Dorman Long Technology

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Welcome to DLT : Technology for modular construction

We develop, manufacture and operate the specialist technology for modular construction of bridges, dams, refineries, power stations, offshore structures, buildings and manufacturing plants. We also offer construction engineering and site services to help our clients get the best value from the equipment we supply.

Our role on most projects is to develop solutions to construction problems, fully engineer these solutions and then to work with our customers to carry out the operations on site. We are happy to offer any combination of erection engineering, equipment supply / rental and site supervision services to suit the needs of each project.

Our product range includes strand jacks, hydraulic gantries, bridge deck erection gantries, skidding systems and synchronised jacking systems. Please click on the 'Products' link above for the full list of our products, and also click on the 'Reference Projects' link above to see many examples of our products and services in use.

All our projects are covered by our company management systems, which are accredited to ISO 9001: 2008 , OHSAS 18001:2007 and ISO 14001: 2004. All these management systems have been written in-house by our own staff to ensure total relevance to our business. Read more »

Dorman Long and Co. Ltd was originally formed in 1875 and we have a page of useful links and resources for anyone interested in finding out more about the history of our famous company.
Read more »


DLT general brochure
DLT company presentation
Latest news......
1200 tonne bridge lifts, Zambia
May 2014
Vanguard have successfully erected two 1200 tonne steel bridges in Zambia using four DL-S418 strand jacks supplied by DLT. Congratulations to Vanguard for a job well done!
Read more »

3600 te capacity weighing system delivered, Vietnam
April 2014
An 8 jack, 3600 te capacity weighing system was delivered, commissioned and used for the first time by client PTSC
Read more »

DL-SE500 bridge erection gantry award, Saudi Arabia
March 2014
DLT have been awarded the contract to design and supply a DL-SE500 bridge deck span erector and a DL-TLC500 transporter for transport and erection of 500 tonne x 36m long precast concrete bridge beams on the Riyadh Metro project, by client FAST Consortium.

DL-TS4000 tower system award, China
March 2014
DLT have been awarded the contract to design a 3200 te lifting capacity jacking tower system to Sinopec No 4 construction company in China

DL-TS3600 tower system award, China
Sept 2013
DLT have been awarded the contract to design and supply a 7200 te lifting capacity jacking tower system to China
Read more »

MYQ5000 tower system award, China
June 2013
DLT have been awarded the contract to design and supply a 5000 te lifting capacity jacking tower system to China
Read more »

Double topside float over, India
Jan 2013
DLT supplied float over jacking system installs 13,400 te & 7,000 te topsides
Read more »

2 No DL-GP1000 skidding units delivered to Nippon Steel
Mar 2013
DLT supplied 2 No 1000 push-pull skidding units to Nippon Steel for load out and installation of offshore jackets
Read more »

Stadium cable net roof erected, Brazil
Dec 2012
The Brasilia stadium cable net roof is erected using a DLT supplied 48 point computer controlled strand jack system
Read more »

Calvary Convention Centre, Malaysia
Sept 2012
A 16 point computer controlled jacking system is installed to open and close two large roof panels
Read more »

Strand Jack systems
15 MT to 1700 MT per jack
Hydraulic Gantries
200 MT to 1200 MT per system
Jacking tower systems
500 MT to 5000 MT per system
Bridge deck erection gantries
Made to order to suit each bridge
pinned climbing jack
Chain Jacks
100 MT to 600 MT per jack
Skidding systems
Up to 2000 MT per point
Pinned climbing & skidding jacks
100 MT to 1000 MT per jack
Synchronous jacking and weighing
100 MT to 3000 MT per jack
Modular bridges
Hydraulic release shackle
winches
Heavy lift & skid control systems
Computer and pendant control
Modular bridges
8m to 200m main span
Subsea hydraulic release shackles
150 MT to 2000 MT per shackle
Hydraulic and electric winches
Up to 300 MT line pull


Hydraulic dampers

Hydraulic sling length adjusters
Made to order to any capacity
Viscous dampers/lock up devices
Made to order to any capacity
Hydraulic power packs
Up to 1000 kW per power pack
Construction Engineering services

We offer a range of construction engineering consultancy services for the design and construction of many types of structure, including bridges, buildings, heavy process plant, petrochemical vessels and offshore structures. We have particular expertise in the erection of long span suspension and cable stayed bridges, and in the engineering of specialist modular construction operations such as heavy lifting, lowering and horizontal skidding operations.

