In recent years, local transport authorities have been following up on the implementation of the party's central and state council decision-making and the implementation of the ministry of transport's mission arrangements for the rehabilitation of dangerous road bridges。
In order to take stock of the typical practices and results of the upgrading of road-risk bridges in various locations and to promote the upgrading of road-risk bridges, the ministry of transport and communications organized a collection of typical cases of road-risk bridge rehabilitation, which resulted in 19 typical cases (5 in the design programme category, 3 in the organizational management category, 6 in the construction process category and 5 in the integrated category) through a process of voluntary referral, departmental referral and expert review。
Look at all this experience
O'kinton songhua river bridge: design fine, structure long
The bridge, which is located in the city of masu in doo jilin province, 102 countries, is 915. 52 metres long and 11 metres wide and was built in september 1989. Over the years, with increasing vehicle loads and natural ageing of structural materials, repair and renovation work has become urgent in the form of leaks in the main beam sections of the bridge, rusty steel and unequal pits。
Under the auspices of the jilin province road authority and the matsuhara city road service centre, china special engineering ltd., in the course of the maintenance and reinforcement process, in addition to the disposal of conventional diseases such as cracks, breakage, stripping, etc., the external stress in the case was reinforced; the surface of the bridge was re-painted and asphalt concrete was re-painted; the bridge board was re-painted and moved to the position of the container passage; the bridge was replaced with a stretcher, a stretcher, the pavement was removed and the sa-grade metal beam fence, discharge pipes were installed。
At the end of october 2021, the build-up of the in vitro response capacity of the ukinton songhua river bridge was completed and the vehicle was restored. This reinforcement increased the capacity limit of the bridge and the normal use limit strength reserve and addressed the safety of large-scale pits on the bridge. Between 2022 and 2023, the bridge's technical condition was rated in category 2 and the bridge performed well。
It is understood that the project will increase testing inputs in the pre-engineering phase and, based on the findings of the test, develop a maintenance reinforcement programme based on a full life-cycle comparison, resulting in savings in construction, shorter construction periods and lower social impacts, consistent with the low-carbon, economical design concept。
In particular, with respect to detailed design, such as archipelagic and cross-bridge design, the project is based on a refined design concept to design a reasonably feasible engineering programme during the design phase of the construction map; during the construction process, the engineering programme is being refined by parameters, taking into account actual conditions on the ground, to reduce vehicle impact while ensuring smoothness and to improve the durability of the anchor area of the stretcher。
The project, which is based on the concept of sustainability, achieves that the in vitro pre-resilient steel beams are detectable, adjustable, renewable and interchangeable; that the in-box passages are transformed from the original “posterous” to a brand-new “walking” to facilitate day-to-day maintenance, detection and access; and that the bridge health monitoring system is used to accumulate raw basic data for bridge maintenance and post-operational analysis while supporting bridge management。
Hin hong bridge: a “just softer” crane system
It was built in 2001 and is located in yangyang county, jiangsu province, 343 state province. Subject to early technical conditions, the jigsaw bridge crane is designed as a pre-resilient component, and the entire bridge crane is controlled with the same anchor-down stress, without taking into account the overall stress state of the bridge. After more than 20 years of operation, the entire bridge crane experienced varying degrees of mistook teeth, retrenchment of the steel winch, accompanied by rust。
The construction of the construction and strengthening of the bridge will address the operational requirements of the bridge after it has been retrofitted and will be designed in a manner that is reasonable, affordable and environmentally sustainable. The project, which was completed in september 2022, fundamentally addressed a number of diseases。
In the preceding period, following an analysis of the situation at the bridge site, the project proposed a replacement programme using the "leaves + steel thrust wholes to squeeze the cricket", which would reduce not only damage to the original structure but also the construction period. In the course of the construction work, the project removed 52 cranes throughout the bridge and replaced them with a more robust “gj steel winch” with smaller anchors. The new pole uses anchors that are reliable and preservative to produce better. At the same time, the project innovatively introduced a new earboard break-up approach, with poles pierced with fine screwd steel anchors and avoiding damage to the arches of the original bridge and to the bars inside the beam。
Through modelling of the crane system of existing bridges, the project proposes the conversion of the pole arch bridge system from a rigid to a flexible crane system. In conjunction with the advanced finished steel beam system, a small reduction in overall rigidity is more suited to the current transformation requirements of the bridge. At the same time, the optimization of the full-bridge pole cable target after “just soft” is further improving structural stress。
