Mabey Hire can help. Contact Mabey Bridge for rapid-build, modular steel bridging solutions for permanent, temporary and emergency applications worldwide. Please note that Mabey Hire ANZ and Mabey Bridge are now in separate ownership to the Mabey Holdings Limited group of companies, further details for each can be found through these links above. Medium Girder Bridge Components. The medium girder bridge (MGB) is lightweight, hand-built, bridging equipment, it can be built in various configurations to provide a full range of.
The Mabey Logistic Support Bridge (in the United States, the Mabey-Johnson Bridge) is a portable pre-fabricatedtrussbridge, designed for use by military engineering units to upgrade routes for heavier traffic, replace damaged civilian bridges, replace assault and general support bridges and to provide a long span floating bridge capability. The bridge is a variant of that Mabey Compact 200 bridge, with alterations made to suit the military user as well as a ramp system that will provides ground clearance to civilian and military vehicles.
Description
US Army Mabey Logistic Support Bridge Iraq
The Logistic Support Bridge is a non-assault bridge for the movement of supplies and the re-opening of communications. The Logistic Support Bridge is a comparatively low cost system that can be used widely throughout the support area, as well as for a range of defined applications. All types of vehicles including civilian vehicles with low ground clearances are accommodated.
The Mabey Logistic Support Bridge originated from the Bailey bridge concept. Compared with World War II material in use throughout the world, LSB is manufactured with chosen modern steel grades. As with all Mabey & Johnson bridging, the LSB has a strong steel deck system. With strong deep transoms, there are only two per bay instead of the four previously needed on Bailey.
Beyond the need for the re-opening of communications, Logistic Support Bridge based equipment (Compact 200) can be used as a rescue bridge for relief in natural disaster situations or as a civilian bridge for semi permanent bridging to open up communications in some of the most remote regions of the world.
US Army Mabey Logistic Support Bridge Iraq
The Logistic Support Bridge is a non-assault bridge for the movement of supplies and the re-opening of communications. The Logistic Support Bridge is a comparatively low cost system that can be used widely throughout the support area, as well as for a range of defined applications. All types of vehicles including civilian vehicles with low ground clearances are accommodated.
The Mabey Logistic Support Bridge originated from the Bailey bridge concept. Compared with World War II material in use throughout the world, LSB is manufactured with chosen modern steel grades. As with all Mabey & Johnson bridging, the LSB has a strong steel deck system. With strong deep transoms, there are only two per bay instead of the four previously needed on Bailey.
Beyond the need for the re-opening of communications, Logistic Support Bridge based equipment (Compact 200) can be used as a rescue bridge for relief in natural disaster situations or as a civilian bridge for semi permanent bridging to open up communications in some of the most remote regions of the world.
Mabey Bridge Usa
Users
The bridge is manufactured by Mabey & Johnson Ltd, England. The name LSB was given by the British Army (Royal Engineers) to supply bridging to satisfy their specific requirements for a logistic or line of communication bridging. The LSB went into service with the British Army on 21 December2001. The system is proved and approved by a number of NATO forces.
Armies from a number of countries around the world own equipment or have trained and deployed on the system, notably during the crisis in the Balkans. These Armies include Argentina, Austria, Belgium, Brazil, Bulgaria, Cambodia, Canada, Chile, Denmark, Ecuador, Finland, France, Germany, Greece, Hungary, Italy, Malaysia, Nepal, Netherlands, Romania, Sri Lanka, Slovakia, Slovenia, Spain, Sweden, Switzerland, Tanzania, Turkey, Venezuela, United Kingdom, United States.
The bridge has been built in many locations across Iraq by the U.S. Naval Mobile Construction Battalions (Seabees) and the U.S. Army Corps of Engineers.
The bridge is manufactured by Mabey & Johnson Ltd, England. The name LSB was given by the British Army (Royal Engineers) to supply bridging to satisfy their specific requirements for a logistic or line of communication bridging. The LSB went into service with the British Army on 21 December2001. The system is proved and approved by a number of NATO forces.