Our engineers draw on first-hand experience of site operations to provide practical schemes supported by clear and concise documentation.  We can develop schemes from initial concept through to detailed design including stage by stage analysis of the permanent works if required

All consultancy services are provided under our ISO 9001:2008 accredited quality management system and covered by professional indemnity insurance.
Our services include the design of the following :

  • Heavy lifting operations
  • Skidding operations
  • Mechanised temporary works
  • Bridge deck erection gantries
  • Bridge deck launching and sliding
  • Power station heavy plant installation
  • Erection of large roof structures
  • Long span bridge erection engineering, including cable stayed and suspension bridges
  • Modular steel bridges, including cable stayed and suspension bridges

We also offer 3rd party independent checking services for construction methods and temporary works designs for projects on a global basis. For example in the UK we have experience in certifying projects for clients Network Rail and the Highways Agency

Honam High Speed Rail viaduct girder erection gantry
Infinity footbridge
Generator installation gantry
Viaduct erection gantry, Korea. Read more»
Infinity footbridge, UK Read more»
Generator installation gantry, India Read more»
Carquinez suspension bridge
Wembley stadium
Boyne Bridge Launch
Carquinez Suspension bridge, USA Read more»
Wembley Stadium roof, UK Read more»
Boyne Bridge, Ireland Read more»
Site Services

Our Site Technicians have many years of experience of carrying out heavy lifting operations and will usually be seconded into a client's team to assist with the first few operations until the client's own staff feel confident to operate the systems themselves. As part of this service we provide a formal training and certification programme to approve client's staff as competent to operate and maintain the equipment. Our Site Technicians usually become a valued member of the site team and are usually requested to return to assist with future operations.

We also maintain a stock of strand jacks for rental or quick delivery, to enable us to respond rapidly to the needs of each project
Reference Projects

The following projects are examples of our involvement in the engineering, equipment supply and operations on site. The highlighted projects demonstrate the full range of our work. Lists of example projects for each sector can be viewed by clicking on the tabs on the left of the page.
  • > Highlights
  • > Bridge projects
  • > Oil and Gas
  • > Power projects
  • > Building projects
Highlighted projects
3600 MT weighing system for PTSC, Vietnam
DLT supplied an eight jack 3600 MT capacity weighing system to PTSC Vietnam in April 2014. The weighing system incorporates load cells for a load accuracy of 0.5% and has a central computer control system for synchronised lifting and lowering of the load and for data logging throughout the weighing operation.
Read more»
Brasilia Stadium cable net roof erection, Brazil
DLT supplied a 48 x 98 tonne computer controlled strand jack system to Protende in Brazil for the erection of a cable net roof structure on the Brasilia stadium, constructed to host the 2014 world cup.
Read more»
B-194 float over
4 x 5,000 te and 4 x 3,750 te float over jacking systems
DLT supplied two complete float over jacking systems to Swiber Offshore Construction for the offshore installation of platforms weighing up to 13,400 tonnes in the ONGC B-193 process complex in the Arabian Sea.
Read more»
B-194 float over
DL-TS3600 jacking tower system for refinery construction
Sinopec Tenth Construction Company have placed a contract with DLT for the supply of a 7200 tonne lifting capacity jacking tower system, for use in the erection of heavy petrochemical vessels. The tower system uses DL-CP600 pinned climbing jacks for lifting, which climb up bars fitted to the inside faces of the towers. The tower system will be delivered in 2014
Read more»
MYQ5000
MYQ5000 jacking tower system for refinery construction
China National Petroleum (CNPCC) have placed a contract with DLT for the supply of a 5,000 tonne lifting capacity jacking tower system, for use in the erection of heavy petrochemical vessels. The MYQ5000 jacking tower system will be able to self-erect and self-dismantle, and will also be able to move with the vessel after lifting. The tower system will be delivered in early 2014
Read more»
honam high speed rail gantry
Honam High Speed rail, Korea. DL-SE35/1000 span erector
DLT were sub-contractors to Samsung C&T for design and supply of a DL-SE1000/35 span erection gantry for erecting the full length of section 4-1 on the Honam High Speed Railway project in Korea. The DL-SE1000/35 can erect precast spans weighing up to 1000 tonnes and up to 35m long at a rate of up to 2 spans per day and is self launching into the next span.
Read more»
New Wembley National Stadium, UK
DLT were responsible for the detailed erection engineering for the 26,000 tonnes of structural steel, including stands, cable suspended roof and main arch structures. The 1,490 tonne main arch was assembled flat and rolled up into position using strand jacks. We were responsible for engineering and supervising this operation.
Read more»
Olmsted Dam project
Olmsted Locks & Dams project, Illinois, USA
The Olmsted Locks and Dams project consists of twin 110-foot wide by 1,200 foot long lock chambers on the Ohio river at Olmsted, Illinois. The lock chambers are constructed from heavy precast concrete units, that will be cast in a yard on shore and then handled on land using a purpose made gantry crane and in the water using a purpose made heavy lift catamaran barge. DLT were awarded the contract to design, supply and operate 2 No 12,000 tonne capacity computer controlled strand jack systems for use as the main lifting systems on both the gantry crane and the catamaran barge.
Read more»
Sutong cable stayed bridge, China. Deck erection and caisson lowering
With a main span of 1088m the Sutong Cable stayed bridge was the longest span cable stayed bridge in the world when completed. DLT were sub-contractors to 2nd Navigation Engineering Bureau for the design, supply and operation of the eight deck erection gantries that were used to erect the 84 No steel orthotropic deck segments, each weighing up to 450 tonnes, between 9th November 2006 and 9th June 2007.
Read more»

These gantries have since been used to erect the decks on two further bridges in China, the shanghai-Yangtze cable stayed bridge and the E-Dong cable stayed bridge.

