You do not have permission to edit this page, for the following reasons:

This IP address has been blocked from editing Wikipedia.
This does not affect your ability to read Wikipedia pages.
Most people who see this message have done nothing wrong. Some kinds of blocks restrict editing from specific service providers or telecom companies in response to recent abuse or vandalism, and can sometimes affect other users who are unrelated to that abuse. Review the information below for assistance if you do not believe that you have done anything wrong.

The IP address or range 35.170.0.0/16 has been blocked (disabled) by ‪JJMC89‬ for the following reason(s):

The IP address that you are currently using has been blocked because it is believed to be a web host provider or colocation provider. To prevent abuse, web hosts and colocation providers may be blocked from editing Wikipedia.
You will not be able to edit Wikipedia using a web host or colocation provider because it hides your IP address, much like a proxy or VPN.
We recommend that you attempt to use another connection to edit. For example, if you use a proxy or VPN to connect to the internet, turn it off when editing Wikipedia. If you edit using a mobile connection, try using a Wi-Fi connection, and vice versa. If you are using a corporate internet connection, switch to a different Wi-Fi network. If you have a Wikipedia account, please log in.
If you do not have any other way to edit Wikipedia, you will need to request an IP block exemption.

How to appeal if you are confident that your connection does not use a colocation provider's IP address:
If you are confident that you are not using a web host, you may appeal this block by adding the following text on your talk page: ((unblock|reason=Caught by a colocation web host block but this host or IP is not a web host. My IP address is _______. Place any further information here. ~~~~)). You must fill in the blank with your IP address for this block to be investigated. Your IP address can be determined here. Alternatively, if you wish to keep your IP address private you can use the unblock ticket request system. There are several reasons you might be editing using the IP address of a web host or colocation provider (such as if you are using VPN software or a business network); please use this method of appeal only if you think your IP address is in fact not a web host or colocation provider.

Administrators: The IP block exemption user right should only be applied to allow users to edit using web host in exceptional circumstances, and requests should usually be directed to the functionaries team via email. If you intend to give the IPBE user right, a CheckUser needs to take a look at the account. This can be requested most easily at SPI Quick Checkuser Requests. Unblocking an IP or IP range with this template is highly discouraged without at least contacting the blocking administrator.

This block will expire on 05:20, 2 July 2025.

Even when blocked, you will usually still be able to edit your user talk page, as well as email administrators and other editors.

For information on how to proceed, please read the FAQ for blocked users and the guideline on block appeals. The guide to appealing blocks may also be helpful.

Other useful links: Blocking policy · Help:I have been blocked
Your IP address is in a range that has been blocked on all Wikimedia Foundation wikis. The block was made by ‪Jon Kolbert‬. The reason given is Open proxy/Webhost: See the help page if you are affected .
- Start of block: 05:38, 21 February 2024
- Expiry of block: 05:38, 21 February 2029
Your current IP address is 35.170.198.190. The blocked range is 35.170.0.0/16. Please include all above details in any queries you make. If you believe you were blocked by mistake, you can find additional information and instructions in the No open proxies global policy. Otherwise, to discuss the block please post a request for review on Meta-Wiki. You could also send an email to the stewards VRT queue at stewards@wikimedia.org including all above details.

You can view and copy the source of this page:

((refimprove|date=September 2013))
[[File:Freybrücke Berlin-Spandau-Juni 2016-27-DSCF0177.jpg|thumb|Strandjack at Freybridge in [[Berlin]]–Spandau<br /><small>52° 30′ 42,11″ N, 13° 12′ 11,7″ O</small>]]
A '''strand jack''' (also known as '''strandjack''') is a [[jack (device)|jack]] used to lift very heavy loads (e.g. thousands of tons or more with multiple jacks) for construction and engineering purposes.<ref>[http://www.brighthubengineering.com/machine-design/19760-strand-jacks-what-are-they Strand Jacks – What are they?]</ref>  Strandjacking was invented by [[Vorspann System Losinger|VSL]] Australia's Patrick Kilkeary & Bruce Ramsay in 1969 for [[Prestressed concrete#Post-tensioned concrete|concrete post tensioning]] systems, and is now widely used for heavy lifting, to erect bridges, offshore structures, refineries, power stations, major buildings and other structures where the use of conventional cranes is either impractical or too expensive.

