Constructive decisions

The design documentation provides for a major overhaul of the bridge in the alignment of the street across the river. The length of the repaired section (artificial structure with approaches) is 74,5 m. The overhaul involves the dismantling of the existing bridge structures and approaches with their subsequent restoration in accordance with modern requirements. Accepted load in the calculation of pavement structures of the roadway - A10, artificial structures - A14H14. The width of the existing carriageway is 9,5 - 10,0 m. The radius of the curve in the plan is 100 m. The cross profile of the street in the section under consideration is single-slope. The restoration of approaches, sidewalks and lawns is provided in accordance with the existing vertical and horizontal layouts. The transverse slope along the carriageway is assumed to be 20‰. The longitudinal slope along the axis is assumed to be 11‰, the radius of the convex curve is assumed to be 2000 m, and the radius of the concave curve is 1000 m. Side stones separating the carriageway from sidewalks - concrete BR100.30.18, in lawns - concrete BR 100.20.8, at pedestrian crossings - granite GPV (baring height 4,0 cm). Pavement designs are adopted in accordance with the calculations according to ODN 218.046-01 and in accordance with the standard ones. 1. Designs of carriageways: hot dense fine-grained asphalt concrete type A, grade I, GOST 9128-2009, - 5,0 cm; hot porous coarse-grained asphalt concrete, grade I, GOST 9128-2009, - 8,0 cm; crushed stone-sand mixture S-4, GOST 25607-2009 - 35,0 cm; fine sand (content of silt-clay fraction 5%), Kf≥3 m/day, GOST 8736-93*, – 45,0 cm; 2. Pavement structures with asphalt concrete pavement: asphalt concrete hot sandy dense type G grade I, GOST 9128-2009 - 4,0 cm; crushed stone-sand mixture S-4, GOST 25607-2009 - 15,0 cm; fine sand (content of silt-clay fraction 5%), GOST 8736-93* - 30,0 cm; 3. Sidewalk structures in tiled paving: concrete paving slabs 17608-91*, - 7,0 cm; dry cement-sand mixture TU 400-24-114-78 - 3,0 cm; crushed stone-sand mixture S-4, GOST 25607-2009 - 20,0 cm; fine sand (content of silt-clay fraction 5%), GOST 8736-93* - 30,0 cm. The bridge to be overhauled was built in 1948. Information about the design and construction organizations has not been preserved. The slope angle of the structure's axis is 450. At 20 m from the bridge, upstream, there is a stop device that regulates the flow of water into the canal from the lake. The design loads are not known, but, given the design and age of the structure, presumably N13, NG30. The length of the bridge (along the carriageway) is 9,5 m, the width (along the railings) is 13,6 m. The roadway is made of asphalt concrete. The sidewalk on the lower side is of an elevated type with a paving stone pavement, on the upper side - at the level of the carriageway. The railing is cast iron. Expansion seams - the closed type. The bridge supports are massive from rubble masonry with a monolithic crossbar. The depth of the foundations is unknown. Roof linings were used as supporting parts. When choosing the recommended option, the following was additionally taken into account: 1. The lack of executive and design documentation for the existing structure, the technical complexity of a complete survey of the foundation part of the bridge did not allow to reliably assess the possibility of strengthening the foundations, to predict the behavior of the existing foundation with increasing loads to A14 and NK100. 2. Unfavorable factors arising from the operation of pile driving equipment and vibratory pile drivers. Vibration and dynamic impact on soils can lead to damage or destruction of existing retaining walls and foundations. Given the above, the project decided to build new supports with foundations from bored piles. Based on a comparison of options for development, a single-span bridge with a reinforced concrete beam span made of beams 12 m long and bearings on pile foundations made of bored piles with a diameter of 0.8 m. The size of the carriageway of the bridge has been increased to 10,0 m, the width of the right sidewalk has been increased to 3,0 m. Supporting parts - ROCH 200x250x5,2. The superstructure was designed using beams according to the standard project 3.503.1-81 inv. No. 32509/14-M with verification of the possibility of using it under loads A14 and NK100. The bridge deck is arranged single-pitched with a transverse slope of 2% and with the location of sidewalks and the roadway at the same level. The slope from the sidewalks towards the carriageway is 2%. The bridge deck includes Dorflex waterproofing, a protective layer of cast asphalt concrete, and a ShchMA-15 coating.

Engineering equipment, utility networks, engineering activities

The design documentation provides for the removal of 2 sections of 10 kV cable lines that fall into the area of ​​work to repair the bridge across the river. Cables are accepted as ASB3x120 (direction TP65 - TP191, TP2 -TP100) and ASB3x240 (direction PS609 f.145 - RTP 1006, PS69 f.20 - RTP1002) 2x30 m each. The project documentation provides for the replacement of the outdoor lighting area that enters the work area. 8 new supports are being installed to replace the dismantled ones, ZhKU250 lamps. The length of the section is 200 m, the connection is designed by SIP from the existing network KUO3-19 TP-19 and from KUO1-45 TP-45. The project documentation provides for the protection of sections of existing communication networks that fall into the repair zone of the bridge through the factory channel. The protection was designed with a steel channel 400x115x8,0 16 m long (for the existing telephone cable) and reinforced concrete slabs 2,99x0,78x0,07 in total 13 pcs. (3 single-channel sections of telephone sewerage). The length of the sections is 12,9 and 9 m, respectively. The project documentation provides for the replacement of the existing reinforcement in well No. 181 with a wellless one. Provision is made for the removal of the well. Surface water diversion is provided according to the existing scheme.