On the Sutong bridge, we were also responsible for lowering of a 3050 tonne caisson.
Read more»
Blast furnace re-lining, Taiwan
DLT were sub-contractors for installation of a new 40.75m high 3115 tonne furnace line in Taiwan. Our scope included full engineering of all temporary works required together with supply of jacking equipment and site labour to carry out the work. The blast furnace was delivered to the site in 8 segments, weighing up to 477 tonnes each, which were lifted and skidded into the furnace house before being jacked vertically and aligned for welding. These operations were carried out using a mix of strand jacks and climbing jacks.
Read more»
Orinoco River Second Crossing, Venezuela
At over 3km long and with two cable stay spans of 300m, this project provided many engineering challenges. The steel box girder deck for the 60m approach spans was launched in pre-assembled units of up to 2413 tonnes. The steel box girder deck of the two cable stay main spans was erected by balanced cantilever in 250 tonne segments using specially designed deck erection gantries. DLT were responsible for supply and operation of the strand jack systems for launching of the approach spans and for lifting and skidding of the main span deck units.
Read more»
Carquinez suspension bridge, California
DLT were sub-contractors for erection of the 24 No. 700 tonne steel deck units, which was carried out in 2003 using a system of computer controlled strand jacks. The deck units were delivered directly to the bridge site by ship and lifted into final position using 4 No 290 tonne capacity strand jacks mounted on the deck units. DLT were also responsible for detailed erection engineering of the main cables, deck hangers and steel orthotropic deck.
Read more»
Boyne cable stayed bridge, Ireland
DLT were responsible for the design of the superstructure, as an alternative to the client's design, detailed design of the erection methods for all elements of the deck and for supply and operation of the strand jacking systems used to launch the deck into final position.
Read more»
Runyang suspension bridge, China
DLT were responsible for the design, supply and commissioning of 4 No 370 tonne capacity deck erection gantries for this 1490m main span suspension bridge. The gantries were designed to walk the main cables and work in pairs to erect steel deck units weighing up to 470 tonnes each. The gantries can be self erected onto the main cables and can be easily adapted for future projects with different cable centres and diameter.
Read more»
Bridge projects
Forth replacement bridge deck erection gantry
Forth Replacement crossing, Scotland, UK.
DLT are appointed by the Main Contractor, Forth Crossing Bridge Constructors, as construction engineers for the launching of the North Approach Viaduct and for the design of the deck erection gantries for the cable stayed spans. The North Approach Viaduct launch section will be 221m long and weigh 4200 tonnes. It will will be launched a distance of 233m. There will be 6 No deck erection gantries which will be used to erect a total of 109 steel/concrete deck sections weighing up to 729 tonnes at an erection rate of 1 section per gantry per week.
Read more»
Ponte Verde steel arch bridge launch, Italy
In February 2011 the 1000 tonne Ponte Verde steel arch bridge was launched into position by Edimo Metallo S.p.A. using DLT strand jacks and site supervision.
Read more»
honam high speed rail gantry
Honam High Speed rail, Korea. DL-SE35/1000 span erector
DLT were sub-contractors to Samsung C&T for design and supply of a DL-SE1000/35 span erection gantry for erecting the full length of section 4-1 on the Honam High Speed Railway project in Korea. The DL-SE1000/35 can erect precast spans weighing up to 1000 tonnes and up to 35m long at a rate of up to 2 spans per day and is self launching into the next span.
Read more»
Rio Negro Bridge
Rio Negro Cable stayed bridge, Brazil
The Ponte Sobre O Rio Negro is a 3505m long crossing of the Rio Negro in the heart of the Amazon rain forest, linking Manaus with Iranduba over the river Negro. DLT were awarded the contract to design, supply and operate 2 No 320 tonne capacity deck erection gantries to handle the 52 precast concrete deck sections of the cable stayed span.
Read more»
E-Dong Cable Stayed Bridge, China
The E-Dong Cable Stayed Bridge is located in Huanggang city, Hubei Province, China, and crosses the Changjiang river. It has a main span of 926m and side spans of 275m, making it the third longest cable stayed bridge in the world. DLT were awarded the sub-contract by Second Highway Engineering Bureau to design a pair of 280 tonne capacity deck erection gantries to erect steel orthotropic deck segments weighing up to 369 tonnes each on one half of the main span.
Read more»

The other half of the deck was erected by Second Navigation re-using the deck erection gantries we supplied to them for the Sutong Bridge and the Shanghai Yantze Bridge

