Architectural and building solutions

In accordance with the terms of reference, the project documentation provides for the construction of an elevated pedestrian crossing. As a temporary design load, the following are accepted: load from pedestrians with an intensity of 400 kg/m2; snow load in accordance with SNiP 2.01.07-85*. The overall calculation of the structure was carried out using the Midas Civil software package for calculation and design. The calculation scheme is adopted in the form of a spatial metal beam combined with a reinforced concrete slab of the walkway. The beam is supported by a rope modeled as a "truss" finite element. The strength of the bridge elements was checked in accordance with SNiP 2.05.03-84* and SNiP II-23-81* "Steel structures". The main technical characteristics of the transition: front length: 84,05 m; width (overall): 51,94 m; total length of ramps (according to development): 2x86,7 m; length of the central part (according to development): 66,0 m; construction height of the span: 1230 mm; walkway width: 3 m. The projected object is located on the territory of the city district.

span structure

The superstructure is steel-reinforced concrete beam of individual design. The scheme of the span structure - 1x66,0 m. In cross section, the superstructure is made in the form of a metal box-shaped beam, combined with a reinforced concrete slab of the walkway. The height of the beam web is variable - from 1000 to 1200 mm. The maximum height of the beam at the support section. In terms of the span structure is located on a circular curve with a radius of R=21000 mm along the axis of the box beam. To reduce stresses in the sections of the beam, a rope is used, located along the inner radius of the beam. The rope passes through the posts of the railing, and through them transfers the forces to the beam. To ensure the design work of the rope and reduce the impact on the racks, it is supposed to ensure free slip of the rope in the places of support. Rope anchoring is carried out in massive reinforced concrete supports. The tension of the rope is carried out in stages, as the constant loads on the superstructure increase. The final tension of the rope is made after concreting the slab and the full set of concrete strength. General data on the design of rope knots are presented on sheet 8. A monolithic reinforced concrete slab is combined with a metal beam by means of flexible rod stops. Walkway slab of variable thickness - from 180 mm above the box beam to 100 mm on the console. The slab is made of B40 class concrete according to GOST 26633-91*. Reinforcement of a reinforced concrete slab with class AIII (A400) and AI (A240) reinforcement in accordance with GOST 5781-82. A general view of the reinforced concrete slab is shown on sheet 5. A schematic diagram of the reinforcement of a reinforced concrete slab is presented on sheet 6. With a step of 2 m, cantilever beams are installed, also combined with a reinforced concrete slab. All metal structures of the superstructure are made of steel grade 15KhSND according to GOST 6713-81. Manufacture and delivery to the place of installation of the superstructure is carried out in separate blocks. Enlargement of blocks is carried out at the construction site. Factory and assembly joints of span elements - on welding and high-strength bolts. The superstructure is rigidly pinched into the support body by embedding the anchor plates.

bridge deck

The design of the bridge deck is shown on sheet 2. The pavement of the walkway is made of a composite material such as Sika Icosit Elastomatic TF 6 mm thick. This material is wear-resistant, moisture-resistant, durable and ideal for this design, as it has a low density. To drain water, the top of the walkway is made with transverse and longitudinal slopes that drain water to the drainage pipes. Drainage tubes are located along the axis of the catchment along the inner side of the span.

Supports

The central superstructure rests on monolithic reinforced concrete supports made of B40 F300 W8 ​​class concrete. The support body has an inclination of 15° away from the superstructure. Anchor devices for rope tension are located in the upper part of the supports. The thickness of the reinforced concrete support is variable, from 1500 mm at the bottom of the support to 1000 mm at the top. Width - 2500 mm. Height - 10 m. The design of the supports is shown on sheets 9-12. The foundations of the supports are made on a pile foundation of bored piles of the Fundex type, 20,5 m long and 520 mm in diameter. There are 6 piles in the foundation of each support. The piles are combined with a monolithic reinforced concrete grillage with plan dimensions of 3,5x8,5 m.

Ramps

Ramps serve to facilitate the movement of people with limited mobility. For these purposes, in accordance with the standards, the longitudinal slope of the ramp part is set equal to 1:8. Every 10 m, horizontal platforms 1.5 m wide are provided. A general view of the ramp part is shown on sheet 13.

span structure

The superstructure of the ramp is presented on sheets 13-14. The superstructure is reinforced concrete continuous beam of individual design. Span structure - 8,95 + 6x11,5 + 9,425 + 2,0 m. In cross section, the span structure is a slab with a thickness 240 mm. The slab is made of B40 class concrete according to GOST 26633-91*. Reinforcement of a reinforced concrete slab with class AIII (A400) and AI (A240) reinforcement in accordance with GOST 5781-82.

bridge deck

The pavement is made of a composite material like Sika Icosit Elastomatic TF with a thickness of 6 mm. and polymer sand paving slabs. Water is drained from the walkway along the longitudinal slope to the drainage facilities located at the supports.

Supports

Supports of the ramp part are rack-mounted, round section with a diameter of 500 mm, made of concrete class B40 F300 W8. The supports of the ramp part rest on a piled foundation of Fundex-type bored piles 19,48 m long and 520 mm in diameter. Each support has 1 pile.

Staircases

To ensure the descent and ascent to the pedestrian crossing, two staircases are arranged. Staircase of individual design with a height of 6,2 m. Prefabricated-monolithic reinforced concrete exit elements are made of heavy concrete class B35 F300 W8. The superstructure rests on supports of circular cross section with a diameter of 500 mm. The foundations of the stairway supports are made of bored piles of the Fundex type, 11,05 m long and 520 mm in diameter. Each support has 1 pile.