Armies from a number of countries around the world own equipment or have trained and deployed on the system, notably during the crisis in the Balkans. These Armies include Argentina, Austria, Belgium, Brazil, Bulgaria, Cambodia, Canada, Chile, Denmark, Ecuador, Finland, France, Germany, Greece, Hungary, Italy, Malaysia, Nepal, Netherlands, Romania, Sri Lanka, Slovakia, Slovenia, Spain, Sweden, Switzerland, Tanzania, Turkey, Venezuela, United Kingdom, United States.
The bridge has been built in many locations across Iraq by the U.S. Naval Mobile Construction Battalions (Seabees) and the U.S. Army Corps of Engineers.
Features
The bridge takes military load class 80 Tracked, 110 Wheeled
The bridge can span up to 61m
LSB has a lane width of 4.2m
Multi-span equipment enables the bridge to be built to any length on fixed or floating supports
Built on a greenfield site using grillages, ground beams and ramps
The bridge is normally built using a 22ton capacity crane or HyEx with an eye attachment on the bucket
The bridge takes military load class 80 Tracked, 110 Wheeled
The bridge can span up to 61m
LSB has a lane width of 4.2m
Multi-span equipment enables the bridge to be built to any length on fixed or floating supports
Built on a greenfield site using grillages, ground beams and ramps
The bridge is normally built using a 22ton capacity crane or HyEx with an eye attachment on the bucket
System description
Intermediate span being floated into position on intermediate piers
Anchor systems with hand winches
Landing Spans launched from the home and far banks
Completed float bridge
The LSB combines standard off the shelf equipment with a range of purpose designed special equipment to meet the expectations of modern military loads and traffic expectations.
Panels —These are the main structural components of the bridge trusses. They are welded items comprising top and bottom chords interconnected by vertical and diagonal bracing. At the end of each panel, chords terminate in male lugs or eyes and at the other end in female lugs or eyes. This allows panels to be pinned together to form the bridge span. There are two different panels; a Super Panel and a High Shear Super Panel. The High Shear Super Panel is used at each end of the bridge span depending upon the loading criteria.
Chord reinforcement —These are constructed in the same way as the chords of the bridge panels and are bolted to the panels to increase the bending capacity of the bridge. For the LSB a heavy chord reinforcement is used.
Transoms —These are fabricated from universal beams and form the cross girders of the bridge, spanning between the panels and carrying the bridge deck. The transom is designed for the appropriate loading criteria and for LSB is designed to accommodate MLC80T/110W.
Decks —Unlike wooden Bailey decks, the steel LSB decks are 1.05m x 3.05m and are manufactured using robotic welding technology. The decks are manufactured to have a long fatigue life and with durbar/checkered plate finish. The decks withstand both wheeled and tracked vehicles.
Bracing —A variety of bracing members are used to connect panels to form the bridge trusses and to brace adjacent transoms to the bridge.
Grillages and Ground Beams —On greenfield sites and when being used as an over bridge, ground beams are available that form an assembly which transmits all dead and live forces from the bridge into the ground. For a 40m (MLC80T/110W) bridge the ground bearing pressure is 200kN/m2. The grillages are located on the top of the ground beams and accommodate the bridge bearings as well as the head of the ramp transom.
Ramps —The slope or profile of the ramps can be adjusted to allow for the passage of a range of civilian and military traffic. The length of a standard ramp at each end of the bridge is 13.5m. The ramps are bolted to the grillages and use standard deck units supported on special transoms. These transoms can be positioned at a variety of heights depending upon the set adopted with a special ramp post. The interface between the ramp and ground is a special toe ramp unit (1.5m)
Intermediate span being floated into position on intermediate piers
Anchor systems with hand winches
Landing Spans launched from the home and far banks
Completed float bridge
The LSB combines standard off the shelf equipment with a range of purpose designed special equipment to meet the expectations of modern military loads and traffic expectations.
Panels —These are the main structural components of the bridge trusses. They are welded items comprising top and bottom chords interconnected by vertical and diagonal bracing. At the end of each panel, chords terminate in male lugs or eyes and at the other end in female lugs or eyes. This allows panels to be pinned together to form the bridge span. There are two different panels; a Super Panel and a High Shear Super Panel. The High Shear Super Panel is used at each end of the bridge span depending upon the loading criteria.