Shanghai Yangtze Cable Stayed Bridge, China
The Shanghai Yangtze cable stayed bridge carries both road and rail traffic and has a main span of 730 m that crosses the navigational channel along the link between Shanghai and Chongming Island. DLT were awarded the sub-contract by Second Navigational Engineering Bureau to provide site supervision during erection of bridge deck units. Modified DLT deck erection gantries from the Sutong Bridge project were used to erect the 46 No steel orthotropic deck segments, each weighing up to 387 tonnes, from Jan-June 2008.
Read more»
A34 Wolvercote Viadust Replacement Project, UK
The A34 Wolvercote viaduct in the UK carries a 4 lane highway across a river, a railway line and the A40. To minimise disruption to traffic a new east carriageway was constructed alongside the existing 4 lane viaduct, followed by demolition of the old east carriageway structure and sideways sliding of the new structure across into final position. DLT were contracted by main contractor Costain Limited to design, supply and operate a hydraulic lifting and skidding system to move the 254m long, 4920 tonne new east carriageway the 16.6m from its construction position into final position on 8 parallel skidding tracks. Skidding, jack down and re-opening of the viaduct took place in a 18 hour overnight road and rail possession using our DL-SU350 bridge sliding system in March 2010.
Read more»
M74 Port Eglinton Viaduct launch
The Port Eglinton Viaduct carries a new 6 lane section of the M74 motorway over the West Coast Mainline railway in Glasgow, Scotland. It has a main span of 138m and a total length of 750m. A 200m length of each carriageway structure, weighing over 4000 tonnes, was launched 170m across the railway. The structures was moved by back-to-back 418t pulling and restraining strand jacks operatiing on a continuous cable running from one end of the launched structure to the other.
Read more»
Xihoumen Suspension Bridge, China
The Xihoumen suspension bridget crosses the Xihoumen straight between the islands of Jintang and Cezi. It forms one part of a chain of bridges that link Zhoushan island to Ningbo, on the Chinese mainland to the south of Shanghai. It has a main span of 1650m and was the second longest suspension bridge in the world when completed. DLT were the designers and suppliers of the deck erection gantries, which were originally used on the Runyang Bridge Read more» and were modified for this project which had a different main cable spacing and diameter. 119 steel deck segments were erected with these gantries. Maximum lift weight was 370 tonnes. DLT also provided site supervision for the operation and maintenance of the gantries
Infinity Footbridge, UK
The award wining Infinity footbridge is a 2-span tied arch crossing the river Tees in Stockton, England. Main span is 120m, side span is 60m. The arches are steel box sections and the deck is made from precast concrete segments that are post tensioned together to form the arch ties. DLT provided expert advice to the designers on erection methods and details for fabrication and buildability and provided full erection engineering to the contractor, including stage by stage analysis, aerodynamic response analysis and detailed design of all temporary works.
Read more»
Sutong cable stayed bridge, China. Deck erection and caisson lowering
With a main span of 1088m the Sutong Cable stayed bridge was the longest span cable stayed bridge in the world when completed. DLT were sub-contractors to 2nd Navigation Engineering Bureau for the design, supply and operation of the eight deck erection gantries that were used to erect the 84 No steel orthotropic deck segments, each weighing up to 450 tonnes, between 9th November 2006 and 9th June 2007.
Read more»

These gantries have since been used to erect the decks on two further bridges in China, the shanghai-Yangtze cable stayed bridge and the E-Dong cable stayed bridge.

