Coupler
• Putlog Coupler
• Putlog Blade
• Check Coupler
• Adjustable Leg / Adjustable Baseplate / Adjustable Swivel Baseplate
• Flange Clamp
• Plain Pintle Castor
• Adjustable Castor

In order to get the working load limit (WLL) the minimum testing forces required to pass the standard should be reduced by a factor of safety. Ταυτός AS / NZS 1576.2 does not explicitly specify the safety of factor except for Adjustable Legs / Baseplates in which a factor of safety of 2.5 is used and for Right-Angle couplers and Swivel couplers for slip resistance in which a factor of safety of 2 χρησιμοποιείται. We have considered a factor of safety of 2.0 for all couplers except bases which generally gives similar working load limits to the BS EN 12811-1:2003. For example a right-angle coupler has a slipping test force of 12.5 ΚΝ. We can then determine a minimum working load limit of 12.5/2 = 6.25 kN for right-angle couplers resisting a slipping force.

Where a manufacturer tests beyond the requirements of the standard they can achieve a higher working load limit for their product. For simplicity we have simply referred to the minimum requirements of the standard. When using the SkyCiv Scaffolding Design Software using the custom connection can allow a user to specify specific working load limits provided by a manufacturer for a connection.

Συζεύκτη ορθής γωνίας
Right-angle couplers connect scaffolding tubes at exactly a 90-degree angle (εξ ου και το όνομα) creating stable joints. Right-angle couplers are commonly used to connect vertical and horizontal scaffolding members.

Swivel coupler
The swivel coupler is similar to the right-angle coupler however allows swivelling rather than having a fixed 90 degree joint. This allows the scaffolding tubes to rotate independently when required and can be used for connecting bracing elements or non-rectangular arrangements within the scaffold structure.

End to End Couplers

End to end couplers join two scaffolding members together in a straight line. These can be placed externally to the scaffolding tube (friction type sleeve couplers, external sleeve couplers) or internally in the scaffolding tube (expanding joint pin couplers). These connections allow the transfer of moments between members and the transfer of compression forces however do not provide resistance in tension. Where tension transfer is required a spliced arrangement should be used instead.

Expanding Joint pin couplers work by fitting inside scaffolding and then expanding flush against the inside of the scaffolding tube.

Sleeve couplers sit outside the scaffolding tubes and are tightened to be flush against the outside of the scaffolding tube.

Παράλληλος ζεύκτης
The parallel coupler is used to create a splice connection or lap connection between scaffolding tubes by connecting them in parallel. This type of connection can be used to transfer axial forces between scaffolding members.

Screw Jack
A screw jack has a thread that allows for an adjustable base for supporting vertical scaffolding members at the base of the scaffolding structure. By adjusting the screw jack, level scaffolding can be erected by the construction team even on uneven surfaces. The screw jack then supports the scaffolding structure by transferring compression and shear forces into the foundation.

Standard scaffolding tube has a 48.3 χιλ (1.900 ίντσα) outer diameter. Since there are only a few section thicknesses and steel grades that are manufactured there are only a few different possible scaffolding load capacities. Since it is difficult to visually identify the section thickness and grade of a scaff tube on site it is generally advised to be conservative and use the thinnest and lowest grade section that would be available on site in design calculations.

When scaffolding tube is resisting tension forces only we can calculate the scaffolding load capacity by the following formula:

Ν_τ = Α_τ * φά_και * φ

όπου:

• ΕΝΑ_τ is the area of the scaffold tube
• φά_και is the yield strength of the scaffold tube
• φ is a strength reduction safety factor

Για ένα 250 MPa yield strength 48.3x3.2 mm CHS the capacity according to the Australian standard is:

Ν_τ = Α_τ * φά_και * φ

Ν_τ = 453.4 χιλ² * 250 MPa * 0.9 = 102.01 ΚΝ

Other tension strengths can be taken from the scaffolding load capacity table below. The values have been adopted based on the scaffolding load capacity formula for the relevant design standards.

Round HSS sections or CHS sections are not susceptible to lateral-torsional buckling (buckling under bending) however they can buckle due to compressive forces. ο SkyCiv Scaffolding Design Software takes a input for the effective length factor which is used in buckling calculations. Where the SkyCiv S3D integration for scaffolding software is used the effective length factors can be automatically generated based on the member restraints in the model.

An integrated version of the calculator for SkyCiv S3D is available to import all eligible members into the scaffolding design module and run all scaffolding load capacity checks at once. The integration can automatically determine appropriate effective length factors based on the member restraints in the model. You can find out more about using the integration in our Scaffolding Design Tutorial in SkyCiv S3D.