Chord reinforcement —These are constructed in the same way as the chords of the bridge panels and are bolted to the panels to increase the bending capacity of the bridge. For the LSB a heavy chord reinforcement is used.
Transoms —These are fabricated from universal beams and form the cross girders of the bridge, spanning between the panels and carrying the bridge deck. The transom is designed for the appropriate loading criteria and for LSB is designed to accommodate MLC80T/110W.
Decks —Unlike wooden Bailey decks, the steel LSB decks are 1.05m x 3.05m and are manufactured using robotic welding technology. The decks are manufactured to have a long fatigue life and with durbar/checkered plate finish. The decks withstand both wheeled and tracked vehicles.
Bracing —A variety of bracing members are used to connect panels to form the bridge trusses and to brace adjacent transoms to the bridge.
Grillages and Ground Beams —On greenfield sites and when being used as an over bridge, ground beams are available that form an assembly which transmits all dead and live forces from the bridge into the ground. For a 40m (MLC80T/110W) bridge the ground bearing pressure is 200kN/m2. The grillages are located on the top of the ground beams and accommodate the bridge bearings as well as the head of the ramp transom.
Ramps —The slope or profile of the ramps can be adjusted to allow for the passage of a range of civilian and military traffic. The length of a standard ramp at each end of the bridge is 13.5m. The ramps are bolted to the grillages and use standard deck units supported on special transoms. These transoms can be positioned at a variety of heights depending upon the set adopted with a special ramp post. The interface between the ramp and ground is a special toe ramp unit (1.5m)
Construction
The bridge can be constructed by the cantilever launch method without the need for any temporary intermediate support. This is achieved by erecting a temporary launching nose at the front of the bridge and pushing the bridge over the gap on rollers.
After pushing the bridge over the gap, the launching nose is dismantled and the bridge is jacked down onto its bearings. The launching nose is largely constructed from standard bridge components.
The bridge can be constructed by the cantilever launch method without the need for any temporary intermediate support. This is achieved by erecting a temporary launching nose at the front of the bridge and pushing the bridge over the gap on rollers.
After pushing the bridge over the gap, the launching nose is dismantled and the bridge is jacked down onto its bearings. The launching nose is largely constructed from standard bridge components.
Floating variants
There are a number of floating versions of the Mabey LSB in use across Iraq: Floating Piers which consist of steel Flexifloat pontoon units, Landing Piers consisting of 16 pontoon units, and Intermediate Piers which consist of 8 pontoons each. Hand winches are mounted on steel trays which are bolted to the pontoons. The anchors are connected to the hand winches and pontoons via steel chain and polypropylene ropes. Special span junction decks allow for the rotation of the floating spans as the spans deflect under live load.
If the bridge is relatively short in terms of the number of spans, it may be possible to launch the complete bridge from one bank. On a long span bridge, launching intermediate spans and floating them into position on intermediate piers is more practical.
There are a number of floating versions of the Mabey LSB in use across Iraq: Floating Piers which consist of steel Flexifloat pontoon units, Landing Piers consisting of 16 pontoon units, and Intermediate Piers which consist of 8 pontoons each. Hand winches are mounted on steel trays which are bolted to the pontoons. The anchors are connected to the hand winches and pontoons via steel chain and polypropylene ropes. Special span junction decks allow for the rotation of the floating spans as the spans deflect under live load.
If the bridge is relatively short in terms of the number of spans, it may be possible to launch the complete bridge from one bank. On a long span bridge, launching intermediate spans and floating them into position on intermediate piers is more practical.
Chapter 1
Medium Girder Bridge Components
The medium girder bridge (MGB) is lightweight, hand-built, bridging equipment, it can be built in various configurations to provide a full range of bridging capability for use both in the forward battle area and in the communications zone. Speed of erection by few soldiers is its major characteristic.