On the Sutong bridge, we were also responsible for lowering of a 3050 tonne caisson.
Read more»
Masalani self anchored suspension bridge, Kenya
DLT were responsible for the detailed erection engineering, including detailed design of all temporary works and the cable system for this self anchored suspension bridge with a main span of 92.3m. The bridge was completed by a local contractor in May 2007.
Read more»
Shibanpo bridge, Chongqing, China
DLT were the sub-contractors for the erection of the three steel deck units forming the main 108m span of this multi-span box girder bridge. Two 2.5m long concrete / steel transition pieces, each weighing 100 tonnes, were erected first. This was followed by the erection of the main 103m long steel centre section weighing 1325te. The three lifts took place in May 2006
Read more»
Orinoco River Second Crossing, Venezuela
At over 3km long and with two cable stay spans of 300m, this project provided many engineering challenges. The steel box girder deck for the 60m approach spans was launched in pre-assembled units of up to 2413 tonnes. The steel box girder deck of the two cable stay main spans was erected by balanced cantilever in 250 tonne segments using specially designed deck erection gantries. DLT were responsible for supply and operation of the strand jack systems for launching of the approach spans and for lifting and skidding of the main span deck units.
Read more»
Taizhou Yangtze River Highway Bridge, China
DLT/FNP JV acted as advisors to the Client on key technical issues regarding the design and construction of the central tower on this 3 tower, 2x1080m span, suspension bridge. Our work included advising on the rigidity of the four leg tower, the risk of main cable slip over the tower, bridge articulation, use of hydraulic dampers and movement limiting devices and seismic analysis and design.
ChaoTianMen arch bridge, Chongqing, China
The ChaoTianMen arch bridge crosses the Yangtze river in the city of Chongqin in South West China. It has a tied arch main span of 552m with continuous side spans of 190m, and was designed to resemble the Sydney Harbour Bridge, completed by Dorman Long and Co. in 1932. DLT acted as consultant to the main contractor, 2nd Navigation Engineering Bureau and were responsible for developing and detailing the construction method to be used. On completion this was the longest arch span in the world.
Carquinez suspension bridge, California
DLT were sub-contractors for erection of the 24 No. 700 tonne steel deck units, which werew erected in 2003 using a system of computer controlled strand jacks. The deck units were delivered directly to the bridge site by ship and lifted into final position using 4 No 290 tonne capacity strand jacks mounted on the deck units. DLT were also responsible for detailed erection engineering of the main cables, deck hangers and steel orthotropic deck.
Read more»
Bishop's bridge replacement, Paddington Station, London
DLT were sub-contractors for design, supply and operation of strand jack and climbing jack systems for vertical lifting and horizontal skidding operations required to replace the existing railway over bridges with a new six lane composite bridge. DLT are also responsible for conceptual and detailed design of all construction methods, all of which took place within limited railway possessions.
Read more»
Boyne cable stayed bridge, Ireland
DLT were responsible for the design of the superstructure, as an alternative to the client's design, detailed design of the erection methods for all elements of the deck and for supply and operation of the strand jacking systems used to launch the deck into final position.
Read more»
Runyang suspension bridge, China
DLT were responsible for the design, supply and commissioning of 4 No 370 tonne capacity deck erection gantries for this 1490m main span suspension bridge. These gantries were designed to walk the main cables and work in pairs to erect steel deck units weighing up to 470 tonnes each. The gantries were able to be self erected onto the main cables and can be easily adapted for future projects with different cable centres and diameter.
Read more»
Tuti suspension bridge, Khartoum
DLT were responsible for the permanent works design and erection engineering for this landmark structure in the centre of Khartoum. The bridge has a main span of 210m and was designed for construction by local labour.
Read more»
El Damar and Doungola bridges, Khartoum
DLT were responsible for the conceptual and detailed design of both of these bridges, which cross the river Nile in Khartoum. Both bridges were designed as a series of approximately 40m span concrete decks on reinforced concrete piers founded on piled foundations into the river bed. The decks were constructed from simply supported precast, post-tensioned T girders with a continuous reinforced concrete slab.
Sheikh Khalifa Bin Salaman Causeway Bridge, Bahrain
DLT were responsible for erection engineering of the bridge steel structure, involving offsite assembly of the 3000 tonne main span, transport to site and lifting in one piece into final position using 8 No 500 tonne capacity strand jacks.
Read more»
Jiangyin suspension bridge, China
DLT were responsible for detailed erection engineering, equipment supply and site supervision for deck erection on this 1385m main span suspension bridge.
Read more»
Tsing Ma suspension bridge, Hong Kong
DLT were responsible for detailed erection engineering, equipment supply and site supervision for deck erection on this 1377m main span suspension bridge.
Read more»
A2/M2 Medway Bridge, Kent, UK
DLT were responsible for the design, supply and operation of a 800 tonne capacity climbing jack system for the lifting and lowering of temporary formwork support trusses for the construction of 80m long in-situ post tensioned concrete approach spans.
Read more»
Tamar suspension bridge strengthening and widening, UK
DLT were responsible for value engineering of the permanent strengthening and widening works and conceptual and detailed design of all erection and demolition methods and related temporary works for carrying out this upgrade to the existing 335m span suspension bridge.
Read more»
Lions Gate suspension bridge deck replacement, Vancouver
DLT were responsible for supply and operation of a strand jacking system to carry out replacement of the complete bridge deck in 54 sections, each within a 10 hour overnight closure of the bridge. 4 No DL-S60 strand jacks (plus 2 No spare jacks) with power and control system for a lifting speed of 60 metres per hour were supplied to the main contractor, American Bridge.
Oil and Gas projects
3600 MT weighing system for PTSC, Vietnam
DLT supplied an eight jack 3600 MT capacity weighing system to PTSC Vietnam in April 2014. The weighing system incorporates load cells for a load accuracy of 0.5% and has a central computer control system for synchronised lifting and lowering of the load and for data logging throughout the weighing operation.
Read more»
B-194 float over
DL-TS3600 jacking tower system for refinery construction
Sinopec Tenth Construction Company have placed a contract with DLT for the supply of a 7200 tonne lifting capacity jacking tower system, for use in the erection of heavy petrochemical vessels. The tower system uses DL-CP600 pinned climbing jacks for lifting, which climb up bars fitted to the inside faces of the towers. The tower system will be delivered in 2014
Read more»
MYQ5000
MYQ5000 jacking tower system for refinery construction
China National Petroleum (CNPCC) have placed a contract with DLT for the supply of a 5,000 tonne lifting capacity jacking tower system, for use in the erection of heavy petrochemical vessels. The MYQ5000 jacking tower system will be able to self-erect and self-dismantle, and will also be able to move with the vessel after lifting. The tower system will be delivered in early 2014
Read more»
4 x 5,000 te and 4 x 3,750 te float over jacking systems