Οι μηχανικοί που εργάζονται σε συστήματα σκαλωσιάς θα πρέπει να τα σχεδιάσουν ώστε να αντέχουν σε διάφορους τύπους φορτίων, αυτά τα φορτία περιλαμβάνουν:

• Νεκρά φορτία γενικά από το βάρος του ίδιου του συστήματος σκαλωσιάς.
• Ζωντανά φορτία γενικά από εργάτες και εξοπλισμό που χρησιμοποιείται στις σκαλωσιές.
• Φορτία ανέμου εξαρτώνται από τις τοπικές συνθήκες και πρότυπα.
• Φορτία χιονιού όπου ισχύει και ανάλογα με τις τοπικές συνθήκες και πρότυπα.
• Σεισμικά Φορτία σε περιοχές επιρρεπείς σε σεισμούς και ανάλογα με τις τοπικές συνθήκες και πρότυπα.

Αφού καθοριστούν τα φορτία από εξειδικευμένο δομικό μηχανικό, μπορούν να εφαρμοστούν στο τμήμα φορτίου σχεδιασμού της αριθμομηχανής με τη μορφή κάμψης, κουρεύω, και αξονική δύναμη.

A screw jack can resist compression and shear forces transferred through scaffolding and can then transfer the forces to the ground. A base plate is used to spread compression forces over a greater bearing area and a sole board is commonly placed under the base to gain additional bearing area and therefore increase bearing capacity. Bases often have holes for anchors that can be installed in a concrete blinding or foundation to help resist shear forces and prevent sliding of the scaffolding base.

The European Scaffolding Standard has a provision for the design of screw jacks located in Annex B.

The Australian Standard AS 1576.2 Ενότητα 4.3 discusses the minimum working load limit for steel and aluminium adjustable screw jacks.

Τι σύστημα μονάδας υποστηρίζεται?

Διατίθενται τόσο μετρικά όσο και αυτοκρατορικά συστήματα μονάδων. Για να αλλάξετε συστήματα μονάδων, κάντε κλικ στο γρανάζι στο επάνω αριστερό μέρος του πίνακα εισόδου.

Ποιες ιδιότητες υλικού λαμβάνονται υπόψη?

Τα εργαλεία σχεδιασμού σκαλωσιάς επιτρέπουν στους χρήστες να εισάγουν τις ακόλουθες ιδιότητες υλικού:

• Μέτρο ελαστικότητας
• Modulus Of Rigidity
• Όριο συμπίεσης λεπτότητας
• Ισχύς απόδοσης μέλους
• Η απόλυτη δύναμη του μέλους

Ποιοι κωδικοί σχεδίασης υποστηρίζονται?

Το λογισμικό σχεδιασμού ικριωμάτων υποστηρίζει το σχεδιασμό σκαλωσιάς σύμφωνα με τα ακόλουθα πρότυπα:

• AISC 360-16 Λογισμικό σχεδιασμού ικριωμάτων.
• AS / NZS 1576 Λογισμικό σχεδιασμού ικριωμάτων.
• BS EN 12811-1:2003 Λογισμικό σχεδιασμού ικριωμάτων.

Αυτές οι επιλογές είναι προσβάσιμες μέσω του εικονιδίου σημαίας στο επάνω μέρος του αριστερού πλαισίου εισόδου για αλλαγή του προτύπου σχεδίασης.

Ποια ανάλυση χρησιμοποιείται για τον υπολογισμό της αντίστασης των συζευκτών?

Η ενότητα σχεδιασμού σκαλωσιάς αποτελείται από την αξιολόγηση των χωρητικοτήτων του συζεύκτη με βάση τη γραμμική στατική ανάλυση των μελών. Για την ευρωπαϊκή έκδοση του σχεδιασμού ελέγξτε τις χωρητικότητες του συζεύκτη όπως δίνονται στο Παράρτημα Γ του ΕΝ 12811.1 are used in combination with the required partial factors of safety. For the Australian version coupler testing requirements are given in AS 1576.2 and these values are used to determine the minimum working load limit of the fitting.

Είναι σκαλωσιά με υποδοχές βάσης που υποστηρίζονται?

The European and Australian version of the tool supports scaffolding with base jacks. The US version of the tool does not currently support the design of scaffolding with base jacks.

• Υπολογιστής χωρητικότητας δέσμης I Beam
• Λογισμικό σχεδίασης αλουμινίου
• Υπολογιστής χωρητικότητας τεγίδων
• Υπολογιστής τάνυσης καλωδίου
• Υπολογιστής σύνδεσης Kicker Brace

Το SkyCiv προσφέρει ένα ευρύ φάσμα λογισμικού ανάλυσης και σχεδιασμού Cloud Structural για μηχανικούς. Ως μια συνεχώς εξελισσόμενη εταιρεία τεχνολογίας, δεσμευόμαστε να καινοτομούμε και να προκαλούμε υπάρχουσες ροές εργασίας για να εξοικονομήσουμε χρόνο στους μηχανικούς στις διαδικασίες εργασίας και τα σχέδιά τους.