== Use ==
[[File:Litzenheber.gif|thumb|upright|Animation of a strand jack]]
Strand jacks can be used horizontally for pulling objects and structures, and are widely used in the oil and gas industry for skidded loadouts. Oil rigs of 38,000 [[Tonne|t]] have been moved in this way from the place of construction on to a [[barge]].
Since multiple jacks can be operated simultaneously by hydraulic controllers, they can be used in tandem to lift very large loads of thousands of tons. Tandem use of even two cranes is a very difficult operation. <ref>[http://www.bygging-uddemann.se/supply/heavy-lifting-systems/strand-jacks.html Strand Jack Lifting]</ref>

== How it works ==
A strand jack is a hollow [[hydraulic]] cylinder with a set of steel cables (the "strands") passing through the open centre, each one passing through two clamps - one mounted to either end of the cylinder.

The jack operates in the manner of a [[caterpillar]]'s walk: climbing (or descending) along the strands by releasing the clamp at one end, expanding the cylinder, clamping there, releasing the trailing end, contracting, and clamping the trailing end before starting over again. The real significance of this device lies in the facility for precision control.

The expansion and contraction can be done at any speed, and paused at any location.  Although a lone jack may lift only 1700 tons or so, there exist computer control systems that can operate 120 jacks simultaneously, offering [[fingertip feel]] movement control over extremely massive objects.

== In construction ==
'''Strand jacking''' is a construction process whereby large pre-fabricated building sections are carefully lifted and precisely placed. The alternative would be to do all assembly ''in situ'', even if expensive, technically risky, or dangerous.

Strand jacks used for heavy lifting and skidding operations are owned and operated by a large number of construction and heavy lifting companies around the world. They are manufactured by a small number of companies based in Europe.((clarify|date=August 2023))((cn|date=August 2023))

== Notable uses ==
*[[Kursk submarine disaster]]
Uses outside of construction 
* [[Costa Concordia disaster]], in the ship salvage phase.

==References==
((Commons category|Strand jacks))
((Reflist))

[[Category:Construction equipment]]
[[Category:Machines]]

Pages transcluded onto the current version of this page (help):

Template:Ambox (view source) (template editor protected)
Template:Category handler (view source) (protected)
Template:Citation needed (view source) (protected)
Template:Clarify (view source) (template editor protected)
Template:Cn (view source) (template editor protected)
Template:Commons category (view source) (template editor protected)
Template:Delink (view source) (protected)
Template:Find sources mainspace (view source) (template editor protected)
Template:Fix (view source) (protected)
Template:Fix-span (view source) (template editor protected)
Template:Fix/category (view source) (protected)
Template:Main other (view source) (protected)
Template:More citations needed (view source) (template editor protected)
Template:Plainlist/styles.css (view source) (protected)
Template:Refimprove (view source) (template editor protected)
Template:Reflist (view source) (protected)
Template:Reflist/styles.css (view source) (protected)
Template:Replace (view source) (protected)
Template:Side box (view source) (template editor protected)
Template:Sister project (view source) (template editor protected)
Module:Arguments (view source) (protected)
Module:Category handler (view source) (protected)
Module:Category handler/blacklist (view source) (protected)
Module:Category handler/config (view source) (protected)
Module:Category handler/data (view source) (protected)
Module:Category handler/shared (view source) (protected)
Module:Check for unknown parameters (view source) (protected)
Module:DecodeEncode (view source) (template editor protected)
Module:Delink (view source) (protected)
Module:Find sources (view source) (template editor protected)
Module:Find sources/config (view source) (template editor protected)
Module:Find sources/links (view source) (template editor protected)
Module:Find sources/templates/Find sources mainspace (view source) (template editor protected)
Module:Message box (view source) (protected)
Module:Message box/ambox.css (view source) (protected)
Module:Message box/configuration (view source) (protected)
Module:Namespace detect/config (view source) (protected)
Module:Namespace detect/data (view source) (protected)
Module:Side box (view source) (template editor protected)
Module:Side box/styles.css (view source) (template editor protected)
Module:String (view source) (protected)
Module:Unsubst (view source) (protected)
Module:WikidataIB (view source) (template editor protected)
Module:WikidataIB/nolinks (view source) (template editor protected)
Module:WikidataIB/titleformats (view source) (template editor protected)
Module:Yesno (view source) (protected)

Return to Strand jack.

Retrieved from "https://en.wikipedia.org/wiki/Strand_jack"