DLT supplied two complete float over jacking systems to Swiber Offshore Construction for the offshore installation of platforms weighing up to 13,400 tonnes in the ONGC B-193 process complex in the Arabian Sea.
Read more»
2,000 tonne skidding system for offshore jacket load out and installation
DLT supplied a 2 x 1000 te capacity (push/pull) jacking system to Nippon Steel in Japan for use on their offshore jacket installation barge that was launched in 2012. The jacking system comprises 2 No DL-GP1000 gripper jacks and was designed to walk along a purpose designed skid track. It will be used for load out of jackets onto the installation barge and for launching of the jackets from the barge at the installation site
Read more»
Maari Field Wellhead Platform, Jacket erection, Malaysia
DLT were sub-contracted to design, supply and operate a skidding and jacking system to incrementally erect a 26m x 22m x 140m high 2800 tonne jacket structure. The jacket was erected in 8 sections, weighing up to 660 tonnes each using our DL-TS3000 tower system.
Read more»
Supply and operation of strand jack systems for replacement of thrusters
DLT have supplied many strand jack systems for the installation and replacement of thruster units weighing up to 50 tonnes on drilling ships and floating platforms. Strand jacks provide a compact and cost effective solution for handling heavy thruster units and we have also developed a system of modular power packs and jacks that can be taken through bulkhead doors into the thruster room. Our client list for this work includes Stenna Drilling, Jurong shipyard, Daewoo shipyard, Resource Rigging, Sea Drill, Frontier Drilling, Larsen Oil and Gas, Noble Corporation, Wartsila, Transocean and Napro Services.
Read more»
Recovery of mooring yoke to release FSO from buoy, Mediterranean Sea
DLT were sub-contracted to provide a strand jacking system to raise a mooring yoke to release an FSO vessel from its mooring buoy where it had be located for 20 years. The original 1000te capacity long stroke ram used to install the yoke was unserviceable. DLT engineered a system using 2No DL-S418 strand jacks mounted on a T-frame attached to the FSO using the existing long stroke ram mounting point. The jacks were powered by a DL-L114/4/D diesel engine operated hydraulic power pack.
Sea Drill pontoon launch, Singapore
DLT were sub-contracted to side shift and launch 2 No 3600 tonne pontoon units at the Jurong Shipyard, Singapore, in May and June 2007 for the Sea Drill floating platform No 8. The first pontoon was launched 125m down a 6 degree slope into the water in May. The second pontoon was side shifted 100m into position for launching and then launched down the same slope as the fist pontoon. The pontoons were supported on inflated air bags for all these operations and moved using 2 no DL-S185 strand jacks and 2 No DL-L30F/1/350/120/E power packs for a launching speed of 17 m/hour, controlled using our DL-P40 computer control system
Corocoro FSO Mooring Line Tensioning, Venezuela
DLT were sub-contracted to assist in the installation of a FSO mooring line system 32 km offshore in the Corocoro Oil Field, Venezuela. DLT designed and supplied the strand jack tensioning system to pull pairs of mooring lines toward one another causing their anchors to plough into the sea bed and subsequently test load the mooring lines to a 700te tension.
Read more»
FPSO mooring yoke and pendulum installation using strand jacks
DLT were responsible for the installation of a number of FPSO mooring yoke and pendulum structures weighing up to 1040 tonnes using strand jacks for lifting and final alignment to make the permanent connections. Our client for these operations were SMOE and Keppel Singmarine in Singapore, with work being carried out in Singapore and Azerbaijan.
Read more»
Formosa Plastics Plant, Taiwan
DLT were responsible for the design, supply and site supervision for a modular jacking tower system that has so far been used to erect 58 vessels weighing up to 1,557 tonnes and up to 114.5m long.
Read more»
2500 tonne strand jack tower system, China
DLT were responsible for the conceptual and detailed design of this 2500 tonne lifting capacity modular strand jack tower system, specifically designed for the Chinese refinery construction market in 2002. The tower system is owned and operated by the No 4 Construction company of SINOPEC and has many features including self-erection, and luffing under full load.
Read more»
Load out of FPSO pontoon, Korea
DLT were responsible for the design, supply and site supervision for a strand jack system to load out a 14,500 tonne FPSO pontoon onto a delivery ship, for main contractor Hyundai. The deck was moved 125 metres using four 580 tonne capacity strand jacks.
Dismantling of the Brent Spar oil storage platform
DLT were responsible for the design of a 2300 tonne lifting capacity lifting gantry for handling cut sections of the Brent Spar as it was decommissioned in a Norwegian fjord in 1999. The gantry used 4 No 580 tonne capacity strand jacks for lifting and a gripper jack system for longitudinal movement over the decommissioning barge. The legs and cross beams of the gantry structure were made from a proprietary tower system which were connected and braced using purpose designed steelwork.
Power and Energy projects
Generator installation gantry, India
In 2012 DLT supplied a 540 tonne capacity modular gantry for installation of generators to Lift and Shift India. The gantry is modular to accommodate the geometry of each site and incorporates folding strand jacks to allow the generator and strand jack carriage to move together into the turbine hall without the need to remove a section of the overhead crane rail to provide extra headroom. The gantry is able to lift, rotate and move the generator into final position and incorporates both transverse and longitudinal movement systems to allow the generator to be set accurately onto its foundations.
Read more»
Steam drum installation, India
In 2010 DLT supplied a 370 tonne capacity strand jack lifting system to BHEL Western Division in India for use in the construction of power stations. The system comprises 2 No DL-S185 strand jacks powered by 2 No DL-L40/1/300/E electrically powered hydraulic power packs for a lifting speed of 20 m/hr and controlled using our DL-M2 pendant control system. The first steam drum was lifted in November 2010.
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Steam generator replacement, USA
In November 2010 Rigging International used 2 No DL-S418 strand jacks to replace a steam generator in the SONGS nuclear power plant in California. The lifting system comprised 2 No DL-S418 strand jacks powered by 1 No DL-L60/4/300/D diesel powered hydraulic power pack for a lifting speed of 14 m/hr and controlled using our DL-P40 computer control system. The operation took place adjacent to a live nuclear reactor in an environment with very high electrical magnetic interference. Our DL-P40 computer control system was approved for use in this environment following a successful 24 hour continuous running test on the site.
Blast furnace re-lining, Taiwan
DLT were sub-contractors for installation of a new 40.75m high 3115 tonne furnace in Taiwan. Our scope included full engineering of all temporary works required together with supply of jacking equipment and site labour to carry out the work. The blast furnace was delivered to the site in 8 segments, weighing up to 477 tonnes each, which were lifted and skidded into the furnace house before being jacked vertically and aligned for welding. These operations were carried out using a mix of strand jacks and climbing jacks.
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BARD Offshore 1 wind farm. Transformer platform self-installation system