Targeted designs for the retrofitting of the crane system have significantly improved the effectiveness of the reinforcement and have ensured the operational safety and durability of this type of bridge. With the design and construction of the replacement of the bridge cranes, a set of technologies for the replacement of the poles has been developed and is being replicated in the tinless and thai regions。
The project achieves intelligent monitoring of the old bridge pole cord from the replacement of the crane to the full life cycle of service, real-time online data collection, long-term assessment of the reinforcement effect and more scientific reference data for bridge maintenance decisions。
Sun-yang bridge: first-ever double-tangled steel tube captivation technology
The sunyang bridge, located in the zakat forest area of lake north province, state 209, was used in 1975, with a total length of 158. 5 metres and a cross-route of 3 metres x 42 metres (net-crossing) of empty cortexed steel arches. After many years of operation, the main arches of the bridge are covered in water and white; there are cracks in the arches; concrete on the bridge concrete is covered by mud and vertical cracks; the surface of the bridge is paved with the presence of the exposed crude bone; and horizontal and horizontal cracks are present。
The consolidation of the sun-yang bridge was completed in april 2023. The project proposes measures for dealing with the problem of the twin-curve arch bridge in light of its ill condition. It pioneered and applied new technologies for strengthening the double-barrel arch bridge, addressing the problem of inadequate carrying capacity of the ageing double-barrel arch bridge, eliminating the security hazards of the bridge, improving the carrying capacity and stability of the bridge structure, extending the life of the bridge and ensuring the safety and comfort of people and vehicles。
In the course of the construction work, the additional crosses of the piped arch are located inside the cavity of the main arch, which ensures that the maintenance reinforcement does not alter the cleanness and water break under the bridge. Between old and new concretes, the project forms the whole through a railing connection, and between a spiral pipe and new concrete the whole through a bolt connection, ensuring the synergy of old and new structures and enhancing the integrity of the hyperbolic arch bridge。
The project's transformation of the main archeals into a fully-resorted box-based combination structure using steel-set arch-enhanced technology has significantly improved the integrity of the hyperbolic arch bridge, which is applied to the maintenance of the hyperbolic arch bridge across different paths and configurations; reduced consumption of concrete material through the placement of helix tubes inside the main archeals, which can also cover part of the construction load as a receptor component; and a reasonable extension of the life of the existing bibolic archeal bridge and reduced road maintenance management costs through research applications to strengthen new technologies。
Dragon bridge: top-to-top shift to address the problem of bias
One of the major traffic nodes in the hoangang district of wuhan city, hubei province, linking east and west lake and central city, is the 318-country road bridge, which was built in 2006. In july 2020, repairs to the bridge were scheduled as a result of the discovery of a longitudinal crack close to 1 cm wide on the bridge's bridge, which had been removed from the two beams as a whole, and the transition of the transfrontier beam and the prefabricated t-beam。
The conventional top-up condensation only applies to the horizontal bias of the beryllium, which is designed for the vertical contour of the beryllium with such characteristics as stress point limitations, difficulty in synchronizing the jacks, inability to reach a larger vertical top-up, and heavy weight. The first was to build a counter-argument on the bridge to provide a platform for the push; the second was to set up the main beam to lift all the beams from the top; the second was to replace the back seat with a penthouse hoist, which would unload the jacks and drop the beams; and the second was to build a horizontal jack, which would load the beams, push the main beam forward, lift the beams and remove the beams before release. Once the scaling is complete, the predefined width of the stretch is determined and, if not, step ii is returned, and the next process is repeated until the predefined width is reached。
It is worth mentioning that the project's homogeneity is based on the use of the homogeneity mechanism to absorb the stress of the existing seat, to maintain the resonance of the sorghum during the resonance process, and to effectively absorb the pressure of the sorghum, making vertical movement of the bridge more balanced and stable. The set-up of the block would also be effective in avoiding over-alignment, making the construction process manageable and ensuring the safety and stability of the bridge。
The homogenous homogeneity of the bridge has wider applicability than that of other bridges. The process is not limited by the type of bridge, the type of support and the direction of the bridge, and can therefore be applied in more cases. In addition, the relatively simple and secure construction process of the methodology facilitated the implementation of the bridge reinforcement work。
