Floating Pontoon Bridge Description:
Floating pontoon bridge by boat or tank instead of bridge pier, the float bridge. Army
together a using standard equipment, military pontoon bridge, says
pontoon bridge. Its structure is not complex, open and convenient,
bridge construction has the characteristics of simple, fast, but
the high cost of maintenance. At ordinary times could be used in
the emergency disaster relief or as a temporary traffic facilities.
The erection of pontoon bridge is a special specialty, which
involves a lot of professional knowledge. This paper mainly
introduces the structure, construction method and simple design
method of pontoon bridge erected by highway steel bridge equipment.
Floating pontoon bridge design basic scheme consideration points
Road condition, performance, pontoon structure, pontoon drawings,
environment
Basic design principle of floating pontoon bridge
Principles to be followed: the performance objectives are
consistent with the purpose, safety, durability, quality, ease of
maintenance and management, harmony with the environment, economy
and other indicators.
Choosing the type of structure: topographic, geological and
geographical conditions should be considered.
The number of pontoon structures and the overall system should meet
the requirements of strength, deformation and stability.
Below table gives the classification of the status performance
levels of the floating pontoon bridge. A state performance level of
0 is mainly compared to other performance levels 1-3. For traffic
loads, storm waves, tsunamis and earthquakes, the pontoons are
designed in several performance levels.
| Performance Level | Hazard Description |
| 0 | No damage to the stability of the bridge |
| 1 | No damage to bridge function |
| 2 | Although the damage has some limitations on the function of the
bridge, these functions can be restored |
| 3 | Hazards can cause loss of bridge function, but are limited in order
to avoid collapse, subsidence and drift |
According to the importance factor, the design of the floating
bridge should ensure that it has the corresponding target
performance level listed in table, such as load, storm wave,
tsunami and earthquake.
Construction of bridge foundation of Floating pontoon
bridge
The bridge base of prefabricated truss pontoon bridge is usually
constructed according to the following requirements:
1. Bridge base position: Depending on the nature of the soil and
the distance from which the bridge base position may be moved when
the pontoon bridge is blocked, it is usually not less than 1.5m
from the riverbank edge.
2. Since the end of the prefabricated truss pontoon bridge is
connected to the river bank through the end columns of the two
sides of the truss, the soil of the river bank bears a large local
pressure. If the pressure per unit area of the seat plate exceeds
the allowable bearing capacity of the soil, dense pillow materials
must be used to expand and strengthen the foundation of the bridge.
The length of the pillow is generally 1~1.5m, and the section is
not less than 15cm × I5cm.
3. The height of the upper surface of the pillow material above the
water surface is generally 30cm lower than the height from the top
surface to the water surface of the bridge foot boat.
Features of Floating pontoon bridge
1. The pontoon bridge can generally only form a single-lane, and
the width for the vehicle is 3.7m. When the double lane bridge is
needed, two bridge span devices are used side by side.
2. The main beam of the pontoon bridge is mainly hinged cantilever
beam system. That is, the bridge gate bridge is connected with the
main beam with an articulated connector.
3. Local strengthening and connection is usually required between
the main beam of the pontoon bridge and the boat (boat) body.
The erection of pontoon bridge is a special specialty, which
involves a lot of professional knowledge. This paper mainly
introduces the structure, construction method and simple design
method of pontoon bridge erected by highway steel bridge equipment.
Limit state of the floating pontoon bridge
The floating pontoon bridge should be have sufficient capacity to
face potential hazards such as ships, debris, wood, floods, mooring
rope failure, and complete separation of the bridge after lateral
or oblique fracture.
Although the water provides buoyancy for the floating pontoon
bridge, if the water leaks into the interior of the floating
pontoon bridge, it will gradually damage the floating pontoon
bridge and eventually lead to the sinking of the bridge. This is
the current research problem facing the floating pontoon bridge.
Specific design and analysis of floating pontoon bridge
Stability: refers to the ability of the ship to tilt under the
action of external forces, and to return to the original balance
position after the external forces disappear.
Three equilibrium states:
1) Stable balance: G is under M, and gravity and buoyancy form a
stability torque after the tilt.
2) Unstable equilibrium: G is above M, and gravity and buoyancy
form an overturning moment after tilting.
3) Accidental balance: G and M coincide, and gravity and buoyancy
act on the same vertical line after tilt, without torque.
The relationship between stability and ship navigation:
1) The stability is too large, and the ship swings violently,
causing discomfort to personnel, inconvenient use of navigation
instruments, easy damage to hull structure, and easy displacement
of cargo in the hold, thus endangering the safety of the ship.
2) The stability is too small, the ship's anti-capsizing ability is
poor, it is easy to appear large inclination Angle, slow recovery,
and the ship is tilted on the water surface for a long time, and
the navigation is ineffective.
As with boats, the overturning of pontoons is related to their
static stability.
Floating pontoon bridge body design:
General pontoons mainly consider the separate pontoon tank. As
explained earlier, the hydrodynamic characteristics of each tank
can be studied individually, and then the results obtained can be
used for global system analysis.
Design of wind speed and effective wave height: the effective wave
height of 2.5m is a key point of the pontoon type bridge. In order
to ensure that the effective wave height is below 2.5m, it is
necessary to set up a wave barrier. The viscous effect and the
potential flow effect are two important factors in the analysis of
the incident water wave motion and the stress of underwater
structures. For potential flow theory, it is mainly the scattering
and radiation effects of water waves around the structure.
Application of floating pontoon bridge:
Pedestrian, road and railway.
Evercross Steel Bridges Overview :
| EVERCROSS STEEL BRIDGE SPECIFICATION |
EVERCROSS
STEEL BRIDGE | Bailey bridge (Compact-200, Compact-100, LSB, PB100, China-321,
BSB)
Modular bridge (GWD, Delta, 450-type, etc.),
Truss Bridge, Warren bridge,
Arch bridge, Plate bridge, Beam bridge, Box girder bridge,
Suspension bridge, Cable-stayed bridge,
Floating bridge, etc. |
| DESIGN SPANS | 10M TO 300M Single span |
| CARRIAGE WAY | SINGLE LANE, DOUBLE LANES, MULTILANE, WALKWAY, ETC |
| LOADING CAPACITY | AASHTO HL93.HS15-44, HS20-44, HS25-44,
BS5400 HA+20HB, HA+30HB,
AS5100 Truck-T44,
IRC 70R Class A/B,
NATO STANAG MLC80/ MLC110.
Truck-60T, Trailer-80/100Ton, etc. |
| STEEL GRADE | EN10025 S355JR S355J0/EN10219 S460J0/ EN10113 S460N/BS4360 Grade
55C
AS/ NZS3678/ 3679/ 1163/ Grade 350,
ASTM A572/A572M GR50/GR65
GB1591 GB355B/C/D/460C, etc. |
| CERTIFICATES | ISO9001, ISO14001, ISO45001, EN1090, CIDB, COC, PVOC, SONCAP, etc. |
| WELDING | AWS D1.1/AWS D1.5
AS/NZS 1554 or equivalent |
| BOLTS | ISO898, AS/NZS1252, BS3692 or equivalent |
| GALVANIZATION CODE | ISO1461
AS/NZS 4680
ASTM-A123,
BS1706
or equivalent
|