The BARD 1 wind farm is located in the North Sea and has a total of 80 wind turbines producing up to 400 MW which is connected into the german extra-high-voltage grid via a 125km long submarine cable. DLT supplied and operated a 16 x DL-S588 computer controlled strand jack system for the self-installation of the central transformer and accommodation platform. The strand jack system was used to suspend the 3,500 tonne jacket from the floating platform during sea transport, then to lower the jacket down onto the sea bed, and finally to lift the 3,320 tonne platform up out of the sea into final operating position where it was then structurally connected to the jacket.
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Steam Drum installations, USA
DLT have provided strand jack systems and site supervision to Rigging International for lifting and installation of a number of steam drums weighing up to 380 te and lifted up to 65 m. The strand jack system supplied comprises 2 No DL-S418 strand jacks and a DL-L60F/4/350/D diesel powered hydraulic power pack, with a combined lifting capacity of 836 tonnes and a lift speed of 15 m/hour
Pinalito Hydroelectric Plant, Dominican Republic
DLT were employed by Odebrecht to supply equipment and site supervision to install a water distribution pipe which was required to pass over one of Dominican's many mountains. DLT's equipment and supervisors assisted in the installation of the pipe, pulling a total of 78 sections, from 10 different locations using DLT strand jacks. The maximum pull was 132 tonnes, and the longest pull was 157m.
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Heat exchanger replacement, Indonesia
DLT were responsible fore the design, supply and operation of a 60 tonne capacity gantry to replace 2 No 60 tonne heat exchangers from deep within a steel framed structure on PT Peni's site in Indonesia. Use of these purpose designed gantries in place of conventional cranes avoided the need to extensively dismantle the steel structure to gain access to the vessels, saving time and money.
Building projects
Calvary Church Convention Centre, Kuala Lumpur, Malaysia
DLT were awarded two contracts from Victor Buyck (Malaysia) on this project. The first was to supply a 4 x DL-S185 strand jack system to lift 2 No 200 tonne 60 m long mega trusses that are used to support the roof over the main hall of the convention centre.
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The second was for the design and supply of a synchronised jacking system to open and close 2 No 270 tonne angel wings located on the roof.
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Brasilia Stadium cable net roof erection, Brazil
DLT supplied a 48 x 98 tonne computer controlled strand jack system to Protende in Brazil for the erection of a cable net roof structure on the Brasilia stadium, constructed to host the 2014 world cup.
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Ventian Theatre Roof Erection, Macau
DLT were sub-contractors for the erection of the 940 tonne steel roof structure for the new 2000 seat theatre as part of the Venetian Development in Macau. Our scope included erection engineering, equipment rental and site operation. The roof trusses were assembled on site at ground level and then lifted into position using a climbing jack system. The roof trusses were erected in 3 separate lifts, each weighing up to 400 tonne.
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Haeco Hangar 3A roof lift, Hong Kong
DLT were sub-contractors to China State-Leighton JV for the lifting of the 3,520 tonne pre-assembled steel roof. The roof was lifted 30m using 8 No DL-S418 strand jacks mounted on 4 No 40m high DL-TS3000 free standing towers and 6 No DL-S185 strand jacks mounted on the permanent concrete columns. All jacks were monitored, synchronised and controlled by a single operator using our DL-P40 computer control system
Heathrow Airport, Terminal 5 building and air traffic control tower, UK
DLT were responsible for the detailed erection engineering for the 18,500 tonne steel roof structure of the new main core terminal building, and for a 1000 tonne air traffic control tower. Both were fabricated off-site and erected on-site using strand jack lifting systems. The roof box girders, purlins and cladding to the core terminal building roof were erected in 6 No 2,000 tonne lifts. The control tower was pre-assembled off-site into 7 fully complete modules and then assembled on-site using a unique vertical jacking technique.
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New Wembley National Stadium, UK
DLT were responsible for the detailed erection engineering for the 26,000 tonnes of structural steel, including stands, cable suspended roof and main arch structures. The 1,490 tonne main arch was assembled flat and rolled up into position using strand jacks. We were responsible for engineering and supervising this operation.
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Hong Kong Convention and Exhibition Centre.
DLT were responsible for erection engineering, heavy lifting equipment supply and operation for the erection of an 8000 tonne prefabricated roof structure and a 5,500 tonne link bridge. The roof structure was fabricated and assembled in the Philippines into modules weighing up to 460 tonnes each, which were then shipped to the site for lifting and skidding into final position. The link bridge was erected piece small by a stiff leg derrick mounted on a purpose made skid track. Access to this part of the site was very restricted, requiring the stiff leg derrick to construct its own skid track and then work backwards along the skid track to erect the permanent works.
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HAECO hangar 1 roof lift, Hong Kong
DLT were responsible for the design, supply and operation of a strand jack lifting system together with associated erection engineering to lift 2 No pre-assembled roof sections, each weighing over 1000 tonnes. Each section of roof was lifted with 9 No DL-S185 strand jacks. Temporary works for the lift comprised 3 No 300 tonne capacity jacking towers, plan bracing to stabilise the roof and a guide track against the concrete core structure.
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Virgin Atlantic Airways hangar roof lift, London
DLT were responsible for the detailed erection engineering for the lifting by strand jacks of an 800 tonne roof truss for this aircraft maintenance hangar at Heathrow Airport. The roof structure was assembled at ground level and then lifted using strand jacks mounted on the top of the permanent columns, which were stabilised by rented proprietary towers that were anchored down to the permanent foundations.
Link bridges, Hong Kong
DLT were responsible for the design, supply and operation of a strand jack heavy lifting and horizontal skidding system for the erection of two 1100 tonne pre-assembled link bridges in Hong Kong for main contractor, Gammon-Skanska.
Cairns Convention Centre Phase II, Australia.
The roof to this convention centre is constructed from a complex series of curved V shaped steel trusses that work with a plan tie system in the finished state to provide a rigid and stable structure. To reduce the roof erection cost and programme, the roof was assembled in fully clad panels adjacent to the site and erected onto temporary supports within the building. We were responsible for the detailed erection engineering of the roof, including all temporary supports and stability bracing, which was required to withstand cyclone wind loads at any erection stage.
HQ1 Building, London
DLT were responsible for detailed connection design and erection engineering of the 6,600 tonnes of steel frame to this 16 storey office block. This included heavy lifting of a 650 tonne module which was built on a lower floor and then raised 30m to the 16th floor. DLT were also responsible for supply and operation of the strand jack system to carry out this lift, using 4 No DL-S185 strand jacks.
Careers with Dorman Long Technology