The MGB parts are fabricated from a specially developed zinc, magnesium, and aluminum alloy (DGFVE 232A). This enables a lightweight, high strength bridge to be built. All except three parts weigh under 200 kg. Most parts can be handled easily by four soldiers. The three heavier parts, used in limited quantities, are six-man loads.
The MGB is a two-girder, deck bridge. The two longitudinal girders, with deck units between, provide a 4.0m wide roadway. Girders of top panels can form a shallow, single-story configuration. This type of bridge is used for short spans that will carry light loads. A heavier double-story configuration using top panels and triangular bottom panels is used for heavy loads or longer spans. Single-story bridges can be constructed by 9 to 17 soldiers. The normal building party for double-story bridges is 25 soldiers.
The bridge can be supported on unprepared and uneven ground without grillages. It is constructed on one roller beam for single-story construction; two roller beams, 4.6m apart, for double-story construction; and on three roller beams when constructing a double-story bridge over 12 bays long. The ends of the roller beams are supported on base plates and each can be adjusted in height. No leveling or other preparation of the ground is required. Single-span bridges are launched using a centrally mounted launching nose (Figure 1).
A third configuration using the link reinforcement set (LRS) is constructed when a long, high class type of bridge is required. The LRS deepens the girder and transfers the load throughout the length of the bridge. This type of construction requires a building party of 34 soldiers, and is built on three roller beams.
ADVANTAGES OF THE MGB/LRS
Lightweight -- no component requires more than six soldiers to lift or carry.
Easy to assemble -- components have special alignment aids built into them.
Minimal maintenance -- very little lubrication required.
Air transportable -- in either standard pallet loads or in partially assembled bridge configurations.
Compatibility -- all US components will fit MGBs in use by allies, except for launching nose cross girder (LNCG) posts.
DISADVANTAGES OF THE MGB/LRS
Length -- Maximum length is 49.7m.
Military Load Class (MLC) -- MLC is 60, not 70.
Army Bailey Bridge Manual
MAJOR PARTS (See Figure 2).
Top panel. | End taper panel. |
Bankseat beam. | Ramps -- US (long) and UK (short). |
Bottom panel. | |
Deck unit. | |
Junction panel. |
An MGB company (corps level) is issued four bridge sets, two erection sets, and two link reinforcement sets. These are divided between two platoons.
MGB DESIGN
STEP 1. Measure the angle of repose (AR) gap. This step is common to all lengths and configurations.
Select a bridge centerline. The centerline should extend from a point approximately 15.2m on the far bank to a point approximately 45.7m on the near bank. This will ensure that there is space on the far bank for vehicle egress and space on the near bank for the R distance of any bridge length. There should be sufficient clear area extending out 3.0m on both sides of the centerline for its full length to allow for bridge construction.
Determine the location of firm ground on the near and far banks.
(1) For the field method of determining firm ground, assume the AR of the soil to be 45 degrees.
(2) At the edge of firm ground on the near bank, place the A' peg. At the edge of firm ground on the far bank, place the A peg. The distance between the two pegs is known as the AR gap. Keep in mind that the MGB must not bear on the ground at either end for more than 2.1 m (SS) or 2.3m (DS), regardless of its length.
If actual slope of bank does not exceed 45 degrees horizontal, place A and A' pegs as shown in a or b below.
If actual slope of bank does exceed 45 degrees from the horizontal, place A and A' pegs a distance H from the toe of slope which is equal to the height of the bank measured from the toe of slope to the top of the gap, as shown in c above.
NOTE: Gaps in illustration are shown with one prepared and one unprepared abutment. Actual sites may be any combination of examples shown.
c. Measure the distance from the edge of firm ground on the near bank (A' peg location) to the edge of firm ground on the far bank (A peg location) using one of the methods described below. This distance is known as the AR gap.
(1) Triangulation method.
(2) A string line with a weight attached thrown across the gap and measured while being retrieved.
(3) If in a relatively secure area and site conditions allow, a tape measure should be used.
d. Select the type of bridge to be built, based on resources available, the MLC desired, and the AR gap.
Join the GlobalSecurity.org mailing list |