Florian Dieterle

Dear TWf member, please refer to the following discussion on the EA discussion page about the Demise of Australian Standards. This is just posted as a link to make the TWf aware of these discussions, which are very relevant to our field. 

https://eaxchange.engineersaustralia.org.au/discussion/the-demise-of-australian-design-standards-and-a-barrier-to-adoption-of-overseas-standards#bmccefc9b3-0678-4731-b245-be66593012b5

All, 

Standards Australia has a vacancy for a committee member CE-022 Concrete Structures Retaining Liquid which is quite an important vacancy.  It is a committee involved in the revision of the Standards AS 2783 – Reinforced Concrete for Small Swimming Pools that is relevant to the area of temporary works in underground structures. 

The criteria and process relating to becoming a nominee is relatively straight forward.  The requirements include being an EA Member, providing an updated and relevant CV and having the nomination for the vacancy circulated to and endorsed by the Working Group.

If interested, please contact: standards@engineersaustralia.org.au

Hi John

Our understanding is that a 5mm thick pipe is used and then a thread is cut. See below At-pac data. It gives an average wall thickness of around 4mm average  (36mm outside, 28mm inside diameter) which can be verified based on the weights. 

See dimensions of the Rd threads:

A typical arrangement for slings is 60 degrees from horizontal but it can be custom designed. Important to consider out-of-plan forces. 

This is a complex operation with cages having significant deflection and a large number of variables that need a robust approach. 

Rotation over a sheave block and analysing each stage of the rotation is recommended. 

As a general comment, equipment that is intended for lifting, already has the necessary safety factors, so on a vertical lift, a 1 ton load can be lifted with a 1 ton shackle. The proprietary produce suppliers then publish reduction factors for different configurations (e.g. side loaded shackles, choked slings, etc). Because these are items that are for general purpose, re-used and have various local effects, the safety factor is high and as mentioned above, around FoS 4. 

Custom designed elements such as steel lugs are then designed to the relevant standards with the appropriate load factors and material factors. Special consideration to be given to lateral loading (out-of-plane) and dynamic effects due to jerky movement and emergency braking. 

The standard AS 4687 presents its own set of performance criteria and risk based approach which appears not necessarily consistent with other Australian Standards. It would be great to discuss these items in this forum thread. 

Thanks for the interesting references. @Shane Groom, yes, especially for transportation, it is often important to have realistic (not too conservative) friction values. Special rubbers (such as Regupol) can be used and perform well even when wet. 

Hi Shane, 

Yes, I think it is a good suggestion to add client side, statutory authorities, and proprietary system suppliers as stakeholders. Any other suggestions what stakeholders should be mentioned? 

Regards,

Florian

Please note that draft standards are published for public comments through Standards Connect https://connect.standards.org.au Log in under public and create a user name.

On 6 April 2021, AS 3610.2 Formwork design just closed their comments for the BD-043 Formwork. 

This thread aims at updating the TWf AU members to any new drafts for comment and ballot. 

AS 5100.4 Bridge bearings in Table 10.1 defines friction coefficients for Bridge bearings, which is relevant to temporary bearings as well such as heavy falsework, temporary sledges and sliding systems. 

This table defines 50% friction coefficient between Steel and concrete with a reduction factor of 0.6, resulting in a friction coefficient of 0.6x50%=30%. Debonding agent/formoil or a very smooth cast surface should be avoided to keep this assumption valid.

For steel to steel interfaces, the friction coefficient depends largely on the surface treatment of the steel but up to 30% friction can be justified. 

Friction is a common topic in temporary works as often temporary stages are relying on friction and a positive connection ignoring friction would result in an design that is inefficient and could create additional risks during the operation. 

Guidance in Australian Standards (AS) on friction coefficients is limited and in this thread we could discuss different references. Friction from laboratory test are often difficult to translate into real world values due to site conditions being humid, greasy, dusty and variability in surface preparation.