We are a multidisciplinary team of engineers working on the design, development, manufacture, commissioning and site operation of the latest equipment & methods for the modular construction of bridges, offshore structures, large buildings, power stations and other structures where there is the need to erect heavy modules. On most projects we work with the client to determine the best method of construction and then provide the complete service of construction engineering, supply of equipment and site supervision. Our design and construction team is a mix of civil, structural, mechanical, electrical and control systems engineers working from our offices in the UK, China and India.

If you have a passion for engineering and wish to develop your career with like minded people then we would love to hear from you. We offer a good package & benefits, opportunities for travel, training for professional development and a stimulating working environment. You will be working with some of the best engineers in the business.

If you would like to join our team then please send your CV with covering email to careers@dormanlong.com. We welcome quality applications at all times.

Contact details

For general enquiries please contact enquiries@dormanlong.com
UK Head Office:
The Charles Parker Building, Midland Road,
Higham Ferrers, Northamptonshire, NN10 8DN,
United Kingdom
Tel. +44 (0)1933 319133
Contact: Mr David Dyer. david.dyer@dormanlong.com

UK Northern Office:
Whessoe Technology Centre
Morton Palms, Darlington
Co Durham, DL1 4WB, United Kingdom
Tel. +44 (0)1325 390010
Contact: Mr Chris Wilkinson. chris.wilkinson@dormanlong.com

China Office:
Dorman Long Technology (Shanghai) Co. Ltd
19D Yu Jia Building, 1336 Huashan Road
Changning District, Shanghai 200052
Tel. +86 (0) 21 62110500/520
Contact: Mr Hongyi Tao. hongyi.tao@dormanlong.com

India Office:
Dorman Long Technology India Pvt. Ltd.
208, Tower A, Spazedge Commercial Complex
Sector - 47, Sohna Road, Gurgaon (Nr New Delhi)
Pin-122018, Haryana, India.
Tel. +91 124 4270791
Mr Amanpreet Singh Lamba. aman.lamba@dormanlong.com