Large Span Painted Steel Arch Bridge Highway Bridge Long Life
Instrction:
The main structural form of steel arch bridge
The upper structure of steel arch bridge is mainly composed of arch ring, suspension rod (or arch column),
tie rod, bridge beam and other components.
The arch shape provides excellent load-bearing capabilities by
efficiently transferring the weight to the supports. The steel
material used in the construction offers high tensile strength,
allowing for longer spans and lighter structures compared to other
bridge types.
1. According to the structure of the form of classification:
(1) According to the section form of the main arch ring, it is
divided into: steel box arch, steel pipe arch, steel truss arch.
(2) According to the space posture of the two arch ribs: parallel
arch ribs, basket arch ribs, butterfly arch ribs.
(3) According to the position of the carriageway system, it is
divided into: upper bearing type, middle bearing type and lower
bearing type arch bridge.
(4) According to the layout of the boom classification: parallel
vertical boom, inclined boom, mesh boom.
According to the structural system classification
Steel arch bridges have both composite system arch bridges and
simple system arch bridges. There are several kinds of combined
system arch bridges, such as tie arch, loser arch, lange arch and
other combined system arch bridges.
(1) Simple system arch bridge: only the arch ring is the main force
component, and the simple system is a thrust arch structure, and
the thrust of the arch is directly borne by the pier or foundation.
(2) Combined system arch bridge: carriageway beam and arch
combination, common force.
Main arch structure
Steel arch can be designed into truss arch, box arch, plate arch.
Many truss arch bridges are built in foreign countries, and more
than ten steel box arch bridges are built in China. Truss arch
bridge is an important form of rigid arch bridge with large span.
The main arch of truss arch bridge along the span direction: equal
height, variable height.
The overall design parameters of long-span steel truss arch bridge
are:
① Layout of arch rib truss.
② Arch axis.
③ Vector span ratio.
④ The selection of the height of the vault and arch foot.
⑤ Boundary conditions.
⑥ Bar section form.
⑦ Bar section area.
Trussed arch rib can be divided into Pratt truss, Warren truss, K
truss, sub-truss and other forms according to the main truss frame
classification.
The mechanical properties of K-type truss are the best.
Economical, W-type truss with the least amount of steel.
Structural construction and aesthetics, P-type truss has
advantages.
First, the structural characteristics of the main components of
steel arch bridge.
1. Arch rib
The main load-bearing members of the structure mainly bear axial
pressure, but also bear part of the bending moment, and the
eccentric compression members are mainly compressed.
According to the form of section is divided into: box, pipe, truss
type.
Trussed arch rib has light weight, greater span capacity and good
economy.
2. Boom
It is a force transfer component, which transfer the deck load to
the arch rib of the bearing member, the boom is mainly an axial
tension member. The rigid boom is made of multi-purpose steel pipe
or section steel and can withstand pressure. The flexible boom is
made of high-strength steel wire bundle or steel strand, which can
only be stretched, convenient construction and beautiful
appearance.
Elevation arrangement of the boom
Boom spacing is the span length of the longitudinal beam of the
carriageway, and it usually takes equal spacing.
According to its layout in the arch plane, the boom is divided
into: parallel vertical boom, inclined boom, mesh boom.
According to the placement quantity the boom is also divided into
single boom, double boom.
The connection between the boom and the arch rib
The anchorage structure of hanger is the key to the connection
structure of hanger and arch rib. For reinforced concrete arch
ribs, if prestressed reinforcement bars with multiple anchor heads
dispersed are used in the suspension rod, the structure in the
anchoring area is similar to that of general prestressed members.
If a high-strength carbon steel wire bundle with centralized single
anchor is used in the boom, or a parallel steel wire finished cable
with hot extruded sheath is used in the boom, and the anchoring
force is large and concentrated, it is generally necessary to adopt
steel anchor box and other structures, which is also convenient for
the replacement and maintenance of the boom (cable).
3. Tie bar (beam)
For the non-thrust arch, the thrust of the arch is borne by the tie
rod, and the tie rod bears the larger axial tension.
Divided into: rigid tie rod, flexible tie rod.
4. Cross brace
In order to ensure the transverse stiffness and stability of the
two arch ribs and withstand the transverse horizontal forces acting
on the arch ribs, bridge deck and boom, it is necessary to set the
transverse supports.
The cross brace can greatly improve the out-of-plane stiffness and
torsional stiffness of the whole bridge, but basically do not
improve the in-plane stiffness.
Basic requirement
It is arranged on the arch section outside the scope of the
clearance height of the bridge floor.
The width of the brace should not be less than 1/15 of the length.
The structural form of the cross brace:
The common ones are "one-word brace", "K-shaped brace", "X-shaped
brace", "meter-shaped brace".
The position of the cross brace corresponds to the position of the
lifting point, and is symmetrical to the odd arrangement of the
arch roof.
The arch is generally set up "one-word support", and the arch ribs
near 1/4L are generally set up "K-shaped support".
The long span wide bridge is usually equipped with "meter-shaped
supports" on the arch roof and "K-shaped supports" on both sides.
5. Arch post
The stand column is used for the upper bearing part of the upper
bearing arch bridge or the middle bearing arch bridge, and is the
force transfer structure between the bridge floor system and the
main arch rib.
Second, the overall design parameters of arch rib
The main design parameters of long-span steel truss arch bridge are
as follows: beam span ratio, selection of arch axis, choice of
vault and arch height.
Rise span ratio
Mainly according to the topography of the bridge site, geological
conditions, bridge clearance requirements and other factors to
determine.
The common range of arch rib span ratio is 1/4~1/7, the span ratio
of steel truss arch bridge is usually 1/4~1/5.
The smaller the span ratio is, the greater the horizontal thrust of
arch foot is. When geological conditions are poor, a larger vector
to span ratio can be used to reduce horizontal thrust.
Axis of arch
The ideal arch axis is consistent with the pressure line on the
arch, and the section only bears the pressure without bending
moment, which can make full use of the material strength.
Common forms of arch axis: arc line, quadratic parabola, catenary.
Arch rib vault and arch foot height selection
According to the variation of arch rib height, it can be divided
into equal height arch rib and variable height arch rib.
When the span is large, the variable height arch rib is used to
adapt to the internal force distribution of arch rib and save the
engineering amount.
Steel arch bridge features:
Span Length: Steel arch bridges can be designed to span various
lengths, ranging from short to long spans. The span length depends
on factors such as the width of the obstacle being crossed, desired
clearance beneath the bridge, and engineering requirements. Steel
arch bridges have the advantage of spanning long distances without
the need for intermediate supports, making them suitable for
crossing wide rivers or deep valleys.
Rehabilitation and Adaptive Reuse: Steel arch bridges have the
potential for rehabilitation and adaptive reuse. In some cases,
existing steel arch bridges can be renovated, strengthened, or
repurposed to meet modern load requirements or accommodate changes
in traffic demands. This feature allows for the preservation and
reuse of historic or significant bridge structures.
Applications of steel arch bridge:
Road Bridges
Pedestrian Bridges
Railway Bridges
Iconic Landmarks
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 |
